This invention relates generally to fluid couplings and more particularly to fluid couplings having seal assemblies including flexible gaskets and flexible retainers for those gaskets.
Ring seals are typically annularly shaped, defining an axially aligned hole for gas or fluid passage, two axially opposed end surfaces, a radial inner surface and a radially outer surface. A simplistic ring seal has planar end surfaces and smooth circular radial inner and outer surfaces which define the inner diameter (ID) and outer diameter (OD) of the ring seal. However, it is common practice in the industry to utilize seals having different radial cross-sections to obtain varying sealing capabilities for different fluid flow environments.
A commonly used ring seal is circular and has a radial cross-section of a “C” shape. These “C seals” are constructed with the open side of the C construction facing the center of the ring such as is described in U.S. Pat. No. 5,354,072, or with the open side of the C facing away from the center of two mating surfaces are brought together with the C seal in the middle, the C seal is compressed with the open side of the C cross-section closing during compression. The ductile properties of the seal permit plastic deformation to occur without damaging the mating surfaces.
Additional seals which have been available include “V” seals which are also circular, but instead of having a “C” cross-section, have a “V” cross-section with the low point of the V constructed to point either inwardly or outwardly towards the center of the seal. Other seals known in the art include “Z” seals and simple 0-rings. These other types of seals are discussed, for example, in U.S. Pat. No. 6,708,985. Both of the '072 and '985 patents are herein expressly incorporated by reference, in their entirety.
Still another type of ring seal known in the industry is the “W”-seal type face seal, particularly adapted for use in surface mount gas panels. Such a sealing system is disclosed, for example, in U.S. Pat. No. 7,140,647, also herein expressly incorporated by reference, in its entirety. The “W” seal in the '647 patent uses a snap ring situated on the inside of a retaining ring, identified in the patent as a guide, to retain the W-seal in the retainer and to keep the sealing surfaces on the W-seal or gasket protected from scratches. The '647 patent retainer or guide also has a snap ring situated on its outside diameter to keep the retainer engaged in the counterbore.
Thus, each prior art W-seal requires four separate parts, including two snap rings, and three formed grooves for accommodating those snap rings, resulting in manufacturing complexity and relatively high cost. Additionally, these snap rings have often been found to make it substantially more difficult to remove the seal from the counterbore when desired, causing productivity problems, and sometimes damage to the seal assembly. Another reason why these types of seals often stick in the counterbore when it is desired to remove them is because the seal is a thick VCR gasket, and tends to compress when expanded, thus causing the retainer to also expand.
There are other problems with prior art ring seals of this type. These problems include the seal sometimes pushing the bead over, causing a leak due to high load, as well as the seal tending to move off-center. The off-center problem is often related to a build-up of tolerances because of the multiple parts, including the two snap rings, as well as over-compression of the snap ring, which causes the round retainer to distort into an oval or ellipse, thus forcing the seal off-center.
What is needed, for above described sealing system applications, is a face seal system which affords certain functional advantages without the necessity and expense involved in employing snap rings, and which is preferably constructed to permit easy removal from the counterbore.
The present invention addresses the issues noted above, by providing a ring sealing system suitable for applications such as a semiconductor manufacturing modular gas delivery system.
Specifically, the inventive sealing system comprises a retainer for a gasket used to connect modular piping in a modular gas delivery system to the gas flow controlling components. The retainer design protects the polished sealing surface of the W-seal gasket from scratches before assembly by suspending the gasket at least 0.003 inches inside the retainer, regardless of orientation. Additionally, a slit or gap in the circumference of the retainer allows the retainer to flex open for insertion of the W-seal gasket. A small chamfer on the ID of the retainer, in certain embodiments, aids the easier insertion of the W-seal into the retainer.
The gap in the circumference of the retainer also allows the retainer to compress to a smaller circumference, for a tight fit inside the sealing counterbore. In the ID of the retainer, there is a groove machined for a protruding portion of the W-seal to engage. The depth of this groove is such that with a complete compression of the retainer where the circumferential gap is completely closed, the protruding edge of the W-seal still has some clearance. This clearance, which acts as a stop to prevent the retainer from being overly compressed, insures that the seal and retainer assembly will not jam while trying to insert the assembly into the counterbore.
The slit or gap in the circumference of the retainer allows for a larger tolerance in the machining on the OD of the retainer. With current designs, a slightly oversized OD will prevent insertion of the retainer and seal assembly into the counterbore because there is no room for compression. In the inventive design, the retainer is free to close up to 0.010 inches as currently manufactured. The gap in the circumference can be made larger and achieve the same results.
There is a slight chamfer around the OD of the retainer for easier location of the retainer on the counterbore. The top half of the retainer has a slightly smaller OD for easy alignment of surface mount components. This is especially important for components with multiple sealing points that engage on the same block.
An additional advantageous feature of the present invention is the employment of a chamfer on at least one outside corner of the annular retaining member for easing installation of the retaining member into a counterbore. A chamfer may also be disposed on at least one inside corner of the annular retaining member for easing insertion of the sealing member into the retaining member. Yet another advantageous feature of the invention is the inclusion of a load adjustment groove disposed on the ID of the seal member, for substantially improving the elastic response of the seal.
More particularly, there is provided a ring seal assembly which comprises an annular metal seal having an ID, an OD, an upper sealing surface, and a lower sealing surface, wherein the OD comprises a larger OD portion and a smaller OD portion. An annular metal retaining ring is also provided, comprising an outer wall having an ID and OD, wherein the ID of the retaining ring is sufficiently large to accommodate the OD of the annular metal seal within its boundaries. Advantageously, the ID of the retaining ring has a groove disposed therein which is circumferentially arranged to receive the larger OD portion of the annular metal seal. The larger OD portion of the seal comprises metal, and extends radially into the groove and the remaining ID portion of the retaining ring bounding the smaller OD portion of the seal.
The retaining ring is circumferentially compressible to a reduced circumferential size. The compressibility arises because a gap exists between at least a portion of the circumference of the retaining ring and a corresponding portion of the circumference of the seal when the retaining ring is in a relaxed state and thus at its full natural circumferential size. This gap permits the retaining ring to be compressed without impacting the seal.
A split is disposed through at least a portion of the retaining ring at a particular circumferential location thereon to provide the retaining ring with its circumferential compressibility. In one illustrated embodiment, this split extends upwardly from a bottom edge of the retaining ring through only the larger OD portion of the retaining ring. Preferably, a plurality of these partial splits are circumferentially spaced about said retaining ring. In other embodiments a single split extends upwardly through the entire height of the circumferential wall defining the retaining ring.
The section of the retaining ring outer wall defining the larger ID portion is relatively thick and the section of the retaining ring outer wall defining the smaller ID portion is relatively thin. In certain inventive embodiments, the OD of the retaining ring is substantially uniform, while in others, the OD of the retaining ring comprises a smaller OD portion and a larger OD portion. In still another illustrated embodiment, a removal groove is disposed in the smaller retaining ring OD portion. This removal groove assists in visually determining the proper orientation of the seal assembly in the counterbore, and preferably groove forms a radially-oriented ledge for assisting in removal of the assembly from a counterbore.
The OD of the seal preferably comprises a load adjusting feature. This load adjusting feature may comprise a groove extending circumferentially about the OD of the seal, or it may comprise a plurality of circumferentially spaced bores. The circumferentially spaced bores may form a single row between the smaller OD portion and the larger OD portion of the seal, or may form a row on the smaller OD portion of the seal and a second row on the larger OD portion of the seal.
An important feature of the present invention is the provision of a chamfer on at least one inside corner of the retaining ring for easing insertion of the sealing member into the retaining member. A second chamfer may be disposed on at least one outside corner of the retaining ring, and even more advantageously, a chamfer or angled step may be provided on the larger OD portion of the seal for engaging the chamfer on the retaining ring.
The inventive seal assembly does not have any snap rings, an important advantage over prior art approaches.
In another aspect of the invention, there is provided a ring seal assembly, which comprises an annular seal member having an inner diameter (ID) and an outer diameter (OD), and having an axial hole defined by the ID for fluid passage, wherein the OD of the seal member comprises a smaller OD portion and a larger OD portion. An annular retaining member is also provided, having an ID and an OD, wherein the ID of the retaining member is larger than the OD of the seal member. A chamfer is provided on at least one inside corner of the annular retaining member for easing insertion of the sealing member into the retaining member. The OD of the seal member comprises a smaller OD portion and a larger OD portion and the ID of the retaining member comprises an axially cylindrical first portion and a second portion comprising a groove extending radially outwardly of the first portion for receiving and accommodating the larger OD portion of the seal, which extends radially outwardly into the groove.
In its assembled state, with the seal disposed within the ID of the retaining ring, there is a gap between the seal and the retaining ring about a portion of the circumference of the assembly, to thereby permit compression of the retaining ring without substantial contact of the retaining ring with the seal. In one embodiment, the OD of the retaining ring comprises a smaller OD portion and a larger OD portion. A recess is disposed between an annular edge of the retaining ring and one of the upper and lower sealing surfaces of the sealing ring when the seal assembly is in an assembled state, the recess functioning to protect the one of the upper and lower sealing surfaces from inadvertent contact damage. A second recess is disposed between an opposing annular edge of the retaining ring and the other of the upper and lower sealing surfaces of the sealing ring when the seal assembly is in the assembled state, to thereby protect the other of the upper and lower sealing surfaces from inadvertent contact damage.
Advantageously, the inventive assembly does not have any snap rings.
In still another aspect of the invention, there is provided a fluid coupling which comprises a base block, a component, wherein the component is assembled to the base block, and a fluid flow passage extending through the assembled base block and component. A counterbore is disposed in the fluid passage and extends radially outwardly into the assembled base block and component, wherein each of the base block and component have a sealing bead extending into the counterbore for engaging a seal. A ring seal assembly is disposed in the fluid flow passage, and comprises an annular metal seal having an ID, an OD, an upper sealing surface, and a lower sealing surface. The OD comprises a larger OD portion and a smaller OD portion. An annular metal retaining ring comprises an outer wall having an ID and OD, wherein the ID of the retaining ring is sufficiently large to accommodate the OD of the annular metal seal within its boundaries. The ID of the retaining ring has a groove disposed therein which is circumferentially arranged to receive the larger OD portion of the annular metal seal. The larger OD portion of the seal comprises metal and extends radially into the groove and the remaining ID portion of the retaining ring bounding the smaller OD portion of the seal. The ring seal assembly is secured into the counterbore such that the sealing beads engage the annular metal seal to seal the joint between the base block and the component.
In yet another aspect of the invention, there is disclosed a method of assembling a resilient retaining ring and an annular seal, wherein the retaining ring comprises a chamfered edge. The method comprises a step of engaging the seal against the chamfered edge to expand the retaining ring, and a further step of sliding the seal into engagement with a groove on an ID surface of the retaining ring. Another step is that of permitting the retaining ring to expand circumferentially to seat and center the seal.
The invention, together with additional features and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. In these accompanying drawings, like reference numerals designate like parts throughout the figures.
a is an elevation of still another modified embodiment of a sealing gasket according to the present invention;
Referring now more particularly to
A retainer ID groove 28 is disposed on the ring 12, within the larger OD portion 26. An outer chamfer 30 is disposed on each corner on the OD of the retainer 12. Inner chamfers 32 are disposed on the lower corners of the ID of the retainer 12, as well.
The gasket 14 comprises a substantially cylindrical ID 34, surrounding and defining the center hole 16. The OD of the gasket 14 comprises a smaller OD portion 36 and a larger OD portion 38. Between these two portions 36, 38 is disposed a load adjustment groove 40, or, in alternative embodiments, cylindrical bores or depressions 40.
As illustrated in
Upon installation of the seal assembly 10 into the flow path 42, the component 46 and base block 48 are compressed axially about the seal assembly 10, causing a sealing bead 54 on each of the blocks 46, 48 to engage the gasket 14. It is noted that, even when fully compressed, the retainer 12 remains spaced from the walls defining the counterbore 50, 52, as shown in
It is important to note that the retainer 12 extends axially substantially above and below the seal 14. The reason for this is to ensure that, even when compressed, the upper and lower surfaces of the seal 14, which are highly polished, are protected from damage such as scratching, in order to preserve optimal seal integrity.
With reference now to
With respect to
As also shown throughout the various embodiments, chamfers 30 and 32 are preferably approximately 45 degrees, though that angle can be varied to a certain extent without substantially affecting ease of assembly.
A somewhat modified embodiment of the retaining ring 12 is illustrated in
Yet another modified embodiment of the gasket 14 is illustrated in
Referring once again to
As noted above, an important feature of the present invention is that both upper and lower sealing surfaces 60 (
To remove the retainer assembly from the counterbore, a slight pressure is applied against one side of the exposed top half of the retainer, thereby closing the slit gap 56, and then applying a slight upward pressure to flip the assembly out of the counterbore. No tools are required.
Advantages of the present invention include the following. The innovative retainer design functions to force the seal to a centered orientation. The retainer ring is chamfered at both ends to allow for easy insertion. This allows the columnar retainer to easily bottom out in the connecting block into which it is inserted prior to closure. The larger diameter portion of the stepped seal is captured top and bottom by the retainer in its relaxed or pre-compression position. There is no interference between the retainer and the elastic modifying portions (groove or bores) of the seal. The stepped seal has bores or a groove disposed thereon for adjusting the elastic response of the seal, and the retainer is internally and externally contoured to the steps for uniform clearance and flexural response to closing forces.
While this invention has been described with respect to various specific examples and embodiments, it is to be understood that various modifications may be made without departing from the scope thereof. Therefore, the above description should not be construed as limiting the invention, but merely as an exemplification of preferred embodiments thereof and that the invention can be variously practiced within the scope of the following claims.
This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. Application Ser. No. 61/420,268, entitled Ring Seal Retainer Assembly and Methods, filed on Dec. 6, 2010, which is commonly assigned herewith and herein expressly incorporated herein by reference, in its entirety.
Number | Date | Country | |
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61420268 | Dec 2010 | US |