GB2025555A - Conduit connector - Google Patents

Abstract

A conduit connector (10) incorporates plural clamp segments (11, 12) operating to cam together flange members (21, 22) producing the coupling. Clamp segments (11, 12) are employed with bolts (18) so as to draw together the flange members (21, 22) employed upon the tightening down of the clamp segments relative to each other. The opposing faces of each of the flange members (21, 22) are provided with recesses mutually accommodating the insertion of a metallic sealing ring. When the flange members (21, 22) are drawn together the sealing ring is held in compression, the ring being arranged so as to distribute the stress pattern and also to remain within its elastic limit. Accordingly, as compression forces are maintained against opposite sides of the sealing ring, the opposite end edges of the ring tend to bow inwardly to increase the sealing effect between the ring margins and their recess seats prior to closure of the faces of the flange members. <IMAGE>

Description

SPECIFICATION Conduit connector 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 the past, many types of couplings have been employed to secure together fluid conduits. These conventionally employ gaskets, rubber or other elastomeric sealing rings, rubber- O-rings, and so forth.

According to the present invention a conduit connector comprising a pair of flange members having opposed surfaces each provided with an annular recess forming an annular, inclined, seal-seat surface; a metal sealing ring disposed in the recesses; and means for advancing the flanges towards each other to compression load the sealing ring in a direction perpendicular to its central axis, to pressure-seat the ring at the seal-seat surfaces and provide fluid seals thereat.

In the present invention, coupling is effected through the employment of a pair of flange members. Each of the flange members may include a forward flange portion and also a respective flange body integral therewith.

The flanges do not produce seals between themselves but rather incorporate, through adjacent recesses a separate sealing ring.

Clamp means surround cam surfaces of the forward flange portions of each flange member so that when the clamp segments are drawn toward each other as by the incorporation of tightening bolt means, the flange members put into annular compression the sealing ring to produce the seal required. This sealing ring is not made of gasket material, rubber or other elastomeric or plastic; rather, the seal ring is chosen to be stainless or low alloy steel, in a preferred form of the invention, and may include annular relief portions to provide for distribution and control of surface seating.

In operation, as the flange members are drawn together to apply a compression seal against the included metal sealing ring, the ring margins tend to bow inwardly to increase the sealing effect on the ring seats and to accommodate surface loading. The seals produced are effective prior to direct contact of flange faces. In general, the seal ring is designed to provide an interference fit within seal recess of the flange members. This inteference is controlled within the elastic limit of the seal ring so material as not to produce plastic deformation or permanent distortion of the seal ring.

Accordingly, by means of the connector of the invention a very tight, high integrity seal is supplied for providing the coupling with the capability of passing high and low pressure fluids, both gases and liquids, corrosive or otherwise, between the flange members and past the sealing ring without leakage. Seal integrity can be maintained even under severe vibration, bending or thermal cycling loads. In addition, seal integrity can be maintained in bimetallic systems where flange members may be of dissimilar material with differing coefficients of thermal expansion.

An example of a connector according to the present invention will now be described with reference to the accompanying drawings in which :- Figure 1 is a perspective view, partially broken away and sectioned, of the conduit connector; Figure 2 is an end view of the connector of Fig. 1 and taken along the section line 2-2 in Fig. 1; Figure 3 is a cross-section of the connector of Fig. land 2 and is taken along the line 3-3 in Fig. 2; Figure 4A is a longitudinal vertical section of the connector illustrating the relative position of the flange members when the clamp segments are tightened; Figure 4B is similar to Fig. 4A but illustrates the configurement of the flange members and interposed seal ring .before the clamp segments are tightened to effect a seal between the flange members; and, Figures 5A and 5B are enlarged fragmentary sections of operative respective portions of the flange members and seal ring shown in Figs. 4A and 4B, respectively, but illustrating the configurement of such seal ring at and prior to substantial closure of the flange members relative to each other when the clamp segments are tightened.

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 with the respective clamp segments and which are provided with apertures 17 receiving bolts 18 (four in number). The bolts have screwthreaded shanks 19 and cooperate with end nuts 20; alternatively the bolts may simply be headed bolts having a single end nut.

The connector includes a pair of flange members 21 and 22 having mutually facing annular surfaces 23 and 24, flanges portions 25 and 26, and flange bodies 27 and 28 integral with the respective flange portions 25 and 26.

Annular, inclined or tapered surfaces 29 and 30 are disposed on the respective flange portions 25, 26 at the same angle as inner inclined surfaces 31 and 32 on each of the clamp segments 11 and 12. Annular recesses 33 and 34 (see Fig. 5b) are formed contiguous with surfaces 23 and 24, respectively, and receive in use a metal sealing ring 35.

A typical longitudinal section of the upper portion of the sealing ring is shown in Fig. 5B wherein it is seen that surfaces 36 and 37 on the sealing ring 35 are parallel to sealing seat surfaces 38 and 39 on the respective flange members 21 and 22. However, there are the annular, indented or relieved areas 40 that accommodate stress distribution when the flange members are mutually advanced toward each other in the manner hereinafter described. A medial apex 41, (see Fig. 5B) of the sealing ring need perform no sealing function and functions simply as a third member to close the triangular spaces formed by the relieved areas 40 to position the sealing ring 35 without severe, non-recoverable misalignment.In actual fact, when pressure is exerted annularly at arrows X and Y (see Fig. 5A) against the sealing ring 35, owing to the tightening of the clamp segments, the space between annular, planar surfaces 23 and 24 will be the last space to tend to close. Prior to this time, and as hereinafter fully explained, there will be a slight displacement of material at the edges 43, 44 of the ring within its elastic limit inwardly from the nominal phantom line 42 in Fig. 5A, so that there will be a very tight, pressured closure of such prestressed material proximate seal surfaces 36 and 37 against surfaces 38 and 39, thereby effecting sealing by the seal ring 35 against the aforesaid surfaces.

Accordingly, Figs. 4B and 5B illustrate the condition of the structure including the flange members and seal ring prior to complete tightening of the clamp segments by bolt attachments 18-20.

Figs. 4A and 5A illustrate that when a torque wrench or other means has been employed to tighten the bolt attachment means 18-20 so as to tend to thrust the flange members 21 and 22 together (see Fig. 4A) then the advance, owing to the cam action of surfaces 30, 31, 29 and 32, will effect a mutual advancement of the flange members 21 and 22 toward each other in the mannershown in Figs. 4A and 5A such that a seal is effected as aforementioned, and also so that surface loading is controlled proximate the relief areas 40 in the seal ring.

The structure herein is intended to satisfy the requirements for high integrity sealing. In accordance therewith, the employment of high strength stainless or low alloy steel is contemplated, such as A286 stainless 4140 low alloy steel, both having a high Young's modulus. Low strength carbon steel can conceivably be employed, but the same has a greater tendency to bend and distort and may not be suitable for corrosive liquids and gases, extremely high pressures, and so forth.

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 permitted in the design. End chamfers 46 and 47 on the flange members 21 and 22 respectively accommodate butt weld connection to align conduits 48 and 49 (see Fig. 1 8 4A).

The welds are shown at 50 and 51.

There are many types of weld configuration 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 conduits 48 and 49 takes the form shown in Fig. 4A.

In fabrication, then the individual flange members 21 and 22 are secured to the respective conduits. The flange members are then brought into alignment in a manner shown in Figs. 2-4 and the clamp segments are installed over the flange portions in the manner seen in Fig. 1. Bolt means 18-20 are employed to secure the two clamp segments together. The bolts are tightened down so as to tend to bring the two flange members together, at least toward each other. In this process, there is a compression between surfaces 38, 39 of the respective flange portions against the adjacent surfaces 36, 37 of the seal ring 35. This compression produces a very tight fit between the parallel surfaces 36-39, with the compression aforementioned causing a bowing in of the opposite annular margins of the seal ring. The compression is radial.

Accordingly, the coupling structure very suitable for fluids, even corrosive fluids operated under high pressure.

Portions 27' and 28' of each of the flange members (see Fig. 4B) are thickened with respect to the conduits 48 and 49 as indicated, to provide additional strength proximate the flange and sealing areas. Relief areas 49' and 50' may comprise simply recesses or slots in the individual upper and lower clamp segments, thereby providing certain stress relief when the clamp segments are tightened down by the bolt structures 18.

Accordingly, very high pressure seals are provided by the camming action of the lamp elements against surfaces 29 and 30 to tend to urge the flange members 21, 22 together, which results in the annular compression of ring margins 43 8 44 to stress the ring within its elastic limit, via the camming action of surfaces 38 and 39 against surfaces 36 and 37.

Claims (8)

1. A conduit connector comprising a pair of flange members having opposed surfaces each provided with an annular recess forming an annular, inclined, seal-seat surface; a metal sealing ring disposed in the recesses; and means for advancing the flanges towards each other to compression load the sealing ring in a direction perpendicular to its central axis, to pressure-seat the ring at the seal-seat surfaces and provide fluid seals thereat.

2. A connector according to claim 1, wherein the ring has a nominal diameter larger than that of the recesses.

3. A connector according to claim or claim 2, wherein the ring is controllably constrained through the combination of ring length, recess size, and flange member mutual advancement.

4. A connector according to any of claim 1 to 3, wherein each of the recesses has a tapered radially outer wall, the sealing ring having corresponding, radially outer, annular, tapered edges respectively for cooperation therewith.

5. A connector according to any of claims 1 to 4, wherein each of the flange members comprises a cylindrical flange body provided with a thickened metal portion and a forward flange portion having an inner annular edge at which a respective one of the recesses is formed.

6. A connector according to any of claims 1 to 5, wherein the flange members have annular, radially outer, sloping, camming surfaces, the advancing means comprising a plurality of clamping segments having camming means operably engaging the camming surfaces and attachment means coupled to the clamping segments for drawing the segments mutually toward each other thereby urging the flange members together.

7. A connector according to claim 4, wherein the sealing ring includes annular relieves in its sealing surfaces either side of a central annular apex.

8. A connector according to claim 1, substantially as described with reference to the accompanying drawings.