Title of Invention

A HYGIENIC FLANGE GASKET

Abstract

A hygienic flange gasket for insertion into a circumferentially continuous groove of a flange joint for joining axially aligned tube ends (10, 12), the flange joint being of the type having axially opposed flanges (16, 18) at the tube ends to form a groove (30) there between when the joint is assembled, the groove being formed by axially opposed seal faces and radial end faces (22, 24) of the flanges, the groove comprising a groove first portion (32) that is open to an interior flow passage of said tubes and a. groove second portion (34) that extends radially outward from said groove first portion, the gasket (38) comprising a gasket first portion (40) that seals said groove, and a gasket second portion (34), the gasket second portion is axially compressed when the joint is assembled and engaged with the radial end faces to produce a radial, compression of gasket

Full Text

BACKGROUND OF THE INVENTION The present invention relates to hygienic flange -type tube joint thermal expansion area of gasket and, more particularly, to a flange-type tube joint incorporating an improved relationship between the face scal and an associated gasket Flange-type tube Joints have soft material gaskets, e.g elastomoric, plastic, etc , that are clamped between opposed flange end faces for sealing purposes These tube joints arc frequently used in hygienic processing systems where fluid retention is highly undesirable to these systems are usually constructed with small angle slopes on the, order of 2° on tubing runs and employ gravity drains Therefore, due to the small angle slope, it is necessary to limit the potential for fluid retention by concentrating on regions where fluid retention may occur For example, it is known to design the gasket and associated flanges such that when the joint is completed, the radially inner face of the gasket forms a substantially flush or smooth continuation between the interior surfaces of the connected tubes joints of this general type are shown, for example, in U S Patent Nos 3,775,832, 4,735,445, and German Patentschrifts CH 674764 A5 and 947,034 2 The prior art has proposed various methods or designs to assure that over or under compression of the gasket cannot occur In spite of this, it has been found that both situations can occur resulting in a variety of process problems that are significant and often unrecognized When gaskets arc ovet compressed the gasket material is extruded into the flow path of the pipe or tubing system This can happen during initial makeup of the fitting or following a period of elevated process temperatures, such as a steam sterilization cycle, when thermal expansion of the gasket will result in excessive extrusion Excessrvc extrusion causes several primary problems including flow restriction, cell sheat, system contamination and fluid retention. Flow restriction can occur, for example, from having the inner periphery of the gasket extend excessively into the flow path thus creating an orifice effect 1 lygienic systems ate validated by the FDA for specific cleaning procedures including minimum flow rates needed to create the turbulent flow conditions fequired to effect the cleaning process. A gasket in a festrictivc flow condition can cause the system to not meet the required fluid velocities and consequently not meet government regulations A second problem-, cell shear, is caused by delicate micro-organisms impacting on the extruded gasket resulting in the destruction of the cell which is the target product of the bioproccss A third problem, system contamination, can result when over time of exposure to proccss conditions, especially steam, an extruded gasket can become buttle and break off pieces that cause system 3 contamination A fourth problem, fluid retention, occurs when draming the system to recover the product The extruded gaskets tesult in rctention of substantial amounts of process fluid in the system this is a significant problem in systems requiring a high degree of cleanliness and/or case of flushing and changeover between process fluids. In the case of under comprcssion two primary problems occur, fluid entrapment and leakage. Under compression can occur from-improper assembly or as a result of thermal cycles. As a gasket extrudes under temperature, as discussed above, when cooled back to normal or ambient process temperatures, it will not return to its original position in conventional hygienic fittings When this condition occurs there is less compressive force on the remaining gasket material within the fitting which can cause the fitting to loosen In some cases only a single thermal cycle can result in a loss of the seal at the bore line which allows process fluid to enter the seal area and become entrapped The isolated fluid cannot be cleaned without disassembly and can cause contamination of the same or subsequent batches In some cases process fluid reaches atmosphere and leakage occurs SUMMMRY THE INVENTION The subject invention provides a tube joint constiuction of the type discussed above that is designed to eliminate or greatly reduce 4 gasket extrusion, reduce flow restriction, reduce contamination, reduce fluid retention, and provide improved alignment during assembly In particular, and m accordance with various aspects of the subject invention, a tube joint assembly of the general type discussed includes a pair of cylindrical tube ends in axially aligned contiguous relationship- Each tube end has a cylindrical interior surface of the same diameter in aligned relationship with the cylindrical interior surface of the opposed tube end Connecting flanges extend radially outwaid of each tube end with axially opposed faces defining a circumferentially continuous packing groove including a first axially narrow portion defined by axially opposed scaling faces The first axially narrow portion -opens to the cylindrical interior surfaces. A second axially wider portion of the groove is located radially outward of the first portion and has a radial outer face radially overlying and aligned with the first axially narrow portion A soft material gasket is positioned in the packing groove A preferred gasket configuration has a nairow pottion or rib that is sized and dimensioned to completely fill the first axially narrow portion of the packing groove and engage the axially sealing facts with substantial scaling pressure. An integral second portion or crown of the gasket is sized and dimensioned to cxtend into the second portion of the packing groove The second portion has an inner radial dimension that forms an 5 interference fit with the tube ends fbr case of assembly and sufficient mass to hold the tube ends in a desired aligned relation during makeup of the joint These structural hatures thus contribute to, improved alignment of the components in the assembled fluid system for case of assembly The second portion of the gasket also has a radial dimension sufficient to extend radially across the second portion of the packing groove and into compressivc engagement with the radial outer face thereof when the joint is completed The axial extent of the packing groove is sufficiently large to provide expansion space into which the gasket can expand when subjected to temperature increases Provision of the expansion space thereby reduces radially inward extrusion of the gasket beyond the cylindrical interior surfaces of the tube ends Preferably, and in accordance with a more limited aspect of the invention, rigid means are defined by surface portions carried on the opposed faces of the connecting flanges to prevent movement of the flanges toward one another beyond a predetermined minimum point The invention as described above results from a finding that materials used for such gaskets undergo an extrusion either as a result of initial makeup of the coupling or as a result of increased temperature By providing expansion space at a location disposed 6 radially ourward of the narrow inner sealing portion of the gasket, there results a significant reduction of gasket expansion into the flow path of the tube ends. The narrow inner sealing portion of the gasket zr radially loaded because the second portion of the gasket is sized to extend radially across the second portion of the packing groove into compressive engagement with the radial outer face of the second portion of the packing groove Moreover, the compressive engagement forms a secondary seal radially outward of the primary seal Additionally, the engagement between the gasket second portion and Lhe radial outer face of the packing groove provides a radial compression, or hoop strength, that permits the expansion of the gasket into the expansion space while holding the gasket, from undesired radial shifting of the narrow inner stating portion from its desired location adjacent the flow path As can be seen from the foregoing, a primary object of the invention is the of a fitting and gasket assembly wherein extrusion of the. gasket into the fluid flow path is substantially reduced and a smooth continuation of the inner wall surfaces of the connected tubes ts maintained thereby reducing fluid retention, flow restriction and system contamination 7 Still another object of the invention resides in the improved alignment of the components of the joint assembly Yet another object is the provision of a pipe or tube joint assembly that provides a secondary seal Still other advantages an benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The invention may take physical form in certain parts and arrangements of parts, preferred embodiments and a method of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, and wherein FIGURE 1 is a transverse cross-sectional view through a preferred form of pipe or tube joint construction formed in accordance with the subject invention, FIGURE 2 is a greatly enlarged view of the gasket recess of the made-up joint of FIGURE 1 to more fully show the relationships between the gasket and the gasket recess; 8 FIGURE 3 is a greatly arged cross-sectional view through the gasket, FIGURE 4 is a cross-sectional view of the gasket in its uncompressed form overlaid on the gasket recess to provide a better understanding of the relative relationships involved, FIGURE 5 is a cross-sectional view of another preferred embodiment of the invention, FIGURE 6 illustrates the addition of ports in the joint assembly fot sensing or monitoring the integrity of the bore line seal and potential contamination, and FIGURES 7A-7E illustrate alternative exemplary configurations and shapes for a gasket in accordance with the invention DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein the showings are for the purposes of illustrating preferred embodiments of the invention only and not for purposes of limiting same 9 A hygienic flange type tube joint thermal expansion area of gasket for insertion into a circumferentially continuous groove of a flange joint for joining axially aligned tube ends 10, 12, the flange joint is of the type having axially opposed flanges 16, 18 at the tube ends to form a groove 30 there between When the joint is assembled, the groove is formed by axially opposed seal faces and radial end faces 22, 24 of the flanges. The groove comprises of a groove first portion 32 that is open to an interior flow passage of the tubes and a groove second portion 34 that extends radially outward from the groove first portion The gasket 38 comprises of a gasket first portion 40 that seals the groove and a gasket second portion 34 that extends from the gasket first portion 40 and into the groove second portion The gasket second portion 42 is axially compressed when the joint is assembled and engages with the radial end faces to produce a radial, compression of the gasket The gasket second portion has a volume that is less than the volume of the gioove second portion to form an expansion space in the groove second portion when the joint is assembled FIGURE 1 shows a pair of axially aligned, cylindrical pipe or tube ends 10, 12 which arc joined in sealed relationship by a flange-type joint assembly 14 The tube ends 10, 12 have uniform inner open diameters D1 and D2, respectively, which are of the same diameter and positioned in, closely aligned relationship 10 Circumfercntially continuous, radially extending flanges 16, 18 respectively, are formed at the ends of each of the tube ends 10, 12. The flanges allow the tube ends to be clamped in the assembled condition shown by a conventional clamp ring 15 which is only schematically illustrated in the drawing Although the flanges 16, 18 could be formed as separate elements and suitably connected to the tube ends, they are shown in the subject embodiment as being integrally formed on the respective tube ends 10, 12 Each of the flanges 16, 18 includes a scaling end face that preferably lies in a plane perpendicular to the center axis 20 End faces 22, 24 of the flanges 16, 18 respectively, cooperate to define a circumferentially continuous packing receiving recess or groove 30. In the subject embodiment, the packing receiving groove 30 is arranged so that when the flange 16, 18 are clamped into the relationship shown in FIGURE 1, the groove 30 has a radial inner first portion 32 (see FIGURE 2) which is relatively narrow and opens toward the interior of the central flow passage. The groove 30 further includes a second axially wider portion 34 that is located radially outward of the first portion 32 and is circumferentially continuous thereabout The control of the width of the packing is provided by rigid extensions 16a, 18a on the radial outer edge of the flanges 1 6, 18 11 respectively, to limit movement of the flanges axially toward one another Positioned within the gtoove 30 is a gasket 38 formed from a suitable soft materil that will, form an effective seal when compressed between the flanges Many different gasket materials could be used including eth\lcne piopylcncs, fluorocarbons, siliconc rubbers, nitriles, ncoprenes, polyethylene and tetrafluoroethylenes. In this embodiment, the gasket 38 has a preferred cross-section as shown in FIGURE 3 As will be described hereinafter, the shape of the gasket 38 can have different configurations and appearances while still achieving the benefits and advantages of the invention. A radially inner portion 40 of the gasket defines a rib that has a substantially constant axial dimension that in an uncompressed state, is slightly greater than the , axial dimension of the radially inner portion of the groove (see the superimposed representation of FIGURE 4) When assembled, the radial inner portion is compressed between the faces 22, 24 to form a first or primary seal that fills the void defined by the inner, narrow portion of the groove Moreover in the illustrated embodiment of Figure 4 the inner radial diameter of the gasket in an uncompressed state is slightly greater than the diameter of the flow path Thus when the joint is fully assembled, the inner diameter of the gasket is displaced into a substantially flush relation with the diameter of the flow path creating a bore line seal that reduces fluid retention and prevents fluid entrapment, even at elevated system process 12 temperatures. In other embodiments, however, the uncompressed rib 40 can have a diameter that is less than, greater than or equal to the diameter of the flow path, depending on the associated fitting configuration, to produce after make-up a flush or substantially flush bore line seal. In some embodiments it will be desirable to permit a small extrusion of the gasket rib 40 into the flow path after make-up, as illustrated in an exaggerated manner in FIGURE 2 In such cases, especially for hygienic applications, it will be desired that the rib portion that extends into the flow path be convex to reduce fluid entrapment. The present invention can be used with such a configuration because the invention provides features that reduce further extrusion at elevated system process temperatures, as will be described hereinafter The radially outer portion 42 of the gasket has an enlarged axial and radial dimension relative to the rib 40 that forms, in the embodiment of Figure 3, a mushroom-shaped cap or crown 42 that extends integrally from the gaskel inner portion 40. Again, with reference FIGURE 4, the axial dimension of the cap (at its widest portion) in an uncompressed state is larger than the axial dimension of the groove in the completed joint. In this manner, the gasket is compressed into scaling contact with radial faces of the enlarged portion of the groove (see FIGURES 1 and 2) The compression resulting fiom these dimensional relationships also displaces the gasket 13 material radially outward so that it engages the radial outer wall of the groove at the rigid extensions 16a, 18a This engagement forms a secondary seal that can significantly increase the rated pressure of the assembly Furthermore, the secondary seal presents a barrier to atmosphere outside the hygienic fitting. For example , the secondary seal serves to make the hygienic fitting splash proof. The engagement also has the additional advantage of causing hoop stress (i.e increasing hoop strength) that prevents the nb of the gasket from moving radially outward in response to pressure in the fluid system Prior art arrangements that use axial compression and include a gap between the outer radial edge of the gasket and the groove wall (here defined by the rigid extensions) arc potentially subject in some applications to radial shifting of the gasket in response 10 pressure in the fluid line. The entire gasket in such prior designs is thus susceptible to radial shifting resulting in the loss of an effective bore line seal and the attendant problems of fluid retention, contamination, etc. In the present invention, the radial engagement between the rigid extensions 16a, 18a and the second portion of the gasket 42 thus inhibits this undesirable action while providing a sccondary seal 01 banter The rounded tapering outer radial region of the cap 42 with the inner portion 40 provides the distinctive mushroom shape to the 14 gasket. The smooth transition and reduction in the axial dimension of the gasket as it extends radially outward from the tube bore provides for expansion spaces 44, 46 The second axially wider portion 34 of the groove 30 is dimensioned to accommodate anticipated expansion of the gasket in response to elevated temperatures and is not intended to be completely filled by the gasket at ambient temperature Thus, even though the gasket engages the rigid extensions to form the secondary seal as described above, the spaces 44, 46 arc defined between the groove wall and the reduced or tapering region of the gasket The enlarged mass of the cap 42 provided by the preferred configuration also has the advantage of improving alignment of the joint components, even while still allowing for an expansion space and the radial compression That is, since the gasket is dimensioned to form an interference fit with the groove at the interface of the first and second portions of the groove, the gasket will remain in place on a first flange while the opposing flange is positioned for initial make-up of the joint assembly, and the opposing tubes are held in temporary alignment while the joint asembly is completed The enlarged mass of the gasket also provides a positive alignment reference in the nature of a "fit" that is tactilely sensed as the flanges arc brought together about the gasket and helps keep the flanges and tubes in alignment during the make-up procedure This allows the user to complete the joint 15 assembly without adjusting the alignment of the tube ends Likewise, the tubing alignment is improved since the initial makeup of the tubes is more accurate and maintained through assembly of the joint As illustrated in FIGURE 5, another preferred embodiment of the gasket incorporating the features of the invention is illustrated Particularly, it is evident that the gasket need not be symmetrically formed about a radial axis Fere, the right-hand face of the gasket has the generally mushroom-shape of the gasket described in connection with the embodiment of FIGURES 1-4 However, the outer radial portion of the gasket is not intended to engage the rigid extensions and form a secondary seal since an annular metal ring 50, is employed for receipt between the rigid extensions The engagement between the metal ring 50 and the faces of the rigid extensions limits the axial compression that can be imposed on the gasket The other features of the present invention such as (I) forming an effective bore line seal and (ii) forming an expansion spare upon makeup of the joint for elevated temperature conditions, are still provided The opposite face, or left-hand face, of the gasket is a conventional configuration and thus docs not incorporate all of the features of the invention It does illustrate, though, that the gasket can adopt a number of different configurations without departing from the overall scope and intent of the invention Thus, the assembly 38, 50 is in the form of an adapter device that permits two different flange configurations to be joined 16 While at the same time maintaining an effective bore fine seal and expansion area As illustrated in FIGURE, 5, a thin layer 38a of the gasket 38 material encapsulates the metal ring 50 This can be accomplished, for example, during a molding process for the gasket 38 The entire ring need not be encapsulated FIGURE 6 is another modification of the invention that incorporates sensing or monitoring capabilities to the joint assembly Particularly, when a secondary seal is formed by the cap or second portion of the -gasket, the flanges may be modified to include capillary ports 52a, 52b that communicate with the expansion spaces 44, 46 Suitable sensors (not shown) will communicate with the ports and provide an indication of the integrity of the bore line seal This provides the system operator with the ability to accurately monitor the integrity of the primary seal through the expansion spaces 44, 46 while the secondary seal still contains the system pressure if a bore line seal fails Moreover, the monitoring arrangement can be incorporated on both sides of the gasket or used on just one side if a modified form of gasket (for example as shown in FIGURE 5) is used. FIGURE 2 and 3 illustrate the preferred nominal dimensional relationships for the groove 30 and the gasket 38, respectively In 17 particular, the seal face of the flange has the general dimensions as shown for tubes having a nominal O D of 1.00 inches and an I D of 0 87 inches, however, the general relationships are valid for a range of tube sizes In reviewing these dimensions and comparing the recess dimensions with the gasket dimensions, it will be seen that the narrower inner portion of the seal is compressed in the axial dimension bv about 20-30% whereas the 'wider outer portion is compressed about 15-20%. This, of course, results in significantly higher sealing pressures between the rib 40 and the radial inner faces of the groove Additionally however, it will be seen that the wider portion of the gasket 38 is axially compressed until it moves to place the radial outer face of the gasket into compressive engagement with the radial outer face of the groove and form the secondary seal. It will also be understood by those skilled in the art that the expansion spaces 44, 46 are not constrained to the configuration shov n and described above Any suitable dimensioning of the gasket and groove that permits the desired expansion can be used Moreover, it is also contemplated that the gasket include void areas in the second portion of the gasket that can serve the same purpose Thus, for example, notches can be formed at spaced 18 circumferential locations of the gasket second portion or through openings in the gasket second portion can achieve this same objective Those skilled in the art will appreciate that the gasket 38 material will affect some of the functional aspects of the gasket. For example, when the gasket is made of an elastomeric material such as silicone rubbers and fluorocarbons to name two examples, the enlarged cap 42 will be compressed as the assembly 14 is made up, to produce the radial compression and secondary seal at the extensions 16a and 18a, When the gasket 38 is made of a relatively harder material, (although suitably soft to form the primary bore line seal at the faces 22, 24) such as polytetrafluoroethylene (PTFE), the enlarged cap 42 does not significantly extend radially so a.s to engage the extensions 16a and 18a Thus, in the case of PTFE, for example, the cap 42 mushroom shaped appearance is ornamental, although an interference fit and enlarged mass is still used to maintain alignment during initial make-up, materials such .is PTFE have sufficient hoop strength to maintain the boreline seal at the intended pressures without the added support of the radial compression. It should further be noted that in the described embodiment, such as FIGURE 2 for example, the end facts 22, 24 that define the groove enlarged portion 34, engage the axial outer portions of the cap 42 before the rib 40 is engaged This produces an initial compression 19 on the cap 42 that supports and helps control radial extension of the rib as the rib is compressed when the fitting is made up With reference to FIGURES 7A-7E, there is illustrated in an exemplary manner different shapes and configurations of the gasket 38, in particular the cross - sectional shapes (in FIGURES 7A-7E only-half of each cross-section of the gaskets 38 is illustrated) For example, FIGURE 7A, the radial taper m the gasket axial dimension is conical to form a flat edge 38a (when viewed in section) The exemplary shapes in FIGURES 7A-7E inclusive can include the interference fit and enlarged mass features vis-&-vis the packing groove 30 as described herein before Furthermore, when the gaskets of FIGURES 7A-7E arc made of an elastomer and with appropriate dimensions relative to the groove 30, they will be compressed and will extend radially to form the radial compression at the extensions 16a, 18a These different embodiments are provided to emphasize that the shape and configuration of the gasket cap 42 is largcy ornamental in terms of its appearance, and that the various desired functional aspects of the gasket 38 in accordance with the invention can be achieved with any number of configurations and shapes In accordance with another aspect of the invention, it will be appreciated from the foregoing descriptions that the gasket 38 can take on three radial dimensions at the rib inner annulus at different points 20 in the make-up of the assembly 14 For example, when the gasket is free standing, not yet mounted on a flange, the innre diameter of the rib 40 will be dimension X, for example, with X being greater than the lube 10, 12 inside diameter In other embodiments, the dimension X can be less than or equal to the tube inside diameter. When the gasket is pushed onto the counter bore 104 that forms the interface between the inner radial portion 32 and the radial outward portion 34 of the groove 30, the rib inner diameter will be dimension X + Y because of the interference fit Thirdly, after the assembly, 14 has been made up, the radial extension of the rib 40 caused by compression of the rib 40 will change the inner diameter of the rib 42 to be substantially equal to, the tube 10, 12 inside diameter to provide the flush bore line seal. Again, in some applications, the compression on the rib 40 will be designed to produce a slight extrusion preferably convex in nature (see FIGURE 1) into the tube inner diameter region to avoid a recess that could be difficult to clean in place In all the drawings herein, some relative dimensions, such as for example the relative squeeze on the rib and cap or the illustrated amount of extrusion into the fluid path, have been cxaggerated for clarity and ease of illustration While the invention has been shown and described with respect to specific embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to 21 those skilled in the art within the intended spirit and scope of the invention as set forth in the appended claims 22 WE CLAIM: 1 A hygienic flange gasket for insertion into a circumferentially continuous groove of a flange joint for joining axially aligned tube ends (10, 12), the flange joint being of the type having axially opposed flanges (16, 18) at the tube ends to form a groove (30) there between when the joint is assembled, the groove being formed by axially opposed seal faces and radial end faces (22, 24) of the flanges, the groove comprising a groove first portion (32) that is open to an interior flow passage of said tubes and a, groove second portion (34) that extends radially outward from said groove first portion, the gasket (38) comprising: a gasket first portion (40) that seals said groove, first portion and a gasket second portion (34) that extends from said gasket first portion (40) and into said groove second portion; said gasket second portion (42) being axially compressed when tihe joint is assembled and engaging with said radial end faces to produce a radial, compression of said gasket; said gasket second portion having a volume that is less than volume of said groove second portion to form an expansion space in said groove second portion when the joint is assembled 23 2 A hygienic flange gasket as claimed in claim 1 wherein said radial compression of said gasket forms a secondary seal that is radially aligned and radially spaced from said gasket first portion seal. 3. A hygienic flange gasket as claimed in claim 1 wherein said radial compression opposes radial pressure from fluid in the flow passage to prevent radial displacement of said gasket. 4. A hygienic flange gasket as claimed in claim 1 wherein said radial compression effectively increases hoop strength of said gasket. 5. A hygienic flange gasket as claimed in claim 1 wherein said gasket second portion has a cross section that tapers axially in a radially outward direction from said gasket first portion. 6. A hygienic flange gasket as claimed in claim 5 wherein said expansion space is formed between the opposed flange faces and said gasket tapered cross section. 7. A hygienic flange gasket as claimed in claim 1 wherein said gasket comprises an elastomer material 24 8 A hygienic flange gasket as claimed in claim 1 wherein said gasket has a symmetrical cross sectional shape 9 A hygienic flange gasket as claimed in claim 1 wherein said radial compression of the gasket provides a barrier to atmosphere 10 A hygienic flange gasket as claimed in claim 1 wherein the groove first portion is axially narrower than the groove second portion to form a shoulder at the radial interface thereof, said gasket being sized to have an interference fit with said shoulder to retain the gasket in position while the joint is assembled 11 A hygienic flange gasket as claimed in claim 10 wherein said gasket second portion when uncompressed has an axial dimension that is greater than an axial dimension of said groove second portion and has sufficient mass to maintain a desired alignment of the, flanges during assembly of the joint Dated this 20th day of February, 1998 25 A hygienic flange gasket for insertion into a circumferentially continuous groove of a flange joint for joining axially aligned tube ends (10, 12), the flange joint being of the type having axially opposed flanges (16, 18) at the tube ends to form a groove (30) there between when the joint is assembled, the groove being formed by axially opposed seal faces and radial end faces (22, 24) of the flanges, the groove comprising a groove first portion (32) that is open to an interior flow passage of said tubes and a. groove second portion (34) that extends radially outward from said groove first portion, the gasket (38) comprising a gasket first portion (40) that seals said groove, and a gasket second portion (34), the gasket second portion is axially compressed when the joint is assembled and engaged with the radial end faces to produce a radial, compression of gasket

Documents:

00274-cal-1998-abstract.pdf

00274-cal-1998-claims.pdf

00274-cal-1998-correspondence.pdf

00274-cal-1998-description(complete).pdf

00274-cal-1998-drawings.pdf

00274-cal-1998-form-1.pdf

00274-cal-1998-form-2.pdf

00274-cal-1998-form-3.pdf

00274-cal-1998-form-5.pdf

00274-cal-1998-priority document.pdf

274-cal-1998-granted-abstract.pdf

274-cal-1998-granted-claims.pdf

274-cal-1998-granted-correspondence.pdf

274-cal-1998-granted-description (complete).pdf

274-cal-1998-granted-drawings.pdf

274-cal-1998-granted-examination report.pdf

274-cal-1998-granted-form 1.pdf

274-cal-1998-granted-form 2.pdf

274-cal-1998-granted-form 3.pdf

274-cal-1998-granted-form 6.pdf

274-cal-1998-granted-letter patent.pdf

274-cal-1998-granted-pa.pdf

274-cal-1998-granted-reply to examination report.pdf

274-cal-1998-granted-specification.pdf

274-cal-1998-granted-translated copy of priority document.pdf