GB2174162A - Conduit connector structure and sealing ring - Google Patents

Abstract

A conduit-connector coupling structure has clamp segments (11,12) operating to cam together two flange members (27,28). The forward flange portions (25,26) of each of the flange members (27,28) together define conical recesses accommodating a metallic sealing ring (35). When the flange members are drawn together the sealing ring (35) is held in radial compression. The ring itself is provided with mutually spaced peripheral sealing lands (36,37) on respective ones of its oppositely tapered sides. The ring (35) is designed so that the recesses (40) separating the lands (36,37) will maintain their integrity for all radial compressions of the ring within the elastic limit and below the yield point of the material of the ring (35). The provision of a plurality of lands (36,37) ensures an effective sealing action even when one of the lands (36,37) is marred or damaged. <IMAGE>

Description

SPECIFICATION Conduit connector structure and sealing ring FIELD OF INVENTION The present invention relates to conduit connector structure or coupling means whereby two fluid conduits may be securely coupled together in a manner to avoid leakage. 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 for the purpose of preserving the seal function even though a portion of the seat, as is 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.

DESCRIPTION OF PRIOR ART In the past, many types of couplings have been employed to secure together fluid conduit. These conventionally employ gaskets, rubber or other elastomeric sealing rings, rubber O-rings, and so forth. While seal rings are certainly not unknown in this art, see following U.S. patents: Latham No. 3,325,176 and Latham No. 4,214,763, this is believed the first time, as the present invention, where multiple sealing 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-adjustment of the ring as may be needed, and (c) provide ease and reliability of ring fabrication.The prior art above-mentioned is relevant as regards the concept of using seal rings having conical cross-sections. Neither of the patents, however, teach the advantage of employing multiple sealing lands so as to preserve overall sealing integrity despite the fact that the seats cooperable with such sealing lands may be scored or deformed, at least as to one or two of the lands. Indeed, in past installations, serious difficulty has been encountered in connection with the use of desirably hardened metal sealing rings made of stainless steel, for example, and cooperation 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 deformations of the seats of the structure.Perhaps even scratches will produce slight inwardly directed protuberances which are difficult to deal with so far as the sealing is concerned.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention, interconduit 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 essentially conical or tapered surface serving as respective 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 incorporate mutually spaced peripheral sealing lands which are intended to serve as sealing surfaces relative to the seats provided the flange members. Typically for a three-inch (I.D.) ring, the raised sealing lands will be raised approximately twelve-thousandths of an inch above adjacent recesses and approximately the same amount relative to the sides forming themedial or central apex.

Typical dimensions, wideth-wise relative to the sealing lands, will be about sixty thousandths of an inch, with eighty-five thousandths clearance existing as between the lands on respective sides of such sealing ring. The attachment bolts accommodating the camming clamps are torqued sufficiently to have desired seal pressure exist as between the individual seal lands and those cooperating portions of the seats of the respective flange members. Pressures of 25 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 of multiple sealing lands, the same can act independently 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 endto-end compression but rather in radial compression. The annular, medial ring recess has perpendicular sides, for machining purposes and ease of fabrication; the recess itself is sufficiently wide to prevent interference between the ring at its central location and the surrounding structure, and also thereby to allow the ring to shift its position, along its axis, so as to self-adjust in the event, e.g., of irregular, expansions of surrounding structure during high temperature operations or should ring-receiving cavities of the surrounding structure be slightly dissimilar.

OBJECTS Accordingly, a principal object of the present invention is to provide new and improved conduit connector structure.

A further object is to provide a new and improved fluid 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 cou pling 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 straightsided, 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 fluid coupling structure a sealing ring and associated flange member structure, the sealing ring engaging inner tapered surfaces of 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 though certain portions of the seats of the flange members might be scored or otherwise deformed.

BRIEF DESCRIPTION OF DRAWINGS The features of the present invention, together with further objects and advantages thereof, may best be understood by reference to the drawings in which: Fig. 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 thereof, showing the flange member faces approaching each other.

Fig. 2 is an enlarged detail of the structure of Fig. 1, taken along the section line 2-2 in Fig. 1, illustrating the sealing ring herein in loaded condition to provide the seals desired.

Fig. 3 is a detail similar to Fig. 2, but drawn in reduced scale, illustrating structural conditions prior to radial compression loading of the sealing ring.

DESCRIPTION OF PREFERRED EMBODIMENTS In the drawings the conduit connector structure 10 is shown to include an upper clamp segment 11 and a lower clamp segment 12.

Each of these segments have respective bosses 13-16 which are integral relative to the respective clamp segments and which are provided with apertures 17 receiving bolts 18, 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 nuts.

Of further importance in the construction of the conduit connector structure 10 is the provision of a pair of flange members 21 and 22, the same having mutually facing annular, mutually facing end surfaces or faces 23 and 24, flange portions 25 and 26, and flange bodies 27 and 28, the latter being integral with the respective flange portions 25 and 26.

Annular, inclined or tapered surfaces 29 and 30 of flange portions 25, 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 surfaces 33A, 34A, and 33B and 34B; recesses 33, 34 are contiguous with surfaces 23 and 24, respectively, 11 and cooperatively receive metal sealing ring 35, the latter having central axis 35C.

A typical longitudinal section of the upper portion of the sealing ring is shown in Fig. 2, wherein it is seen that the combined, conical, extrapolated surfaces 36 and 37 of the ring's sealing lands, are parallel to and congruent with annular, tapered, sealing seat surfaces 33B and 34B having extrapolation intersection of the respective flange members 21 and 22.

Raised annular sealing lands 38A, 38B and 38C and 39A, 39B and 39C thus have the outer surfaces 36, 37 congruent with respective seat surfaces 33B, 34B of flange members 21, 22 respectively, and also are respectively mutually spaced apart by interland recesses 40. Any medial, annular apex as exist in prior sealing ring designs is now eliminated in preference for the existance of a central groove having essentially 90 annular sides or shoulders.

Of prime importance is the inclusion of central groove 42 having base 43 and opposite shoulders or sides 44, 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, 34B, thereby enabling the ring to self-adjust through axial longitudinal movement. The 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, 34B and the corresponding sealing land surfaces become non-symmetrical.

Continuing, as to operation, broadly, the upper and lower clamp segments 11 and 12 are brought together vertically by the tightening of nuts 20 relative to bolts 18. Owing to the tapered character of the surfaces 29-32, see Fig. 4, the flange members will be progressively brought together such that surfaces 23 and 24 in Fig. 4 gradually approach each other. These latter surfaces are not intended to contact one another until after the requisite seal pressures have been produced as between the surfaces 36 and 37 of the peripheral sealing ring lands 38A-38C and 39A-39C and their seals against seal surfaces 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 oneeighth the per unit loading at the seal surfaces, the total axial loading supplied at faces 23 and 24 will be sufficient 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 liquids and gases, extremely high pressures, and so forth.

It should be noted at this juncture that should either the seats 33B or 34B, or even a sealing land of the sealing ring itself, become misshapen, scored or deformed, this will not deter the sealing effect as to the remaining sealing lands and such seats. The flange members will be formed such that the axial recess depths, from a longitudinal standpoint, will exceed in their combined dimension the overall width of the ring. Surfaces 33A and 34A should not be designed to pressure-contact the opposite sides of the 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 interference with apex X and surfaces 41A, 41B, thereby facilitating proper ring closure and subsequent self adjustment as may be required during, e.g., elevated temperature operating conditions and differences as in coefficients of thermal expansion dissimilar metals employed during fabrication.

Accordingly, Fig. 3 illustrates the condition when the clamps are being initially tightened after the ring is preliminarily installed.

It is noted that, importantly, all of the parts will be made of metal. No 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 weld connection to align conduit 48 and 49, see Fig. 1. The welds are shown at 50 and 51.

There are many types weld configurations recessed, closings and attachment means that can be employed in lieu of the butt weld approach here given. What is important is that the coupling between the two conduit 48 and 49 take the form as that shown in Fig. 1.

In fabrication, then, the individual flange members 21 and 22 are preliminarily secured to the intended conduit. The flange members are then brought into alignment in a manner shown in drawings and the clamp segments are installed over the flange portions in the manner seen in Fig. 1.

As to certain additional structural details, portions 27A and 28A of each of the flange members are thickened with respect to the conduits 48 and 49, as indicated, to provide additional 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 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.

Accordingly, very high pressure seals are provided by the camming action of the clamp elements against surfaces 29 and 30 which urge the flange members 21, 22 toward each other, this resulting in the annular compression of the ring, whereby to stress the sealing ring 35, 35B within its elastic limit.

Claims (3)

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, 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, mutuallyspaced 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 perpendicular 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 in dividually provided with annular, oppositely sloping seal surfaces and means for urging said members toward each other: an 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 900 raised annular recess sides, contiguous with and mutually spacing inner ones of said sealing lands of said opposite sides.

3. A connector conduit structure and sealing ring substantially as hereinbefore described with reference to the accompanying drawings.