CA1284160C - Conduit connector structure and sealing-ring - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A conduit-connector coupling structure, otherwise sometimes known as a clamp-type connector, incorporating plural clamp segments operating to cam together flange members, producing the coupling. Clamp segments are employed with connecting attachment means so as to draw together the flange members employed upon the tightening down of the clamp segments relative to each other. The forward flange portions of each of the flange members are provided with conical recesses mutually accommodating the insertion of a metallic sealing ring. When the flange members are drawn together the sealing ring is held in radial compression. The ring itself is provided with mutually spaced peripheral sealing lands on respective ones of its oppositely tapered sides. The ring is designed so that the recesses separating the lands will essentially maintain their integrity for all radial compressions to the ring which is intended for use solely within the elastic limit and below the yield point of the material of such ring. The ring has a central annular recess which is straight-sided, for machining and related purposes. This recess reduces the pressure contact areas so as to increase effective seal pressures and also allow for free, unobstructed self-adjustment as may be needed through elevated temperature operating conditions or otherwise. It is to be noted that should a portion of the seat structure of the flange members become scored or damaged, so as to prevent a complete sealing action to take effect as between such flange member and one of the sealing lands of the ring, the remaining lands will still be present to effect the sealing function. An equivalent advantage obtains where it is one of the lands that might have a marred surface; the remaining lands will effect the seal. The recesses between the sealing lands of the sealing ring are provided, additionally in such sealing ring, to distribute the stress pattern and also to enable the ring to remain within the elastic limit of the seal ring material.

Description

~284~L60 The present invention relates to a conduit connector structure or coupling means whereby two fluid conduits may be securely coupled together in a manner -to avoid leaXage. In this invention the sealing ring employed -to effect seal integrity has oppositely tapered outer peripheral sides which have plural, mutually spaced sealing lands, this Eor ~he purpose of ; preserving the seal function even though a portion of the seat engaged by one of the lands might be damaged to otherwise deter seal effectiveness. Structural provision in the ring for self-adjustment and also ease and reliability of fabrication.

In the past many types of couplings have been employed to secure together a fluid conduit. These conventionally employ gaskets, rubber or other elastometric sealing rings, rubber O-rings and so forth. While seal rings are certainly not unknown in this art, see following U.S. Patent Number 3,325,176 issued to Latham and Number 4,214,763 issued to Latham, this is believed to be the first time where multiple sealings lands are chosen at the oppositely tapered peripheral surfaces of the ring, this in combination with a straight-sided relieved area at a central outer portion of the ring, so as to (a) increase sealing land pressures for a given clamping torque, ~b) permit self-ad]ustment of the ring as may be needed, and (c) provide ease and reliability o ring ~abrication. The prior art above mentioned is relevant as regards the concept of using seal r1ngs having conical cross sections. ~either of the patents however .

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teach -the advantage of employing multiple seaIings lands so ~s to preserve overall sealing integrity despite the fac-t that the seats co-operable with such sealing lands may be scored or de~ormed, at least as to one or two o the lands. Indeed, in past installations serious dificulty has been encountered in connection with the use of desirably hardened metal ~ealing rings, made of stainless steel for example, and co-operation with seats of softer metal or portions thereof might be deformed or scored. In the prior art this has been a difficulty chancing leakage just by virtue of the deformation of the seats of the structure. Perhaps even scratches will provide slight inwardly directed protuberances which are difficult to deal with so far as the sealing is concerned.
According to the present invention inter-conduit coupling is effected through the employment of a pair of flange members which are urged together by camming clamps, the latter being secured together and tightened down by bolts, threaded studs and the like. Each of the flange members include an inner, essentlally conical or~ tapered surface, serving as respectlve seats for the sealing ring employed. The sealing ring itself has opposite, annular, downwardly sloping sides, separated by a central, annular, normal sided recess. These sides incoxporate mutually spaced peripheral sealing lands which are intsnded to serve as seallng surfaces relatlve to the seats provided the~ ;
flangs members. Typically, for a three inch ~I.D.) ring, the , ?

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raised sealing lands will be raised approximately twelve-thousandths of an inch above adjacent recesses and approximately the sa~e amount relative to the sides orming the medial ox central apex. Typical dimensions, width~wise relative to the sealing lands, will be about sixty thousandths Oe an inc~, with eighty-five thousandths clearance existing between the land~ on respective sides of such sealing ring. The attachment bolts accommodating the camming clamps are torqued sufficien-tly to have desired seal pressure exist as between the individual seal lands and those co-operating portions o~ t'ne seats of the respective flange members. Pressures of ~S to 30 thousand psi at the seal surfaces are generally satisfactory. It is to be noted that at these pressures the material for the sealing ring will be chosen and the recesses dimensioned so that these will not "close out" during the torquing of the clamping bolts. By the employment oE multiple sealing lands the same can act indapendently to provide seals thereat, even though lands or, more probably, seal surfaces for other lands are scarred and might otherwise fail when taken separately as to the sealing function. It is to be noted that seals are maintained not in end-to-end compression but rather in radial compression. The annular, medial ring recess has perpendicular sides for machining pruposes and ease of fabrication; the recess itself is sufficiently wide to prevent interference between the ring at its central location and the surrounding structurel and also ~2~ 0 thereby to allow the ring to shift its position along its axis so as to self-adjust in the event of irregular expansions o - surrounding structure, during high -temperature operations, or should ring-receiving cavities of the surrounding structure be slightly dissimilar.
Accordingly, a principal object o~ the presenk inven~ion is to provide a new and improved conduit connec-~or ~tructure.
A further object is to provide a new and improved ~luid coupling.
A further object is to provide a fluid coupling suitable for handling corrosive or other fluids under all pressure~ or vacuum conditions.
A further object is to provide, in a fluid coupling, a metal sealing ring means having an outer surface recessed to control stress distribution and elastic deformation when the ring is brought into radial compression.
A further object is to provide, in conduit coupling structures, a sealing ring having oppositely tapered sides each provided with multiple sealing lands and also with a straight-sided central-recess or relief area.

A further object is to provide a new and useful type of fluid seal ring wherein the sealing function not be effective as to certain portions of the ring and its seat, other portions of the ring will be effective to retain the seal desired.
A further object is to provide in a fluid coupling ' . :

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- -~2~34~60 structure, a sealing ring and associated flange member - structure, the sealing ring engaging inner tapered sur~aces o~
such flange members, and with such sealing ring having multiple or sealing lands and a straight-sided annular recess area for ensuring seal integrity, even through certain portions o~ the ~: seats of the flange members might be scored or othe~wise deformed.
The features of the present inven-tion together with : further objects and advantages thereof may best be understood by reference to the draiwngs, in whicho FIGURE 1 is a fragmentary perspective view, partially broken away and sectioned, of the conduit connector structure and ring of ;the present invention in a preferred embodiment thereo~, showing the flange member faces approaching each other.
~ lS FIGURE 2 is an enlarged detail of the structure of Figure : 1 taken along the section line 2-2 in Figure 1 illustrating the sealing ring herein in loaded condition to provide the seals desired.
:~ FIGURE 3 is a detail similar to Figure 2 but drawn in reduced scale, illustrating structural conditions prior to radial compression loading of the sealing ring. ::
In the drawings the conduit connector structure 10 is shown to include an ùpper clamp segment 11 and a lower clamp segment 12. Each of these segments have respective bosses 13-16 which are integral relative to ~he respective segmants and which -7~
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are provided with apertures 17 receiving bolts 18k the same being four in number. The bolts may comprise threaded shanks 19 having opposite end nuts 20, or may simply be headed bolts having respective end ~uts.
Of -further importance in the construction oE -the conduit connec-tor structure 10 is the provis.ion o a pair oE fla~ge members 21 and 22, the same having mutually Eacing annular, mutually facing end surfaces or faces 23 and 24, flange portions 25 and 26 and flange bodies 27 and 28, the latter being inteyral with the respective flange portions 25 and 26.
Annular inclined or tapered surfaces 29 and 30 of flange por-tions 25 and 26 are essentially disposed at the same angle as the inner inclined surfaces 31 and 32 of each of the clamp segments 11 and 12. Importantly, annular recesses 33 and 34 are essentially defined by base sur-faces 33A, 34A and 33B and 34B;
recesses 33, 34 are contiguous with surfaces 23 and 24 respectively, 11 and co-operatively receive ~etal sealing ring : 35, the latter having central axis 35C.
A typical longitudinal section of the upper portion of the sealing ring is shown in Flgure 2 wherein it is seen that the combined, conical, extrapolated surfaces 36 and 37 of ~he ring's sealing lands are parallel to and congruent with annular, tapered, sealing seat surfaces 33B and 34B having extrapolation inter-section of the respeciive flange members 21 and 22.
Raised annular sealing lands 38A, 38B and 38C and 39A, 3~B and ~ ~

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39C thus have the outer surfaces 36 and 37 congruent with respective seat surfaces 33B and 34B of flange members 21 and 22 respectively and are also respectively mutually spaced apart by interland recesses 40. Any medial annular apex as exist in prior sealing ring designs is now eliminated in preerence ~or the existence of a central groove 42 having essentially 90 degree annular sides or shoulders.
Of prime importance is the inclusion of central groove 42 having base 43 and opposite shoulders or sides 44 and 45 that are essentially at right angles to horizontal groove base 43 for ease of machining and related purposes. Importantly, this central groove reduces combined land width so as to increase seal pressures at the land surfaces for a given torquing of nuts ; 20, and likewise frees the central part of the ring from interference with the proximate interior surface portions of flange surfaces 33B and 34B, thereby enabling the ring to self-adjust through axial longitudinal movement. ~he latter provision is or may be necessary in the event of differences in ;~ machining, or differences in materials and temperature elevations where, as a consequence, the interior surfaces 33B

and ~4B and the corresponding sealing land surfaces become non-symmetrical.
Continuing as to operation, broadly, the upper and lower clamp segments ll and 12 are brought together vertically by the tightening of nuts 20 relative to bolts 18~ Owing to the _g_ :~

- . ~ , ~2~ 6~3 tapered character o~ the sur~aces 29-32, (see Fi~ure 4) the flange members will be progressively brought together such that sur~aces 23 and 24 in Figure 4 gradually approach each o~her.
These la-tter surfaces are not intended to contact one another until after the requisite seal pressures have been produced as between the surEaces 36 and 37 of -the peripheral sealing ri~g lands 38A-38C and 39A-39C and their seals agains~ seal ~urfaces 33B and 34B. Accordingly, the sealing ring is maintained in radial compression and -the sealing pressure should be at least 25 to 30,000 psi at the seal surfaces. The torquing of the clamp segment bolts however is continued until the compression loading between faces 23 and 24 of flange members 21 and 22 is approximately two-thirds of the overall loading supplied by the clamps. Thus, even though interface per unit loading is only perhaps one-eighth the per unit loading at the seal surfaces, the total axiaI loading supplied at faces 23 and 24 will be suf~icient to deter the effects of thermal cycling and anticipated extreme bending moments at the coupling junction.
For high integrity sealing the employment of a high-strength stainless or low alloy steel is contemplated for the seal ring, such as a 286 stainless or 4140 low alloy steel, both having a high Young's modulus. A softer low strength carbon steel could be employed for the seal ring, but the same would have a greater tendency to distort and may not be suitable for corrosive li~uids and gases, extremely high pressures and so ~orth~

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~Z~ 60 It should be noted at this juncture that should ei-ther the seats 33B or 34B or even a sealing land of the sealing ring itself become misshapen, scored or de-formed, this will not deter the sealing effec-t as to the remaining sealing lan~s and such seats. l~e flange members will be ~ormed such -that the axial recess depths ~rom a longitudinal standpoint, will exceed in their combined dimensions -the overall width of the ring.
Surfaces 33A and 34A should not be designed to pressure-contact the opposite sides ofthe sealing ring, which if that were to happen would deleteriously influence the seals intended for the peripheral sealing lands.
The absence of ring material at groove 42 prevents inter-ference with apex X and surfaces 41A and 41B, thereby facilitating proper ring closure and subsequent sel-f-adjustmen-t as may be requ;red during, -for example, elevated temperature operating conditions and differences as in co-efficients of ; thermal expansion of dissimilar metals employed during fabrication.
Accordingly, Figure 3 illustrates the condition when the clamps are being initially tightened after the ring is preliminary installed.
It is noted that importantly, all of the parts will be made of metal. NG rubber gaskets, rubber seal rings, O-rings and so forth are generally intended in this particular high-pressure design. End chamfers as at 46 and 47 accommodate butt .
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weld connection to align conduit 48 and 49 (see Fiyure 1). 1~le welds are shown at 50 and 51.
There are many types of weld conEigurations, recessed, closings and attachment means, that can be emloyed in lieu o~
the butt weld approach here given. What is important is that the coupling between the two conduits 48 and 49 take the form as that shown in Figure 1.
In fabrication then the individual flange members 21 and 2~ are preliminarily secured to the intended conduit. The -flange members are then brought into alignment in a manner shown in the drawings and the clamp segments are installed over the flange portions in the manner seen in Figure 1.
As to certain additional structural details, portions 27A

and 28A of each of the flange members are thickened with respect lS to the conduits 48 and 49 as indicated, to provide additionai strength proximate the flange and sealing areas.
It is to be noted that should a portion of the seat structure of the flange members become scored or damaged, so as to prevent a complete sealing action to take efect between such flange member and one of the sealing lands of the ring, the remaining lands will still be present to effect the sealing function. An equivalent advantage obtains where it is one of the lands that might have a marred surface; the remaining lands will effect the seal. The recesses between the sealing lands o~
the seallng ring are provlded, additionally, in such sealing ~ ..

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ring to distribute the s-tress pattern and also to enable the ring to remain within the elastic limit of the seal ring material.
Accordingly, very high pressure seals are provided by the camming action of the clamp elemenks against surfaces 29 and 30 which urge -the flange members 21 and 22 toward each other, ~hia resulting in the annular compression o the ring whereby to :~ stress the sealing ring 35 and 35B within its elastic limit.
: While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifica-tions may be made without departing ~rom this invention in its broader aspects and :
therefore the aim in the appended claims is to cover all such changes and modiications as fall within the true spirit and scope o this invention.

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Claims (2)

1. In combination, a pair of flange members having mutually facing faces each provided with mutually corresponding annular recesses, having base surfaces and forming inner ring, essentially conical, seal-seat surfaces, a metal fluid sealing ring disposed in and between said recesses, said sealing ring having oppositely tapered opposite annular sides, each side being provided with integral, raised, mutually spaced annular sealing lands engaging respective ones of said seal-seat surfaces, said ring also having a central peripheral recess defined by a cylindrical base and normally raised annular opposite sides, said recess being contiguous with adjacent inner ones of said sealing lands of said opposite sides, whereby to provide a straight-sided relief area disposed therebetween and means for advancing said flange members toward each other to compression-load said sealing ring in radial directions perpend-icular to its central axis, whereby to pressure-seat said ring at said seal seat surfaces and thereby provide fluid seals thereat, said base surfaces of said recesses always being spaced from said ring.

2. In fluid conduit coupling structure having first and second fluid conducting members individually provided with annular oppositely sloping seal surfaces and means for urging said members toward each other; and improvement comprising a metal sealing ring interposed between said members for radially inward compression loading thereby, said ring having opposite, oppositely downwardly tapered sides each having outer, raised, mutually-spaced similarly sloping, annular sealing land surfaces pressure engaging and seating at corresponding ones of said seal surfaces, said ring having a peripheral medial cylindrical recess with 90 degree raised annular recess sides, contiguous with and mutually spacing inner ones of said sealing lands of said opposite sides.