Patent Publication Number: US-2021172530-A1

Title: Shaft Seal Assembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of and claims priority under 35 U.S.C. § 120 to U.S. application Ser. No. 15/801,220, filed on Nov. 1, 2017, which claims priority to U.S. Application Ser. No. 62/416,082, filed Nov. 1, 2016, and is a continuation-in-part and claims priority to U.S. application Ser. No. 15/134,714, filed on Apr. 21, 2016 and U.S. Application Ser. No. 62/210,066, filed on Aug. 26, 2015 and U.S. Application Ser. No. 62/150,633, filed on Apr. 21, 2015, each of which are incorporated by reference herein in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a shaft seal assembly and/or bearing isolator with multiple embodiments. In certain embodiments, the shaft seal assembly may be used as a product seal between a product vessel and a shaft therein. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     No federal funds were used to create or develop the invention herein. 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX 
     N/A 
     BACKGROUND OF THE INVENTION 
     For years there have been a multitude of attempts and ideas for providing a satisfactory seal when a rotatable shaft is angularly misaligned resulting in run out of the shaft. Typically the solutions presented have failed to provide an adequate seal while allowing for an acceptable amount of shaft misalignment during operation. The problem is especially acute in product seals where the potential for shaft to bore misalignment may be maximized. A typical solution in the prior art is to increase the operating clearance between the rotating shaft and sealing members to create a “loose” clearance or operating condition. “Loose” running for adjustment or response to operational conditions, especially misalignment of the shaft with respect to the stator or stationary member, however, typically reduces or lowers the efficiency and efficacy of sealing members. 
     Labyrinth seals, for example, have been in common use for many years for application to sealing rotatable shafts. A few of the advantages of labyrinth seals over contact seals are increased wear resistance, extended operating life and reduced power consumption during use. Labyrinth seals, however, also depend on a close and defined clearance with the rotatable shaft for proper function. Shaft misalignment is also a problem with “contact” seals because the contact between the seal and misaligned shaft typically results in greater wear. Abrasiveness of the product also affects the wear pattern and the useful life of the contact seals. 
     Prior attempts to use fluid pressure (either vapor or liquid) to seal both liquid and solid materials in combination with sealing members such as labyrinth seals or contact seals have not been entirely satisfactory because of the “tight” or low clearance necessary to create the required pressure differential between the seal and the product on the other side of the seal (i.e., the tighter the seal, the lower the volume of fluid required to maintain the seal against the external pressure of material.) Another weakness in the prior art is that many product seals expose the movable intermeshed sealing faces or surfaces of the product seal to the product resulting in aggressive wear and poor reliability. Furthermore, for certain applications, the product seal may need to be removed entirely from the shaft seal assembly for cleaning, because of product exposure to the sealing faces or surfaces. 
     The prior art then has failed to provide a solution that allows both a “tight” running clearance between the seal members and the stationary member for efficacious sealing and a “loose” running clearance for adjustment or response to operational conditions especially misalignment of the rotatable shaft with respect to the stator or stationary member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description, serve to explain the principles of the shoe covering. 
         FIG. 1  is a perspective exterior view of an illustrative embodiment of a shaft seal assembly. 
         FIG. 2  is an exterior end view of the embodiment of a shaft seal assembly shown in  FIG. 1  with the shaft element aligned. 
         FIG. 3  is a cross-sectional view of a first embodiment of the shaft seal assembly, as shown in  FIG. 2  and mounted to a housing. 
         FIG. 3A  provides a detailed view of a top portion of the first embodiment of a shaft seal assembly during angular and radial shaft alignment. 
         FIG. 3B  provides a detailed view of a bottom portion of the first embodiment of a shaft seal assembly during angular and radial shaft alignment. 
         FIG. 4  is an exterior end view of the first illustrative embodiment of a shaft seal assembly with the shaft misaligned. 
         FIG. 5  is a cross-sectional view of the first embodiment of a shaft seal assembly as shown in  FIG. 3  during both angular and radial misalignment of the shaft. 
         FIG. 5A  provides a detailed view of a top portion of the first embodiment of a shaft seal assembly during angular and radial shaft misalignment. 
         FIG. 5B  provides a detailed view of a top portion of the first embodiment of a shaft seal assembly during angular and radial shaft misalignment. 
         FIG. 6  is a cross-sectional view of a second embodiment of a shaft seal assembly  FIG. 7  is a cross-sectional view of a third embodiment of a shaft seal assembly. 
         FIG. 8  is a perspective view of a fourth embodiment of a shaft seal assembly engaged with a vessel wall. 
         FIG. 9  is a cross-sectional of view of another embodiment of the shaft seal assembly with the shaft aligned with respect to the housing. 
         FIG. 9A  provides a detailed view of a top portion of the embodiment of the shaft seal assembly shown in  FIG. 9 . 
         FIG. 9B  provides a detailed view of a bottom portion of the embodiment of the shaft seal assembly shown in  FIG. 9 . 
         FIG. 10  is a cross-sectional view of another embodiment of the shaft seal assembly with the shaft aligned with respect to the housing. 
         FIG. 10A  provides a detailed view of a top portion of the embodiment of the shaft seal assembly shown in  FIG. 10 . 
         FIG. 10B  provides a detailed view of a bottom portion of the embodiment of the shaft seal assembly shown in  FIG. 10 . 
         FIG. 11  is a cross-sectional view of the embodiment shown in  FIG. 10  with the shaft misaligned with respect to the housing. 
         FIG. 12  is a cross-sectional view of the embodiment shown in  FIG. 9  with the shaft misaligned with respect to the housing. 
         FIG. 13  is a cross-sectional view of the embodiment shown in  FIG. 9  with the shaft misaligned with respect to the housing. 
         FIG. 14  is a cross-sectional view of a third embodiment of the shaft seal assembly. 
         FIG. 15  is a perspective view of a first embodiment of a multi-shaft seal assembly. 
         FIG. 16  is a plane vertical view of another embodiment of a shaft seal assembly. 
         FIG. 17  is an axial, cross-sectional view of the shaft seal assembly shown in the embodiment in  FIG. 16 . 
         FIG. 18  is an axial, cross-sectional view of another embodiment of a shaft seal assembly. 
         FIG. 18A  is an axial, cross-sectional view of a top portion of the embodiment of a shaft seal assembly shown in  FIG. 18 . 
         FIG. 19  is a perspective view of a first embodiment of a multi-shaft seal assembly. 
         FIG. 19A  is a perspective view of the embodiment of a multi-shaft seal assembly shown in  FIG. 19  with the second seal removed for clarity. 
         FIG. 19B  is a rear perspective view of the embodiment of a multi-shaft seal assembly shown in  FIG. 19 . 
         FIG. 20  is a plane vertical view of the embodiment shown in  FIG. 19 . 
         FIG. 21  is an axial, cross-sectional view of the embodiment shown in  FIG. 19 . 
         FIG. 22A  is perspective view of another embodiment of a shaft seal assembly. 
         FIG. 22B  is an axial, cross-sectional view of the embodiment of a shaft seal assembly shown in  FIG. 22A . 
         FIG. 22C  is an axial, exploded cross-sectional view of the embodiment of a shaft seal assembly shown in  FIG. 22A . 
         FIG. 22D  is a detailed cross-sectional view of the embodiment of a shaft seal assembly shown in  FIGS. 22A-22C  wherein the shaft is vertically oriented. 
         FIG. 23  is an axial, cross-sectional view of another embodiment of a porous media shaft seal assembly. 
         FIG. 24  is an axial, cross-sectional view of another embodiment of a porous media shaft seal assembly. 
         FIG. 25  is an axial, cross-sectional view of another embodiment of a porous media shaft seal assembly. 
         FIG. 26  is an axial, cross-sectional view of another embodiment of a porous media shaft seal assembly. 
         FIG. 27A  is an axial, cross-sectional view of another embodiment of a porous media shaft seal assembly. 
         FIG. 27B  is an axial, cross-sectional view of a portion of the embodiment of a porous media shaft seal assembly shown in  FIG. 27A . 
         FIG. 27C  is an axial, cross-sectional view of another embodiment of a portion of a porous media shaft seal assembly similar to that shown in  FIG. 27A . 
         FIG. 28A  is an axial, cross-sectional view showing other aspects of a shaft seal assembly. 
         FIG. 28B  is an axial, cross-sectional view of a top portion of the shaft seal assembly shown in  FIG. 28A . 
         FIG. 28C  is an axial, cross-sectional view of a bottom portion of the shaft seal assembly shown in  FIG. 28A . 
         FIG. 28D  is a perspective, cross-sectional view of the shaft seal assembly shown in  FIGS. 28A-28C . 
         FIG. 28E  is a cross-sectional view of the shaft seal assembly shown in  FIGS. 28A-28D  wherein the stator and rotor have been separated from one another. 
         FIG. 29  is an axial, cross-sectional view showing alternative aspects of a shaft seal assembly. 
         FIG. 30  is an axial, cross-sectional view showing further alternative aspects of a shaft seal assembly. 
     
    
    
     DETAILED DESCRIPTION—ELEMENT LISTING (FIGS.  1 - 12 ) 
       
     
       
         
           
               
               
             
               
                   
               
               
                 Description 
                 Element No. 
               
               
                   
               
             
            
               
                 Shaft 
                  1 
               
               
                 Fixed stator 
                  2 
               
               
                 Fixed stator (part-line) 
                  2a 
               
               
                 Labyrinth seal 
                  3 
               
               
                 Radiused face 
                  3a 
               
               
                 Floating stator 
                  4 
               
               
                 Fluid return pathway 
                  5 
               
               
                 Shaft seal clearance 
                  6 
               
               
                 First o-ring 
                  7 
               
               
                 Anti-rotation pin 
                  8 
               
               
                 Vent 
                  9 
               
               
                 Anti-rotation groove (floating stator) 
                 10 
               
               
                 Spherical interface 
                 11 
               
               
                 Anti-rotation pin 
                 12 
               
               
                 Second o-ring 
                 13 
               
               
                 Labyrinth seal pattern grooves 
                 14 
               
               
                 First o-ring channel 
                 15 
               
               
                 Cavity for anti-rotation device (fixed stator) 
                 16 
               
               
                 Axial face of labyrinth seal 
                 17 
               
               
                 Axial face of floating stator 
                 18 
               
               
                 Second o-ring channel 
                 19 
               
               
                 First clearance between floating stator/fixed stator 
                 20 
               
               
                 Second clearance between floating stator/fixed stator 
                 21 
               
               
                 Throttle groove 
                 22 
               
               
                 Labyrinth pattern annular groove 
                 23 
               
               
                 Sleeve 
                 24 
               
               
                 Shaft seal assembly 
                 25 
               
               
                 Throttle (alignment skate) 
                 26 
               
               
                 Floating stator annular groove 
                 27 
               
               
                 Labyrinth seal passage 
                 28 
               
               
                 Floating stator passage 
                 29 
               
               
                 Housing 
                 30 
               
               
                 Angle of misalignment 
                 31 
               
               
                 Bearings and bearing cavity 
                 32 
               
               
                 Mounting bolts 
                 33 
               
               
                 Vessel wall 
                 34 
               
               
                 Pressure balanced shaft seal assembly 
                 40 
               
               
                 Labyrinth seal interior face 
                 42 
               
               
                 Floating stator interior face 
                 44 
               
               
                 Pressure balancing annular channel 
                 46 
               
               
                 First radial interface 
                  47a 
               
               
                 Second radial interface 
                  47b 
               
               
                 Fixed stator annular groove 
                 48 
               
               
                 Annular groove radial-interior surface 
                  48a 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION 
     Before the various embodiments of the present invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “front”, “back”, “up”, “down”, “top”, “bottom”, and the like) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as “first”, “second”, and “third” are used herein and in the appended claims for purposes of description and are not intended to indicate or imply relative importance or significance. Furthermore, any dimensions recited or called out herein are for exemplary purposes only and are not meant to limit the scope of the invention in any way unless so recited in the claims. 
       FIGS. 1-5  provide a view of a first embodiment of the shaft seal assembly  25  that allows for sealing various lubricating solutions within bearing housing  30 .  FIGS. 6 and 7  provide alternative embodiments of the shaft seal assembly  25  wherein sealing fluids are used. Applicant herein defines sealing fluids to include both liquids and vapors. Applicant considers air, nitrogen, water and steam as well as any other fluid which may work with the proposed shaft seal assembly to provide a pressurized fluid barrier for any and all embodiments disclosed herein to be within the purview of the present disclosure. The gas or fluid chosen is based on process suitability with the product to be sealed. 
       FIG. 1  is a perspective exterior view of the shaft seal assembly  25  arranged and engaged with a shaft  1  inserted through the fixed stator  2  of shaft seal assembly  25 .  FIG. 2  is an exterior end view of the shaft seal assembly with shaft  1  aligned within the shaft seal assembly  25 . 
       FIG. 3  is a sectional view of a first embodiment of the shaft seal assembly  25  shown in  FIG. 2  illustrating the shaft seal assembly  25  as a labyrinth seal for retaining lubrication solution within the bearing cavity  32  of housing  30 . The shaft  1  shown in  FIG. 3  is the type which may experience radial, angular or axial movement relative to the fixed stator element or portion of the fixed stator  2  during rotation. The fixed stator portion of the shaft seal assembly  25  may be flange-mounted or press-fit or attached by other means to a housing  30 . The invention will also function with a rotating housing and stationary shaft. (Not shown) As required by the particular application, the shaft  1  is allowed to move freely in the axial direction in relation to the shaft seal assembly  25 . 
     A labyrinth seal  3  having an interior surface is engaged with shaft  1 . A defined clearance  6  exists between the interior surface of said labyrinth seal  3  and the shaft  1 . Opposite the interior surface of said labyrinth seal  3  is the radiused surface  3   a  of said labyrinth seal  3 . The radiused surface  3   a  of the labyrinth seal  3  and the interior of the floating stator  4  forms a spherical interface  11 . O-ring channels  15  and o-rings  7  are disposed to cooperate with said radiused surface  3   a  of said labyrinth seal  3  to seal (or trap) fluid migration through, between and along engaged labyrinth seal  3  and floating stator  4  while maintaining spherical interface  11  which allows limited relative rotational movement (articulation) between labyrinth seal  3  and floating stator  4 . O-ring channels  15 , as shown, are machined into the floating stator  4  and positioned at the spherical interface  11  with labyrinth seal  3 . O-ring channels  15  are annular and continuous in relation to labyrinth seal  3 . The o-ring channel  15  and o-ring  7  may also be placed in the labyrinth seal  3  adjacent the spherical interface  11 . O-rings  7  should be made of materials that are compatible with both the product to be sealed and the preferred sealing fluid chosen. O-ring channels  15  and o-rings  7  are one possible combination of sealing means that may be used within the shaft seal assembly  25  as recited in the claims. Strategically placed anti-rotation pin(s)  12  inserted into anti-rotation grooves  10  limit relative rotational movement between labyrinth seal  3  and floating stator  4 . A plurality of anti-rotation grooves  10  and pins  12  may be placed around the radius of the shaft  1 . If the shaft seal assembly  25  is used in combination with a sealing fluid, strategic anti-rotation pins  12  may be removed allowing corresponding anti-rotation grooves  10  to serve as a fluid passage through vent  9  and lubricant return  5 . (See  FIG. 7 ) Additionally, the relationship of the diameters of anti-rotation pins  12  and anti-rotation grooves  10  may be selected to allow more or less angular misalignment of the shaft  1 . A small diameter anti-rotation pin  12  used with a large diameter anti-rotation groove  10  would allow for greater relative movement of the labyrinth seal  3  in relation to the floating stator  4  in response to angular misalignment of shaft  1 . Labyrinth seal  3  is one possible embodiment of a sealing means that may be used adjacent to the shaft  1  within the shaft seal assembly  25  as recited in the claims. 
     A continuous annular channel is formed within fixed stator  2  and defined by clearance  20  and  21  as allowed between the exterior of said floating stator  4  and said interior of said fixed stator  2  of shaft seal assembly  25 . The annular channel of fixed stator  2  is highlighted as A-A′ in  FIG. 2 . The annular channel of the fixed stator has interior surfaces which are substantially perpendicular to said shaft  1 . The exterior surfaces of the floating stator  4 , which is substantially encompassed within the annular channel of the fixed stator  2 , cooperatively engage with the first and second interior perpendicular faces of the fixed stator  2 . An inner annular interface is formed by the first (shaft seal assembly inboard side) perpendicular annular channel surface of the fixed stator  2  engaging with the first (inboard side) perpendicular face of the floating stator  4 . An outer annular interface is formed by the second (shaft seal assembly outboard side) perpendicular annular interior channel surface of the fixed stator  2  engaging with the second (outboard side) perpendicular face of the floating stator  4 . O-ring channels  19  and o-rings  13  disposed therein cooperate with the surfaces of floating stator  4  which are in perpendicular to relation to shaft  1  to seal (or trap) fluid migration between and along engaged floating stator  4  while allowing limited relative rotational movement between floating stator  4  and fixed stator  2 . Floating stator  4  and fixed stator  2  are one possible embodiment of cooperatively engaged sealing means that may be used in combination with labyrinth seal  3  within the shaft seal assembly  25  as recited in the claims. 
     O-ring channels  19  are annular and continuous in relation to shaft  1 . The o-ring channels  19  and o-rings  13  may be placed in the body of the floating stator  4  instead of the fixed stator  2  (not shown) but must be placed in similar proximal relation. O-rings  13  should be made of materials that are compatible with both the product to be sealed and the preferred sealing fluid chosen. O-ring channels  19  and o-rings  13  are one possible combination of sealing means that may be used within the shaft seal assembly  25  as recited in the claims. 
     Strategically placed anti-rotation pin(s)  8  inserted into anti-rotation groove(s)  16  limit both relative radial and rotational movement between floating stator  4  and interior side of fixed stator  2 . A plurality of anti-rotation grooves  16  and pins  8  may be placed around the radius of the shaft  1 . The relationship of the diameters of anti-rotation pins  8  and anti-rotation grooves  16  may also be selected to allow more or less angular misalignment of the shaft. A small diameter anti-rotation pin  8  and large diameter fixed stator anti-rotation groove allow for greater relative movement of the labyrinth seal  3  in response to angular misalignment of shaft  1 . 
     The labyrinth pattern seal grooves  14  may be pressure equalized by venting through one or more vents  9 . If so desired, the vents may be supplied with a pressurized sealing fluid to over-pressurize the labyrinth area  14  and shaft seal clearance  6  to increase the efficacy of shaft seal assembly  25 . A spherical interface  11  between the labyrinth seal  3  and the floating stator  4  allow for angular misalignment between the shaft  1  and fixed stator  2 . O-ring channels  19  are annular with the shaft  1  and, as shown, are machined into the fixed stator  2  and positioned at the interface between the fixed stator  2  and floating stator  4 . O-ring channel  19  may also be placed in the floating stator  4  for sealing contact with the fixed stator  2 . 
       FIG. 3A  illustrates seal-shaft integrity during angular and radial shaft alignment. This view highlights the alignment of the axial face  17  of the labyrinth seal  3  and the axial face  18  of the floating stator  4 . Particular focus is drawn to the alignment of the axial faces  17  and  18  at the spherical interface  11  between the floating stator  4  and labyrinth  3 .  FIG. 3B  illustrates the shaft-seal integrity during angular and radial shaft alignment at the surface opposite that shown in  FIG. 3A . This view highlights the alignment of the axial faces  17  and  18  of labyrinth seal  3  and floating stator  4 , respectively, for the opposite portion of the shaft seal assembly  25  as shown in  FIG. 3A . Those practiced in the arts will appreciate that because the shaft  1  and shaft seal assembly  25  are of a circular shape and nature, the surfaces are shown 360 degrees around shaft  1 . Again, particular focus is drawn to the alignment of the axial faces  17  and  18  at the spherical interface  11  between the labyrinth seal  3  and floating stator  4 .  FIGS. 3A and 3B  also illustrate the first defined clearance  20  between the floating stator  4  and the fixed stator  2  and the second defined clearance  21  between the floating stator  4  and fixed stator  2  and opposite the first defined clearance  20 . 
     In  FIGS. 2, 3, 3A and 3B , the shaft  1  is not experiencing radial, angular or axial movement and the width of the defined clearances  20  and  21 , which are substantially equal, indicate little movement or misalignment upon the floating stator  4 . 
       FIG. 4  is an exterior end view of the shaft seal assembly  25  with the rotatable shaft  1  misaligned therein.  FIG. 5  is a sectional view of the first embodiment of the shaft seal assembly  25  as shown in  FIG. 3  with both angular and radial misalignment of the shaft  1  applied. The shaft  1  as shown in  FIG. 5  is also of the type which may experience radial, angular or axial movement relative to the fixed stator  2  portion of the shaft seal assembly  25 . 
     As shown at  FIG. 5 , the defined radial clearance  6  of labyrinth seal  3  with shaft  1  has been maintained even though the angle of shaft misalignment  31  has changed. The shaft  1  is still allowed to move freely in the axial direction even though the angle of shaft misalignment  31  has changed. The arrangement of the shaft seal assembly  25  allows the labyrinth seal  3  to move with the floating stator  4  upon introduction of radial movement of said shaft  1 . The labyrinth seal  3  and floating stator  4  are secured together by one or more compressed o-rings  7 . Rotation of the labyrinth seal  3  within the floating stator  4  is prevented by anti-rotation means which may include a screws, pins or similar devices  12  to inhibit rotation. Rotation of the labyrinth seal  3  and floating stator  4  assembly within the fixed stator  2  is prevented by anti-rotation pins  8 . The pins as shown in  FIGS. 3, 3A, 3B, 5, 6 and 7  are one means of preventing rotation of the labyrinth seal  3  and floating stator  4 , as recited in the claims. Lubricant or other media to be sealed by the labyrinth seal  3  may be collected and drained through a series of one or more optional drains or lubricant return pathways  5 . The labyrinth seal  3  may be pressure equalized by venting through one or more vents  9 . If so desired, the vents  9  may be supplied with pressurized air or other gas or fluid media to over-pressurize the labyrinth seal  3  to increase seal efficacy. The combination of close tolerances between the cooperatively engaged mechanical portions of the shaft seal assembly  25  and pressurized sealing fluid inhibit product and contaminate contact with the internals of the shaft seal assembly  25 . The spherical interface  11  between the labyrinth seal  3  and the floating stator  4  allow for angular misalignment between the shaft  1  and fixed stator  2 . O-ring channel  19  and o-ring  13  disposed therein cooperate with the opposing faces of the floating stator  4 , which are substantially in perpendicular relation to shaft  1 , to seal (or trap) fluid migration between and along engaged floating stator  4  while allowing limited relative radial (vertical) movement between stator  4  and fixed stator  2 . 
       FIG. 5A  illustrates seal-shaft integrity allowed by the shaft seal assembly  25  during angular and radial shaft misalignment. This view highlights the offset or articulation of the axial faces  17  of the labyrinth seal in relation the axial faces  18  of the floating stator  4  for a first portion of the shaft seal assembly  25 . Particular focus is drawn to the offset of the axial faces  17  and  18  at the spherical interface  11  between labyrinth seal  3  and floating stator  4 . 
       FIG. 5B  illustrates seal-shaft integrity for a second surface, opposite the first surface shown in  FIG. 5A , during angular and radial shaft misalignment. This view highlights that during misalignment of shaft  1 , axial faces  17  and  18 , of the labyrinth seal  3  and floating stator  4 , respectively, are not aligned but instead move (articulate) in relation to each other. The shaft to seal clearance  6  is maintained in response to the shaft misalignment and the overall seal integrity is not compromised because the seal integrity of the floating stator  4  to fixed stator  2  and the floating stator  4  to labyrinth seal  3  are maintained during shaft misalignment. Those practiced in the arts will appreciate that because the shaft  1  and shaft seal assembly  25  are of a circular shape and nature, the surfaces are shown 360 degrees around shaft  1 . 
       FIGS. 5A and 5B  also illustrate the first clearance or gap  20  between the floating stator  4  and the fixed stator  2  and the second clearance or gap  21  between the floating stator  4  and fixed stator  2  and opposite the first clearance or gap  20 . 
     In  FIGS. 4, 5, 5A and 5B , the shaft  1  is experiencing radial, angular or axial movement during rotation of the shaft  1  and the width of the gaps or clearances  20  and  21 , have changed in response to said radial, angular or axial movement. (Compare to  FIGS. 3, 3A and 3B .) The change in width of clearance  20  and  21  indicate the floating stator  4  has moved in response to the movement or angular misalignment of shaft  1 . The shaft seal assembly  25  allows articulation between axial faces  17  and  18 , maintenance of spherical interface  11  and radial movement at first and second clearance,  20  and  21 , respectively, while maintaining shaft seal clearance  6 . 
       FIG. 6  is a sectional view of a second embodiment of the shaft seal assembly  25  as shown in  FIG. 2  for over-pressurization with alternative labyrinth seal pattern grooves  14 . In this figure the labyrinth seal pattern grooves  14  are composed of a friction reducing substance such as polytetrafluoroethylene (PTFE) that forms a close clearance to the shaft  1 . PTFE is also sometimes referred to as Teflon® which is manufactured and marketed by Dupont. PTFE is a plastic with high chemical resistance, low and high temperature capability, resistance to weathering, low friction, electrical and thermal insulation, and “slipperiness.” The “slipperiness” of the material may also be defined as lubricous or adding a lubricous type quality to the material. Carbon or other materials may be substituted for PTFE to provide the necessary sealing qualities and lubricous qualities for labyrinth seal pattern grooves  14 . 
     Pressurized sealing fluids are supplied to over-pressurize the lubricious labyrinth pattern  26  as shown in  FIG. 6 . The pressurized sealing fluids make their way into the annular groove  23  of the throttle  26  through one or more inlets. Throttle  26  is also referred to as “an alignment skate” by those practiced in the arts. Throttle  26  allows the labyrinth seal  3  to respond to movement of the shaft caused by the misalignment of the shaft  1 . The pressurized sealing fluid escapes past the close clearance formed between the shaft  1  and labyrinth seal  3  having throttle  26 . The close proximity of the throttle  26  to the shaft  1  also creates resistance to the sealing fluid flow over the shaft  1  and causes pressure to build-up inside the annular groove  23 . Floating annular groove  27  in cooperation and connection with annular groove  23  also provides an outlet for excess sealing fluid to be “bled” out of shaft seal assembly  25  for pressure equalization or to maintain a continuous fluid purge on the shaft sealing assembly  25  during operation. An advantage afforded by this aspect of the shaft sealing assembly  25  is its application wherein “clean-in place” product seal decontamination procedures are preferred or required. Examples would include food grade applications. 
       FIG. 7  illustrates shaft seal assembly  25  with the anti-rotation pin  12  removed to improve visualization of the inlets. These would typically exist, but are not limited to, a series of ports, inlets or passages about the circumference of the shaft seal assembly  25 .  FIG. 7  also shows the shape and pattern of the labyrinth seal  3  may be varied. The shape of throttles  26  may also be varied as shown by the square profile shown at throttle groove  22  in addition to the circular-type  26 . Also note that where direct contact with the shaft  1  is not desired, the shaft seal assembly  25  be used in combination with a separate sleeve  24  that would be attached by varied means to the shaft  1 . 
       FIG. 8  shows that another embodiment of the present disclosure wherein the shaft seal assembly  25  has been affixed to a vessel wall  34 . The shaft seal assembly  25  may be affixed to vessel wall  34  through securement means such as mounting bolts  33  to ensure improved sealing wherein shaft  1  is subjected to angular misalignment. The mounting bolts  33  and slots (not numbered) through the shaft seal assembly  25  exterior are one means of mounting the shaft seal assembly  25 , as recited in the claims. 
     In certain applications, especially those wherein the process side of shaft seal assembly  25  (generally the area to the left of the shaft seal assembly  25  as shown in  FIGS. 3-3B and 5-7 ) is at an increased pressure, it is desirable for the shaft seal assembly  25  to be configured to balance the pressure experienced by the shaft seal assembly  25  in the axial direction. A pressure balanced shaft seal assembly  40  that balances the pressure (in the axial direction) the product applies to the labyrinth seal interior face  42  and floating stator interior face  44  is shown in  FIGS. 9-12 . 
     In the first embodiment of the pressure balanced shaft seal assembly as shown in  FIGS. 9-10B , the shaft sealing member (i.e., the labyrinth seal  3  in combination with the floating stator  4 ) includes a pressure balancing annular channel  46 . Save for the pressure balancing annular channel  46 , the pressure balanced shaft seal assembly  40  operates in the same manner as the shaft seal assembly  25  shown in  FIGS. 1-8  and described in detail above. That is, the floating stator  4  is positioned in the fixed stator annular groove  48 . The first clearance between floating stator/fixed stator  20 , which in the embodiments pictured herein is between the floating stator radial-exterior surface  45  and the annular groove radial-interior surface  48   a  (shown in  FIGS. 9A and 9B ), accounts at least for radial perturbations of the shaft  1 . The spherical interface  11  between the floating stator  4  and the labyrinth seal  3  accounts at least for angular perturbations of the shaft  1 . 
     The pressure balancing annular channel  46  is formed in the floating stator  4  adjacent the first radial interface  47   a  between the floating stator  4  and the fixed stator  2 , as shown in  FIGS. 9-10  for the first embodiment. As shown in the various embodiments pictured herein, the first radial interface  47   a  between the floating stator  4  and the fixed stator  2  is adjacent the portion of the fixed stator  2  fashioned with the cavity for anti-rotation device  16 . That is, the axial face of the floating stator  4  that is positioned within the fixed stator  2  and furthest from the process side of the pressure balanced shaft seal assembly  40 . A second radial interface  47   b  between the floating stator  4  and fixed stator  2 , which is substantially parallel to the first radial interface  47   a , is positioned closer to the process side of the pressure balanced shaft seal assembly  40  as compared to the first radial interface  47   a.    
     In many applications the optimal radial dimension of the pressure balancing annular channel  46  will be the substantially similar to the radial dimension of the floating stator interior face  44  so that the area of the floating stator  4  acted upon by the product and the area of the floating stator  4  acted upon by the sealing fluid have equal surface areas. In such a configuration, the axial forces will balance if the product and the sealing fluid are pressurized to approximately the same value. Accordingly, the optimal radial dimension of the pressure balancing annular channel  46  will depend on the design characteristics of the entire system, and the radial dimension of the pressure balancing annular channel  46  may be any suitable amount for a particular application, whether greater or less than the radial dimension of the floating stator interior face  44 . The axial dimension of the pressure balancing annular channel  46  will also vary depending on the design characteristics of the entire system, including but not limited to the specific sealing fluid that is used, the product pressure, and the pressure of the sealing fluid. In some applications the optimal axial dimension of the pressure balancing annular channel  46  will be 0.005 of an inch, but may be greater in other embodiments and less in still other embodiments. 
     The pressure balancing annular channel  46  allows sealing fluid introduced into the first clearance between floating stator/fixed stator  20  (from where the sealing fluid may enter the pressure balancing annular channel  46 ) to act upon the floating stator in an axial direction. Typically, the process side of the pressure balanced shaft seal assembly  40  (generally the area to the left of the pressure balanced shaft seal assembly  40  as shown in  FIGS. 9-12 ) experiences forces from the process fluid acting upon the labyrinth seal interior face  42  and floating stator interior face  44 . These forces are most often due to the pressure generated by the rotating equipment to which the shaft  1  is coupled. For example, if the shaft  1  is coupled to a fluid pump generating seventy pounds per square inch (psi) of head pressure, the process side of the pressure balanced shaft seal assembly  40  will be pressurized to approximately seventy psi. This pressurized fluid will act upon the labyrinth seal interior face  42  and floating stator interior face  44 , and consequently urge the labyrinth seal  3  and floating stator  4  in the axial direction away from the process side of the pressure balancing shaft seal assembly  40  (i.e., generally to the right side of the drawing as depicted in  FIGS. 9-12 ). By contrast, sealing fluid located in the pressure balancing annular channel  46  will urge the labyrinth seal  3  and floating stator  4  in the axial direction toward the process side of the pressure balancing shaft seal assembly  40 , which may substantially cancel the axial force the product exerts upon the pressure balancing shaft seal assembly  40 , depending on the design of the sealing fluid system. 
       FIGS. 11 and 12  show a second and third embodiment of the pressure balanced shaft seal assembly  40 . The second and third embodiments of the pressure balanced shaft seal assembly  40  generally correspond to the second and third embodiments of the shaft seal assembly  25  as shown in  FIGS. 7 and 8  and described in detail above. However, as with the first embodiment of the pressure balanced shaft seal assembly  40  as shown in  FIGS. 9-10B , the second and third embodiments include a pressure balancing annular channel  46 . 
     The various embodiments of the pressure balanced shaft seal assembly  40  pictured and described herein are formed with a fixed stator  2  and floating stator  4  that are comprised of two distinct portions. These embodiments facilitate assembly of the pressure balanced shaft seal assembly  40  since in the embodiments pictured herein the majority of the floating stator  4  is positioned within the fixed stator  2 . When installing a pressure balanced shaft seal assembly  40  according to the first embodiment (as pictured in  FIGS. 9-10B ), the first portion of fixed stator  2  (i.e., the portion adjacent the process side of the pressure balanced shaft seal assembly  40 ) would be affixed to a housing  30 . Next, the floating stator  4  and labyrinth seal  3  may be positioned as one assembled piece (wherein the components forming the spherical interface  11  have been preassembled) between the shaft  1  and the first portion of the fixed stator  2 . The placement of the floating stator  4  and labyrinth seal  3  within the fixed stator  3  forms the second axial interface  47   b  between the fixed stator  2  and floating stator  4 . Finally, the second portion of the fixed stator  2  (i.e., the portion furthest from the process side of the pressure balanced shaft seal assembly  40 ) may be positioned adjacent to and affixed to the first portion of the fixed stator  2 . The positioning of the second portion of the fixed stator  2  subsequently forms the first radial interface  47   a  between the fixed stator  2  and floating stator  4 . 
     Alternatively, the floating stator  4  and labyrinth seal  3  may be separately positioned within the fixed stator annular groove  48 . For example, after the first portion of the fixed stator  2  has been affixed to the housing  30 , the first portion of the floating stator  4  may be positioned within the fixed stator annular groove  48 . The placement of the first portion of the floating stator  4  within the fixed stator annular groove  48  forms the second axial interface  47   b  between the fixed stator  2  and floating stator  4 . Next, the labyrinth seal  3  may be positioned adjacent the shaft  3 , the placement of which forms a portion of the spherical interface  11  between the floating stator  4  and labyrinth seal  3 . Next, the second portion of the floating stator  4  may be positioned adjacent the first portion of the floating stator  4  and affixed thereto with a plurality of anti-rotation pins  8 , which completes the spherical interface  11  between the floating stator  4  and labyrinth seal  3 . Finally, the second portion of the fixed stator  2  is affixed to the first portion of the fixed stator  2  with a plurality of bolts or rivets, the placement of which forms the first axial interface  47   a  between the floating stator  4  and fixed stator  2 . Any suitable securing members known to those skilled in the art may be used to affix the first and second portions of the floating stator  4  to one another or to affix the first and second portions of the fixed stator  2  to one another. 
     Although the embodiments pictured herein are directed to pressure balanced shaft seal assemblies  40  wherein the fixed stator  2  and floating stator  4  are comprised of two separate portions, in other embodiments not pictured herein, the fixed stator  2  and/or floating stator  4  are formed of one integral member. 
     Element Listing (FIGS.  13 - 22 D) 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Description 
                 Element No. 
               
               
                   
                   
               
             
            
               
                   
                 Shaft 
                  10 
               
               
                   
                 Bearing isolator 
                  18 
               
               
                   
                 Housing 
                  19 
               
               
                   
                 Rotor 
                  20 
               
               
                   
                 Stator 
                 30, 31a 
               
               
                   
                 Fixed stator 
                  31 
               
               
                   
                 Passage 
                 40, 40a 
               
               
                   
                 Spherical surface 
                 50, 51  
               
               
                   
                 Clearance 
                  52 
               
               
                   
                 Frictional seal 
                  60 
               
               
                   
                 Flange unit 
                  61a 
               
               
                   
                 Center point 
                  80 
               
               
                   
                 Conduit 
                  99 
               
               
                   
                 Fluid 
                 100 
               
               
                   
                 Pin 
                 101 
               
               
                   
                 Annular recess 
                 102 
               
               
                   
                 Shaft seal assembly 
                 200 
               
               
                   
                 Multi-shaft seal assembly 
                 202 
               
               
                   
                 Fastener 
                 204 
               
               
                   
                 Aperture 
                 206 
               
               
                   
                 Fixed stator 
                 210 
               
               
                   
                 Main body 
                 211 
               
               
                   
                 Face plate 
                 212 
               
               
                   
                 Pin recess 
                  212a 
               
               
                   
                 Inlet 
                 214 
               
               
                   
                 Annular recess 
                 216 
               
               
                   
                 Sealing member 
                 218 
               
               
                   
                 Floating stator 
                 220 
               
               
                   
                 Radial exterior surface 
                 222 
               
               
                   
                 Pin 
                 224 
               
               
                   
                 First radial passage 
                 226 
               
               
                   
                 Concave surface 
                 228 
               
               
                   
                 Rotor 
                 230 
               
               
                   
                 Roller cavity 
                 232 
               
               
                   
                 Cavity wall 
                 233 
               
               
                   
                 Roller 
                 234 
               
               
                   
                 Second radial passage 
                 236 
               
               
                   
                 Convex surface 
                 238 
               
               
                   
                 First seal 
                 240 
               
               
                   
                 Collar 
                 241 
               
               
                   
                 Collar lip 
                  241a 
               
               
                   
                 Collar cutaway 
                 242 
               
               
                   
                 Second seal 
                 250 
               
               
                   
                 Cutaway 
                 251 
               
               
                   
                 Shaft seal assembly 
                 300 
               
               
                   
                 O-ring channel 
                 302 
               
               
                   
                 O-ring 
                 303 
               
               
                   
                 Unitizing ring 
                 304 
               
               
                   
                 Slip ring 
                 305 
               
               
                   
                 First cooperating cavity 
                  306a 
               
               
                   
                 Second cooperating cavity 
                  306b 
               
               
                   
                 Axial passage 
                 307 
               
               
                   
                 Radial passage 
                 308 
               
               
                   
                 Stator 
                 310 
               
               
                   
                 Stator body 
                 311 
               
               
                   
                 Shoulder 
                 312 
               
               
                   
                 Radial bore 
                 313 
               
               
                   
                 Axial projection 
                 314 
               
               
                   
                 Radial projection 
                 315 
               
               
                   
                 Axial channel 
                 316 
               
               
                   
                 Radial channel 
                 317 
               
               
                   
                 Unitizing ring channel 
                 318 
               
               
                   
                 Rotor 
                 320 
               
               
                   
                 Rotor body 
                 321 
               
               
                   
                 Rotor axial projection 
                 324 
               
               
                   
                 Rotor radial projection 
                 325 
               
               
                   
                 Rotor axial channel 
                 326 
               
               
                   
                 Rotor radial channel 
                 327 
               
               
                   
                 Rotor unitizing ring channel 
                 328 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 13  shows another embodiment of a bearing isolator  18  mounted on a shaft  10 . The shaft  10  extends through the bearing isolator  18  and the housing  19 . A source of gas or fluid,  100  which may include water or lubricant, may also be in communication with the bearing isolator  18  via conduit  99 . The rotor  20  is affixed to the shaft  10  by means by a frictional seal  60 , which may be configured as one or more o-rings. The rotor  20  follows the rotational movement of the shaft  10  because of the frictional engagement of the seals  60 . The passages  40  and  40   a  are as shown but will not be described in detail here because such description is already understood by those skilled in the art. 
     A pair of corresponding spherical surfaces  50  and  51  may be used to create a self-aligning radial clearance  52  between the rotor  20  and the stator  30  prior to, during, and after use. This clearance  52  may be maintained at a constant value even as the shaft  10  becomes misaligned during use. Various amounts and direction of misalignment between the centerline of the shaft  10  and the housing  19  are illustrated in  FIGS. 15-17 . An annular recess  102  between the stator  30  and fixed stator  31  allows the bearing isolator  18  to accommodate a predetermined amount of radial shaft displacement. 
     In the embodiments shown herein, the spherical surfaces  50 ,  51  have a center point identical from the axial faces of both the rotor and stator  20 ,  30 , respectively. However, the spherical surfaces  50 ,  51  may be radially, and/or as shown, vertically spaced apart. These spherical surfaces  50 ,  51  may move radially in response to and/or in connection with and/or in concert with the radially positioning of other components of the bearing isolator  18 . Typically, if the shaft  10  becomes misaligned with respect to the housing  19 , the rotor  20  will consequently become misaligned with respect thereto, and then the spherical surfaces  50 ,  51  and/or the stator  30  moving radially within the annular recess of the fixed stator  31  may compensate for the misalignment. 
       FIGS. 15 and 17  illustrate that in one embodiment of the bearing isolator  18 , the rotor  20  may move with respect to the stator  30 ,  31  as shaft  10  is misaligned with respect to housing  19  through the interaction between spherical surfaces  50 ,  51  so as to ensure the distances between the center points of the rotor  20  and stator  30  and a fixed point on the housing  19  are constant. 
     In the embodiment of the bearing isolator  18  shown in  FIGS. 14 &amp; 15 , the spherical surfaces  50 ,  51  may be positioned on a fixed stator  31  and stator  31   a  rather than on the rotor  20  and stator  30 . Still referring to  FIGS. 14 &amp; 15 , this design allows the rotor  20  and stator  31   a  to move with respect to the fixed stator  31 , flange unit  61   a , and housing  19 . The rotor  20 , stator  31   a , and fixed stator  31  may move radially with respect to the flange unit  61   a  (and consequently with respect to the housing  19 ) as best shown in  FIG. 15 . In this embodiment of the bearing isolator  18  there is a very minimal amount of relative rotation between the spherical surfaces  50 ,  51 . 
     The embodiment of the bearing isolator  18  shown in  FIGS. 14 &amp; 15  may provide for controlled radial movement of the fixed stator  31 , stator  31   a , and rotor  20  with respect to flange unit  61   a , which flange unit  61   a  may be securely mounted to a housing  19 . Rotational movement of the fixed stator  30  with respect to the flange unit  61   a  may be prevented by anti-rotational pins  101 . The fixed stator  31  may be frictionally secured to the flange unit  61   a  using a frictional seal  61 , which may be made of any material with sufficient elasticity and frictional characteristics to hold the fixed stator  31  in a fixed radial position with respect to the flange unit  61   a  but still be responsive to the radial forces when the shaft  10  is misaligned. Changes to the radial position of the fixed stator  31 , stator  31   a , and rotor  20  and the resulting positions thereof (as well as the resulting position of the interface between the fixed stator  31  and stator  31   a ) occurs until the radial force is fully accommodated or unit the maximum radial displacement of the bearing isolator  18  is reached. 
     In operation, the rotor  20  may be moved radially as shaft  10  is misaligned with respect to the housing  19 . Radial movement of the spherical surfaces  50 ,  51  between the stator  31   a  and fixed stator may result from this pressure.  FIG. 3  shows the resultant radial movement of center point  80  as the shaft  10  is misaligned. During normal operation, the shaft  10  is typically horizontal with respect to the orientation shown in  FIG. 3 , as represented by line A. As the shaft  10  becomes misaligned in a manner represented by line B, the center point  80  may move to a point along line A″. As the shaft  10  becomes misaligned in a manner represented by line B′, the center point  80  may move to a point along line A′. However, in other shaft  10  misalignments, the radial positions of the rotor  20 , stator  30 , and/or fixed stator  31  may be constant and the spherical surfaces  50 ,  51  may compensate for the shaft misalignment. From the preceding description it will be apparent that the bearing isolator  18  provides a constant seal around the shaft  10  because the distance between the spherical surfaces  50 ,  51  is maintained as a constant regardless of shaft  10  misalignment of a normal or design nature. 
     The physical dimensions of the spherical surfaces  50  and  51  may vary in linear value and in distance from the center point  80 , depending on the specific application of the bearing isolator. These variations will be utilized to accommodate different sizes of shafts and seals and different amounts of misalignment. 
     Axial Displacement Shaft Seal Assembly 
     Another embodiment of a shaft seal assembly  200  is shown in  FIGS. 18 &amp; 18A . This embodiment is similar to the embodiment of the bearing isolator  18  described above and shown in  FIGS. 13, 16 , &amp;  17 . The shaft seal assembly  200  may include a fixed stator  210 , floating stator  220 , and a rotor  230 , as shown. In the pictured embodiment, the rotor  230  typically rotates with the shaft  10  while the fixed stator  210  and stator  220  do not. Accordingly, a rotational interface may exist between a concave surface  228  of the floating stator  220  and a convex surface  238  of the rotor  230 . In other embodiments of the shaft seal assembly  200  not pictured herein, but which embodiments are a corollary to the embodiment of the bearing isolator  18  shown in  FIGS. 14 &amp; 15 , the floating stator  220  may be configured with a convex surface that corresponds to a concave surface of the fixed stator. In such an embodiment, the rotational interface may be located at a position other than the interface between the concave and convex surfaces. 
     The embodiment of the shaft seal assembly  200  shown in  FIGS. 18 &amp; 18A  includes a fixed stator  210  that may be securely mounted to a housing (not shown in  FIGS. 18 &amp; 18A ) my any suitable methods and/or structure. The fixed stator  210  may include a main body  211  and a face plate  212  that may be secured to one another. It is contemplated that a fixed stator  210  formed with a main body  211  and face plate  212  may facilitate ease of installation of the shaft seal assembly  200  in certain applications. In such applications, the main body  211  may be affixed to the housing, the rotor  230  and floating stator  220  may be positioned appropriately, and then the face plate  212  may be secured to the main body  211 . 
     The fixed stator  210  may be formed with an annular recess  216  into which a portion of the floating stator  220  and/or rotor  230  may be positioned. A predetermined clearance between the radial exterior surface  222  of the floating stator  220  and the interior surface of the annular recess  216  may be selected to allow for relative radial movement between the fixed stator  210  and floating stator  220 . At least one pin  224  may be affixed to the floating stator  220 , and a portion of the pin  224  may extend into a pin recess  212   a  formed in the face plate  212  so as to prevent the floating stator  220  from rotating with the rotor  230 . The axial interfaces between the floating stator  220  and fixed stator  210  may be sealed with sealing members  218 , which sealing members may be configured as o-rings. 
     The floating stator  220  may also be formed with a concave surface  228  in a radial interior portion thereof. This concave surface  228  may form a semi-spherical interface with a corresponding convex surface  238  formed in the radial exterior portion of the rotor  230 . Accordingly, the shaft seal assembly  200  shown in  FIGS. 18 &amp; 18A  accommodates shaft  10  misalignment and radial movement in an identical and/or similar manner to that previously described for the bearing isolators  18 . 
     The shaft seal assembly  200  may be configured to accommodate for axial movement of the shaft  10 . In the pictured embodiment this is accomplished by forming at least one roller cavity  232  in the rotor  230  adjacent the shaft  10 . The illustrative embodiment includes two roller cavities  232  bound by a cavity wall  233  on either end thereof. At least one roller  234  may be positioned in each roller cavity  232 . Axial movement of the shaft  10  may be accommodated by a roller  234  rolling along the surface of the shaft  10  and within the roller cavity  232 . The illustrative embodiment includes two roller cavities  232  with one roller  234  in each roller cavity  232 , but the shaft seal assembly  200  is in no way limited by the number of roller cavities  232  and/or rollers  234  associated therewith. The roller(s)  234  may be constructed of any suitable material for the specific application of the shaft seal assembly  200 . It is contemplated that an elastomeric material (e.g., rubber, silicon rubber, other polymers) will be especially suitable for many applications. 
     The illustrative embodiment of the shaft seal assembly  200  also includes various fluid conduits for applying a sealing fluid to the shaft seal assembly  200 . The fixed stator  210  is formed with an inlet  214  for introduction of a sealing fluid to the shaft seal assembly  200 . The inlet  214  may be in fluid communication with one or more first radial passages  226  in the floating stator  220 , which first radial passages  226  may in turn be in fluid communication with one or more second radial passages  236  in the rotor  230 . The roller(s)  234 , roller cavity(ies)  232 , and cavity wall(s)  233  may be configured so that the sealing fluid introduced to the inlet  214  exits the shaft seal assembly  200  from an area between the rotor  230  and shaft  10  at a predetermined rate for a given set of operation parameters (e.g., sealing fluid viscosity and pressure, shaft  10  rpm, etc.). The illustrative embodiment of the shaft seal assembly  200  may be formed with eight first radial passages  226  formed in the floating stator  220 , which correspond to eight second radial passages  236  formed in the rotor  230 , and the first radial passages  226  and second radial passages  236  may be evenly spaced about the circumference of the shaft seal assembly  200 . However, in other embodiments, different numbers, spacing, and/or configurations of the first radial passages  226  and/or second radial passages  236  may be used without departing from the spirit and scope of the shaft seal assembly  200  as disclosed and claimed herein. 
     In an embodiment of the shaft seal assembly  200  not pictured herein, but which embodiment is a corollary to that shown in  FIGS. 14 &amp; 15 . It will be apparent in light of the present disclosure that in such an embodiment, the rotor  20  will include at least one roller cavity adjacent the shaft  10  with at least one roller positioned therein rather than a frictional seal  60 . As with the previous embodiments of the shaft seal assembly  200  described herein, the roller(s) may be configured to rotatively couple the rotor  20  with the shaft  10 . The rotor cavity and/or roller may be also be configured to allow the shaft  10  to move axially with respect to the shaft sealing assembly  200 . 
     Multi-Shaft Seal Assembly 
       FIG. 19  provides a perspective view of a first embodiment a multi-shaft seal assembly  202 . It is contemplated that a multi-shaft seal assembly  202  may be especially useful in applications wherein two shafts  10  are positioned in relative close proximity to one another, as shown for the illustrative embodiment pictured herein. The shafts  10  pictured herein are also oriented such that the longitudinal axes thereof are parallel with respect to one another. However, the multi-shaft seal assembly  202  is not so limited, and other embodiments thereof exist for use with shafts  10  that are oriented differently than those pictured herein. 
     The illustrative embodiment of the multi-shaft seal assembly  202  includes a first seal  240 . A sealing portion of the first seal  240  surrounds one shaft  10  and may be configured to operate in a manner substantially similar to other bearing isolators  18  and/or shaft seal assemblies  25 ,  200  disclosed herein or otherwise. A sealing portion of a second seal  250  surrounds the other shaft  10  and also may be configured to operate in a manner substantially similar to other bearing isolators  18  and/or shaft seal assemblies  25 ,  200  disclosed herein or otherwise. For example,  FIG. 21  provides an axial, cross-sectional view of a first embodiment of the multi-shaft seal assembly  202 , wherein both the first and second seals  240 ,  250  are configured to operate in a manner substantially similar to the bearing isolator  18  shown in  FIGS. 13-17 . However, in other embodiments of the multi-shaft seal assembly  202 , either the first or second seal  240 ,  250  may be differently configured. For example, the first and second seals  240 ,  250  may be configured like the embodiment of a shaft seal assembly  200  shown in  FIGS. 18 &amp; 18A . Furthermore, in other embodiments of the multi-shaft seal  202 , the first seal  240  and second seal  250  may be configured differently from one another. For example, the first seal  240  may be configured to operate in a manner substantially similar to the bearing isolator  18  shown in  FIGS. 13-17  and the second seal  250  may be configured to operate in a manner substantially similar to the shaft seal assembly  200  shown in  FIGS. 18 &amp; 18A . Accordingly, the specific internal configuration of either the first or second seal  240 ,  250  in no way limits the scope of the multi-shaft seal assembly  202  as disclosed herein. 
     As shown in  FIG. 21 , each seal  240 ,  250  may be configured to include a fixed stator  210 , floating stator  220 , face plate  212 , and a rotor  220 , all of which are shown in  FIG. 21  as being configured to operate in a manner substantially similar to the embodiment of a bearing isolator  18  as shown in  FIGS. 13-17 , as previously mentioned. The rotor  230  may be secured to a shaft  10  such that the rotor  230  is coupled thereto and rotates therewith in any suitable manner (several of which are described above for other embodiments of a bearing isolator  18  and/or shaft seal assemblies  25 ,  200 ). The fixed stator  210  may be secured to a housing  19  in any suitable manner (several of which are described above for other embodiments of a bearing isolator  18  and/or shaft seal assemblies  25 ,  200  and which include but are not limited to mechanical fasteners  204 , chemical adhesives, welding, interference fit, and/or combinations thereof). One such suitable manner includes fasteners  204  as shown in  FIGS. 19, 20 , &amp;  22  and corresponding apertures  206 . The floating stator  220  may be positioned within a portion of an annular recess  216  formed in the fixed stator  10 , wherein the exterior axial boundary of the annular recess  216  may be defined by the interior surface of a face plate  212 , which may be engaged with the fixed stator  210  as previously described for other embodiments of the bearing isolator  18  and shaft seal assemblies  25 ,  200 . 
     The fixed stator  210 , floating stator  220 , rotor  230 , and/or face plate  212  may cooperate to form a labyrinth seal. The fixed stator  210 , floating stator  220 , and/or the rotor  230  may be constructed in a two-piece manner. As mentioned, in the illustrative embodiment, the fixed stator  210  may be configured to engage a face plate  212  via a plurality of fasteners  204 , which may be distinct from the fasteners  204  used to engage the fixed stator  210  with the housing  19 . Other methods and/or structures for engaging the face plate  212  with the fixed stator  210  may be used without limitation. Additionally, an interface between two portions of the rotor  230 , two portions of the fixed stator  210 , the fixed stator  210  and the floating stator  220 , the rotor  230  and the floating stator  220 , and/or the rotor  230  and fixed stator  210  may be semi-spherical, as shown for the interface between the rotor  230  and floating stator  220  for the embodiment pictured in  FIG. 21 . Furthermore, the seals  240 ,  250  may be formed with an inlet  214  therein, as previously described for the other embodiments of a bearing isolator  18  and shaft seal assemblies  25 ,  200  disclosed herein to provide a sealing fluid to various passages within the multi-shaft seal assembly  202 . 
     To accommodate two shafts  10  in relative close proximity, the illustrative embodiment of a multi-shaft seal assembly  202  employs a configuration in which the first and second seals  240 ,  250  are configured in a stacked arrangement (see  FIGS. 20 &amp; 21 ). That is, the first seal  240  may reside in a different radially oriented plane than that in which the second seal  250  resides. In the illustrative embodiment, the planes are parallel with respect to one another. However, in other embodiments of the multi-shaft seal assembly  202  not pictured herein, the planes may have other orientations, which orientations may be dependent at least in part on the orientation of the shafts  10  and/or housing  19 . 
     A collar  241  may be secured to the housing  19  and/or the first seal  240  to provide the proper axial spacing for the stacking arrangement of the first and second seals  240 ,  250 . In the illustrative embodiment the collar  241  may be formed separately from either the first seal  240  or the housing  19 , and later secured to the first seal  240  and/or housing  19 . As clearly shown in  FIG. 19B , which provides a rear side perspective view of the illustrative embodiment of a multi-shaft seal assembly  202 , the collar  241  may be formed with a collar cutaway  242  therein to accommodate a portion of the second seal  250 . As shown, the collar cutaway  242  may be configured with an angled portion to interface with the exterior surface of the first seal  240 . 
     In most applications, the surface prominently shown in  FIG. 19B  is adjacent a housing  19  during use of the multi-shaft seal assembly  202 . Accordingly, the surface of the collar  241  and/or first seal  240  adjacent the housing  19  may be formed with an o-ring channel therein to accommodate an o-ring. An o-ring so positioned may serve to prevent air and/or other fluid from egress/ingress between the collar  241  and housing  19  and/or between the first seal  240  and housing  19 . The specific shape, dimensions, and/or configuration of the collar cutaway  242  will vary from one embodiment of the twin-shaft seal assembly  202  to the next, and may be at least dependent upon the spacing of the shafts  10  and/or configuration of the first and second seals  240 ,  250 , and is therefore in no way limiting to the scope of the multi-shaft seal assembly  202 . As shown for the illustrative embodiment, the collar  241  may be secured to the housing  19  via one or more fasteners  204  and corresponding apertures  206 . However, in other embodiments of the multi-shaft seal assembly  202  pictured herein, the collar  241  may be integrally formed with a portion of the first seal  240 . In still other embodiments of the multi-shaft seal assembly  202  not pictured herein the collar  241  may be integrally formed with the housing  19 . In another embodiment of a multi-shaft seal assembly  202  not pictured herein the collar  241  may be integrally formed with the second seal  250 . Accordingly, the multi-shaft seal assembly  202  is not limited by the specific configuration of the first collar  241  with respect to the housing  19 , first seal  240 , and/or second seal  250 . 
     The collar  241  may serve as an axial spacer between the equipment housing and the second seal  250  as clearly shown in  FIGS. 20 &amp; 21 . In this embodiment, the axial dimension of the collar  241  is approximately equal to that of the first and second seals  240 ,  250 . However, the collar  240  may be formed with a collar lip  241   a  into which a portion of the second seal  250  may seat, as shown in  FIG. 21 . Accordingly, in applications wherein the radial dimension of the first and/or second seal  240 ,  250  is too great for mounting thereof in the same radial plane due to the spacing of two adjacent shafts  10 , the first and second seals  240 ,  250  may be applied to the shafts  10  in an axially offset configuration. 
     The multi-shaft seal assembly  202  may also include a cutaway  251  formed in a portion of the second seal  250 . A cutaway  251  may be required to accommodate certain configurations of adjacent shafts  10  wherein the shafts  10  are in relative close proximity to one another. As best shown in  FIGS. 20 &amp; 22 , the configuration of shafts  10  in the illustrative embodiment of the multi-shaft seal assembly  202  are in relatively close proximity to one another such that the second seal  250  must be formed with a cutaway  251  to accommodate adequate clearance with the shaft  10  corresponding to the first seal  240 . However, in other configurations of adjacent shafts  10 , the multi-shaft seal assembly  202  may not require a cutaway  251 . Accordingly, the multi-shaft seal assembly  202  is in no way limited the presence, absence, and/or configuration of a cutaway  251 . Generally, a cutaway  251  may reduce the radial dimension of the fixed stator  210  and/or face plate  212 , as shown in  FIG. 21 . However, in other configurations the cutaway  251  may alternatively or additional reduce the radial dimension of the floating stator  220  and/or rotor  230 . 
     Although the illustrative embodiment of a multi-shaft seal assembly  202  is configured to accommodate two shafts  10 , other embodiments not pictured herein are configured to accommodate more than two shafts  10 . Accordingly, the multi-shaft seal assembly  202  is not limited by the number of shafts  10  and/or seals  240 ,  250  associated therewith. 
     Additional Embodiments of a Shaft Seal Assembly 
     Another embodiment of a shaft seal assembly  200  is shown in perspective view in  FIG. 22A . The illustrative embodiment shown in  FIG. 22A  includes both a stator  310  and a rotor  320 , which may rotate with respect to one another. The stator  310  may engage a housing  19  and surround a shaft  10  that is rotatable with respect to and extends from the housing  19 . In the illustrative embodiment, an o-ring  303  positioned in an o-ring channel  302  formed in the stator  310  may be used to properly engage the stator  310  with the housing  19 . However, any other suitable method and/or structure for adequately engaging the stator  310  with the housing  19  may be used with the shaft seal assembly  300  without departing from the spirit and scope as disclosed herein. 
     The rotor  320  may also surround the shaft  10 , and it may also be engaged with the shaft  10  so as to rotate therewith. In the illustrative embodiment, an o-ring  303  positioned in an o-ring channel  302  formed in the rotor  320  may be used to properly engage the rotor  320  with the shaft  10 . However, any other suitable method and/or structure for adequately engaging the rotor  320  with the shaft  10  may be used with the shaft seal assembly  300  without departing from the spirit and scope as disclosed herein. It is contemplated that this embodiment may be especially suited for applications in which the shaft  10  and/or housing  19  is oriented in a generally vertical arrangement and extends upward with respect to the housing  19 , but the application of the shaft seal assembly  300  in no way limits the scope thereof. Furthermore, any embodiments of a shaft seal assembly  25 ,  200 ,  202  may be configured with advantageous features disclosed herein related to the embodiment of a shaft seal assembly  300  shown in  FIGS. 22A-22D  without limitation alone or in combination. 
     The stator  310  may be formed with a stator body  311  having one or more axial projections  314  and/or radial projections  315  extending therefrom. Additionally, an axial projection  314  may extend from a radial projection  315  or vice versa. The embodiment of a shaft seal assembly  300  from  FIG. 22A  is shown in  FIG. 22C  with the stator  310  and rotor  320  separated from one another. As shown, a shoulder  312  may be formed in the stator body  311  to provide an interface with a housing  19 . An o-ring channel  302  may be formed in the shoulder  312  to accommodate an o-ring  303  to facilitate proper engagement of the stator  310  and housing  19 , as previously described above. Another o-ring channel  302  may be formed on the interior surface of the stator body  311  adjacent the shaft  10 . A slip ring  305  may be positioned in this o-ring channel  302  to mitigate egress of lubricant from the housing  19  and ingress of contaminants to the housing  19  via the space between the shaft  10  and stator  310 . The stator body  311  may also be formed with one or more radial bores  313  to facilitate an optional sealing fluid (e.g., air, water, etc.) to further mitigate the egress and/or ingress described above. 
     The rotor  320  may be formed with a rotor body  321  having one or more rotor axial projections  324  and/or rotor radial projections  325  extending therefrom. Additionally, a rotor axial projection  324  may extend from a rotor radial projection  325  or vice versa. A unitizing ring  304  may reside partially within a unitizing ring channel  318  formed in the stator  310  and partially within a rotor unitizing ring channel  328  and function to allow only a predetermined amount of relative axial motion between the stator  310  and rotor  320 . From a comparison of  FIGS. 22B and 22C , it will be apparent to those of ordinary skill in the art that the various axial projections  314 , radial projections  315 , axial channels  316 , and/or radial channels  317  formed in the stator  310  may cooperate with various rotor axial projections  324 , rotor radial projections  325 , rotor axial channels  326 , and/or rotor radial channels  327  to create a labyrinth seal having a laborious and/or circuitous path of one or more axial channels  316  and/or one or more radial channels  317  for egress of lubricants from the housing  19  and/or ingress of contaminants to the housing  19 . An infinite number of configurations for the various axial projections  314 , radial projections  315 , axial channels  316 , and/or radial channels  317  formed in the stator  310  may cooperate with various rotor axial projections  324 , rotor radial projections  325 , rotor axial channels  326 , and/or rotor radial channels  327  exist, and accordingly, the specific number, existence, and/or configuration thereof in no way limits the scope of the shaft seal assembly  300  as disclosed and claimed herein. 
     In the illustrative embodiment of a shaft seal assembly  300  shown herein, the axial projections  314 , radial projections  315 , axial channels  316 , and/or radial channels  317  formed in the stator  310  may cooperate with various rotor axial projections  324 , rotor radial projections  325 , rotor axial channels  326 , and/or rotor radial channels  327  may be configured to form a first cooperating cavity  306   a , a second cooperating cavity  306   b , and an axial passage  307  for the first potential ingress point for contaminants. Referring to  FIG. 22D , which shows the illustrative embodiment of the shaft seal assembly  300  engaged with a generally vertically oriented shaft  10  protruding upward from a housing  19 , the path contaminants must traverse to pass through the illustrative embodiment of the shaft seal assembly  300  is exceedingly tortuous. The only ingress point is a downwardly oriented terminus of an axial passage  307 , entry to which requires overcoming gravity. After a radial passage  308 , contaminants are faced with another axial passage  307  requiring overcoming gravity once again. This axial passage  307  leads to a first cooperating cavity  306   a . Contaminants retained in the first cooperating cavity  306   a  may simply drain downward therefrom via gravity. An axial passage  307  at the top of the first cooperating cavity  306   a  requires contaminants to completely fill the first cooperating cavity  306   a  and then overcome gravity to exit the first cooperating cavity  306   a  via the top axial passage  307 . 
     A radial passage  308  may fluidly connect the axial passage  307  at the top of the first cooperating cavity  306   a  to a second cooperating cavity  306   b . In the illustrative embodiment, three sides of the second cooperating cavity  306   b  may be formed via the rotor  320 , which generally rotates with the shaft  10  during use. Accordingly, contaminants reaching the second cooperating chamber  306   b  may be flung radially outward due to centrifugal force imparted to the contaminants via rotation of the rotor  320 . If contaminants within the second cooperating chamber  306   b  drain via gravity through an axial passage  307  at the bottom of the second cooperating chamber  306   b , those contaminants must traverse a radial passage  308  prior to encountering a comparatively long radial passage  308  that leads to another axial passage  307  adjacent the distal end of an axial projection  314  formed in the stator  310 . Another comparatively long radial passage  308  may be in fluid communication with the axial passage  307  adjacent the distal end of an axial projection  314  formed in the stator  310 , the path through which radial passage  308  may be interrupted by a unitizing ring  304  occupying a portion of a unitizing ring channel  318  formed in the stator  310  and a portion of a rotor unitizing ring channel  328 . Should contaminants traverse this radial passage  308 , those contaminants must also traverse an axial passage  307  in fluid communication with that radial passage  308  before contacting the shaft  10 . To enter the housing  19 , contaminants positioned on the shaft  19  between the stator  310  and rotor  320  must traverse a slip ring  305  that, in the illustrative embodiment of a shaft seal assembly  300 , may be positioned in an o-ring channel  302  in the stator  310  adjacent the shaft  10 . 
     In the illustrative embodiment of the shaft seal assembly  300  pictured herein, the various transitions between axial passages  307  and radial passages  308  may be configured as right angles. Additionally, all axial passages  307  may be parallel with one another and perpendicular to all radial passages  308 . However, in other embodiments the axial passages  307  and/or radial passages  308  may have different orientations without limitation. For example, in an embodiment not pictured herein, an axial passage  307  may be angled at 45 degrees with respect to the rotational axis of the shaft  10 . 
     Porous Media Shaft Seal Assembly 
     Element Listing (FIGS.  23 - 27 ) 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Description 
                 Element No. 
               
               
                   
                   
               
             
            
               
                   
                 Shaft 
                 10 
               
               
                   
                 Housing 
                 12 
               
               
                   
                 Housing contents 
                 13 
               
               
                   
                 Porous media 
                 14 
               
               
                   
                 Sealed surface 
                  14a 
               
               
                   
                 Open surface 
                  14b 
               
               
                   
                 O-ring 
                 16 
               
               
                   
                 Stator 
                 20 
               
               
                   
                 Stator groove 
                  20a 
               
               
                   
                 Pin cavity 
                  20b 
               
               
                   
                 Stator main body 
                 21 
               
               
                   
                 Port 
                  21a 
               
               
                   
                 Passage 
                  21b 
               
               
                   
                 Floating stator first portion 
                  22a 
               
               
                   
                 Floating stator second portion 
                  22b 
               
               
                   
                 Stator cap 
                 23 
               
               
                   
                 Cap groove 
                  23a 
               
               
                   
                 Connector 
                 24 
               
               
                   
                 Pin 
                 26 
               
               
                   
                 Seal 
                 30 
               
               
                   
                 Seal convex surface 
                 32 
               
               
                   
                 Seal passage 
                 34 
               
               
                   
                 Rotor 
                 40 
               
               
                   
                 Rotor collar 
                 42 
               
               
                   
                 Interface member 
                 44 
               
               
                   
                 Rotor connector 
                 46 
               
               
                   
                 Biasing member 
                 50 
               
               
                   
                 Cone sealing structure 
                 60 
               
               
                   
                 First end 
                 62 
               
               
                   
                 Second end 
                 64 
               
               
                   
                 Fastener 
                 66 
               
               
                   
                 Porous media shaft seal assembly 
                 100  
               
               
                   
                   
               
            
           
         
       
     
     A perspective view of a first illustrative embodiment of a porous media shaft seal assembly  100  is shown in  FIG. 23 . Unless otherwise indicated, the orientation of all  FIGS. 23 and 25-27  places the fluid side of the porous media shaft seal assembly  100  toward the left of the drawing and the outboard side toward the right of the drawing. Generally, the embodiment of a porous media shaft seal assembly  100  shown in  FIG. 23  functions in a manner analogous to that of the shaft seal assembly  25  shown in  FIG. 1-7 or 9-12 . 
     Generally, the porous media shaft seal assembly  100  may accommodate angular misalignment of the shaft  10 , as well as axial and radial movement thereof using generally the same principles as those previously explained for the shaft seal assembly  25  shown in  FIG. 1-7 or 9-12 . Accordingly, the stator  20  may include a stator main body  21  and a floating stator first and second portion  22   a ,  22   b  positioned within a cavity formed by the stator main body  21  and a stator cap  23 . The seal  30  may be engaged with the floating stator first and/or second portion  22   a ,  22   b  about a spherical or semi-spherical interface as previously described above for the shaft seal assembly  25 . 
     As with the embodiment of a shaft seal assembly  25  shown in  FIG. 1-7 or 9-12 , a seal fluid (which oftentimes may be pressurized, and which may be a gas, liquid, vapor, and/or combination thereof) may be introduced into the porous media shaft seal assembly  100  via a port  21   a , which may be formed in the stator  20 . The seal fluid may be communicated to the seal  30  through the stator  20  (e.g., via passages  21   b  formed in the floating stator first and/or second portions  22   a ,  22   b ). It is contemplated that in one embodiment, a plurality of radially oriented passages  21   b  may be formed in the floating stator second portion  22   b  and may serve to communicate seal fluid from an area between the stator main body  21  to the seal  30 . These same passages  21   b  may correspond to one or more seal passages  34  formed in the seal  30 , which seal passages  34  also may be radially oriented. In the porous media shaft seal assembly  100 , a layer of porous media  14  may be engaged with the surface of the seal  30  that faces the shaft  10 , as shown in  FIG. 23 . The porous media  14  may comprise one or more sealed surfaces  14   a  and one or more open surfaces  14   b.    
     The sealed surfaces  14   a  may be configured to be impermeable to a desired fluid and/or group of fluids (which may comprise the seal fluid). Accordingly, the open surface(s)  14   b  may be configured to be permeable to a desired fluid and/or group of fluids (which may comprise the seal fluid). In this manner, seal fluid may be introduced to the porous media  14  and exit the porous media  14  only at the open surface(s)  14   b , which may constitute the active surface of the porous media shaft seal assembly  100 . Special compounds are used in the porous air bearing industry to provide this sealing capability. For the embodiment shown in  FIG. 23 , it is contemplated that the axial faces of the porous media  14  may comprise sealed surfaces  14   a , as well as the surface of the porous media  14  positioned adjacent the seal  30 . This configuration may serve to retain internal seal fluid pressure, but other configurations of sealed surfaces  14   a  and open surfaces  14   b  may be used with the porous media shaft seal assembly  100  without limitation. It is further contemplated that the interior periphery (or a portion thereof) of the porous media  14  may be configured as an open surface  14   b  such that seal fluid may exit the porous media shaft seal assembly  100  along the shaft  10 . 
     A perspective view of a second illustrative embodiment of a porous media shaft seal assembly  100  is shown in  FIG. 24 . Generally, this embodiment of a porous media shaft seal assembly  100  functions in a manner analogous to that of the bearing isolator  18  and/or shaft seal assembly  200 , various embodiments of which are shown in  FIGS. 13-18A  and described in detail above. However, in the porous media shaft seal assembly  100 , a layer of porous media  14  may be engaged with the surface of the rotor  40  adjacent the interface between a floating stator first portion  22   a  and the rotor  40  (which may be configured as a semi-spherical interface). Alternatively, a layer of porous media  14  may be engaged with the surface of the floating stator first portion  22   a  adjacent the interface between the floating stator first portion  22   a  and the rotor  40 . As with the embodiment shown in  FIG. 23 , the porous media  14  in this embodiment may comprise one or more sealed surfaces  14   a  and one or more open surfaces  14   b.    
     As with the embodiment of a porous media shaft seal assembly  100  shown in  FIG. 23 , a seal fluid may be introduced into the porous media shaft seal assembly  100  via a port  21   a , which may be formed in the stator  20 . The seal fluid may be communicated to the interface between the floating stator first portion  22   a  and the rotor  40  (e.g., via passages  21   b  formed in the floating stator first portion  22   a ). For the embodiment shown in  FIG. 24 , it is contemplated that for most applications it will be advantageous to configure the porous media  14  on an interior portion of the floating stator first portion  22   a , such that the porous media  14  does not rotate and is secured with the stator  20 . In one embodiment, a plurality of radially oriented passages  21   b  may be formed in the floating stator first portion  22   a  and may serve to communicate seal fluid from a stator groove  20   a  to the interface between the floating stator first portion  22   a  and the rotor  40 . These same passages  21   b  may correspond to one or more open surfaces  14   b  in the porous media on a surface of the porous media  14  adjacent the floating stator first portion  22   a . It is further contemplated that the axial faces of the porous media  14  may comprise sealed surfaces  14   a , as well as at least a portion of the surface of the porous media  14  positioned adjacent the floating stator first portion  22   a  (e.g., any portion of that surface that does not align with a passage  21   b ). This configuration may serve to retain internal seal fluid pressure. 
     It is further contemplated that the interior periphery (or a portion thereof) of the porous media  14  may be configured as an open surface  14   b  such that seal fluid may exit the porous media shaft seal assembly  100  along the interface between the floating stator first portion  22   a  and the rotor  40 . However, other configurations of sealed surfaces  14   a  and open surfaces  14   b  may be used with the porous media shaft seal assembly  100  without limitation. Furthermore, in any embodiments of the porous media shaft seal assembly  100 , one or more O-rings (with or without a corresponding groove) may be used to provide a seal between various surfaces. 
     In another embodiment of a porous media shaft seal assembly  100  not pictured herein but similar to that shown in  FIG. 24 , the rotor  40  may be comprised to two separate portions biased away from one another (and consequently, toward the stator  20 ). The biasing member may be a magnetic field, a spring, or any other suitable method and/or apparatus for biasing the relevant portions away from one another. The seal fluid may serve to urge the two portions toward one another. Accordingly, the biasing member may cooperate with the rotor  40  and stator  20  (and/or floating stator first and/or second portions  22   a ,  22   b ) to physically seal the housing  12  from the external environment in the instance of loss of pressurized fluid to the porous media shaft seal assembly  100 . 
     The top portion of another embodiment of a porous media shaft seal assembly  100  is shown in cross-section in  FIG. 25 . In this embodiment, the rotor  40  may include a rotor collar  42  and an interface member  44 . The rotor collar  42  may be engaged with the shaft  10  such that the axial position of the rotor collar  42  on the shaft  10  may be fixed. This engagement may be accomplished via a rotor connector  46 , which may be a set screw as shown in the illustrative embodiment. However, any suitable structure and/or method may be used to adequately engage the rotor collar  42  with the shaft  10 , and the scope of the porous media shaft seal assembly  100  is in no way limited by the structure and/or method used therefor. The interface member  44  may be configured to be moveable along a portion of the shaft  10  in the axial dimension. An O-ring  16  may be positioned in a groove in the interface member  44  adjacent the shaft  10  and configured to allow movement of the interface member  44  with respect to the shaft  10  in the axial dimension with a predetermined amount of force applied to the interface member  44  in an axial dimension with respect to the shaft  10 . 
     A stator  20  may be engaged with a housing  12 . This engagement may be accomplished via any suitable structure and/or method for the specific application of the porous media shaft seal assembly  100 , including but not limited to mechanical fasteners, press-fit engagement, chemical adhesives, and/or combinations thereof. A biasing member  50  may be employed to urge the interface member  44  of the rotor  40  toward a portion of the stator  20 . Accordingly, the axial position of the interface member  44  on the shaft  10  may be variable in a manner as previously described. As with the previously described embodiments, a layer of porous media  14  may be positioned between the stationary and rotating portions of the porous media shaft seal assembly  100 . The porous media  14  may comprise one or more sealed surfaces  14   a  and one or more open surfaces  14   b.    
     A seal fluid may be introduced into the porous media shaft seal assembly  100  via a port  21   a , which may be formed in the stator  20 . The seal fluid may be communicated to the porous media  14  via one or more passages  21   b  formed in the stator  20 . In the embodiment pictured in  FIG. 25 , it is contemplated that the interface member  44  may rotate with respect to the stator  20 , such that a layer of porous media  14  may be positioned on the stator  20 . In the embodiment shown in  FIG. 25 , the biasing member  50  may comprise a single spring that fits over the outside diameter of the shaft  10 . However, other types of biasing members  50  may be used without limitation. Shoulders and/or corresponding recesses formed in the rotor collar  42  and/or interface member  44  may be used to adequately retain the biasing member  50  within the porous media shaft seal  100 . 
     The seal fluid may be communicated to the porous media  14  in an array around the stator  20 . The porous media  14  may be configured such that only the surface(s) adjacent a passage  21   b  in the stator  20  and the surface of the porous media  14  adjacent the interface member  44  of the rotor  40  are open surfaces  14   b  and the remaining surfaces of the porous media may be configured as sealed surfaces  14   a . In this configuration, seal fluid may exit the stator  20  adjacent the interface member  44  of the rotor  40  (in the direction shown by the arrows in  FIG. 25 ) to form an air barrier therebetween (which may be configured as any air bearing). Accordingly, the flow characteristics of the seal fluid may be manipulated such that under normal operating conditions, the seal fluid acts against the biasing member  50  and urges the interface member  44  away from the porous media  14 . If the flow characteristics of the seal fluid deviate in a predetermined manner (e.g., pressure drop), the force of the biasing member  50  may overcome the force of the seal fluid and cause the interface member  44  to contact the porous media  14 , thereby closing the porous media shaft seal assembly  100  and isolating the interior thereof from the exterior thereof. However, other configurations of sealed and open surfaces  14   a ,  14   b  may be used without limitation. 
     An axial, cross-sectional view of another embodiment of a porous media shaft seal assembly  100  is shown in  FIG. 26 . This embodiment is similar to that shown in  FIG. 25  and may be configured to function in a similar manner to that shown in  FIG. 25 . The rotor collar  42  and interface member  44  may engage the shaft  10 , and the stator  20  may engage a housing  12  in any of the manners previously described for the embodiment shown in  FIG. 25 , and the structure and/or method used therefor in no way limits the scope of the porous media shaft seal assembly  100 . 
     The embodiment shown in  FIG. 26  may employ multiple biasing members  50  between the rotor collar  42  and interface member  44 . Accordingly, in the embodiment shown in  FIG. 25 , one or more biasing members may be positioned around the periphery of the shaft  10  in an array or other arrangement. It is contemplated that both the embodiment shown in  FIG. 25  and that shown in  FIG. 26  may be configured to mount directly to a housing  12  having a rotating shaft  10  protruding from the housing  12 , or either embodiment may be configured to be used in conjunction with a stuffing box, wherein the porous media shaft seal assembly  100  may be used in addition to or in lieu of packing material. 
     A cone sealing structure  60  is shown in the embodiment of a porous media shaft seal assembly  100  shown in  FIG. 27A . In this embodiment, the cone sealing structure  60  may be mounted internally or externally to a housing  12  depending on the specific application, as described in further detail below. The cone sealing structure  60  may include a first end  62  and a second end  64 . In the illustrative embodiment shown in detail in  FIG. 27B , the first end  62  may provide an engagement area for the shaft  10  and the second end  64  may provide an engagement area with the rotor  40 . The first end  62  may be engaged with a shaft  10  via a fastener  66  engaging a portion of the first end  62 . The second end  64  may be engaged with a rotor  40  via a fastener  66  engaging a portion of the second end  64 . Both fasteners may be configured as elastomeric members, wherein the fastener for the first end  62  comprises an elastomeric band and the fastener for the second end  64  comprises an elastomeric ring. Each fastener  66  may be configured to allow a certain amount of movement of the first end  62  with respect to the second end  64 . However, any suitable fastener  66  may be used without limitation, including but not limited to chemical adhesives, other mechanical fasteners, and/or combinations thereof. An O-ring  16  may be positioned between a bottom surface of the rotor  40  and the shaft  10  and configured to allow movement of the rotor  40  with respect to the shaft  10  in the axial dimension with a predetermined amount of force applied to the interface member  44  in an axial dimension with respect to the shaft  10 . 
     As in previous embodiments described herein, a biasing member  50  may be used to bias a portion of the cone sealing structure  60  toward or away from a second surface, which may be a portion of a housing  12  or a stator  20  mounted thereto. In the illustrative embodiment shown in  FIG. 27A , a stator  20  may be engaged with a housing  12 , which engagement may be accomplished via any suitable structure and/or method as previously disclosed herein for other embodiments of the porous media shaft seal assembly  100  without limitation. The force of the biasing member  50  may be opposed by pressurized fluid flowing through a portion of the porous media shaft seal assembly  100 . The force of the biasing member  50  may be supplemented by a fluid within a vessel acting on the cone sealing structure  60  in a substantially parallel direction to that at which the biasing member  50  acts on the cone sealing structure  60 . Additionally or alternatively, the cone sealing structure  60  may have an integrated biasing member between the first and second ends  62 ,  64 . 
     Generally, it is contemplated that porous media  14  may be most advantageously applied to and/or engaged with a nonrotating portion of the porous media shaft seal assembly  100  to limit complexity for providing seal fluid to the porous media. For the embodiments shown in  FIGS. 27A-27C , the cone sealing structure  60  may rotate with the shaft  10  via the engagement between the first end  62  and the shaft  10 , which may consequently cause the second end  64  and rotor  40  to rotate. Accordingly, it is contemplated that porous media  14  may most advantageously be applied to and/or engaged with a surface of the stator  20  facing the rotor  40  for those embodiments. However, in other embodiments, it may be advantageous to apply porous media  14  to different elements and/or surfaces thereof. For example, in an embodiment not pictured herein, the cone sealing structure  60  may be engaged with a housing  12  adjacent the second end  64 , such that the cone sealing structure  60  does not rotate with the shaft  10 . A rotor  40  may be engaged with the shaft  10  such that it rotates therewith, and such that a portion of the rotor  40  is positioned adjacent the first end of the cone sealing structure  60 . Porous media  14  may be engaged with the first end  62  either directly via the first end  62  of the cone sealing structure or via a stator  20  engaged with the cone sealing structure  60 . 
     In either configuration (stationary or rotating cone sealing structure  60 ), seal fluid may be communicated to the porous media  14  of the porous media shaft seal assembly  100  via one or more ports  21   a  and/or passages  21   b  as previously described for other embodiments of the porous media shaft seal assembly  100 . The porous media  14  may be configured with sealed surfaces  14   a  and open surfaces  14   b  to retain internal seal fluid pressure, as previously described for other embodiments of the porous media shaft seal assembly  100 . Also as previously described for other embodiments, the flow characteristics of the seal fluid may be controlled such that under normal operating conditions, the seal fluid acts against the biasing member  50  and urges the rotor  40  away from the porous media  14 . If the flow characteristics of the seal fluid deviate in a predetermined manner (e.g., pressure drop), the force of the biasing member  50  may overcome the force of the seal fluid and cause the rotor  40  to contact the porous media  14 , thereby closing the porous media shaft seal assembly  100  and isolating the interior thereof from the exterior thereof. However, other configurations of sealed and open surfaces  14   a ,  14   b  may be used without limitation. 
     Another embodiment of a porous media shaft seal assembly  100  using a cone sealing structure  60  is shown in detail in  FIG. 27C . This embodiment may function in a manner substantially the same as the embodiment shown in  FIG. 27B . However, the porous media  14  may be configured as a ring embedded in the stator  20 . The porous media  14  may comprise sealed surfaces  14   a  and open surfaces  14   b , as previously described for other embodiments of the porous media shaft seal assembly  100 . The porous media  14  may be secured to the stator  20  via any suitable method and/or structure, including but not limited to mechanical interference, mechanical fasteners, chemical adhesives, and/or combinations thereof. 
     It is contemplated that the embodiments shown in  FIGS. 27A-27C  may be positioned in a stuffing box of a pump or other housing. The cone sealing structure  60  may be used in place of packing, which is typically employed in a stuffing box. Alternatively, the embodiments shown in  FIGS. 27A-27C  may be mounted outside of a housing  12  rather than within a stuffing box. 
     In the various embodiments pictured in  FIGS. 25-27 , the seal fluid flow characteristics (pressure, flow rate, configuration of surface on which seal fluid flow acts) required to overcome the force of the biasing member  50  and separate the porous media  14  from the opposing face produces a pressurized fluid barrier between the porous media  14  and the opposing face. However, unlike mechanical seals found in the prior art, the porous media shaft seal  100  is not sensitive to the clearance between the porous media  14  and the opposing face—as long as there is a clearance, the seal fluid pressure may act to prevent product egress from the porous media shaft seal assembly  100  and contaminant ingress to the porous media shaft seal assembly  100 . Furthermore, in the embodiments shown in  FIGS. 25-27 , the fluid pressure of the product within the vessel (or housing  12 ) may urge the porous media  14  and opposing face together to close any gap therebetween. 
     The porous media  14  may be comprised of carbon graphite, or any other suitable natural or synthetic material. It is contemplated that the porous media  14  may have characteristics that allow fluid pressure to be evenly distributed throughout the porous media  14 . Additionally, it is contemplated that certain surfaces of the porous media  14  may be configured as sealed surfaces  14   a  such that fluid within the porous media  14  may not exit the porous media  14  via those sealed surfaces  14   a . The sealant used to prevent seal fluid exiting the porous media  14  may be any suitable sealant for the particular application of the porous media shaft seal assembly  100 , and in some applications may be comprised of an epoxy material. The porous media  14  may be engaged with and/or secured to the desired element using any suitable method and/or structure including but not limited to mechanical fasteners, press-fit securement, O-rings  16 , chemical adhesives, and/or combinations thereof without limitation. 
     Typically during operation, the porous media  14  may become saturated with the seal fluid introduced through port  21   a  (which seal fluid may be communicated to the porous media  14  via one or more passages  21   b  in the stator  20  and/or seal passages  34  in the seal  30 ), and consequently flow out of the porous media  14  through any open surface  14   a  at a generally predictable and predetermined rate. Accordingly, the porous media  14  may provide a throttle to the seal fluid flow regardless of the clearance between the open surfaces  14   a  of the porous media  14  and adjacent components (e.g., the shaft  10  in  FIG. 23 ). This results in the consumption of seal fluid to be dictated by the characteristics of the porous media  14  rather than the clearance between the porous media  14  and the other relevant structure. Accordingly, in such a configuration this clearance may dictate the pressure of the product within the housing  12  and/or other structure that the porous media shaft seal assembly  100  can effectively seal. If air is used as the seal fluid, then the air may act as a lubricant between the porous media  14  and adjacent component. This configuration may allow for lower air consumption and a more predictable rate thereof than that compared with product seals found in the prior art. 
     Additional Aspects of a Shaft Seal Assembly 
     Element Listing (FIGS.  28 - 30 ) 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Description 
                 Element No. 
               
               
                   
                   
               
             
            
               
                   
                 Shaft seal assembly 
                 10 
               
               
                   
                 Housing 
                 12 
               
               
                   
                 Shaft 
                 14 
               
               
                   
                 Shaft radial gap 
                 15 
               
               
                   
                 Drive ring 
                 16 
               
               
                   
                 Housing radial gap 
                 17 
               
               
                   
                 O-ring 
                 18 
               
               
                   
                 Sealing ring 
                 19 
               
               
                   
                 Stator 
                 20 
               
               
                   
                 Stator main body 
                  20a 
               
               
                   
                 Stator/shaft clearance 
                 21 
               
               
                   
                 Stator inward radial projection 
                 22 
               
               
                   
                 Annular recess 
                  22a 
               
               
                   
                 Radial stator/rotor clearance 
                 23 
               
               
                   
                 Barrier 
                 24 
               
               
                   
                 Exterior groove 
                  24a 
               
               
                   
                 Shoulder 
                  24b 
               
               
                   
                 Axial stator/rotor clearance 
                 25 
               
               
                   
                 Atypical stator/rotor clearance 
                  25a 
               
               
                   
                 Collection groove 
                 26 
               
               
                   
                 Drain 
                  26a 
               
               
                   
                 Ramped projection 
                 27 
               
               
                   
                 Ramp surface 
                  27a 
               
               
                   
                 Inboard wall 
                  28a 
               
               
                   
                 Outboard wall 
                  28b 
               
               
                   
                 Floor 
                  28c 
               
               
                   
                 Stator sealing ring groove 
                 29 
               
               
                   
                 Rotor 
                 30 
               
               
                   
                 Rotor main body 
                  30a 
               
               
                   
                 Rotor axial projection 
                 32 
               
               
                   
                 Rotor ramped projection 
                 37 
               
               
                   
                 Rotor ramp surface 
                  37a 
               
               
                   
                 Rotor sealing ring groove 
                 39 
               
               
                   
                   
               
            
           
         
       
     
     In an aspect, a shaft seal assembly  10  such as that shown in  FIGS. 28-30  herein may be designed specifically to provide a level of protection to the industry standard IP-66 level, as defined by the International Electrotechnical Commission (IEC) IP level of protection codes (IEC standard 60529). In an aspect of a shaft seal assembly  10  shown in  FIGS. 28A-30 , the shaft seal assembly  10  may achieve this level of performance in a much shorter axial length (in an aspect, 0.375 inches; 9.5 mm, but not limited thereto unless so indicated in the following claims) than has been previously possible. Previously, such a level of protection required an axial length of at least 0.700 inches; 1.778 cm; which is nearly twice as much axial length than what is possible with the shaft seal assembly  10  according to the present disclosure. Providing this level of protection in a smaller shaft seal assembly  10  allows the IP-66 level of protection to be applied to smaller size rotating equipment than was possible in the prior art. 
     In an aspect, the shaft seal assembly  10  shown in  FIGS. 28-30  may comprise a stator  20  and a rotor  30 . Generally, the stator  20  and rotor  30  may cooperate so as to prevent ingress of contaminants to a housing  12  having a shaft  14  protruding therefrom, while simultaneously prevent egress of lubricant from the housing  12 . The stator  20  of the shaft seal assembly  10  may include a stator main body  20   a  and may be mounted to a relatively stationary housing  14  (which may be a housing  14  having an electrical motor therein, but which housing  14  is not so limited unless so indicated in the following claims). 
     The rotor  30  may include a rotor main body  30   a  and may be engaged with a rotatable shaft  14  protruding from the housing  12  such that the rotor  30  rotates with a shaft  14 . In an aspect, the rotor  30  may be engaged with the shaft  14  via a drive ring  16 . The drive ring  16  may be constructed of an elastomeric material and may be configured to seal a shaft radial gap  15  between the shaft  16  and the rotor  30 . The drive ring  16  may also be configured to cause the rotor  20  to rotate with the shaft  16 . 
     The stator  20  may be engaged with the housing  12  via an O-ring  18 , which O-ring  18  may be employed in conjunction with an interference fit between an external surface of the stator  20  and an interior surface of the housing  12 . In an aspect, an exterior portion of the stator  20  may be configured with a stair-step annular channel into which the O-ring  18  may be positioned. The stair-step feature of the annular channel may be positioned on the inboard side of the annular channel such that the outboard side of the annular channel is deeper (i.e., greater in the radial dimension) than the inboard side of the annular channel. It is contemplated that such a configuration of an annular channel may ease installation of the shaft seal assembly  10  into a housing  12 , while simultaneously providing adequate sealing between the stator  20  and the housing  12  at least in part via the O-ring  18 . The O-ring  18  may be constructed of an elastomeric material and may be configured to seal a housing radial gap  17  between the housing  12  and the stator  20 . However, the stator  20  may be engaged with and/or secured to a housing  12  and the rotor  30  may be engaged with and/or secured to a shaft  14  using any suitable structures and/or methods (several of which are described above for other embodiments of a bearing isolator  18  and/or shaft seal assemblies  10 ,  25 ,  200  and which include but are not limited to mechanical fasteners, chemical adhesives, welding, interference fit, and/or combinations thereof) without limitation unless so indicated in the following claims. 
     In an aspect of a shaft seal assembly  10  as shown in  FIGS. 28-30 , the entire rotor  30  may be positioned within a portion of the stator  20 , such that the rotor  30  may be effectively encapsulated by the stator  20 . That is, the shaft seal assembly  10  may be configured such that the surfaces thereof that are directly exposed to the exterior environment may be surfaces of the stator  20  rather than one or more surfaces of the rotor  30 , such that the entire rotor  30  is positioned inboard with respect to at least one surface of the stator  20 . It is contemplated that such a configuration may provide for superior sealing attributes in a smaller axial dimension when compared to the prior art. 
     The shaft seal assembly  10  may be configured to effectively seal (and/or mitigate) contamination from entering the housing  12 . In an aspect, an exterior stator inward radial projection  22  may form a stator/shaft clearance  21  between the distal end of the exterior stator inward radial projection  22  and the shaft  14 . The resulting stator/shaft clearance  21  may be configured as a close gap seal clearance between the exterior stator inward radial projection  22  and the shaft  14 , which close gap seal clearance may be between 0.018 inches (0.457 mm) and 0.007 inches (0.178 MM). This close gap seal clearance may serve to prevent and/or mitigate ingress of contaminants due to the small space available to such contaminants. Any contaminants that do enter the shaft seal assembly  10  through the stator/shaft clearance  21  may subsequently encounter a first radial stator/rotor clearance  22 . In an aspect, a first radial stator/rotor clearance  22  may be formed between generally radially oriented corresponding surfaces of the stator  20  and rotor  30 . 
     The first radial stator/rotor clearance  23  may be in communication with and/or lead to an axial stator/rotor clearance  25 . As shown, the first radial stator/rotor clearance  23  may be perpendicular to the axial stator/rotor clearance  25 , but other orientations between them may be used (e.g., less than ninety degrees, greater than ninety degrees) without limiting the scope of the shaft seal assembly  10  unless so indicated in the following claims. 
     The axial stator/rotor clearance  23  may be in communication with and/or lead to a second radial stator/rotor clearance  25 . As shown, the second radial stator/rotor clearance  23  may be perpendicular to the axial stator/rotor clearance  25 , but other orientations between them may be used (e.g., less than ninety degrees, greater than ninety degrees) without limiting the scope of the shaft seal assembly  10  unless so indicated in the following claims. Generally, it is contemplated that in an aspect of the shaft seal assembly  10  the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25  may be configured to impede ingress of contaminants into the shaft seal assembly  10 . 
     Contaminants passing through the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25  may encounter a collection groove  26 , which may be formed in the stator  20  and which may be relatively large in size compared to the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25 . For example, in an aspect the axial length of the collection groove  25  may be more than ten times greater than the axial stator/rotor clearance  25  and the radial depth of the collection groove  25  may be more than ten times greater than the radial depth of the radial stator/rotor clearance(s)  23 . 
     Referring now specifically to  FIG. 28C , the limit on the inboard radially oriented surface of the collection groove  26  (wherein “inboard” is generally in the direction toward the left side of  FIG. 28C  and “outboard” is generally in the direction toward the right side of  FIG. 28C ) may be formed as an inboard wall  28   a . The outboard radially oriented surface of the collection groove  26  may be formed as an outboard wall  28   b . Together, the inboard wall  28   a  and the outboard wall  28   b  may serve to define the width of the collection groove  26  (wherein “width” is used do denote the axial dimension of the collection groove  26 ). In an aspect of the shaft seal assembly  10 , the height of the inboard wall  28   a  (i.e., radial dimension) may great enough to accommodate a predetermined volume of contaminants within the collection groove  26  without rising to a level that would cause the contaminants to flow over the distal end of the inboard wall  28   a.    
     During operation, it is contemplated that the rotor  30  may impart centrifugal force to contaminants passing through the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25  and encountering the collection groove  26 . This centrifugal force may cause the contaminants to move radially outward to the axially oriented surface of the collection groove  26 , which surface is referred to herein as a floor  28   c . Referring again to  FIGS. 28B and 28C , contaminants in contact with the floor  28   c , inboard wall  28   a , and/or outboard wall  28   b  may drain via gravity toward the lower portion of the collection groove  26 , and exit the shaft seal assembly through a drain  26   a  in fluid communication with the collection groove  26 . Generally, a drain  26   a  may be formed in a portion of an exterior groove  24   a  (which exterior groove  24  is discussed in further detail below) to provide a fluid passageway from the collection groove  26  to an exterior groove  24   a.    
     In an aspect, it may be advantageous to have the drain  26   a  positioned at the lowest point of the collection groove  26  to aide expulsion of contaminants from the shaft seal assembly  10 . In an additional aspect, it may be advantageous to position a barrier  24  adjacent the drain  26   a  and on the outboard side thereof. Still referring to  FIG. 28C , a barrier  24  may be configured as an annular, radially extending wall. It is contemplated that such a barrier  24  may prevent direct ingress of contaminants into the shaft seal assembly  10  and/or collection groove  26 . In an aspect of the shaft seal assembly  10 , the distal edges of the barrier  24  may be radiused and/or smooth. As shown in  FIGS. 28B and 28C , the corners on the distal end of the barrier  24  may be curved or otherwise configured such that there is no right angle thereon. It is contemplated that such a configuration may at least prevent unintended catching and/or snagging of foreign objects on the stator  20 , which may increase safety of operators near the shaft seal assembly  10 . 
     Additionally, an annular barrier  24  like that shown in  FIGS. 28 and 29  may facilitate an exterior groove  24   a , which may be formed as an annular channel on an axially oriented exterior surface of the stator  20 . The annular barrier  24  may cooperate with an annular shoulder  24   b  to form two radially oriented walls of an exterior groove  24   a . It is contemplated that an exterior groove  24   a  may serve to guide contaminants on the outboard face of the housing  12  around the opening of the housing  12  (into which a portion of the shaft seal assembly  10  may be positioned), thereby reducing the likelihood of the contaminants entering the shaft seal assembly  10  via the stator/shaft clearance  21  and/or reducing the exposure of the stator/shaft clearance  21  to contaminants on the outboard face of the housing  12 . 
     The rotor  30  may be formed with a rotor axial projection  32 . In an aspect of the shaft seal assembly  10  it is contemplated that a rotor axial projection  32  may cooperate with an annular recess  22   a  formed in the stator inward radial projection  22  to form one or more radial stator/rotor clearances  23  and/or one or more axial stator/rotor clearances  25 . Although an aspect of the shaft seal assembly  10  shown in  FIGS. 28 and 29  depicts two radial stator/rotor clearances  23  with one axial stator/rotor clearance  25  positioned therebetween adjacent the rotor axial projection  32 , the scope of the present disclosure is not so limited unless indicated in the following claims. Accordingly, in other aspects of the shaft seal assembly  10  additional rotor axial projections  32  may be formed in the rotor  30  along with cooperating additional annular recesses  22   a  formed in the stator inward radial projection to facilitate additional radial stator/rotor clearances  23  and/or one or more axial stator/rotor clearances  25 . For example, and as described in further detail below, a sealing ring  19  between the stator  20  and the rotor  30  may be arranged such that an axial rotor/stator clearance  25  may be positioned on either side of the sealing ring  19 . 
     A phenomena observed in the study of the prior art is that air movement caused by the rotation of the rotor  30  inside a large annular channel (such as the collection groove  26 ) may cause the formation of a lubricant bubble. The lubricant bubble may form when air movement caused by the rotation the rotor  30  impedes contaminants within the collection groove  26  from exiting the shaft seal assembly  10  via the drain  26   a . If the lubricant bubble grows large enough such that it contacts the rotor  30 , a seal is likely to fail due to leakage of contaminants through the seal and into the housing  12 . Configuring the collection groove  26  such that the radial dimension (depth) thereof is sufficiently large in relation to the diameter of the shaft  14  to prevent and/or mitigate the likelihood of a lubricant bubble contacting the rotor  30  increases the performance capabilities of the shaft seal assembly  10 . 
     In an aspect of the shaft seal assembly  10  shown in  FIGS. 28 and 29 , the dimensions of the collection groove  26  may be correlated with the overall length (axial dimension) of the shaft seal assembly  10 . For example, if the overall length of the shaft seal assembly  10  is 0.375 inches, the collection groove  26  may be configured such that it is 0.150 inches deep and 0.175 inches wide. In such and aspect the width of the collection groove  26  may be approximately 46.7% of the overall length of the shaft seal assembly  10  and the depth of the collection groove  26  may be approximately 40.0% of the overall length of the shaft seal assembly  10 . However, the shaft seal assembly  10  may employ other relative dimensions of the overall length of the shaft seal assembly  10  with respect to the depth and/or width of the collection groove  26  without limitation unless so indicated in the following claims. 
     In an aspect, if the diameter of the shaft  14  is 2.0 inches, the depth of the collection groove  26  may be 0.375 inches. Accordingly, the depth of the collection groove  26  may be approximately 19% of the diameter of the shaft  14 . The radial dimension (width) of the collection groove  26  may be 0.375 inches, such that also may be approximately 19% of the diameter of the shaft  14 . However, in other aspects of the shaft seal assembly  10  the depth and/or width of the collection groove  26  may be greater than approximately 19% of the diameter of the shaft  14  without limitation unless so indicated in the following claims. And in still further aspects of the shaft seal assembly  10  the depth and/or width of the collection groove  26  may be less than approximately 19% of the diameter of the shaft  14  without limitation unless so indicated in the following claims. 
     A sealing ring  19  may be positioned between the stator  20  and rotor  30  in an inboard direction with respect to the collection groove  26 . The sealing ring  19  may serve as an additional barrier for ingress of contaminants into the housing  12  through the seal and/or from egress of lubricant from the housing  12 . A stator sealing ring groove  29  and a rotor sealing ring groove  39  may cooperate to properly position the sealing ring  19  between the stator  20  and rotor  30 . In an aspect of the shaft seal assembly  10  shown in  FIGS. 28 and 29 , the shaft seal assembly  10  may be configured such that an axial stator/rotor clearance  25  leads to the sealing ring  19  from the outboard side thereof, and such that another axial stator/rotor clearance  25  leads to the sealing ring from the inboard side thereof. 
     In an aspect of the shaft seal assembly  10  shown in  FIG. 28 , the width (axial dimension) of both the stator sealing ring groove  29  and the rotor sealing ring groove  39  may be approximately equal to one another and to the cross-sectional width of the sealing ring  19 . However, as described below other configurations exist, and the specific configuration of the stator sealing ring groove  29  and rotor sealing ring groove  39  in no way limit the scope of the shaft seal assembly  10  unless so indicated in the following claims. 
     In an aspect, the sealing ring  19  may be static with respect to the rotor  30 , and the sealing ring  19  may be configured such that it does not rotate with the shaft  14 . One benefit of a static sealing ring  19  that does not rotate with the rotor  30  and/or shaft  14  is that the sealing ring  19  may provide for and function as another close-clearance gap seal in a manner similar to that previously described for the stator/shaft clearance  21 . The sealing ring  19  simultaneously may be configured such that it is compliant in that it may allow for the rotor  20  to move both radially and axially with corresponding movements of the shaft  12  while preventing and/or mitigating metal-to-metal contact typically associated with those types of shaft  12  movements. In an aspect, preventing and/or mitigating metal-to-metal contact generally increases the longevity of the shaft seal assembly  10  and/or prevents and/or mitigates premature failure thereof. 
     In an aspect, the shaft seal assembly  10  shown in  FIGS. 28 and 29  may be disassembled, unlike many prior art seals and/or bearing isolators. Additionally, an aspect of this shaft seal assembly  10  having a portion of the stator  20  be the most outboard portion of the entire shaft seal assembly  10  (i.e.,  12 ) may reduce the likelihood of separation of the rotor  30  from the stator  20  during installation of the shaft seal assembly  10  with an equipment housing  12 . That is, a portion of the stator inward radial projection  22  immediately adjacent the rotor  30  (i.e., in an aspect, the distal portion of the stator inward radial projection  22 ) may prevent and/or mitigate unwanted movement of the rotor  30  in an axially outboard direction during installation of the shaft seal assembly  10  as the rotor  30  engages the shaft  14 . Because the rotor  30  may be secured to the shaft  14  via a drive ring  16  having elastomeric properties, it is contemplated that in such a configuration a predetermined amount of axially directed force will be required to push the rotor  30  onto the proper position of the shaft  14 . It is contemplated that to install the shaft seal assembly  10 , a user may apply axially directed force to the outboard surface of the stator inward radial projection  22  (which surface may be collinear with the outboard surface of the barrier  24 ), and temporary engagement between the inboard surface of the stator inward radial projection  22  and the rotor  30  during installation may communicate that force to the rotor  30  so as to move it axially in the same direction as the stator  20  until the shaft seal assembly  10  is properly located with respect to the housing  12  and the shaft  14 . The stator  20  may be formed with an annular shoulder  24   b  (as previously discussed in relation to an exterior groove  24   a  that may be formed in the stator  20 ), which may serve at least in part to properly locate the stator  20  and/or shaft seal assembly  10  with respect to the housing  12 . 
     In an aspect of the shaft seal assembly  10  shown in  FIG. 29 , the stator sealing ring groove  29  and/or rotor sealing ring groove  39  may be configured differently than those shown in the shaft seal assembly in  FIG. 28 . The cross-sectional area of the rotor sealing ring groove  39  may be less in an aspect of the shaft seal assembly  10  shown in  FIG. 29  than in that shown in  FIG. 28 . The smaller cross-sectional area may be a result of reduced width (in the axial dimension) and/or depth (in the radial dimension). In this aspect, a smaller volume of a sealing ring  19  is positioned within the rotor sealing ring groove  39  when compared to the volume of a sealing ring  19  positioned within the rotor sealing ring groove  39  shown in  FIG. 28 . It is contemplated that the rotor sealing ring groove  39  advantageously may be deep enough to prevent the sealing ring  19  from becoming axially misaligned with the rotor sealing ring groove  39  during installation. It is further contemplated that configuring the rotor sealing ring groove  39  with a width approximately equal to the cross-sectional width of the sealing ring  19  may serve to mitigate and/or prevent axially misalignment between the sealing ring  19  and the rotor sealing ring groove  39  during installation of the shaft seal assembly  10 . 
     Furthermore, the cross-sectional area of the stator sealing ring groove  29  may be less in an aspect of the shaft seal assembly  10  shown in  FIG. 29  than in that shown in  FIG. 28 . The smaller cross-sectional area may be a result of reduced width (in the axial dimension) and/or depth (in the radial dimension). In other aspects of a shaft seal assembly  10  the stator sealing ring groove  29  and/or rotor sealing ring groove  39  may be differently configured without limitation unless so indicated in the following claims. Accordingly, the specific amount of O-ring  17  that is positioned within the annular groove in the rotor and the specific amount of O-ring  17  that is positioned within the annular groove in the stator in no way limits the scope of the present disclosure unless so indicated in the following claims. It is contemplated that for some applications of the shaft seal assembly  10 , it may be advantageous to increase the depth of the stator sealing ring groove  29  to accommodate radial expansion of the sealing ring  19 . However, it may be desirable to ensure that the depth of the stator sealing ring groove  29  is selected such that it is not greater than the cross-sectional width of the sealing ring  19  such that when the sealing ring  19  is at the radial limit of the stator sealing ring groove  29  contaminants do not have a straight path between the sealing ring  19  and the rotor  30  to the inboard side of the shaft seal assembly  10 . 
     Further aspects of a shaft seal assembly  10  are shown in  FIGS. 30 &amp; 30A , which provides an axial, cross-sectional view of another shaft seal assembly  10 . Generally, this shaft seal assembly  10  shown in  FIG. 30  may provide some or all of the benefits and/or features previously described for the shaft seal assemblies  10  disclosed herein, and specifically those shown in  FIGS. 28 and 29 , without limitation unless so indicated in the following claims. 
     Accordingly, in an aspect, the shaft seal assembly  10  shown in  FIGS. 30 &amp; 30A  may comprise a stator  20  and a rotor  30 . Generally, the stator  20  and rotor  30  may cooperate so as to prevent ingress of contaminants to a housing  12  having a shaft  14  protruding therefrom, while simultaneously prevent egress of lubricant from the housing  12 . The stator  20  of the shaft seal assembly  10  may include a stator main body  20   a  and may be mounted to a relatively stationary housing  14  (which may be a housing  14  having an electrical motor therein, but which housing  14  is not so limited unless so indicated in the following claims). 
     The rotor  30  may include a rotor main body  30   a  and may be engaged with a rotatable shaft  14  protruding from the housing  12  such that the rotor  30  rotates with a shaft  14 . In an aspect, the rotor  30  may be engaged with the shaft  14  via a drive ring  16 . The drive ring  16  may be constructed of an elastomeric material and may be configured to seal a shaft radial gap  15  between the shaft  16  and the rotor  30 . The drive ring  16  may also be configured to cause the rotor  20  to rotate with the shaft  16 . 
     The stator  20  may be engaged with the housing  12  via an O-ring  18 , which O-ring  18  may be employed in conjunction with an interference fit between an external surface of the stator  20  and an interior surface of the housing  12 . In an aspect, an exterior portion of the stator  20  may be configured with a stair-step annular channel into which the O-ring  18  may be positioned. The stair-step feature of the annular channel may be positioned on the inboard side of the annular channel such that the outboard side of the annular channel is deeper (i.e., greater in the radial dimension) than the inboard side of the annular channel. It is contemplated that such a configuration of an annular channel may ease installation of the shaft seal assembly  10  into a housing  12 , while simultaneously providing adequate sealing between the stator  20  and the housing  12  at least in part via the O-ring  18 . The O-ring  18  may be constructed of an elastomeric material and may be configured to seal a housing radial gap  17  between the housing  12  and the stator  20 . However, the stator  20  may be engaged with and/or secured to a housing  12  and the rotor  30  may be engaged with and/or secured to a shaft  14  using any suitable structures and/or methods (several of which are described above for other embodiments of a bearing isolator  18  and/or shaft seal assemblies  25 ,  200  and which include but are not limited to mechanical fasteners, chemical adhesives, welding, interference fit, and/or combinations thereof) without limitation unless so indicated in the following claims. 
     In an aspect of a shaft seal assembly  10  as shown in  FIGS. 30 &amp; 30A , the entire rotor  30  may be positioned within a portion of the stator  20 , such that the rotor  30  may be effectively encapsulated by the stator  20 . That is, the shaft seal assembly  10  may be configured such that the surfaces thereof that are directly exposed to the exterior environment may be surfaces of the stator  20  rather than one or more surfaces of the rotor  30 , such that the entire rotor  30  is positioned inboard with respect to at least one surface of the stator  20 . It is contemplated that such a configuration may provide for superior sealing attributes in a smaller axial dimension when compared to the prior art. 
     The shaft seal assembly  10  may be configured to effectively seal (and/or mitigate) contamination from entering the housing  12 . In an aspect, an exterior stator inward radial projection  22  may form a stator/shaft clearance  21  between the distal end of the exterior stator inward radial projection  22  and the shaft  14 . The resulting stator/shaft clearance  21  may be configured as a close gap seal clearance between the exterior stator inward radial projection  22  and the shaft  14 . This close gap seal clearance (having dimensions as previously disclosed herein) may serve to prevent and/or mitigate ingress of contaminants due to the small space available to such contaminants. Any contaminants that do enter the shaft seal assembly  10  through the stator/shaft clearance  21  may subsequently encounter a first radial stator/rotor clearance  22 . In an aspect, a first radial stator/rotor clearance  22  may be formed between generally radially oriented corresponding surfaces of the stator  20  and rotor  30 . 
     The first radial stator/rotor clearance  23  may be in communication with and/or lead to an axial stator/rotor clearance  25 . As shown, the first radial stator/rotor clearance  23  may be perpendicular to the axial stator/rotor clearance  25 , but other orientations between them may be used (e.g., less than ninety degrees, greater than ninety degrees) without limiting the scope of the shaft seal assembly  10  unless so indicated in the following claims. 
     The axial stator/rotor clearance  23  may be in communication with and/or lead to a second radial stator/rotor clearance  25 . As shown, the second radial stator/rotor clearance  23  may be perpendicular to the axial stator/rotor clearance  25 , but other orientations between them may be used (e.g., less than ninety degrees, greater than ninety degrees) without limiting the scope of the shaft seal assembly  10  unless so indicated in the following claims. Generally, it is contemplated that in an aspect of the shaft seal assembly  10  the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25  may be configured to impede ingress of contaminants into the shaft seal assembly  10 . 
     Contaminants passing through the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25  may encounter a collection groove  26 , which may be formed in the stator  20  and which may be relatively large in size compared to the radial stator/rotor clearance(s)  23  and/or axial stator/rotor clearance(s)  25 . For example, in an aspect the axial length of the collection groove  25  may be more than ten times greater than the axial stator/rotor clearance  25  and the radial depth of the collection groove  25  may be more than ten times greater than the radial depth of the stator/rotor clearance(s)  23 . The collection groove  26  may be configured in any manner as previously described for the shaft seal assemblies  10  shown in  FIGS. 28 and 29  without limitation unless so indicated in the following claims. 
     A limit on the inboard radially oriented surface of the collection groove  26  (wherein “inboard” is generally in the direction toward the left side of  FIG. 30  and “outboard” is generally in the direction toward the right side of  FIG. 30 ) may be formed as an inboard wall  28   a . The outboard radially oriented surface of the collection groove  26  may be formed as an outboard wall  28   b . Together, the inboard wall  28   a  and the outboard wall  28   b  may serve to define the width of the collection groove  26  (wherein “width” is used do denote the axial dimension of the collection groove  26 ). In an aspect of the shaft seal assembly  10 , the height of the inboard wall  28   a  (i.e., radial dimension) may be great enough to accommodate a predetermined volume of contaminants within the collection groove  26  without rising to a level that would cause the contaminants to flow over the distal end of the inboard wall  28   a.    
     The stator  20  may be formed with a ramped projection  27  extending radially inward from the stator main body  20   a . The ramped projection  27  may be formed with a ramp surface  27   a  at the distal end thereof. The rotor  30  may be formed with a rotor ramped projection  37  extending radially outward from the rotor main body  30   a , which may be formed with a rotor ramp surface  37   a  at the distal end of the rotor ramped projection  37 . The stator ramped projection  27  and rotor ramped projection  37  may be configured such that a radial stator/rotor clearance  23  exists between them, and such that this radial stator/rotor clearance  23  leads to an atypical stator/rotor clearance  25   a  in the inboard direction. Generally, at least the ramped projection  27  (and additionally in various aspects, the rotor ramped projection  37 ) may be oriented inboard with respect to the collection groove  26 , but the scope of the present disclosure is not so limited unless so indicated in the following claims such that additional ramped projections  27  and/or rotor ramped projections  37  may be employed. 
     It is contemplated that in an aspect of the shaft seal assembly  10  shown in  FIG. 30 , an interaction between the ramped projection  27  and rotor ramped projection  37  may provide a unitizing function to the shaft seal assembly  10 , such that a sealing ring  19  may be omitted from a shaft seal assembly  10  so configured. It is contemplated that for a desired performance level, it may be required that the most-outboard located radial stator/rotor clearance  23  and/or the radial stator/rotor clearance  23  on either side of the collection groove  26  be formed as close clearance gap seals, as previously discussed above, and that the relative dimensions of those radial stator/rotor clearances  23  be maintained as much as possible during operation. Accordingly, in certain applications, axial shaft  14  movement in the inboard direction may cause an increase in the axial dimension of one or more of the radial stator/rotor clearances  23 , which may in turn decrease the effectiveness of the entire shaft seal assembly  10 . Such axial shaft  14  movement may occur as a result of thermal growth, shaft  14  loading, or axial shaft  14  movement may be an essential required feature of the rotating equipment on which the shaft seal assembly  10  is installed, though other causes may result in axial shaft  14  movement. 
     To prevent or mitigate the negative effects of axial shaft  14  movement, it may be desirable to configure the rotor  30  and/or stator  20  such that the relative axial positions therebetween are secure or relatively secure. In an aspect, this may be accomplished via a ramped projection  27  formed in the stator  20  having a ramp surface  27   a  on the distal end thereof and a rotor ramped projection  37  formed in the rotor  30  having a rotor ramp surface  37   a  on the distal end thereof. The ramp surface  27   a  and rotor ramp surface  37   a  may be configured such that they are generally parallel with respect to one another, and such that the angle thereof may allow the rotor  30  to be inserted into the stator  20  by moving the rotor  30  in a generally outboard direction with respect to the stator. The ramp surface  27   a  and rotor ramp surface  37   a  may be angled such that when an axial force is applied to the rotor  30  in an outboard direction, the stator  20  may be deformed momentarily as the ramp surface  27   a  and rotor ramp surface  37   a  interact with one another so as to allow the rotor  30  to be properly positioned within the stator  20  and with properly dimensioned and positioned radial stator/rotor clearance(s)  23 . During this insertion process, it is contemplated that it may be essential that the deformation of the stator  20  be within the elastic limits of the material comprising the stator  20  so that once the rotor  30  is in proper position the stator  20  will return to its essentially original size and shape. 
     It is contemplated that the ramp surface  27   a  may be angled radially inward in the inboard-to-outboard direction, and that the rotor ramp surface  37   a  may be angled radially inward in the inboard-to-outboard direction though the scope of the shaft seal assembly  10  is not so limited unless indicated in the following claims. Further, it is contemplated that the ramp surface  27   a  and rotor ramp surface  37   a  may be generally parallel, though the scope of the shaft seal assembly  10  is not so limited unless indicated in the following claims. 
     Once the rotor  30  is properly positioned with respect to the stator  20  and the stator  20  generally returns to its original size and shape, the close clearance gap seals of the radial stator/rotor clearance(s)  23  may be maintained by the formation of a relatively small radial stator/rotor clearance  23  adjacent the overlapping axial surfaces between the largest diameter of the rotor ramped projection  37  and the smallest diameter of the ramped projection  20 . This overlap may prevent shaft  14  movement in a generally inboard direction from separating the rotor  30  from the stator  20 , which may compromise the effectiveness of the close clearance gap seals formed at a radial stator/rotor clearance(s)  23 . 
     Generally, it may be desirable for the shaft seal assembly  10  to be configured such that if the rotor  30  experiences a force in a generally inboard direction (which may be caused by axial movement of the shaft  14  in a generally inboard direction), the shaft  14  may slide axially with respect to the rotor  30 , and the overlapping ramp surface  27   a  and rotor ramp surface  37   a  may serve to retain the rotor  30  in the proper position relative to the stator  20 . Axial movement of the shaft  14  with respect to the rotor  30  may require slippage at the drive ring  16  or other structure and/or method used to engage the rotor  30  with the shaft  14 . Accordingly, it is contemplated that it may be advantageous to provide a sufficient amount of overlap at the ramp surface  27   a  and rotor ramp surface  37   a  such that the integrity of the overlap will prevent separation of the stator  20  and rotor  30  while the shaft  14  is slid through the rotor  30  in a generally inboard direction. In an aspect the amount of overlap may be between 0.1 and 1.0 inches without limitation unless so indicated in the following claims. Generally, it is contemplated that an optimal operating condition may be when the rotor  30  turns freely inside the stator  20  in such a manner that forced contact between the rotor  30  and stator  20  at any radial stator/rotor clearance  23  and/or any axial stator/rotor clearance  25  is mitigated and/or prevented. 
     It is contemplated that optimal functioning of a shaft seal assembly  10  such as those shown in  FIGS. 28-30  may require the axial dimension of the most-outboard radial stator/rotor clearance  23  be less than the axial dimension of the radial stator/rotor clearance  23  adjacent outboard wall  28   b  of the collection groove  26 . If the shaft seal assembly  10  is subjected to axial shaft  14  movement in a generally outboard direction during operation, the axial dimension of the radial stator/rotor clearances described immediately above may be reduced and/or eliminated, which may cause frictional dynamic contact between the adjacent surfaces of the stator  20  and rotor  30 . This frictional dynamic contact may result in undesired heat generation, or the friction between the static and dynamic surfaces may be sufficient to overcome the friction between the drive ring  16  and shaft  14  and/or friction between the drive ring  16  and rotor  30 . Any of these scenarios could result in failure of the shaft seal assembly  10 . Accordingly, maintaining a closer clearance at radial stator/rotor clearances  23  described immediately above reduces the surface area that may be subjected to dynamic contact, which may result in less friction and/or heat generation upon contact, which may lower the likelihood of failure. 
     The materials used to construct the shaft seal assemblies  10 ,  25 ,  100 ,  200 ,  202  and various elements thereof will vary depending on the specific application, but it is contemplated that bronze, brass, stainless steel, or other non-sparking metals and/or metallic alloys and/or combinations thereof may be especially useful for some applications. Accordingly, the above-referenced elements may be constructed of any material known to those skilled in the art or later developed, which material is appropriate for the specific application of the shaft seal assembly, without departing from the spirit and scope of the shaft seal assemblies  25 ,  100 ,  200 ,  202  as disclosed and claimed herein. Further, the drive ring  16 , O-ring  18 , and/or sealing ring  19  may be constructed of any material suitable for the specific application of the shaft seal assembly  10 , which material includes but is not limited to polymers, synthetic materials, elastomers, natural materials, and/or combinations thereof without limitation unless so indicated in the following claims. 
     Having described the preferred embodiments, other features of the shaft seal assemblies disclosed herein will undoubtedly occur to those versed in the art, as will numerous modifications and alterations in the embodiments as illustrated herein, all of which may be achieved without departing from the spirit and scope of the shaft seal assemblies disclosed herein. Accordingly, the methods and embodiments pictured and described herein are for illustrative purposes only, and the scope of the present disclosure extends to all method and/or structures for providing the various benefits and/or features of the shaft seal assemblies unless so indicated in the following claims. Furthermore, the methods and embodiments pictured and described herein are no way limiting to the scope of the shoe covering  10  unless so stated in the following claims. 
     It is understood that the shaft seal assemblies as disclosed herein extends to all alternative combinations of one or more of the individual features mentioned, evident from the text and/or drawings, and/or inherently disclosed. All of these different combinations constitute various alternative aspects of the shaft seal assemblies and/or components thereof. The embodiments described herein explain the best modes known for practicing the shaft seal assemblies and/or components thereof and will enable others skilled in the art to utilize the same. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     While the shaft seal assemblies have been described in connection with preferred embodiments and specific examples, it is not intended that the scope be limited to the particular embodiments set forth, as the embodiments herein are intended in all respects to be illustrative rather than restrictive. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including but not limited to: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification. 
     It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as illustrative only, with a true scope and spirit being indicated by the following claims.