GB2146722A - Pipe couplings - Google Patents

Abstract

A coupling for connecting two spaced coaxial pipes (10, 11 Figs. 2, 3) anchored against longitudinal movement comprises a sleeve 12 having outwardly flared ends 13, a pair of elastomeric gaskets 14, a pair of followers 16, a pair of jaw members 19,30, a pair of back up rings 16a,31), tightening means 17,17a,18,18a and auxiliary tightening means 18b. Tightening the tightening means forces the gaskets into sealing engagement with the sleeve and pipe ends and also forces the jaw member 19 into holding engagement with the pipe 10. Tightening the auxiliary tightening means forces the jaw member 30 into holding engagement with the pipe 11. In another embodiment (See Figs. 4 to 6) the back up ring 16a is formed separately from the follower and a further auxiliary tightening means is provided for the jaw member 19. <IMAGE>

Description

SPECIFICATION Pipe couplings The invention relates to pipe couplings, and particularly to a coupling for connecting two ends of anchored pipe which will provide both a seal and a strong grip on the two separate pipe ends.

There are a wide variety of pipe couplings available for gripping and sealing two pipe ends where at least one of the pipes being connected is unanchored and free for at least limited longitudinal movement. Typical of such devices are those illustrated in United States patent Specification Nos. 4070046, 411 9335 and 3865410. All of these devices have a common characteristic, namely, that the gripping ring or member at each end engages the pipe end around which it is placed before the seal ring completes the seal.

Further tightening draws the coupling gripping members towards each other completing the seal. This requires that at least one pipe end be free to move toward the other. Where the two pipe ends are anchored and not free to move, the gripping members engage the pipe circumference tightly before the seal occurs as they normally do, however, further tightening will not complete the seal unless the gripping members slide or the pipe ends move, neither of which can or should occur.

As a result the pipe ends are gripped tightly but not sealed.

The invention solves this problem by providing a coupling which has one independently movable gripping member which can be tightened into gripping engagement after the seal has been completed and the other gripping member tightly engaged on one pipe end.

More specifically, the invention provides a coupling for connecting two ends of pipe both of which are anchored remote from the connection including an elongate sleeve adapted to receive coaxially two opposing pipe or tube ends to be connected, said sleeve having frusto conical enlarged ends, a pair of frusto conical elastomer sealing gaskets adapted to fit in said frusto conical ends in tight engagement around the pipe ends to be connected, said gaskets extending out of said frusto conical ends of the sleeve, a follower member at each end of the sleeve bearing on said gaskets to force them into the frusto conical ends of the sleeve, a frusto conical opening in one of said follower members around one of the pipe ends being connected, a frusto conical jaw means in said conical opening of said one follower member, surface engaging means on the inside of said jaw means adapted to engage the surface of said one pipe end against movement, tightening means extending between the follower means acting to move them axially together to force the gaskets into tight sealing engagement with the pipe ends being joined and simultaneously force said frusto conical jaw means into tight radial engagement with said one pipe end, a back up ring spaced from the other follower means and having a frusto-conical opening therein, a second frusto-conical jaw means in said frusto-conical opening in said back up ring, surface engaging means on the inside of said jaw means adapted to engage the surface of the other pipe end against movement and auxiliary tightening means between the other follower means and the back up ring for drawing said back up ring axially toward the said other follower means to force the frustoconical jaw means into tight radial engagement with the said other pipe end. The frustoconical jaw means may be a single split ring as in German Patent P 1944782.6, a plurality of spaced jaw members or a multiple split ring as in U.S. patent 4,070,046. The sealing gaskets may be of rubber or any other suitable elastomeric material capable of creating a seal under pressure.Preferably the tightening means and auxiliary tightening means is a plurality of elongate bolts extending through both follower means and the back up ring and threaded to take tightening nuts bearing on said other follower means and on the back up ring separately so that they are movable independently of one another.

There are also situations where, particularly with large diameter pipe, it is desirable to have two independently movable gripping members with or without internal insulators and electrical continuity wiring capacity.

For such situations I provide a coupling member for connecting two ends of pipe both of which are anchored remote from the connection including an elongate sleeve adapted to receive coaxially two opposing pipe or tube ends to be connected, said sleeve having frusto-conical enlarged ends, a pair of frustoconical elastomer sealing gaskets adapted to fit in said frusto-conical ends in tight engagement around the pipe ends to be connected, said gaskets extending out of said frustoconical ends of the sleeve, a follower member at each end of the sleeve bearing on said gaskets to force them into the frusto-conical ends of the sleeve, tightening means extending between the follower means acting to move them axially together to force the gaskets into tight sealing engagement with the pipe ends being joined to create a tight seal between the pipe ends and sleeve, a back up ring spaced from each of the follower means at opposite ends of the sleeve, each having a frusto-conical opening therein, a frusto-conical jaw means in each said frusto-conical opening in each said back up ring, surface engaging meanss on the inside of said jaw means adapted to engage the surface of the other pipe end against movement and auxiliary tightening means between each of the fol lower means and the adjacent back up ring for drawing said back up ring axially toward the said adjacent follower means to force the frusto-conical jaw means into tight radial engagement with the said other pipe end. Here again, the frusto-conical jaw means may be a single split ring as in German Patent P 1944782.6, a plurality of spaced jaw members or a multiple split ring as in U.S. patent 4,070,046.The sealing gaskets may be of rubber or any other suitable elastomeric material capable of creating a seal under pressure. Preferably, the tightening means and auxiliary tightening means is a plurality of elongate bolts extending through both follower means and the back up ring and threaded to take tightening nuts bearing on said follower means and on the back up ring separately so that they are movable independently of one another.

The back up ring and split frusto-conical jaw ring disclosed herein may be combined with old couplings of standard type using only seals by using double threaded end layer bolts with such couplings to produce the structure here disclosed.

The invention is illustrated by the drawings, of which: Figure 1 is a section through a connector according to the invention; Figure 2 is an exploded isometric fragmentary view of the right end of the connector of Figure 1 showing the parts involved; Figure 3 is an exploded isometric fragmentary view of the left end of the connection of Figure 1 showing the parts involved; Figure 4 is a section through a second embodiment of a connector according to the invention; Figure 5 is an exploded isometric fragmentary view of the right end of the connector of Figure 4 showing the parts involved; and Figure 6 is an exploded isometric fragmentary view of the left end of the connection of Figure 4 showing the parts involved.

Referring to Figures 1 to 3 of the drawings, there is illustrated a pair of pipe ends 10 and 11 to be connected. The opposite ends of the two pipes are anchored so that the pipe ends cannot move toward each other. A sleeve 12 having a slightly larger internal diameter than the external diameter of pipes 10 and 11 is placed coaxially around the pipe ends 10 and 11 to be connected. Each end of sleeve 12 has a flared or frusto-conical portion 13 receiving an elastomeric gasket 14 having a short, cylindrical portion and a frusto-conical end portion 14a adapted to fit in flared end 13 of the sleeve. The elastomeric gasket 14 is adapted to fit snugly around the pipe ends 10 and 11 to be joined.An annular cup shaped follower 16 surrounds each pipe end 10 and 11, abuts the gasket 14 and is provided with radial lugs 1 7 having holes 17a receiving bolts 18 with tightening nuts 18a for drawing the followers axially toward the sleeve to force the gaskets into the frusto-conical ends of sleeve 12 and into sealing engagement with the outside surface of pipes 10 and 11. At least one of said followers 16 is provided with a generally frusto-conical opening 16a receiving the frusto-conical split jaw 19 or its equivalent in separate connected jaw members.

The jaw 19 has toothed grooves 20 adapted to engage the surface of pipes 10 and 11.

The jaw 19 may bear against gasket 14 or against an intermediate washer (not shown).

When the followers 16 are drawn together by bolts 18 and nuts 18a the jaw means 19 is compressed by the frusto-conical opening 16a of follower 16 into tight engagement with the exterior of one of the pipe ends 10 as shown, forcing toothed grooves 20 into the surface of the pipe to hold it against withdrawal from the pipe. When the gaskets 14 and jaw 19 have been completely tightened into position a second frusto-conical jaw means 30 similar to split jaw 19 is placed in abutment against the follower means 16, opposite jaw means 19. A back up ring 31 similar to followers 16 having a frusto-conical opening 31 a is placed over the jaw means 13. Radial lugs 32 with holes 32a receiving the threaded ends of bolts 18 are formed on the periphery of back up ring 31.Nuts 18b draw the back up ring 31 tightly over jaw means 30 with opening 31 a compressing the jaw means 30 tightly around pipe end 11 so that toothed grooves 33 are forced into the surface of the pipe and to hold it against withdrawal.

Referring to Figures 4 through 6, there is illustrated a second embodiment in which like parts from Figures 1 through 3 are given the same numbers with a prime sign. In these figures there is illustrated a pair of pipe ends 10' and 11' to be connected. The opposite ends of the two pipes are anchored so that the pipe ends cannot move toward each other.

A sleeve or middle ring 12' having a slightly larger internal diameter than the external diameter of pipes 10' and 11' is placed coaxially around the pipe ends 10' and 11' to be connected. Each end of sleeve 12' has a flared or frusto-conical portion 13' receiving an elastomeric gasket 14' having a short, cylindrical portion and a frustoconical end portion 14a' adapted to fit in flared end 13' of the sleeve. The elastomeric gasket 14' is adapted to fit snugly around the pipe ends 10' and 11' to be joined. An annular cup shaped follower 16' surrounds each pipe end 10' and 11', abuts the gasket 14' and is provided with radial lugs 17' having holes 17a' receiving bolts 18' with tightening nuts 18a' for drawing the followers axially toward the sleeve to force the gaskets into the frustoconical ends of sleeve 12' and into sealing engagement with the outside surface of pipes 10' and 11'. The follower means 16' are drawn together by bolts 18' and nuts 18a' at each end and at opposite ends of sleeve 12'.

Spaced from the follower means 16' at each end are back up rings 31' with conical openings 31a' receiving split jaws 30'. The split jaw 30' or its equivalent may be a split ring or separately connected jaws as in US 4070046 or US 4119335, supra. The jaw 30' has toothed grooves 33' adapted to engage the surface of pipe ends 10' and 11'.

Radial lugs 32' with holes 32a' receiving the threaded ends of bolts 18' are formed on the periphery of each back up ring 31'. Nuts 18b' draw the back up rings 31' tightly over jaw means 30' with opening 31a' compressing the jaw means 30' tightly around pipe ends 10' and 11' so that toothed grooves 33' are forced into the surface of the pipe ends and hold them against withdrawals.

Claims (6)

1. A coupling for connecting two spaced coaxial pipes anchored against longitudinal movement, the coupling comprising an elongate sleeve for receiving the two opposing ends of the pipes, the sleeve having frustoconical enlarged ends opening outwardly; a pair of elastomeric gaskets, one associated with each pipe, each having a frustoconical end portion for receipt in the associated sleeve end; a pair of followers, one associated with each pipe; a pair of jaw members, one associated with each pipe, each being frusto-conical with its large end facing the sleeve, each having at least one slot permitting expansion and contraction around the associated pipe, and each having an internal surface adapted to engage and hold the associated pipe; a pair of back up rings, one associated with each jaw member, each having a frusto-conical opening for bearing on the associated jaw member; tightening means for acting on the followers to draw them axially toward one another, thereby forcing the gaskets into sealing engagement with the sleeve ends and the pipe ends; auxiliary tightening means acting on one of the back up rings to force the associated jaw member into holding engagement with the associated pipe; the other jaw member being forced, in use, into holding engagement with the other pipe either by the tightening means or by a further auxiliary tightening means acting on the back up ring associated with the said other jaw member.

2. A coupling according to claim 1 in which one of the back up rings is integrally formed with one of the followers and the jaw member associated with the said one of the back up rings is forced, in use, into engagement with the associated pipe by the tightening means.

3. A coupling according to claim 1 in which each back up ring is a member formed independently of the followers, and a separate auxiliary tightening means is provided for each back up ring.

4. A coupling according to any preceding claim wherein the tightening means is a plurality of elongate bolts and tightening nuts extending through radial lugs on rings bearing on each follower and the or each auxiliary tightening means is an extension of the elongate bolts through radial lugs on the or each back up ring with tightening nuts.

5. A coupling according to any preceding claim wherein the internal surface of each jaw member is provided with axially spaced annular teeth.

6. A coupling according to any preceding claim wherein the elastomeric gaskets are rubber.