Abstract:
A sealing device employing interfitting relatively rotatable rings, namely a stator and a rotor disposed for cooperation between a housing and a rotatable shaft. The stator is nonrotatably and sealingly engaged within an opening formed in the housing. An elastomeric O-ring maintains a seal between the stator and housing. The rotor snugly surrounds and is nonrotatably carried with the shaft and is provided with elastomeric seal ring therebetween to prevent leakage along the shaft. The stator closely externally surrounds the rotor to define a complex pathway therebetween which inhibits flow of liquids or contaminants in either direction therethrough. This pathway includes a pair of annular collecting chambers disposed in axially spaced relationship, whereby the outer chamber collects and discharges to the environment any contaminants which enter from the environment, and the inner chamber collects and discharges back to the reservoir any lubricant or fluid which enters into the pathway from its inner end.

Description:
FIELD OF THE INVENTION 
     This invention relates to a device, hereinafter referred to as a bearing protector, for use between a relatively rotatable housing and shaft to prevent flow of either internal or external contaminants axially along the shaft, such as into or away from the region of the bearing. 
     BACKGROUND OF THE INVENTION 
     Within most industries, it is important that there be provided some type of seal device which prevents fluids from leaking externally from an associated bearing housing or support, and which also preventing foreign particles in the pumped fluid or environment from working themselves through the seal into the bearing. 
     While many sealing devices employ various types of elastomeric sealing rings, specifically lip seals, nevertheless such lip seals have a short life since they undergo rapid wear, particularly when used in environments involving fluids of a high temperature, high pressure, abrasive or corrosive characteristic. While lip seals continue to be used in many environments, nevertheless it is well documented and well known to those who are experienced in such technologies that lip seals provide only a relatively short life and hence do not provide a satisfactory solution to the sealing problem presented. 
     In an attempt to improve upon such problem and the solution thereto, various types of sealing ring devices have been employed. Such sealing ring devices, sometimes referred to as &#34;bearing isolators&#34;, typically employ a pair of relatively rotatable rings (i.e. a rotor and a stator) which are respectively fixed to the rotatable shaft and stationary housing. These relatively rotatable rings have a close fitting relationship to create a complex pathway therebetween, such as a labyrinth, to hence greatly inhibit the flow or movement of fluids or contaminants in either direction therebetween. While such sealing devices have proven at least partially effective in selected use conditions, nevertheless one of the disadvantages of any such device has been the extremely complex configuration of the rings, and the consequent cost of such devices. Further, many of these nonsealing devices have been unable to prevent flow of fluids or contaminants therethrough to the desired degree, particularly due to their inability to successfully capture and expel any fluids or contaminants which gain entry into the labyrinth or pathway between the rings. 
     While numerous sealing devices of this general type have been developed, exemplary embodiments of such devices are illustrated by U.S. Pat. Nos. 2,524,124, 4,484,754, 3,897,072, 4,466,620, 4,572,517, 4,114,902, 4,022,479, 3,893,674 and British specification No. 2035472A. 
     Accordingly, the present invention relates to a sealing device of the type which employs a pair of interfitting relatively rotatable rings, namely a stator and a rotor, disposed for cooperation between a housing and a shaft rotatable relative thereto, which sealing device is believed to represent a significant improvement over prior art devices of this general type with respect to its improved level of performance, its simplicity and efficiency of manufacture, and its simplicity of installation. 
     In the improved sealing device of this invention, which device is known as a &#34;bearing protector&#34; or a bearing isolator, the stator is nonrotatably and sealingly engaged within an opening formed in the housing. A sealing relationship is achieved by use of a simple elastomeric O-ring to ensure a proper seal is maintained between the stator and the housing. Similarly, the rotor snugly surrounds and rotates with the shaft and is preferably provided with a conventional elastomeric O-ring therebetween to prevent leakage along the shaft. The stator closely externally surrounds the rotor to define a complex pathway or labyrinth therebetween which inhibits flow of liquids or contaminants in either direction therethrough. This pathway or labyrinth includes a pair of annular collecting chambers disposed in axially spaced relationship, whereby the outer chamber collects and readily discharges to the environment any contaminants which enter from the environment, and the inner chamber collects and discharges back to the reservoir any lubricant or fluid which enters into the pathway from its inner end. The configuration of these contaminant-collecting chambers ensures that the collected contaminants or fluids can be readily discharged back to their source, and at the same time the cooperation between the stator and rotor are such as to severely restrict or prevent flow of the contaminants from one collection chamber to the other. 
     Other objects and purposes of the invention will be apparent to persons familiar with devices of this general type upon reading the following specification and inspecting the accompanying drawings 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view which diagrammatically illustrates a bearing protector according to the present invention installed at both ends of a bearing housing 
     FIG. 2 is a fragmentary, enlarged sectional view showing the bearing protector cooperating between the bearing housing and shaft, substantially as enclosed within the circle designated II in FIG. 1. 
     FIG. 3 diagrammatically illustrates, on an enlarged scale, a cross-sectional detail of the bearing protector. 
     FIG. 4 is a fragmentary perspective view of the bearing protector. 
     FIG. 5 is a view similar to FIG. 2 but illustrating a variation thereof. 
    
    
     Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words &#34;upwardly&#34;, &#34;downwardly&#34;, &#34;leftwardly&#34; and &#34;rightwardly&#34; will refer to directions in the drawings to which reference is made. The words &#34;inwardly&#34; and &#34;outwardly&#34; will refer to directions toward and away from, respectively, the geometric center of the overall apparatus and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
     Referring to FIG. 1, there is illustrated a bearing housing 11 which defines a reservoir or compartment 12 therein. A shaft 13, such as a pump shaft, extends through and is rotatably supported on the bearing housing, such as by conventional bearings 14 and 15. The shaft 13 projects outwardly through a suitable cylindrical opening or bore 16 as associated with a detachable end plate 17, the latter being part of the bearing housing. 
     To prevent external contaminants such as water and the like from gaining access to the bearings, and to additionally prevent the bearing lubricant from escaping externally, the present invention provides a sealing device or bearing protector 21 disposed for cooperation between the rotatable shaft 13 and the stationary housing 11. This bearing protector 21 is normally disposed in fairly close proximity to the bearing, and the design of the bearing protector 21 is such as to effectively prevent contaminants from passing therethrough into contact with the bearing, and similarly to prevent the bearing lubricant from escaping. 
     The bearing protector 21, as illustrated by FIGS. 2 and 3, basically comprises inner and outer rings which concentrically and relatively rotatably fit one within the other. More specifically, the bearing protector includes a ringlike rotor 22 which closely surrounds and is both sealingly and nonrotatably coupled to the shaft 13. This ringlike rotor 22 in turn is concentrically and closely surrounded by a ringlike stator 23 which is nonrotatably and stationarily secured relative to the surrounding housing 17. The rings 21 and 22 both project at least axially partway into the housing bore 16 substantially as illustrated by FIG. 2. While the rings 22 and 23 closely concentrically surround one another, nevertheless they are slightly spaced apart so as to permit free relative rotation therebetween, and for this purpose the concentric rings define a narrow annular passageway 24 therebetween, the latter involving numerous changes in direction and in effect defining a complex path or labyrinth which effectively prevents the lubricant from passing outwardly therethrough, and at the same time effectively prevents the external contaminants from passing inwardly therethrough. 
     The rotor 22 is of a stepped configuration and, in the embodiment of FIGS. 1-4, is of a three-step configuration defined by inner, intermediate and outer annular portions 27, 28 and 29, respectively. 
     The inner annular portion 27 is bounded by an annular outer wall 31. An annular channel-like groove 32 is formed in and projects radially inwardly from the wall 31, this groove 32 being spaced axially outwardly a small distance from the inner axial end face 33 of the rotor. 
     The intermediate annular portion 28 is also defined within an outer annular wall 34 which is of larger diameter than the outer annular wall 31 of the inner portion 27. This outer annular wall 34 also has an annular channel-like groove 35 formed in and projecting radially inwardly therefrom. This outer annular wall 34 terminates at an inwardly facing axial end surface 36 which is located at the interface between the inner and intermediate portions 27 and 28, respectively. 
     The outer annular portion 29 is defined by an outer annular wall 37 which is significantly larger in diameter than the outer annular wall 34 of the intermediate portion. In fact, whereas the outer annular walls 31 and 34 are both smaller than the diameter of the housing bore 16 (FIG. 2), this outer annular wall 37 is of a diameter which is significantly larger than the diameter of the housing bore 16. The outer annular portion 29 defines thereon the outer axial end face 38 of the rotor. Outer annular portion 29 also defines thereon an inwardly facing axial end surface 39 which is located at the interface between the annular portions 28 and 29. 
     The outer annular portion 29 has an annular channel-like groove 41 which projects axially outward from the end surface 39. This groove 41 results in the defining on the outer annular portion 29 of a part 42 which in effect constitutes an annular axially-extending flange which projects axially inwardly toward the housing 
     The rotor 22 has a bore or opening of substantially uniform diameter extending axially therethrough, which bore hence defines the inner annular wall 44. The diameter of this wall 44 is close to but generally slightly larger than the exterior diameter of the shaft 13. An annular channel-like groove 45 is formed in this wall 44 for accommodating therein a conventional elastomeric O-ring 46. This O-ring 46 hence creates a sealed relationship between the shaft 13 and the rotor 22, and in addition results in the rotor 22 being nonrotatably coupled to the shaft 13. 
     The stator 23 is, in this illustrated embodiment, also of a stepped configuration and includes inner and outer annular portions 51 and 52, respectively. 
     The inner annular portion 51 is defined between outer and inner annular walls 53 and 54, respectively. The outer annular wall 53 is of a diameter close to but normally slightly less than the diameter of the housing wall defining the bore 16. This outer annular wall 53 has a channel-like annular groove 55 formed therein, which groove accommodates a conventional elastomeric O-ring 56 so as to create a sealed relationship between the stator 23 and the housing member 17. 
     The inner annular portion 51 also has a channel-like groove 57 which is formed in and projects radially outwardly from the inner annular wall 54 thereof. This channel-like groove 57 is disposed generally radially opposite and in surrounding relationship to the channel-like groove 32 formed in the rotor, whereby these opposed channel-like grooves 32 and 57 hence cooperate so as to define an annular channel 58 between the stator and rotor, which channel is of significant cross section both radially and axially. The purpose of channel 58 is explained hereinafter. 
     The stator, at its inner axial end, is defined by an inner axial end face 59, the latter being the inner end of the annular portion 51. 
     The outer annular portion 52 of the stator is also defined between outer and inner annular walls 62 and 63, respectively. The outer annular wall 62 terminates at an inwardly facing axial end surface 61 which defines the interface between the inner and outer annular portions 51 and 52. This end surface 61 in effect defines a shoulder or stop which abuts against the outer face of the housing member 17 for permitting proper positioning of the bearing protector 21 relative to the housing. 
     The inner annular surface 63 of the portion 52 has an annular channel-like groove 64 formed therein and opening radially outwardly thereof. This channel-like groove 64 is disposed directly radially opposite and in surrounding relationship to the channel-like groove 35. These opposed grooves 35 and 64 hence define an annular channel 65 between the stator and rotor, which channel is of significant cross section both axially and radially. The purpose of this channel 65 is also explained hereinafter. 
     The outer annular portion 52 of the stator defines thereon an outer axial end face 66, the latter being adapted for disposition closely adjacent and directly opposite the inner surface 39 of the rotor. This outer annular portion 52 of the stator also has an annular flange 67 which is formed integrally therewith and projects axially outwardly from the end face 66 at a location spaced radially inwardly from the outer annular wall 62 thereof. This annular flange 67 is disposed so as to project into the annular groove 41 formed in the rotor. This flange 67 has a cross section which closely conforms to the groove 41 but is spaced slightly from the walls thereof to permit free relative rotation between the stator and rotor. 
     The concentric interfitting relationship between the stator 23 and rotor 22 results in the defining of the pathway 24 (FIG. 2) therebetween, which pathway at its outer end communicates with the surrounding environment, and at its inner end communicates with the interior of the bore 16 in the vicinity of the adjacent bearing. This pathway 24 includes, at the outer end thereof, a passageway 71 (FIG. 3) which extends from the outside of the bearing protector to the channel 65. This passageway 71 is narrow throughout its length, and passes radially inwardly past the radial end face 66 of the stator, and thence outwardly, downwardly and inwardly around the flange 67, prior to communication with the channel 65. This complex contour of the passageway 71, including the three rather sharp turns and the flow reversal created by the flange 67, hence makes it difficult for contaminates, such as water, to pass therethrough into the channel 65. If water or other contaminants do gain access to the channel 65 through the passageway 71, then the rotation of the rotor 22 and the effect of centrifugal force causes the contaminant to be thrown outwardly into the channel-like groove 64, from which the contaminant then drains outwardly from the groove through a drain slot or opening 74 (FIG. 2) which extends radially through the wall of the outer stator portion 52 for communication with the bottom side of the groove 64. This drain opening 74 discharges externally of the housing. 
     The pathway 24 also includes a narrow annular passage 73 (FIG. 3) which is defined between the opposed surfaces 31 and 54, which passageway 73 extends axially between the channel 58 and the reservoir or compartment 12. The radial width of this passageway 73 is very small and this hence tends to restrict flow of lubricant therethrough into the compartment 58. However, if any lubricant does gain access into the compartment 58, then the rotation of the rotor 22 causes the lubricant to be thrown radially outwardly by centrifugal force so as to collect within the groove 57 formed in the stator. This groove 57, as its lowermost or bottom point as illustrated in FIG. 2, communicates with the compartment 12 through a small drain hole or slot 75 which opens axially through the end face 59. 
     To minimize the chance of lubricant or contaminant flowing between the channels 58 and 65, the portion 72 of the pathway 24 which extends between these channels is generally Z-shaped substantially as illustrated by FIG. 3. Further, the outer channel 65 is displaced radially outwardly from the rotational axis of the shaft by a distance which is greater than the radial spacing of the channel 58 from the shaft axis, whereby the Z-shaped intermediate passageway 72 hence has a middle leg which, as it extends from the inner channel 58 to the outer channel 65, projects radially outwardly. Thus, any external contaminant such as water within the channel 65 cannot freely pass into the channel 58 since the rotational centrifugal force effect created by rotation of the rotor 22 always tends to pump the contaminants radially outwardly of the passageway 72 so as to maintain such contaminants within the outer channel 65, from which they can be discharged through the drain hole 74. 
     OPERATION 
     While the operation of the invention has been briefly described above, nevertheless same will be summarized to ensure a complete understanding thereof. 
     During rotation of the shaft 13 relative to the housing 11, the lubricant associated with the bearing and/or the fluids associated with the interior compartment 12 can be positively maintained interiorly of the housing due to the presence of the bearing protector 21. The rotation of the rotor 22 along with the shaft 13, and the close interfitting relationship of the rotor 22 within the stator 23, is such as to severely restrict any outward flow of lubricant or fluid through the pathway 24, and in fact is such as to cause any such fluid or lubricant to be drained back to the interior compartment 12. For example, any lubricant which passes through the passageway 73 will become trapped within the channel 58 due to the rather large size of this channel. Further, the rotation of the rotor 22 causes any trapped lubricant or fluid to be thrown outwardly of the channel 58 into the outer groove 57 defined in the stator, from which the lubricant flows downwardly into the bottom part of this groove 57 and thence flows axially inwardly through the drain hole 75 back into the inner compartment 12. Any tendency for the fluid or lubricant to escape outwardly of the pathway 24 from the channel 58 is further resisted by the narrow Z-shaped passageway 72. 
     With respect to any attempt by external contaminants such as water to pass inwardly through the pathway 24, any such inward passage is initially resisted by the narrow passageway 71 and the configuration thereof, specifically the numerous turns and reverse flow caused by this passageway. Further, the rotation of the rotor wall defining the bottom of the groove 41, and its closeness to the axial end wall of the annular stator flange 67, also creates a centrifugal force effect which tends to force any fluid or contaminants in the passageway 71 radially outwardly, and thus further resists any tendency for external contaminants to flow inwardly along the passageway 71. In the event that any such external contaminants, such as water, do successfully flow through the passageway 71, then they become trapped in the enlarged annular chamber 65. Again, the centrifugal force effect created by the rotor 22 causes these contaminants to collect in the outer groove 64 of the stator, from which they flow downwardly into the bottom portion of this groove and then are discharged outwardly by gravity through the bottom drain hole 74 whereby they are thus again discharged back to the surrounding environment. Any tendency for the contaminants such as water to continue to flow inwardly through the pathway 24 beyond the channel 65 is resisted by the Z-shaped configuration of the intermediate passageway 72 and specifically the outward centrifugal effect achieved within this passage due to the rotation of the rotor. 
     Hence, the bearing protector of this invention assures positive lubrication of the bearing and at the same time can successfully prevent access of contaminants to the bearing, whereby positive lubrication and hence long life of the bearing can be achieved. The pathway 24 between the rotor 22 and stator 23 provides an additional significant function in that it defines an outlet so as to eliminate any potential pressure buildup which may occur within the lubricant associated with the bearing, whereby a separate pressure release opening (a typical source of contamination) can hence be eliminated. 
     FIG. 5 illustrates therein a variation of the bearing protector 21&#39; according to the present invention. Accordingly, corresponding parts have been designated by the same reference numerals but with the addition of a prime (&#39;) thereto. 
     The bearing protector 21&#39; illustrated by FIG. 5 again utilizes a rotor 22&#39; and stator 23&#39; which cooperate with one another and interfit between the shaft and housing in a manner substantially corresponding to that as described above relative to the FIG. 2 embodiment. In this variation of FIG. 5, the rotor 22&#39; is of a two-step configuration than a three-step configuration as shown by 52. This is achieved by defining the inner and intermediate portions of the same diameter as defined by the outer annular wall 84, which wall has axially-spaced annular channel-like grooves 35&#39; and 32&#39; formed therein. 
     The stator 23&#39; is basically of a three-step configuration, with the outer and intermediate annular portion 52&#39; and 51&#39; respectively having a uniform bore extending coaxially inwardly thereof so as to define an inner annular wall 85 of uniform diameter, the latter being disposed in close surrounding relationship to the outer annular wall 84 on the stator. These portions 51&#39; and 52&#39; again define the axially spaced channel-like grooves 57&#39; and 64&#39; therein so as to respectively cooperate and partially define the channels 58&#39; and 65&#39;. The channel-like groove 64&#39;, however, penetrates radially outwardly to a greater depth than the groove 57&#39; so as to provide for a more positive collection of contaminants within the channel 65&#39; and the external discharge thereof, thereby providing a more positive assurance that external contaminants cannot flow inwardly between the stator and rotor for access to the interior compartment 12&#39;. 
     The stator 23&#39;, however, does include the third annular portion, namely the inner annular portion 86. This latter portion defines thereon the inner axial end face 59&#39;, and in addition projects radially inwardly so as to closely radially overlap the axial end face 33&#39; of the rotor. In fact, this inner annular portion 86 in effect defines a radially inwardly projecting flange which closely radially overlaps the inner end of the rotor and projects radially inwardly so as to terminate in an inner annular surface 83 which closely concentrically surrounds the periphery of the rotatable shaft 13&#39;. Hence, the passageway 73&#39; which exists between the inner compartment 12&#39; and the channel 58&#39; is now of a generally L-shaped configuration which includes both a short horizontal leg extending directly along the periphery of the shaft and a radially projecting leg defined between the annular portion 86 and the adjacent end face 33&#39; of the rotor. This configuration of the passageway 73&#39; further restricts any attempt of the lubricant to gain access to the channel 58&#39;. This latter channel is also preferably provided with the one side wall 81 thereof, namely the side wall disposed closest to the inner compartment 12&#39;, sloped axially inwardly as it projects radially outwardly. Hence, due to the effect of centrifugal force caused by rotation of the rotor 22&#39;, coupled with the slope of this side wall 81, any lubricant which gains access to and is trapped in the channel 58&#39; is hence forced radially outwardly and the slope of this side wall 81 tends to direct the trapped lubricant radially outwardly and at the same time axially inwardly so that it can be readily discharged through the drain hole 75&#39; back into the inner compartment 12&#39;. 
     With the improved bearing protector 21 or 21&#39; according to the present invention, assembly of the bearing protector in association with the shaft and housing can be easily and readily achieved. For example, the stator 23 or 23&#39; is initially sealingly positioned within the outer end of the bearing housing opening 16 until the shoulder 61 abuts a front face of the bearing housing. The rotor 22 or 22&#39; can then be concentrically slid onto and along the shaft 13 or 13&#39; and into the mating rotor so as to assume an assembled position substantially as illustrated by FIGS. 2 or 5. Upon startup, the rotor will automatically axially space or &#34;set&#34; itself. 
     The rotor and stator are each constructed as continuous one-piece rings, preferably of bronze. However, the rotor and stator can also be constructed of other materials, such as stainless steel or other non-metallic materials in order to meet special requirements. 
     Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.