Patent Description:
These pipe couplings require, however, very high radial compression loads, and associated bolt torques, in order to crush gripper elements of the couplings against the periphery of the pipe sufficiently to prevent release of the pipes from the couplings under normal, operative axial loads.

The extent of these compressive loads is such as to require the use of an internal stiffening liner, typically formed of stainless steel of coated mild steel, within the pipe in order that the pipe can withstand the crush loading without collapsing.

Moreover, these existing pipe couplings usually require a compression seal, the efficiency of which is determined by the radial compression, and thus there are competing factors in requiring a predetermined radial compression to ensure optimal sealing of the compression seal, but requiring an often-higher radial compression in order to ensure sufficient grip on the pipe.

It is an aim of the present invention to provide a pipe coupling which enables operation with much lower compressive loading of pipes, and can allow in some embodiments for use without a stiffening liner.

In one aspect the present invention provides a gripper ring for a pipe connector or coupling according to claim <NUM>.

Preferred embodiments of the present invention will now be described hereinbelow by way of example only with reference to the accompanying drawings, in which:.

<FIG> illustrate a pipe coupling or connector in accordance with a first embodiment of the present invention.

The pipe coupling comprises an annular gripper ring <NUM> which receives a pipe P therewithin, and a clamp <NUM> which acts to apply a radially-inward compressive load on the gripper ring <NUM> in order to displace the gripper ring <NUM> against an external peripheral surface S of a wall W of the pipe P, as will be described in more detail hereinbelow.

In this embodiment the gripper ring <NUM> comprises a gripper <NUM> which is inserted into the external surface S of the pipe P when the gripper ring <NUM> is clamped to the pipe P by operation of the clamp <NUM>, and a carrier <NUM> which supports the gripper <NUM> with a defined orient in relation to the external surface S of the pipe P.

In this embodiment the gripper <NUM> comprises a plurality of blade elements <NUM>, which are arranged in circumferential relation and, when clamped to the pipe P by the clamp <NUM>, are inserted into the external surface S of the pipe P, here cutting into the external surface S of the pipe P.

In this embodiment the blade elements <NUM> each have a main body section 17a by which the blade element <NUM> is supported with a predetermined orient in relation to the external surface S of the pipe P, an external edge section 17b by which the blade element <NUM> is displaced inwardly during operation of the clamp <NUM>, and an internal edge section 17c which provides a blade <NUM> which is inserted into the external surface S of the pipe P, here cutting into the external surface S of the pipe P, in order to engage the pipe P.

In this embodiment the blade elements <NUM> are configured such that the blades <NUM> are inserted into the external surface S of the pipe P at a predetermined angle thereto.

In this embodiment the blades <NUM> are inclined in relation to the external surface S of the pipe P, as illustrated in <FIG>, such that the blades <NUM> each enclose an acute angle β with the external surface S of the pipe P rearwardly of the point of insertion of the blade <NUM> in relation to the distal end of the pipe P.

In this embodiment the insertion angle β is <NUM> degrees.

In one embodiment the insertion angle β is at least about <NUM> degrees.

In one embodiment the insertion angle β is not greater than about <NUM> degrees.

<FIG> shows the relationship of the maximum axial load which can be withstood by the pipe coupling, where the blade elements <NUM> are arranged in symmetrical relation, with insertion angles β of <NUM>, <NUM>, <NUM> and <NUM> degrees. As will be seen, for axial loads greater than about <NUM> kN, configuring the blades <NUM> to have an insertion angle β of between <NUM> and <NUM> degrees, optimally about <NUM> degrees, provides for substantially greater resistance to axial loads for any given insertion depth.

In this embodiment the blade elements <NUM> are inserted a predetermined depth d into the wall W of the pipe P, as illustrated in <FIG>, with the insertion depth d being less than <NUM>% of the thickness of the wall W of the pipe P. By way of example, for a <NUM> SDR17 pipe, the blade elements <NUM> could be inserted <NUM> into the wall W of the pipe P.

In this embodiment the blades <NUM> each comprise first and second spaced blade sections 18a, b, which allow the blade <NUM> to conform the outer peripheral surface S of the pipe P when displaced inwardly by operation of the clamp <NUM>.

In this embodiment the blade sections 18a, b are coupled by a web section <NUM>, here of V shape, which supports the blade sections 18a, b in the axial direction and enables relative movement of the blade sections 18a, b in the radial direction, such as to promote preferential movement in relation to the web section <NUM> during compression of the gripper <NUM> and thereby promote uniform displacement of the blade elements <NUM>.

In this embodiment the blades <NUM> together define an inner opening <NUM> which has a diameter greater than the outer diameter of the pipe P, as illustrated in <FIG>, thereby facilitating fitting of the pipe coupling to the pipe P, especially when the pipe P is out of round.

In this embodiment the diameter of the inner opening <NUM> is such as to allow for the pipe P being <NUM>% out of round from the nominal outer diameter, optionally being <NUM>% out of round.

In one embodiment the blades <NUM> form a substantially-continuous annular ring.

In another embodiment the blades <NUM> are located at spaced locations about the gripper ring <NUM>, with the arrangement and spacing therebetween being determined by the operational loading of the pipe P. In one embodiment the blades <NUM> have a space therebetween of at least half the width of the blades <NUM>, optionally at least the width of the blades <NUM>, and optionally at least twice the width of the blades <NUM>.

In this embodiment the blade elements <NUM> are formed of sheet material, here a spring stainless steel.

In an alternative embodiment the blade elements <NUM> could be formed of a coated mild steel.

In one embodiment at least the inner edge sections 17c of the blade elements <NUM> are formed of sheet material.

In this embodiment the gripper <NUM> is formed from a single sheet, here by a stamping operation, but could alternatively be formed by other cutting and bending operations, with adjacent ones of the blade elements <NUM> being interconnected by web elements <NUM>, here in the form of strips.

In this embodiment the web elements <NUM> comprise sections 23a, b which are inclined in relation to the radial direction, such as to promote preferential bending of the web elements <NUM> during compression of the gripper <NUM> and thereby promote uniform displacement of the blade elements <NUM>.

In an alternative embodiment the blade elements <NUM> could be formed as separate elements which are not interconnected.

In this embodiment, as particularly illustrated in <FIG>, the blade elements <NUM> comprise at least one, here first and second guides <NUM>, which are arranged in relation to the edge of the blade <NUM>, such that, on insertion of the blade element <NUM> to the required extent into the wall W of the pipe P, the guides <NUM> abut the external surface S of the pipe P, thereby providing a clear visual indication to the operator when the clamp <NUM> is applied to the required extent.

In this embodiment the clamp <NUM> comprises an annular body <NUM> which includes a recess <NUM> which captively receives the gripper ring <NUM>, in this embodiment being defined by first and second flange members <NUM>, <NUM> which are spaced in axial relation.

In this embodiment the carrier <NUM> comprises at least one, here first and second support members 37a, b, which act to sandwich the gripper <NUM> therebetween.

In this embodiment the support members 37a, b each have a support surface <NUM>, and the support surfaces <NUM> receive the main bodies 17a of the blade elements <NUM> therebetween, such as to orient the blade elements <NUM> at the predetermined insertion angle β.

As discussed above, the pipe coupling of the present invention operates by displacement of the blade elements <NUM> by application of a radial load F1, such that the blade elements <NUM> are inserted into the wall W of the pipe P to a predetermined extent, which does not require the maintenance of a high crush loading on the pipe P.

In use, the pipe P will be subjected to an axial load F2, which the pipe coupling is configured to withstand. With an increasing axial load F2 below the rated load for the pipe coupling, the blades <NUM> of the blade elements <NUM> are configured to pivot and elastically deform, as illustrated in <FIG> where the blade <NUM> pivots through an angle θ in relation to the insertion angle β, allowing the pipe coupling to withstand a significant axial load F2, and to return to the original configuration on release of the axial load F2.

In this embodiment the clamp <NUM> comprises a ring clamp and the clamp body <NUM> has open ends <NUM>, with a fixing <NUM>, here a bolt arrangement, connecting the open ends <NUM> and being operative to provide for closure of the annular body <NUM> and thus clamping of the gripper ring <NUM>.

In an alternative embodiment the clamp <NUM> could be a multi-segment clamp comprising a plurality of clamp body parts <NUM> with adjacent open ends <NUM>, and a plurality of fixings <NUM> which interconnect the same.

The pipe coupling further comprises a coupling member <NUM> which is connected to the clamp <NUM> and provides for connection to a pipe component.

In this embodiment the coupling member <NUM> comprises a flange adaptor, but could be any kind of pipe component.

The pipe coupling further comprises an annular seal <NUM> which maintains a fluid-tight seal with the external surface of the pipe P. In this embodiment the coupling member <NUM> includes an annular recess <NUM>, which receives the seal <NUM>.

In this embodiment the seal <NUM> is a lip seal, which utilizes the fluid pressure to maintain the seal, with an increasing sealing force being applied with increasing fluid pressure. As noted above, existing pipe couplings necessitate the use of a compression seal, which relies on the compression force to achieve sealing, and does not provide for an increasing sealing force with increasing fluid pressure.

<FIG> illustrate a pipe coupling in accordance with a second embodiment of the present invention.

The pipe coupling of this embodiment is similar to the pipe coupling of the first-described embodiment, and thus, in order to avoid unnecessary duplication of description, only the differences will be described in detail, with like parts being designated by like reference signs.

In this embodiment the blade elements <NUM> are separate elements, and omit the formed external edge section 17b.

In this embodiment the carrier <NUM> comprises a plurality of recesses <NUM>, which each provide the support surfaces <NUM>, which support the main body sections 17a of the respective blade elements <NUM>.

In this embodiment the carrier <NUM> comprises a plurality of carrier members <NUM> which are disposed in the recess <NUM> in the annular body <NUM> of the clamp <NUM>.

In this embodiment the carrier members <NUM> each having oppositely-directed, axial faces 79a, b which engage the recess <NUM> in the annular body <NUM> of the clamp <NUM>, oppositely-directed circumferential faces 83a, b, and oppositely-directed, inner and outer radial faces 84a, b.

In this embodiment the carrier members <NUM> are interconnected, here interengaged, as an annulus which extends around the external surface S of the wall W of the pipe P.

In this embodiment the carrier members <NUM> each have first and second engagement elements 85a, b, here male and female elements, by which adjacent ones of the carrier members <NUM> are interengaged.

In this embodiment the engagement elements 85a, b are disposed to the circumferential faces 83a, b of the carrier member <NUM>.

In this embodiment the recess <NUM> in the annular body <NUM> of the clamp <NUM> has first and second opposed, axial faces 87a, b and an inner radial face <NUM>, and the axial faces 87a, b of the annular body <NUM> of the clamp <NUM> and the axial faces 79a, b of the carrier members <NUM> are of corresponding tapered or wedge shape, maintaining the carrier members <NUM> in a fixed orientation in relation to the pipe P during the application of a radial load F1 to the clamp <NUM>.

In this embodiment the recess <NUM> in the annular body <NUM> of the clamp <NUM> and the carrier members <NUM> are configured to allow for limited radial displacement of the carrier members <NUM> in relation to clamp <NUM> during the application of a radial load F1 to the clamp <NUM>, as will be described further hereinbelow.

In this embodiment one, first faces 79a, 87a of the recess <NUM> and the carrier members <NUM> extend in a plane which is substantially perpendicular to the external surface S of the pipe P, and the other, second faces 79b, 87b of the recess <NUM> and the carrier members <NUM> are inclined outwardly in relation to the one, first faces 79a, 87a of the recess <NUM> and the carrier members <NUM>.

In this embodiment at least one of the axial faces 79a, b of the carrier members <NUM> includes at least one, here a plurality of first deformable elements <NUM>, which are configured to maintain the relative orientation of the carrier members <NUM> but are deformable on application of a radial load F1 to the clamp <NUM>, so as to enable the carrier members <NUM> to be displaced, to a limited extent, further into the recess <NUM> in the annular body <NUM> of the clamp <NUM>.

In this embodiment the first deformable elements <NUM> comprise an array of projections.

In this embodiment the carrier members <NUM> each further include at least one, here a plurality of second deformable elements <NUM>, which engage the inner radial face <NUM> of the recess <NUM> in the annular body <NUM> of the clamp <NUM> and, with the application of increasing radial load F1 during tightening of the clamp <NUM>, can be deformed.

This configuration allows the pipe coupling to accommodate the pipe P when out-of-round or having some ovality, in that the second deformable elements <NUM> of ones of the carrier members <NUM> which first engage the external surface S of the pipe P can be displaced outwardly in relation to the clamp <NUM> while the clamp <NUM> is continued to be tightened, until the clamp <NUM> is tightened sufficiently that the inner radial faces 84b of the carrier members <NUM> abut the external surface S of the wall of the pipe P.

Finally, it will be understood that the present invention has been described in its preferred embodiments and can be modified in many different ways without departing from the scope of the invention as defined by the appended claims.

Claim 1:
A gripper ring (<NUM>) for a pipe connector or coupling which receives a pipe (P) therewithin, wherein the gripper ring (<NUM>) comprises a gripper (<NUM>) which includes a plurality of blade elements (<NUM>) which are displaceable between a first, pipe-receiving configuration in which the pipe (P) is receivable within the at least one gripper ring (<NUM>) and a second, inwardly-displaced inserted configuration in which the blade elements (<NUM>) are insertable into an external wall (W) of the pipe (P); wherein the blade elements (<NUM>) each comprise a main body section (17a) and an internal blade edge section (17c) which includes at least one blade edge (<NUM>) which is insertable into the external wall (W) of the pipe (P), with at least the blade edge sections (17c) being formed of sheet material, wherein adjacent ones of the blade elements (<NUM>) are interconnected by webs (<NUM>) or the blade elements (<NUM>) are separate elements which are not interconnected.