Abstract:
A method for installing an auxiliary ring around a shaft. The method comprises providing an auxiliary ring comprising a plurality of ring elements, wherein each ring element includes at least one radial joint. Each ring element is installed around the shaft and positioned such that the radial joint of at least one of the ring elements is rotationally offset from the radial joint of each adjacent ring element. The plurality of ring elements are then secured to each other by adhesive, welding, or a fastener. Each ring element may include an aperture wherein the aperture of each ring element is aligned with the aperture of each adjacent ring element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a division of U.S. patent application Ser. No. 11/518,158, filed Sep. 11, 2006, which claims the benefit of U.S. Provisional Patent Application No. 60/716,284, filed Sep. 12, 2005, the disclosures of which are hereby incorporated by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to an element for sealing along a rotary member. More particularly, the present invention relates to a two-piece sealing element for use in a stuffing box assembly. 
       BACKGROUND 
       [0003]    Compression packing is used to control leakage about shafts. Compression packing generally has an assembly of radially expandable rings that coaxially surrounds a shaft. Such packing is used in a wide variety of applications including packing for pumps, valves and hydraulic and pneumatic equipment. Shafts are conventionally surrounded by a compartment generally extending outward from the housing surrounding the shaft referred to as a “packing box” or “stuffing box.” The interior of the stuffing box is generally of a diameter sufficiently greater than the shaft to accommodate compressible “packing rings” and a number of relatively non-compressible auxiliary rings. 
         [0004]    The packing rings in the stuffing box are compressed by an annular “gland” fitted about the shaft and bolted to the exterior of the stuffing box. Axial compressive loading force from the gland is applied to the packing rings, causing them to expand radially to some extent, forcing the inner peripheries against the outer surface of the shaft and causing the packing rings to fill the stuffing box. This aims to prevent or minimize the escape of the contents of the housing at the intersection of the shaft and housing. Tightening of the gland is conventionally by means of a flange. Bolts pass through the flange and are threaded into threaded holes in the stuffing box. When the gland is tightened, the packing rings are further compressed in the stuffing box. 
         [0005]    The auxiliary rings employed in packing sets include bushing rings, excluder rings, spacer rings, gaskets, restriction bushings, lantern rings, flush rings, or combinations thereof. These auxiliary rings are generally constructed of non-compressible materials and aid in the retention and/or function of the compressible packing rings. Traditionally, when maintenance is performed on a stuffing box assembly, the entire apparatus must be disassembled and the rings must be removed from the stuffing box, new rings put in place, and the apparatus is reassembled. 
         [0006]    Additionally, this requires the removal of machine parts that surround or are adjacent to the part being sealed, such as the rotary member, in order to allow ample access room to permit ring replacement. Disassembly and re-assembly of such parts often require a great expenditure of time and labor, along with a consequent monetary cost. For example, where a shaft extends from a housing, the exterior bearing or journal member for such shaft, as well as the coupling parts to the shaft and external parts of the housing, may have to be removed before the integral seals can be brought into access position for removal. The cost for such repair may be considerable, as product is lost during the interval of machine down-time. 
         [0007]    One conventional solution to this problem is to provide split-ring elements, which are used in many applications wherein integral solid seals would be difficult or time-consuming to install. Employment of split seals may reduce the time for replacing a seal from 24 hours (if a solid integral seal was employed) to less than an hour. Split seals can be slipped around the shaft without dismantling the apparatus and are frequently bolted together, squeezed together with an “O” ring or squeezed together on a taper. 
         [0008]    Bolted split seal elements are relatively expensive and generally require a large amount of space for the seal. Split seal elements that are squeezed together with an “O” ring are generally limited to use with respect to shafts having a low rotational speed, since centrifugal forces tend to open the split halves at high rotational speeds. While split seal elements which are squeezed together with a taper are somewhat more adaptable, the alignment of surfaces has to be near perfect in order to prevent leakage. Further, while generally providing for more flexibility in the shaft diameter ranges in which they may be employed, split seal elements like integral-solid seals suffer from a relatively inflexibility in the array of rotary diameters on which they may be employed. 
       SUMMARY OF THE INVENTION 
       [0009]    It would, therefore, be desirable to provide a system of and a method for constructing ring elements that can be installed in a stuffing box assembly without the need for dismantling the apparatus, while overcoming the disadvantages of split seals of the prior art. 
         [0010]    In a first exemplary embodiment, a system for positioning around a rotary element comprises a substantially circular ring element having a circumference around an outer edge of the ring element. The ring element comprises a first section comprising a first section outer rounded edge, a first section first mating edge, a first section inner rounded edge, and a first section second mating edge. A second section comprises a second section outer rounded edge, a second section first mating edge for abutting the first section first mating edge, a second section inner rounded edge, and a second section second mating edge for abutting the first section second mating edge. The first section outer rounded edge and the second section outer rounded edge form the circumference of the outer edge of the ring element when the first section first mating edge and the second section first mating edge are substantially aligned and when the first section second mating edge and the second section second mating edge are substantially aligned. 
         [0011]    In a second exemplary embodiment, a system comprises at least two rings, each ring comprising a first ring component and a second ring component each comprising a substantially flat top and bottom, a substantially circular outer edge, a substantially circular inner edge, and a pair of complementary edges between the outer edge and the inner edge. The complementary edges on the first ring component align with the complementary edges on the second ring component to form a ring. The outer edges of the first and second ring components comprise the circumference of the first ring or the second ring when the first and second sections are aligned. The first ring is positioned on top of the second ring to align the outer edges of the first and second rings. 
         [0012]    In a third exemplary embodiment, a method for producing a ring, the ring comprising a first section comprising a first section outer rounded edge, a first section first mating edge, a first section inner rounded edge, and a first section second mating edge, and a second section comprising a second section outer rounded edge, a second section first mating edge for abutting the first section first mating edge, a second section inner rounded edge, and a second section second mating edge for abutting the first section second mating edge, wherein the first section outer rounded edge and the second section outer rounded edge form the circumference of the outer edge of the ring element when the first section first mating edge and the second section first mating edge are substantially aligned and when the first section second mating edge and the second section second mating edge are substantially aligned, the method comprising the steps of cutting the first section and second section from a sheet material and aligning the first and second sections. 
         [0013]    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    The present invention will be more clearly understood from a reading of the following description in conjunction with the accompanying exemplary figures wherein: 
           [0015]      FIG. 1   a  shows a first section of a ring according to an embodiment of the present invention; 
           [0016]      FIG. 1   b  shows a second section of a ring according to an embodiment of the present invention; 
           [0017]      FIG. 2  shows a ring having a first section and a second section according to an embodiment of the present invention; 
           [0018]      FIG. 3   a  shows a top view of a ring according to an embodiment of the present invention; 
           [0019]      FIG. 3   b  shows a cross section of a ring according to an embodiment of the present invention; 
           [0020]      FIG. 4   a  shows a top view of a ring according to an embodiment of the present invention; 
           [0021]      FIG. 4   b  shows a cross section of a ring according to an embodiment of the present invention; 
           [0022]      FIG. 5   a  shows a top view of a ring according to an embodiment of the present invention; 
           [0023]      FIG. 5   b  shows a cross section of a ring according to an embodiment of the present invention; 
           [0024]      FIGS. 6   a  and  6   b  show a system of rings according to embodiments of the present invention; 
           [0025]      FIG. 7  shows a sheet for providing a component according to an embodiment of the present invention; and 
           [0026]      FIG. 8  shows a system incorporating an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
         [0028]    A method, according to one embodiment, for manufacturing and installing components in a stuffing box packing assembly is as follows. Generally, rings can be constructed in a two-piece design that can allow installation and removal of the rings without substantial disassembly of the apparatus. Although the embodiments described herein refer to a two-piece design, it is understood that more than two pieces can be used. Further, the rings of the present invention can be substantially locked together, thereby providing additional stability and a tighter seal. Moreover, although the embodiments described herein refer to a ring design, it is understood that other shapes and configurations can be used. 
         [0029]    In one embodiment, illustrated in  FIGS. 1   a ,  1   b  and  FIG. 2 , a ring R comprises a first section  10   a,    20   a  and a second section  10   b,    20   b.  In this embodiment, an outer surface  12   a  of the first section  10   a  has a greater length than an outer surface  12   b  of the second section  10   b,  wherein the outer surface  12   a  of first section  10   a  and the outer surface  12   b  of second section  10   b  comprise the outer circumference of the ring  26 . In other words, the first section  10   a,    20   a  comprises a majority of the circumference of the ring  26  and the second section  10   b,    20   b  comprises a minority of the circumference of the ring  26 . In one embodiment, the first section  10   a,    20   a  comprises about ⅔ of the circumference of the ring  26 . 
         [0030]    The first section  10   a  substantially mates or aligns with second section  10   b  to form the ring  26 . More specifically, edges  14   a  of the first section  10   a  can align with edges  14   b  of the second section  10   b.  In this embodiment, the edges  14   a  and  14   b  are along an axis directed radially inwardly towards the center of the ring  26 . As shown in  FIG. 2 , a dotted line  26  represents the radially inward axis along which the edges  14   a,    14   b  are configured. However, the present invention is not intended to be limited to this configuration. In other exemplary embodiments, the edges are not substantially straight and/or is not aligned with an axis directed radially inwardly towards the center of the ring  26 . Additionally, the edges can comprise flanges or other shapes that can engage the mating section. 
         [0031]    When the first section  14   a  and the second section  14   b  are substantially aligned, a complete ring  26  is formed, as shown in  FIG. 2 . Conventionally, apertures can be provided in a ring. Accordingly, in order to compliment standard ring configurations, a plurality of apertures  18   a,    18   b,    28  can be provided through the faces of the ring  26  for receiving a fastening device. As illustrated in the  FIGS. 1   a ,  1   b ,  2 , and  3   a,  in a standard configuration comprising four apertures  18   a,    18   b,    28  along the face of the ring  26 , each of the first section  14   a  and the second section  14   b  have two apertures  18   a,    18   b.  Alternatively, the ring  26  can have any number of apertures or none at all. 
         [0032]    In an alternative embodiment, two or more rings  26  can be stacked to construct a composite ring. The rings can be stacked such that the first section and the second section of each successive ring unit are rotated about the axis so at least two of the ring units have different alignment of the first and second sections. In this manner, a “brick like” configuration of intermeshing ring segments can be constructed. Additional ring units can be stacked in this staggered pattern until a complete ring of desired height is constructed. Apertures in the composite ring can align with each ring and extend substantially and completely through the composite ring. 
         [0033]      FIGS. 3   a - 3   b  and  4   a - 4   b  illustrate a complete ring having four layers of ring units, each layer comprising a first section and a second section. However, as discussed earlier, the ring can have more or less than four layers.  FIG. 3   a  shows a top view of a ring R having a plurality of layers of rings and a plurality of apertures  38 . As shown in  FIG. 3   b , a cross section of composite ring R through line a-a, each of the four layers can comprise staggered and differently-sized first sections A 1 , A 2 , A 3 , A 4  and second sections B 1 , B 2 , B 3 , B 4 . In an example of the staggered relationship, the edge between first section A 1  and second section B 1  does not align with the edge between first section A 2  and second section B 2 . Different staggering schemes are possible and the configurations illustrated herein are merely exemplary. A ring that is constructed wherein the joints between the edges are staggered throughout the structure can provide increased overall strength and unity to the ring. Also shown in  FIG. 3   b  is an indication of a potential aperture  38  through each layer. Because of the staggered configuration of each layer, the first and second sections may not have the apertures in the same position on the first and second sections. For example, first section A 4  may have an aperture in a different position than an aperture in first section A 3  in order for the apertures to align. 
         [0034]    In another embodiment,  FIG. 4   a  shows a top view of a ring R having a plurality of layers of rings and a plurality of apertures  48 . As shown in  FIG. 4   b , a cross-section of ring R through line b-b, each of the four layers can comprise staggered first sections A 1 , A 2 , A 3 , A 4  and second sections B 1 , B 2 , B 3 , B 4  with the aperture  38  extending therethrough. In this particular embodiment, each alternating layer is substantially aligned. For example, second section B 2  is aligned with second section B 4 . As a result of aligning the second sections in this or a similar configuration, the aperture  48  can be used for riveting, joining, or other method of attaching the second sections together and the first sections together. In one example, a rivet extends through aperture  48  to connect second sections B 1 , B 2 , B 3 , B 4 . When disassembling the system, the second sections B 1 , B 2 , B 3 , B 4  can be removed as a single unit. Additionally, when configuring the first and second sections to determine where the apertures  48  can be positioned, it can be useful to have a configuration where the second sections are substantially aligned such that an aperture can extend through each second section B 1 , B 2 , B 3 , B 4 . 
         [0035]    In yet another embodiment,  FIG. 5   a  shows a top view of ring R having a plurality of layers of rings. As shown in  FIG. 5   b , a cross-section of ring R through line c-c, the ring R has four layers R 1 , R 2 , R 3 , R 4  stacked upon each other. Because each joint between first and second section edges is staggered, ring layers R 1 , R 2 , R 3 , R 4  can be either a first or second section of a ring. Additionally, in this exemplary embodiment, the cross-section of each layer R 1 , R 2 , R 3 , R 4  results in that first or second section comprising the entire cross-section of that layer. 
         [0036]    Referring to  FIGS. 6   a  and  6   b , exemplary embodiments are shown for a configuration of ring layers. As shown in  FIG. 6   a , a ring has a first section  60  and second section  61 , each having a plurality of apertures  63 . A first section  64  of a second ring is offset from the first section  60  of the top ring. In this particular embodiment, the apertures  63  are aligned substantially throughout the layers. As shown in  FIG. 6   b , a ring has a first section  65  and second section  66 , each having a plurality of apertures  67 . In this particular embodiment, a first section  68  of a second ring is not offset from the first section  65  of the top ring. However, a first section  69  of a third ring is offset from both the first and second ring first sections  65 ,  68 . In this embodiment, the apertures  67  are aligned substantially throughout the layers. As an alternative to these exemplary embodiments, the ring layers can be formed as a single unit. For example, the first sections  60 ,  64 , and the alternating layers beneath, can be formed as a single first section with extending flanges that interlock with the second sections. In this alternative configuration, the system retains the ability to disassemble the ring structure by separating a first section from a second section. 
         [0037]    In  FIG. 6   a , the second section  61  in the top layer is offset from the second section  62  of the second layer. This pattern can repeat throughout the system. In this configuration, apertures  63  extending through both second section  61  and second section  62  can utilize the same configuration for both second section  61  and second section  62 . In other words, when manufacturing second sections, a manufacturer can make only one second section having apertures therein. For example, as shown in  FIG. 6   a , the apertures  63  on second section  61  can align with the apertures in second section  62 , even though second section  62  is offset from second section  61 . This can be accomplished by flipping or turning over second section  62  before installation in the assembly. Accordingly, the apertures that were offset can now be aligned. Once the apertures are aligned, as discussed herein, the first sections can be substantially attached together and the second sections can be substantially attached together. 
         [0038]    Rings that can be constructed in the manner described herein directly on the shaft can eliminate the need to disassemble the entire apparatus. Another advantage to constructing rings as described herein is that when pressure is exerted on the ring in an axial direction, the interlocked sections of the ring can be forced together to form a tighter seal. 
         [0039]    The sets of complementary first and second sections can be held together with fasteners, such as set screws, pins, or other fastening means known in the art, extending through the apertures in the faces of the rings. In one embodiment, each layer has identically-sized first and second sections. By rotating each subsequent layer  90  or 180 degrees, no two adjacent layers have the same configuration of segments, but yet the four apertures will be aligned. Accordingly, a more unified ring can be produced. In addition to the fasteners mentioned above, the ring segments can be held together by welding (such as PTFE welding), hot melt glue, or polymer adhesive injected into the apertures. Further, in an alternative embodiment, the ring segments may be held together with an adhesive placed between the layers of the rings. The means for attaching or affixing the layers to each other can be any means known to one of ordinary skill in the art. 
         [0040]    In one embodiment of the present invention, a flush ring or lantern ring can be constructed according to the method described herein. To create such a ring, the first and second complementary sections comprise slightly less than 100% of the circumference of the ring. Accordingly, when the flush ring or lantern ring is assembled, at least one channel can be created between the edges of the first and second sections to creates a flow path for flushing media to enter the packing set or, alternatively, a path for fluid to exit the packing set in a controlled manner so as to reintroduce it into the apparatus. Additionally, ports, vents, etching, relieving, or similar enhancement known in the art can be applied to give the ring variable flush media performance characteristics. 
         [0041]    The material of the ring can be any material known to one of ordinary skill in the art. In one embodiment, the ring is constructed from a material such as polytetrafluoroethylene (PTFE). In another embodiment, the ring material comprises a PTFE selected from the GYLON® family of PTFE materials manufactured by Garlock Sealing Technologies, LLC (Palmyra, N.Y.). GYLON® is a restructured PTFE with bi-directional orientation, which reduces creep and cold flow problems associated with PTFE products, while retaining other positive characteristics of PTFE. 
         [0042]    Generally, the materials employed can comprise plates or sheets of material that are cut to a desired shape, including both the inner diameter and outer diameter. The thickness of each ring unit can depend upon the material from which the pieces are constructed. The use of standard sheet material can be used to provide the complimentary first and second sections for assembly. Generally, standard material sizes comprise thicknesses of 1/32 in, 1/16 in, ⅛ in, and 3/16 in. In an example of using a standard sheet material to assemble a multi-layer ring, if a ⅛ in gasket material were used, 6 ring units would be stacked upon one another to complete a finished ring that is ¾ in high. Referring to  FIG. 7 , a standard sheet  70  is shown from which a plurality of first sections  75  can be cut. This is merely exemplary and is not intended to be drawn to scale or represent the minimum, maximum, or preferred configurations of first and second sections that can be cut from a standard sheet. Optionally, a plurality of apertures  77  can be produced before, during, or after the process of cutting the first or second sections. 
         [0043]    The process of producing ring sections can be performed to assemble any of the variety of non-packing rings employed in a conventional stuffing box known to one of ordinary skill in the art, such as excluder rings, spacer rings, gaskets, and restriction bushings. As such, the rings can be fabricated out of suitable materials including, but not limited to, rubber, cast iron, plastics, and other such materials that perform a sealing function. The material from which a ring is fabricated is generally dictated by the application in which it is intended to be used. Additionally, one skilled in the art will recognize that the method described herein can be employed to replace rings or seals around a shaft in a variety of applications where it would be cumbersome or time consuming to dismantle the apparatus and/or remove the shaft. 
         [0044]    Referring to  FIG. 8 , a system  80  is shown utilizing a ring described herein. In this exemplary embodiment, the system  80  is used for water conservation by providing a substantially leak-free rotary seal. An excluder ring  81  comprises three rings composed of complimentary first and second sections, as described above. A pressure barrier ring  85  comprises five rings composed of complimentary first and second sections, as described above. As shown in  FIG. 8 , joints between the first and second sections of each ring layer do not align with the adjacent layer. For example, a first layer has a first section  85   a  and a second section  85   b,  which abut at joint  85   c.  A second layer has a first section  85   d  and a second section  85   e , which abut at joint  85   f.  Because of the staggered relationship between the first and second layers, the joint  85   c  is not aligned with the joint  85   f.  The system  80  also comprises a first braided flexible graphite ring  82 , a spacer ring  83 , a second braided flexible graphite ring  84 , an adapter ring  86 , at least two center rings  87   a,    87   b,  and a second adapter ring  88 . By using the ring layers described herein, this system does not require a costly dismantling process or back-up equipment. The layers can be split so that machinery can be serviced without uncoupling a motor. 
         [0045]    Although the present invention has been described with reference to particular embodiments, it should be recognized that these embodiments are merely illustrative of the principles of the present invention. Those of ordinary skill in the art will appreciate that the apparatus and methods of the present invention may be constructed and implemented in other ways and embodiments. Accordingly, the description herein should not be read as limiting the present invention, as other embodiments also fall within the scope of the present invention.