Swivel joint boot with assembly gauge and seal wear indicator

Abstract

A rotary union for connecting a stationary body to a rotating body. The rotary union has a rotatable wear plate connectable to the rotating body and a seal ring disposed in the wear plate. A spring biased piston engages the seal ring against the wear plate with a compression spring between an end flange and the piston. The end flange and piston are at least partially disposed within a shroud, wherein the shroud has at least one aperture extending therethrough. An alignment ring is formed on the piston and is viewable through the aperture in the shroud to confirm proper distance between the end flange and the piston and proper force applied to the piston. A seal wear indicator is connected to the piston and moves between an exposed position where the seal ring is not worn and a non-exposed position where the seal ring is worn.

Description

[0001] Cross Reference to Related Applications

[0002] This claims priority to U.S. Patent Application Serial No. 17 / 089,235, filed November 4, 2020, which is a formal patent application claiming priority to U.S. Provisional Patent Application Serial No. 62 / 935,764, filed November 15, 2019. TECHNICAL FIELD

[0003] The present disclosure relates generally to a piston-type rotary union primarily used in the papermaking industry, and in particular to a rotary union having a shroud that provides a fit gauge for proper installation of the rotary union and a seal wear indicator to enhance preventive maintenance of the rotary union. BACKGROUND

[0004] Rotary unions are commonly used in the papermaking industry to couple steam and condensate sources to a rotating drying cylinder of a papermaking machine. The rotary union provides a pressure-sealed joint formed between a journal of the drying cylinder in rotation and a stationary structure for delivering steam and condensate to and from the drying cylinder. By using a spring-loaded piston and steam pressure, a seal ring is positioned and pressed against a rotating wear plate attached to an end of the journal of the drying cylinder. A steam pipe and a condensate pipe pass through the piston, the wear plate, and the journal of the drying cylinder, and are surrounded by the seal ring.

[0005] Installation of prior art rotary unions is a time-consuming and difficult process. For example, a rotary union can provide a piston, where a compression spring is used between an end flange and the piston to force the piston against a seal ring, which in turn forces the seal ring against a rotating wear plate and a journal of the drying cylinder. The force applied to the seal ring by the piston is critical since the seal ring seals the non-rotating piston against the rotating wear plate and journal. The force applied to the seal ring by the piston is a function of the amount of compression applied to the piston by the compression spring. Therefore, when assembling the rotary union to the drying cylinder, the length to which the compression spring is compressed must be accurately measured. This requires the installer to accurately measure the distance between the end flange and the piston, which can be difficult given the structure of the rotary union, the surrounding equipment, and the biasing force of the compression spring.

[0006] As the rotating wear plate rotates against the seal ring, the seal ring begins to wear significantly. The spring-biased piston continuously applies pressure to the seal ring, thereby compensating for any material loss or wear of the seal ring caused by friction between the seal ring and the wear plate, such that the seal ring remains properly seated against the wear plate. Nonetheless, the thickness of the seal ring will eventually decrease, thereby necessitating replacement of the seal ring. However, there are few or no effective indicators as to when the seal ring must be replaced. For example, previous wear indicators included a protrusion fastened to the spring-biased piston, wherein, once the seal ring is excessively worn, the protrusion eventually contacts the wear plate. When this occurs, the protrusion engages the rotating wear plate, thereby emitting a loud, high-pitched noise that should alert workers and indicate the need for replacement of the seal ring. However, the facilities of paper mills are often very noisy, and thus the noise produced by the protrusion engaging the wear plate can be difficult to hear. Furthermore, once the protrusion engages the rotating wear plate, the protrusion can be sheared off by the piston, thereby preventing any noise from being emitted and potentially causing the sheared-off protrusion to damage the seal ring or other components of the rotary joint. If a wear indicator is not used, the operator can continuously measure the distance from the end flange to the piston to determine the amount of wear on the seal ring, or the operator can disassemble the rotary joint to inspect the seal ring. Either way, if a seal ring indicator is not used to indicate whether the seal ring is worn, the operator must shut down the entire papermaking process and perform the appropriate measurements and inspections. Such measurements and inspections are time-consuming, difficult, and create inefficiencies that are undesirable in an industrial setting.

[0007] Finally, the compression spring between the end flange and the piston is typically exposed to components of the papermaking process. As the compression spring is often made of a metal material, the compression spring is often rusted or corroded due to steam and condensate that collects on the compression spring and other chemicals that can be used in conjunction with the papermaking process. This requires periodic replacement or cleaning of the compression spring, which is a time-consuming and costly process that creates inefficiencies in the papermaking process.

[0008] It is desirable to create a rotary joint for papermaking industry manufacturing that can be quickly and accurately installed and assembled, while providing a simple indicator for seal ring wear and providing protection for the compression spring from rusting and corrosion due to steam, condensate, and other chemicals associated with the papermaking process. SUMMARY

[0009] The present disclosure provides a rotary joint for connecting a stationary body to a rotating body, the rotary joint having a rotatable wear plate connectable to the rotating body and a seal ring disposed in the wear plate. A spring biased piston engages the seal ring and holds the seal ring disposed against the wear plate, wherein the piston is spring biased by a plurality of compression springs compressed between an end flange and the piston to bias the piston toward the seal ring. A shroud is connected to the end flange and the end flange and the piston are at least partially disposed within the shroud, wherein the shroud has at least one aperture extending therethrough. A plurality of annular alignment rings are formed on the piston and are observable through the at least one aperture in the shroud to confirm proper distance between the end flange and the piston to establish proper spring force applied to the piston against the seal ring.

[0010] The plurality of annular alignment rings include annular recesses that are substantially parallel while being spaced apart axially and at equal predetermined distances.

[0011] A seal wear indicator can be connected to the piston and movable between an exposed position where the seal ring is not worn and a non-exposed position where the seal ring is worn. The seal wear indicator has an annular ring disposed within an annular recess on the piston, wherein the annular ring is visible between the shroud and the seal ring when in the exposed position, and wherein the annular ring is not visible between the shroud and the seal ring when the annular ring is in the non-exposed position.

[0012] The shroud can have a pointer that extends into each of the at least one aperture to assess the position of the plurality of alignment rings.

[0013] An identifier can be located on the piston to identify which of the plurality of alignment rings identifies the ideal position of the piston. An aperture can extend through one of the plurality of alignment rings in the piston, wherein the aperture in the piston is circumferentially aligned with the at least one aperture in the shroud to observe the aperture in the piston through the at least one aperture in the shroud.

[0014] The shroud can be connected to the end flange via a snap fit, wherein the end flange has a protrusion extending therefrom and received and extending into a corresponding aperture in the shroud. The shroud can further have at least one vent including an aperture extending through the shroud to be observed and to allow fluid to escape through the at least one vent in the event that any fluid inadvertently escapes from the rotary joint. The shroud can be positioned to cover and contain the compression springs to avoid or reduce corrosion of the compression springs. BRIEF DESCRIPTION OF DRAWINGS

[0015] The disclosure is best understood from the following detailed description when read in connection with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Like numerals refer to like elements throughout.

[0016] Figure 1 is a perspective view of a rotary joint of the present disclosure attached to an inlet coupling and an outlet coupling;

[0017] Figure 2 is a cross-sectional view of a rotary joint, an inlet coupling, and an outlet coupling of the present disclosure;

[0018] Figure 3 is an exploded perspective view of a rotary joint of the present disclosure;

[0019] Figure 4 is a partial front view and cross-sectional view of a rotary joint of the present disclosure;

[0020] Figure 5A is a front plan view showing a seal wear indicator of a rotary joint of the present disclosure when the seal ring has worn;

[0021] Figure 5B is a front plan view showing a seal wear indicator of a rotary joint of the present disclosure when the seal ring has not worn;

[0022] Figure 6A is a cross-sectional view showing a seal wear indicator and a seal ring of a rotary joint of the present disclosure when the seal ring has worn;

[0023] Figure 6B is a cross-sectional view showing a seal wear indicator and a seal ring of a rotary joint of the present disclosure when the seal ring has not worn; and

[0024] Figure 7 is a perspective view showing an alignment recess ring of a piston and an alignment aperture of a shroud of a rotary joint of the present disclosure. DETAILED DESCRIPTION

[0025] The present disclosure relates to a rotary joint or rotary joint box 10 that can be used in combination with a rotary drying cylinder (not shown) of a papermaking machine (not shown). The rotary joint 10 provides a sealed connection to the drying cylinder to transfer pressurized steam, water, and air from and to the drying cylinder. As Figure 1As seen, the rotary joint 10 has a body portion 12, one end of which is connected to the drying cylinder and the opposite end to an inlet connector or connector body 14, which receives pressurized steam and air from a pressurization source (not shown). An outlet connector 16 is connected to and communicates with the inlet connector 14 to guide steam, condensate, and air from the drying cylinder. A separate passage (not shown) is provided to allow pressurized steam and air to flow from the inlet connector 14 to the drying cylinder. A siphon (not shown) is installed below the center of the inlet connector 14, against a conical cone within the inlet connector 14, and secured to the outlet connector 16 with a hollow bolt (not shown), thereby allowing steam, condensate, and air from the drying cylinder to exit through the outlet connector 16.

[0026] To direct pressurized steam and air to the drying cylinder, the inlet connector 14 has an inlet 18 for receiving pressurized steam and air from the pressurization source, such as Figures 1-2 As seen in the diagram. Inlet 18 communicates with an inlet passage (not shown) extending through inlet connector 14 and through the body portion 12 of rotary joint 10. Outlet connector 16 is connected to inlet connector 14 and has an outlet 20 for allowing pressurized steam, condensate, and air to escape from the drying cylinder. Outlet 20 communicates with an outlet passage (not shown) extending through outlet connector 16 and with an outlet pipe (not shown) extending from outlet connector 16, through inlet connector 14 and the body portion 12 of rotary joint 10, and into the drying cylinder. The interior of the outlet pipe defines the outlet passage, and the inlet passage is defined by an annular space (not shown) adjacent to the outer periphery of the outlet pipe. The outlet pipe is sealed between inlet connector 14 and outlet connector 16, such that incoming pressurized steam and air are separated from outgoing pressurized steam, condensate, and air.

[0027] To provide a seal between the rotating drying cylinder of the paper machine and the stationary body portion 12 of the rotary joint 10, the drying cylinder provides a generally cylindrical rotating journal end 22 extending from the drying cylinder, as shown in... Figures 2-4The rotary union 10 provides a generally cylindrical wear plate 24 having a plurality of similar holes that align with corresponding threaded holes in the journal end 22 of the drying cylinder. Conventional fasteners 26 extend through the holes in the wear plate 24 and are threaded into the threaded holes in the journal end 22 to connect the front side 32 of the wear plate 24 to the journal end 22, thereby causing the wear plate 24 to rotate with the journal end 22. The wear plate 24 further provides a generally concave or angular recess 30 that extends from the inner diameter of the wear plate 24 toward a back side 34 of the wear plate 24 that faces the body portion 12 of the rotary union 10. The recess 30 in the wear plate 24 complementarily or matingly receives a generally cylindrical seal ring 36 having an outer surface that is generally convex or frustoconical in shape so as to be complementarily or matingly received by the recess 30 in the wear plate 24. The wear plate 24 rotates over the seal ring 36, wherein the seal ring 36 is allowed to rotate with the wear plate 24, remain stationary with the piston 38, or rotate at an intermittent speed depending on the tribological characteristics of the mating components. Thus, the seal ring 36 is susceptible to wear while still maintaining a seal between the body portion 12 of the rotary union 10 and the wear plate 24. The seal ring 36 is made of a material that is resistant to wear while still having sealing properties, such as but not limited to a metalloid, such as antimony.

[0028] To maintain the position and sealing properties of the seal ring 36 as the wear plate 24 rotates, a piston or nipple 38 is spring biased and disposed in the body portion 12 of the rotary union 10. The piston 38 is generally cylindrical and has a mushroom shape with a larger head portion 40 and a smaller stem portion 42 that extends integrally from the head portion 40. The substantially flat front end 44 of the head portion 40 of the piston 38 engages the seal ring 36 by continuously applying a spring bias force to the seal ring 36 such that the seal ring 36 remains seated in the recess 30 of the rotating wear plate 24.

[0029] The piston 38 is spring biased by use of a generally cylindrical end flange 46 having a plurality of similar circumferentially spaced apart recessed rings 48 formed in a front side 62 of the end flange 46 for receiving and seating a first end 54 of each of a plurality of similar compression springs 50. The back side 52 of the head portion 40 of the piston 38 also has a similar generally circular recessed portion 56 for seating a second end 60 of each of the compression springs 50. A plurality of similar holes 58 extend through the head portion 40 of the piston 38 and are aligned with but coaxially offset from the recessed rings 48 in the end flange 46 and the circular recess 56 in the head portion 40 of the piston 38. The end flange 46 also has a plurality of similar holes 66 that extend through the end flange 46 and are aligned with and coaxial to the holes 58 in the head portion 40 of the piston 38, thereby being aligned with and axially offset from the recessed rings 48 in the end flange 46. A plurality of quick release pins 65 (as Figure 2a plurality of U-shaped clip pins 64 (as shown) or Figure 3 、 Figure 4 、 Figure 6A and Figure 6B extend from the rear side 84 of the end flange 46 through the aperture 66 in the end flange 46, the compression spring 50, and the aperture 58 in the head portion 40 of the piston 38. It should be noted that either the quick release pins 65 or the U-shaped clip pins 64 or a combination thereof can be used. In the non-limiting disclosure, either six quick release pins 65 or six U-shaped clip pins 64 can be used; however, other numbers of quick release pins 65 and U-shaped clip pins 64 can be used. Since the apertures 58, 66 are coaxially offset from the recessed ring 48 in the end flange 46 and the circular recess 56 in the head portion 40 of the piston 38, the quick release pins 64 or the U-shaped clip pins 64 extend through the compression spring 50 in a non-coaxial manner. The quick release pins 65 and the U-shaped clip pins 64 each have a head 68 that is larger than the aperture 66 in the end flange 46, thereby preventing the head 68 of the quick release pins 65 or the U-shaped clip pins 64 from passing through the aperture 66 in the end flange 46. An end cap 70 has a generally cylindrical mushroom shape with a larger head portion 72 and a smaller stem portion 74. The head portion 72 engages the head 68 of the quick release pins 65 or the U-shaped clip pins 64, and the stem 74 of the end cap 70 extends between the piston 38 and the compression spring 50. The stem 74 of the end cap 70 coaxially receives the stem 42 of the piston 38, with the head 40 of the piston 38 providing an annular recess 76 for receiving the end of the stem 74 of the end cap 70. A pair of similar flexible O-rings 78 are seated in a pair of similar annular recesses 82 in the stem 42 of the piston 38 to provide a seal between the stem 74 of the end cap 70 and the stem 42 of the piston 38. The head 72 of the end cap 70 is connected to the end flange 46 by a pair of set screws 80. The inlet coupler 14 is substantially coplanar with and abuts the head 72 of the end cap 70 and the rear side 84 of the end flange 46, and the end flange 46 is connected to the inlet coupler 14 by the use of conventional fasteners 86.

[0030] To hold the body portion 12 of the rotary union 10 in an assembled and loaded position prior to installation of the rotary union 10 to the journal end 22 of the drying cylinder, the free ends of the quick release pins 65 or the clevis pins 64 extend beyond the second end 60 of the compression spring 50 and are received by the holes 58 in the piston 38, which correspond in number and alignment to the holes 66 in the end flange 46. The holes 58 in the piston 38 have a constriction 90 toward the second end 60 of the compression spring 50, and become larger than the constriction 90 toward the front end 44 of the piston 38. Each quick release pin 65 has a spring loaded protrusion 88 located toward the free end of the quick release pin 65, such that when the quick release pin 65 is inserted into the hole 58 of the piston 38, the protrusion 88 retracts at the constriction 90 of the hole 58 and expands outward as it passes the constriction 90 and into the larger portion of the hole 58. The protrusion 88 is shaped such that without the use of a tool (not shown) to retract the protrusion 88, the quick release pin 65 cannot be withdrawn toward the compression spring 50 beyond the constriction 90 in the hole 58 of the piston 38. Alternatively, the clevis pins 64 can be inserted into the holes 58 of the piston 38, with the clevis pins 64 extending through the constriction 90 of the hole 58 and into the larger portion of the hole 58. A retaining ring 89 is inserted into an annular recess provided on at least two of the clevis pins 64 to prevent the clevis pins 64 from being withdrawn toward the compression spring 50 beyond the constriction 90 in the hole 58 of the piston 38 without removal of the retaining ring 89. The protrusions 88 of the quick release pins 65 and the retaining rings 89 of the clevis pins 64 allow the body portion 12 of the rotary union 10 to be held in an assembled, slightly loaded position for shipping and installation, as the end flange 46, compression spring 50, piston 38, quick release pins 65 and / or clevis pins 64, and end cap 70 are assembled together with the compression spring 50 slightly compressed. It should be noted that the present disclosure is not limited to the use of the disclosed quick release pins 65 or clevis pins 64, but other pin mechanisms can be used.

[0031] The amount of pressure applied to the seal ring 36 by the piston 38 is critical in order to provide the proper wear and sealing characteristics of the seal ring 36 relative to the wear plate 24. The distance between the end flange 46 and the piston 38 determines the amount of compression applied to the compression spring 50, which in turn relates to the amount or force of pressure applied to the seal ring 36 by the piston 38. Therefore, the distance between the end flange 46 and the piston 38 must be carefully monitored, especially during the installation and assembly of the rotary union 10 to the drying cylinder. In order to provide a simple and accurate method for determining the proper distance between the end flange 46 and the piston 38, a generally cylindrical shroud 92 is placed between the end flange 46 and the piston 38. A first end 94 of the shroud 92 is seated within an annular recess provided in the end flange 46, and in addition, the end flange 46 has a plurality of arcuate protrusions 96 extending outwardly from the front side 62 of the end flange 46. In the non-limiting disclosure, three arcuate protrusions 96 are shown, but other numbers of arcuate protrusions 96 can be used. Each protrusion 96 has an engagement portion 98 extending radially outwardly that engages a corresponding slot 100 in the shroud 92 by a snap fit. That is, the shroud 92 is slightly flexible such that when the shroud 92 is placed over the protrusions 96, the shroud 92 flexes outwardly until the engagement portions 98 engage the slots 100, thereby allowing the shroud 92 to flex back to its relaxed position. The protrusions 96 allow the shroud 92 to be easily assembled onto the rotary union 10 without the need for fasteners or other connecting devices. The second, opposite end 102 of the shroud 92 extends over the outer diameter of the head portion 40 of the piston 38, thereby allowing the shroud 92 to enclose and house the compression spring 50. By housing the compression spring 50, the shroud 92 helps to prevent steam, water, and chemicals from corroding the compression spring 50, thereby reducing or eliminating the need to clean and maintain the compression spring 50 due to corrosion and rust. Vent openings 104 in the form of holes can extend through the shroud 92 to help identify leaks from the seal and to prevent internal pressurization caused by leaks. The vent openings 104 can be in the form of letters to advertise the manufacturer of the rotary union 10.

[0032] In order to determine the proper compression of the compression spring 50 and to provide an assembly gauge for the rotary union 10, the head portion 40 of the piston 38 has a plurality of axially and equidistantly spaced, substantially parallel, similar annular recesses or rings 106 formed in the outer diameter of the head portion 40 of the piston 38, as shown in Figure 3 and Figure 7Best seen. It should be noted that the present disclosure is not limited to multiple annular recesses or rings 106, but rather the present disclosure also contemplates the use of one annular recess or ring 106. Since the annular recess rings 106 are axially spaced apart, the annular recess rings 106 serve as a way to measure the distance between the end flange 46 and the piston 38 when compared to the relative position of the second end 102 of the boot 92 on the head portion 40 of the piston 38. To further aid in identifying the desired distance between the end flange 46 and the piston 38, the boot 92 has several similar holes 108 that extend through the second end 102 of the boot 92 that overlap the head portion 40 of the piston 38. The holes 108 in the boot 92 serve as a window to observe the annular recess rings 106 in the piston 38. A similarly shaped pointer or locator 110 can be formed in the holes 108 by extending the triangular portion of the boot 92 into the holes 108 to accurately assess the position of the annular recess rings 106 in the piston 38. A small circular recess or marker 112 can be placed in one of the annular recess rings 106 to identify the ideal or target assembly position of the rotary union 10. The annular recess rings 106 that extend beyond the annular recess ring 106 with the circular recess 112 can then correspond to varying amounts of extension from the target assembly position. For example, each annular recess ring 106 can correspond to an additional plus or minus 3 mm of extension from the target assembly position.

[0033] To monitor the wear of the seal ring 36, a seal wear indicator 114 is placed on the head portion 40 of the piston 38, as shown in FIG. 6. The seal wear indicator 114 is a circular ring that is placed on the head portion 40 of the piston 38. The seal wear indicator 114 is placed on the head portion 40 of the piston 38 so that the seal wear indicator 114 is in contact with the seal ring 36. The seal wear indicator 114 is made of a material that is harder than the seal ring 36. As the seal ring 36 wears, the seal wear indicator 114 will be pushed into the seal ring 36. The seal wear indicator 114 is designed to be pushed into the seal ring 36 by a distance of 3 mm. When the seal wear indicator 114 is pushed into the seal ring 36 by 3 mm, the seal ring 36 is considered to be worn out and should be replaced. The seal wear indicator 114 is designed to be pushed into the seal ring 36 by a distance of 3 mm. When the seal wear indicator 114 is pushed into the seal ring 36 by 3 mm, the seal ring 36 is considered to be worn out and should be replaced. Figure 5A , Figure 5B , Figure 6A and Figure 6BThe seal wear indicator 114 can include an annular ring seated in an annular recess in the head portion 40 of the piston 38 and can be observed in the annular space established between the second end 102 of the boot 92 and the wear plate 24. The seal wear indicator 114 is "auto-zeroing" in that the seal wear indicator 114 does not require installer intervention to set a starting point for the seal wear indicator 114. The seal wear indicator 114 can have a bright color to facilitate visibility. When the seal ring 36 is at its maximum size, such as when the seal ring 36 has little or no wear, the space between the boot 92 and the wear plate 24 is at its maximum. When the seal ring 36 has little or no wear, the entire seal wear indicator 114 can be observed from the exterior of the swivel 10, indicating to the user that the seal ring 36 has little or no wear and therefore does not need to be replaced. This is referred to as the exposed position. As the seal ring 36 wears, the seal ring 36 becomes smaller and the spring-biased piston 38 moves closer to the stationary boot 92 and toward the wear plate 24 to maintain the seal ring 36 seated and engaged against the wear plate 24. As this occurs, the seal wear indicator 114 begins to move into the wear plate 24 below the outer peripheral lip 116 of the wear plate 24, thereby blocking part of the seal wear indicator 114 from being seen from the exterior of the swivel 10. Once the seal ring 36 becomes too worn, the seal wear indicator 114 is completely blocked from being observed from the exterior of the swivel 10, indicating to the user that the seal ring 36 must be replaced. This is referred to as the unexposed position. The seal wear indicator 114 provides a simple method and device to indicate the amount of wear on the seal ring 36 without having to disassemble or measure the swivel 10.

[0034] When the rotary joint 10 is installed to the drying cylinder of the paper machine, the wear plate 24 is connected to the journal end 22 of the rotating drying cylinder of the paper machine and the seal ring 36 is seated within the wear plate 24. The body portion 12 of the rotary joint 10 is pre-assembled and moved into position for connection to the wear plate 24 as previously described, with the forward end 44 of the piston 38 engaging the seal ring 36. The body portion 12 of the rotary joint 10 is properly positioned by overlapping the shroud 92 with the head portion 40 of the piston 38 and extending the holes 108 in the shroud 92 over the recessed alignment rings 106 in the head portion 40 of the piston 38. The end flange 46 is then driven or pushed toward the piston 38, thereby compressing the compression spring 50 and moving the quick release pin 65 or clevis pin 64 forward in the hole 58 in the piston 38. Once the end flange 46 is driven toward the wear plate 24 and the spring 50 is compressed, the end flange 46 is rigidly connected to the rigid bracket 118 using a plurality of conventional fasteners 120. The bracket 118 in turn is connected to a stationary mounting flange (not shown) on the drying cylinder. The bracket 118 is pre-measured and the rotary joint 10 is designed so that the spring 50 is properly compressed when the rotary joint 10 is connected to the bracket 118 in the installed position. To ensure and check the proper position or fit of the end flange 46 relative to the piston 38, the alignment of the rotary joint 10 is determined by viewing the alignment recessed rings 106 in the head portion 40 of the piston 38 through the holes 108 of the shroud 92. Ideally, the circular recess 112 on one of the recessed alignment rings 106 should be aligned with the pointer 110 in the hole 108 of the shroud 92. However, if the circular recess 112 is not visible in the hole 108 of the shroud 92, but one of the other alignment rings 106 is visible in the hole 108 of the shroud 92, then the alignment is still acceptable. The alignment rings 106 are axially spaced 3 mm from each other, indicating that the rotary joint 10 is off alignment by 3 mm for each adjacent alignment ring 106 viewed through the hole 108 in the shroud 92. The rotary joint 10 can only be off center or out of alignment by plus or minus 6 mm or two alignment rings 106. Once connected to the bracket 118, the alignment of the rotary joint 10 is checked by viewing the alignment rings 106 in the hole 108 of the shroud 92. If the alignment is not proper, appropriate steps can be taken to properly align the rotary joint 10 by adding shims between the end flange 46 and the bracket 118 or by some other adjustment means. If the alignment is proper, the inlet coupling 18 is connected to the end flange 46 via conventional fasteners 86 and the outlet coupling 16 is connected to the inlet coupling 18 by conventional fasteners 122.

[0035] While the disclosure has been presented in connection with presently contemplated practical and preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements.

Claims

1. A rotary union for connecting a stationary body to a rotating body, the rotary union comprising: a rotatable wear plate connectable to the rotating body and against which a seal ring is seated; a non-rotatable piston having a plurality of annular alignment rings formed thereon and the piston is biased toward the seal ring by at least one compression spring, wherein the piston engages the seal ring to bias the seal ring against the wear plate and maintain the seal ring seated against the wear plate; and a shroud in which at least a portion of the piston is disposed and the shroud has at least one aperture extending therethrough for viewing the position of the annular alignment rings and determining the position of the piston and proper compression of the at least one compression spring during installation and assembly of the rotary union.

2. The rotary joint of claim 1, wherein, the plurality of annular alignment rings further comprising: a plurality of substantially parallel annular recesses axially and equally spaced at predetermined distances.

3. The rotary union of claim 1 further comprising: the shroud having a positioner extending into each of the at least one aperture to assess the position of the plurality of annular alignment rings.

4. The rotary union of claim 1 further comprising: an identifier on the piston to identify which of the plurality of annular alignment rings is the ideal position of the piston.

5. The rotary union of claim 1 further comprising: a seal wear indicator formed on the piston and at least partially viewable between the shroud and the wear plate, wherein the amount of the seal wear indicator viewed corresponds to an amount of wear associated with the seal ring.

6. A rotary union for connecting a stationary body to a rotating body, the rotary union comprising: a rotatable wear plate connectable to the rotating body and in which a seal ring is seated; a spring-biased piston for engaging the seal ring and maintaining the seal ring seated against the wear plate, wherein the piston is spring-biased by a plurality of compression springs compressed between an end flange and the piston to bias the piston toward the seal ring; a shroud connected to the end flange and the end flange and the piston are at least partially disposed within the shroud, wherein the shroud has at least one aperture extending therethrough; and a plurality of annular alignment rings are formed on the piston and are viewable through the at least one aperture in the shroud to confirm proper distance between the end flange and the piston during setup and installation of the rotary union prior to wear of the seal ring so as to establish proper spring force applied to the piston against the seal ring and proper compression of the compression springs.

7. The rotary union of claim 6 further comprising: The plurality of annular alignment rings includes annular recesses that are substantially parallel and axially and equally spaced apart by a predetermined distance.

8. The rotary union of claim 6, further comprising: a seal wear indicator connected to the piston and movable between an exposed position in which the seal ring is un-worn and a non-exposed position in which the seal ring is worn.

9. The rotary union of claim 8, further comprising: the seal wear indicator has an annular ring seated within an annular recess on the piston, wherein in the exposed position the annular ring is visible between the shroud and the seal ring, and wherein when the annular ring is in the non-exposed position the annular ring is not visible between the shroud and the seal ring.

10. The rotary union of claim 6, further comprising: the shroud has a pointer that extends into each of the at least one aperture to assess a position of the plurality of annular alignment rings.

11. The rotary union of claim 6, further comprising: an identifier on the piston to identify which of the plurality of annular alignment rings identifies a desired position of the piston.

12. The rotary joint of claim 11, wherein, the identifier further comprises: an aperture extending through one of the plurality of annular alignment rings in the piston and the aperture in the piston is circumferentially aligned with the at least one aperture in the shroud to view the aperture in the piston through the at least one aperture in the shroud.

13. The rotary union of claim 6, further comprising: the shroud is connected to the end flange via a snap fit, wherein the end flange has a protrusion extending therefrom and received and extending into a corresponding aperture in the shroud.

14. The rotary union of claim 6, further comprising: the shroud has at least one vent including an aperture extending through the shroud to be observed and to allow fluid to escape through the at least one vent in the event that any fluid inadvertently escapes from the rotary union.

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