阅读说明：本技术 旋转接头 (Rotary joint ) 是由 A·A·彼得鲁 大卫·伯勒斯 于 2019-12-16 设计创作，主要内容包括：转子包括沿径向方向延伸穿过该转子的内部流体开口以及以相反方向设置在该转子上的两个环形密封件。该两个环形密封件中的每一个以可密封且可滑动方式接合该转子。定子围绕该转子及该两个环形密封件设置,且形成沿该径向方向延伸穿过该定子的外部流体开口。该定子包括设置在其轴向远端处的两个环形凸缘。该两个环形密封件中的每一个以可滑动方式接触该两个环形凸缘中的相应一个,以形成机械滑动面密封件。(The rotor includes an inner fluid opening extending through the rotor in a radial direction and two annular seals disposed on the rotor in opposite directions. Each of the two annular seals sealingly and slidably engages the rotor. A stator is disposed about the rotor and the two annular seals and forms an outer fluid opening extending through the stator in the radial direction. The stator includes two annular flanges disposed at axially distal ends thereof. Each of the two annular seals slidably contacts a respective one of the two annular flanges to form a mechanical sliding face seal.)

1. A swivel joint, comprising:

a rotatable assembly adapted to be mounted to a shaft, the rotatable assembly including an internal fluid opening extending through the rotatable assembly in a radial direction, the rotatable assembly including two annular seals disposed on a rotor in opposite directions, each of the two annular seals being sealably engaged on the rotor and slidable relative to the rotor in an axial direction perpendicular to the radial direction;

a non-rotatable assembly disposed about the rotatable assembly, the non-rotatable assembly forming an outer fluid opening extending through the non-rotatable assembly in the radial direction, the non-rotatable assembly including two annular flanges disposed at axial distal ends thereof;

wherein each of the two annular seals slidably contacts a respective one of the two annular flanges to form a mechanical sliding face seal;

wherein a radial gap is defined between the rotatable assembly and the non-rotatable assembly; and is

Wherein the radial gap is sealed in the axial direction at least in part by the mechanical sliding face seal between the two annular seals and the two annular flanges.

2. The rotary joint of claim 1, wherein the rotor further comprises a radial wall, wherein the inner fluid opening extends through the radial wall, and wherein the two annular seals slidably seal in the axial direction relative to the radial wall.

3. The rotary joint of claim 1, wherein each of the two annular flanges is attached to a stator, the stator having a generally hollow cylindrical shape.

4. The rotary joint of claim 3, further comprising mating threads on the two annular flanges and the axially distal end of the stator, wherein the two annular flanges are threadably engaged to the stator.

5. The rotary joint of claim 1, further comprising a plurality of compression springs disposed to apply a force biasing the two annular seals away from each other and toward the two annular flanges.

6. The rotary joint of claim 1, wherein the rotor includes a male segment having a ramped surface and a shoulder, each of the two annular seals includes a female segment having a ramped portion and a corner portion, and the female segments matingly engage the male segment when the two annular seals are disposed on the rotor such that the two annular seals are rotatably engaged for rotation with the rotor.

7. The rotary joint of claim 1, further comprising an anti-rotation device configured to:

a collar associated with the rotatable assembly, the anti-rotation collar comprising one or more notches adapted to engage corresponding slots in the shaft such that the rotatable assembly rotates with the shaft; or

A spring loaded pin extending outwardly from the shaft and engaging an angled notch formed in the rotor.

8. The rotary joint of claim 1, wherein during operation, the rotatable assembly is configured to rotate relative to the non-rotatable assembly, the non-rotatable assembly being stationary.

9. The rotary joint of claim 1, wherein during operation, the non-rotatable assembly is configured to rotate relative to the rotatable assembly, the rotatable assembly being stationary.

10. A swivel joint, comprising:

a rotor adapted to be mounted to a shaft, the rotor including an inner fluid opening extending through the rotor in a radial direction;

two annular seals disposed on the rotor in opposite directions, each of the two annular seals being sealably engaged on the rotor and slidable relative to the rotor in an axial direction perpendicular to the radial direction;

a stator disposed about the rotor and the two annular seals, the stator forming an outer fluid opening extending through the stator in the radial direction, the stator including two annular flanges disposed at axially distal ends thereof;

wherein each of the two annular seals slidably contacts a respective one of the two annular flanges to form a mechanical sliding face seal;

wherein a radial gap is defined between the rotor and the stator; and is

Wherein the radial gap is sealed in the axial direction at least in part by the mechanical sliding face seal between the two annular seals and the two annular flanges.

11. The rotary joint of claim 10, wherein the rotor further comprises a radial wall, wherein the inner fluid opening extends through the radial wall, and wherein the two annular seals slidably seal in the axial direction relative to the radial wall.

12. The rotary joint of claim 10, wherein the stator has a generally hollow cylindrical shape.

13. The rotary joint as set forth in claim 10 further including mating threads on said two annular flanges and said axially distal end of said stator, said two annular flanges being threadably engaged to said stator.

14. The rotary joint of claim 10, further comprising a plurality of compression springs disposed to apply a force biasing the two annular seals away from each other and toward the two annular flanges.

15. The rotary joint of claim 10, wherein the rotor includes a male segment having a ramped surface and a shoulder, each of the two annular seals includes a female segment having a ramped portion and a corner portion, and the female segments matingly engage the male segment when the two annular seals are disposed on the rotor such that the two annular seals are rotatably engaged for rotation with the shaft.

16. The rotary joint of claim 10, further comprising an anti-rotation feature such that the rotor and the two annular seals rotate with the shaft.

17. A method for operating a rotary joint, comprising:

providing a rotor mounted to a shaft, the rotor including an internal fluid opening extending through the rotor in a radial direction and in fluid communication with a fluid passage in the shaft;

providing two annular seals disposed on the rotor in opposite directions, each of the two annular seals being sealably engaged on the rotor and slidable relative to the rotor in an axial direction perpendicular to the radial direction;

providing a stator disposed about the rotor and the two annular seals, the stator forming an outer fluid opening extending through the stator in the radial direction, the stator including two annular flanges disposed at axially distal ends thereof;

slidably contacting each of the two annular flanges with a respective one of the two annular seals to form a mechanical sliding face seal; and

biasing the two annular flanges away from each other and towards the two annular flanges.

18. The method of claim 17 further including providing a radial wall on said rotor and slidably sealing said two annular seals against said radial wall.

19. The method of claim 17, further comprising releasably attaching each of the two annular flanges to an axially distal end of the stator.

20. The method of claim 17 further including providing a male segment on the rotor having a sloped surface and a shoulder; providing a female segment having a beveled portion and a corner portion on the two ring seals; and matingly engaging the female segment about the male segment such that the two annular seals are rotatably engaged for rotation with the shaft.

Technical Field

The present invention relates to rotary devices such as rotary union, slip ring, and the like.

Background

Fluid coupling devices, such as rotary union or rotary union, are used in a variety of applications, such as industrial applications, e.g., machining of metals or plastics, workpiece clamping, printing, plastic film manufacturing, paper making, and other industrial processes that require delivery of fluid media from a stationary source, such as a pump or reservoir, to a rotating assembly, such as a machine spindle, workpiece clamping system, or rotating drum or cylinder. Additional types of applications include use on vehicles for inflating tires, for example, during vehicle movement, or in marine applications delivering pneumatic or hydraulic fluid into a rotating shaft to activate a propeller pitch adjustment device. Typically, such applications require relatively high media pressures, flow rates, or high machine tool speeds.

One example of a rotary joint can be found in Ott et al, U.S. patent No. 7,407,198, which describes a radial rotary feed assembly. In the Ott device, the annular shaped rotor and stationary member include a sealing ring therebetween to seal fluid passages extending through the stationary member and into a shaft disposed within the rotor. While Ott's radial rotary delivery assembly is at least partially effective in providing a fluid seal between a rotating shaft and a stationary component, its arrangement requires disassembly and/or reassembly from one side of the shaft (e.g., during service), and further requires a cut-out in its seal ring to prevent it from rotating as the rotor rotates.

Disclosure of Invention

In one aspect, the present disclosure describes a rotary joint. The rotary joint includes a rotatable assembly adapted to be mounted to the shaft. The rotatable assembly includes an inner fluid opening extending in a radial direction through the rotatable assembly, and two annular seals mounted on the rotor in opposite directions. Each of the two annular seals is sealably engaged on the rotor and is slidable relative to the rotor in an axial direction perpendicular to the radial direction. A non-rotatable assembly is disposed about the rotatable assembly and forms an outer fluid opening extending through the non-rotatable assembly in the radial direction. The non-rotatable assembly includes two annular flanges disposed at axially distal ends thereof. Each of the two annular seals slidably contacts a respective one of the two annular flanges to form a mechanical sliding face seal. A radial gap is defined between the rotatable assembly and the non-rotatable assembly. The radial gap is sealed in an axial direction at least in part by the mechanical sliding face seal between the two annular seals and the two annular flanges.

In another aspect, the present disclosure describes a rotary joint including a rotor adapted to be mounted to a shaft, the rotor including an inner fluid opening extending through the rotor in a radial direction; and two annular seals disposed on the rotor in opposite directions, each of the two annular seals being sealably engaged on the rotor and slidable relative to the rotor in an axial direction perpendicular to the radial direction. The rotary joint further includes a stator disposed about the rotor and the two annular seals, the stator forming an outer fluid opening extending through the stator in the radial direction, the stator including two annular flanges disposed at axially distal ends thereof. Each of the two annular seals slidably contacts a respective one of the two annular flanges to form a mechanical sliding face seal. A radial gap is defined between the rotor and the stator. The radial gap is sealed in an axial direction at least in part by the mechanical sliding face seal between the two annular seals and the two annular flanges.

In another aspect, the present disclosure describes a method for operating a rotary joint. The method includes providing a rotor mounted on a shaft, the rotor including an internal fluid opening extending through the rotor in a radial direction and in fluid communication with a fluid passage in the shaft; providing two annular seals disposed on the rotor in opposite directions, each of the two annular seals being sealably engaged on the rotor and slidable relative to the rotor in an axial direction perpendicular to the radial direction; providing a stator disposed about the rotor and the two annular seals, the stator forming an outer fluid opening extending through the stator in the radial direction, the stator including two annular flanges disposed at axially distal ends thereof; bringing a respective one of said two annular flanges into slidable contact with each of said annular seals to form a mechanical sliding face seal; and biasing the two annular flanges away from each other and towards the annular flanges.

Drawings

Fig. 1 is a profile view of a rotary joint according to the present invention.

Fig. 2 is a cross-sectional view through a portion of the rotary joint of fig. 1.

Fig. 3 is a partially exploded view of the rotary joint of fig. 1 to illustrate an inner structure thereof.

Fig. 4 and 5 are different angled profile views of a seal ring used in the rotary joint of fig. 1.

FIG. 6 is an enlarged and partial cross-sectional view and pressure diagram of an alternative embodiment of a rotary joint according to the present invention.

Fig. 7 is a cross-sectional view of an alternative embodiment of a rotary joint according to the present invention.

Detailed Description

In the accompanying drawings which form a part of the specification, fig. 1 shows a profile view of a rotary joint 100 according to the present invention, and fig. 2 shows a cross-sectional view of the rotary joint 100 to show its internal structure. Referring to these figures, the rotary joint 100 generally includes a rotatable assembly 102 having a generally cylindrical shape that is rotatably disposed within a non-rotatable assembly 104. It should be understood that the terms "rotatable" and "non-rotatable" are used for descriptive purposes and are not to be construed as limiting the functionality of the assembly. For example, depending on the application, the rotatable assembly 102 may remain stationary while the non-rotatable assembly 104 is configured to rotate about the rotatable assembly 102 during operation. Further, in some applications, one or both of the assemblies 102 and 104 may rotate or turn at an angular displacement that is less than the full rotational angle. Thus, in general, such terms are used to refer to various components that are rotatably engaged with one another, regardless of their actual operational movement. In the illustrated exemplary embodiment, the rotatable assembly 102 is configured to be rotatably engaged such that it rotates with a propeller shaft of a marine vehicle (not shown), and the non-rotatable assembly 104 is configured to be mounted to a hull of the marine vehicle (not shown) and, in such mounting, remains stationary with the hull as the propeller shaft rotates.

As can be seen from the profile view of fig. 1, one or more inner fluid openings 106 are formed along an inner surface 110 of the rotatable assembly 102 that is adapted to be disposed about a portion of the propeller shaft, and one or more outer fluid openings 108 are formed along an outer surface 112 of the non-rotatable assembly 104. During operation, fluid may be sealably transported between the inner fluid opening 106 and the outer fluid opening 108 while the rotatable assembly 102 rotates relative to the non-rotatable assembly 104 (or vice versa). Sealing of the fluid transfer between the inner fluid opening 106 and the outer fluid opening 108 is achieved by using a sealing ring providing a sliding mechanical face seal, as can be seen more clearly in the cross-section of fig. 2.

Referring to FIG. 2, it can be seen that the rotatable assembly 102 includes a rotor 202 having an inner sleeve 204. The inner sleeve 204 has a generally hollow cylindrical or tubular shape that extends axially along a longitudinal axis. The rotor 202 further includes a radial wall 206 that extends radially outward relative to the longitudinal axis. Radial wall 206 defines one or more inner fluid openings 106, each of which extends in a radial direction through rotor 202 to fluidly connect inner surface 110 with an outer surface 208 of radial wall 206 (also shown in FIG. 3)

When the rotary joint 100 is mounted on a shaft (not shown), the inner sleeve 204 is disposed about an outer surface of the shaft in a clearance fit and overlaps a section of the shaft that may include fluid openings, for example, for supplying hydraulic fluid to operate a pitch control mechanism for the propeller blades (not shown). To seal against fluid leakage at the inner surface 110, the inner sleeve 204 includes two radial sealing grooves 210, the two radial sealing grooves 210 being disposed axially along the inner surface 110 on either side of the inner fluid opening 106. In the illustrated embodiment, the anti-rotation collar 211 includes a notch 212 that matingly engages a corresponding notch or keyway formed in the exterior of the shaft (not shown) to rotatably engage the rotor 202 with the rotating shaft (not shown).

The non-rotatable assembly 104 includes a stator 214 having a generally hollow cylindrical shape and surrounding the rotor 202 in a radial direction. The stator 214 forms an outer fluid opening 108, the outer fluid opening 108 extending through the stator 214 in a radial direction to fluidly connect the outer surface 112 with an inner surface 216 of the stator 214. As can be seen from fig. 2, there is an open space or radial gap 218 between the outer surface 208 of the rotor 202 and the inner surface 216 of the stator 214, which open space or radial gap 218 can transfer fluid between the inner fluid opening 106 and the outer fluid opening 108. The radial gap 218 extends circumferentially around the stator 214 and the rotor 202 such that fluid may be transferred regardless of the direction of rotation or movement between the rotor 202 and the stator 214. Fluid from the outer fluid opening 108 may be communicated to other components, such as a hollow sleeve (not shown), and may be provided with a radial seal (not shown) disposed in the groove 220, or alternatively, to a fitting (not shown) mounted directly onto or into the opening 108 in a typical manner.

To prevent fluid leakage through the radial gap 218, the rotary joint 100 includes two mechanical face seals 222, the two mechanical face seals 222 being disposed axially on either side of the radial gap 218 relative to the longitudinal axis L. Each face seal 222 has an annular shape and slidingly contacts two opposing annular flanges 224 and two opposing annular seals 226. In the particular embodiment shown in fig. 2, an annular flange 224 is connected to both axial ends and is disposed radially within the stator 214. As shown, threads 228 engage the annular flanges 224 to the stator 214, thereby permitting removal of each annular flange 224 for servicing, although other mounting arrangements may be used.

The annular seals 226 are disposed in opposite directions and form a portion of the rotatable assembly 102. In the particular embodiment shown in fig. 2, the annular seal 226 is slidably disposed on the rotor 202 and is allowed to slide in an axial direction along the longitudinal axis L. A spring 230 is disposed between the rotor 202 and the annular seal 226 and biases the annular seal 226 away from the rotor 202 and away from each other and toward the annular flanges 224 of the respective words. A radial seal 232 is disposed between the stator 214 and the annular flange 224, and also between the rotor 202 and the annular seal 226, to complete the sealing of the radial gap 218.

In the exemplary embodiment shown in fig. 2, and with reference also to fig. 5, which illustrates the annular seals 226 removed from the spin adapter 100, each annular seal 226 includes an outer annular surface 234 extending in a radial direction. The outer annular surface 234 includes a raised portion 236 that projects away from the annular surface 234 in the axial direction. The raised portions 236 contact and slide against the inner annular face 238 of the respective annular flange 224 to form the sliding mechanical face seal 222 on both sides of the rotary joint 100. An outer annular face 234 extends from the cylindrical body 240 of each annular seal 226. The cylindrical body 240 provides a surface that slidably and sealably engages the radial wall 206 of the rotor 202 via the radial seal 232.

To assemble the rotary joint 100 between a shaft (not shown) and a static receiver (also not shown), the rotor 202 may be installed around a section of the shaft, and then the annular seals 226 installed on both sides of the rotor 202. The stator 214 may then be placed around the annular seal 226 and the annular flange 224 mounted on both sides. To install the annular flange, an opening 242 may be formed in the exterior of the flange to allow engagement with a tool (not shown). Chamfers 244 may be formed on the inner, leading and trailing edges of the rotor 202 to facilitate mounting to the shaft.

As described above, the annular seal 226 is rotatably engaged to rotate with (or not rotate with) the rotor 202 and form a portion of the rotatable assembly 102. The rotatable engagement between the annular seal 226 and the rotor 202 may be achieved in various ways, such as keying, splines, and the like. In the illustrated embodiment, and as shown in fig. 3 and 4, an octagonal interface is used between the rotor 202 and each annular seal 226. As shown in FIG. 3, FIG. 3 is a partially disassembled rotatable assembly 102, wherein the annular seal 226 has been removed and the rotor 202 forms an octagonal male segment 302. The octagonal male section 302 includes symmetrically disposed inclined surfaces 304 and shoulders 306. The angled face 304 is generally oriented to overlap the same symmetrically spaced spring 230 locations. As shown in fig. 5, the octagonal male segment 302 is in mating engagement with an internally located octagonal female segment 402 formed in the annular seal 226. The octagonal female segment 402 includes an angled portion 404 that mates with the angled face 304 and a corner portion 406 that receives the shoulder 306. As can be seen from this view, a notch 408 formed on an inner surface 410 of the octagonal female section 402 receives and retains an end of the spring 230.

An enlarged cross-section of an alternative embodiment of a rotary joint 600 is shown in fig. 6. Also in this description, for descriptive purposes, the operating pressure on certain portions of the mechanical face seal 222 is shown. In the embodiment shown in fig. 6, the structures and features of rotary joint 600 that are the same or similar to the corresponding structures and features of rotary joint 100 are identified by the same reference numerals used previously for simplicity. Also in this description, for descriptive purposes, the operating pressure on certain portions of the mechanical face seal 222 is shown.

In the embodiment shown in fig. 6, the structures and features of rotary joint 600 that are the same or similar to the corresponding structures and features of rotary joint 100 are identified by the same reference numerals used previously for simplicity. Referring to fig. 6, it can be seen that the rotor 202 is disposed to a shaft 602. Rather than being made of two separate spring segments disposed mounted on either side of radial wall 206 (fig. 2), spring 230 is made of a single spring segment that extends through a bore 604 formed axially through radial wall 206. In its installed position, the spring 230 may be in a compressed state and thus exert a restoring force equally on the two annular seals 226 tending to push them apart and against the annular flange 224. Various forces acting on the sliding mechanical face seal 222 are illustrated with respect to the annular seal 226 shown on the right side of fig. 6.

Neglecting frictional or other external forces and accelerations that may act on the annular seal 226 in its operating environment, for purposes of this description, in the presence of pressurized fluid within the radial gap 218, a hydraulic closing force 606 may act on the seal 226 when the seal's closing hydraulic surface is exposed to fluid pressure. It should be noted that for the seal on the right side of fig. 6, the closing hydraulic force is in the rightward direction, i.e., the force that tends to push the annular seal 226 toward and against the annular flange 224. Also acting in the closing direction is a spring force 608 that comes from the restoring force exerted by the compression spring 230 on the annular seal 226.

In the opposite opening direction (which is the direction to the left or away from the annular flange 224 for the annular seal 226 described herein), a hydraulic opening force 610 acts on the annular seal 226 when the open hydraulic face of the seal is exposed to fluid pressure. The sealing pressure 612 acts along the mechanical face seal 222, which has a linear profile for incompressible fluids or a curved profile for compressible fluids. If the spring force 608 is not considered, the ratio of the opening hydraulic force to the closing hydraulic force may be defined as a balance ratio B for the annular seal 226 that is selected to be equal to 1 for transitional seals (B-1), less than 1 for stable seals (B < 1), and greater than 1 for unstable seals (B > 1). In the illustrated embodiment, the balance ratio is less than 85%, but other ratios may be used. Depending on the type of fluid used, the operating pressure, whether an open spring, a closed spring, or no spring is used, the type of spring and the spring constant value, among other parameters. For example, a larger contact area between sliding surfaces in the mechanical face seal 222 may reduce the balance ratio, and likewise, a smaller contact area may increase the balance ratio.

An enlarged cross-section of an alternative embodiment of a rotary joint 700 is shown in fig. 7. In this description, for the sake of simplicity, structures and features that are the same as or similar to corresponding structures and features already described for other embodiments are denoted by the same reference numerals as used previously. Referring to fig. 7, an alternative structure for mounting the rotor 202 to the shaft 602, for sealing the annular flange 224 to the stator 214, and for mounting the spring 230 between two opposing annular seals 226 is shown.

More specifically, unlike the embodiment shown in fig. 2, the threaded connection 228 between the annular flange 224 and the stator 214, where the threads 228 extend axially the entire length of the annular flange 224, in the embodiment shown in fig. 7 the length L of the threads 228 extending inwardly from the axial end face 702 of the stator 214 is less than the plate thickness of the annular flange 224 in the axial direction, leaving a radial seal 232 and corresponding grooves to accommodate the radial seal formed in the material of the stator 214 to enclose the radial seal 232 on three sides (i.e., radially outward and axially inward and outward of the radial seal). The radial seal 232 thus contacts the radially outward and axially inward edges of the annular flange 224, improving its sealing function because the outer diameter of the annular flange 224, rather than the final installed axial position, determines the compression of the seal 232.

With respect to spring placement, as can be seen in fig. 7, the radial wall 206 of the rotor 202 is much shorter than in the embodiment of fig. 2, thereby increasing the radial distance of the radial gap 218. In this manner, the spring 230 (see also fig. 6) is arranged to fit between the two ring seals 226 without being received in the guide opening or recess 408 (see fig. 4) or bore 604 (see fig. 6) of the rotatable assembly 102. This simplifies installation of the rotatable assembly components and reduces the complexity of the rotor 202.

Finally, to mount the rotor 202 to the shaft 602, the anti-rotation collar 211 and the notch 212 (FIG. 2) are replaced with spring-loaded pin fasteners 704, which spring-loaded pin fasteners 704 are mounted within threaded bores 706 formed through the shaft 602. Referring to the particular embodiment shown in fig. 7, a threaded bore 706 extends diametrically across a section of the shaft 602 and intersects a fluid passage 708 extending through the shaft 602. The bore is threadably engaged with a fastener 704, the fastener 704 including an externally threaded section 710, the externally threaded section 710 slidably receiving a pin 712 therein. The pin 712 is biased outwardly by a spring 714 such that a tip 716 extends radially outwardly relative to the outer diameter of the shaft 602.

When the rotor 202 is mounted on the shaft 602 alone or with the remaining components of the rotary joint 700 assembled thereon, the rotor 202 slides along the shaft 602 until it overlaps the tip 716 of the pin 712. As the rotor 202 continues to move, the tips retract thereby compressing the spring to an axial position in which the ramped notches 718 clear the tips 716, thereby allowing the tips 716 to extend into the ramped notches 718. The inclined notch 718 has a generally U-shape with an inclined axial face or ramp 720 on both axial ends that defines an inwardly facing concave recess. The ramp 720 allows the rotor 202 to be disassembled as the rotor 202 moves axially along the shaft 602 by causing the spring 714 to compress and the tip 716 to retract as the tip 716 follows the ramp 720.

When the tip 716 of the pin 712 is disposed within the notch 718, the flat side 722 extending parallel to the longitudinal axis L is pushed laterally (into or out of the page in the orientation shown in fig. 7) to rotatably engage the rotor 202 and the shaft 602 together via interference between the side 722 and the pin 712. The radial depth d of the ramped indentation 718, as well as the angle a of the ramp relative to the longitudinal axis, may be selected to be suitable for transferring a desired torque to the rotor 202 without shearing the tip 716 during operation.

Referring to fig. 6, it can be seen that the rotor 202 is disposed to a shaft 602. Rather than being made of two separate spring segments disposed on either side of radial wall 206 (fig. 2), spring 230 is made of a single spring segment that extends through a bore 604 formed axially through radial wall 206. In its installed position, the spring 230 may be in a compressed state and thus exert a restoring force equally on the two annular seals 226 tending to push them apart and against the annular flange 224. Various forces acting on the sliding mechanical face seal 222 are illustrated with respect to the annular seal 226 shown on the right side of fig. 6.

All references, including publications, patent applications, technical and user manuals, patents, and other materials, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms, i.e., meaning "including, but not limited to," unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all embodiments or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.