GB2164714A - Pipe coupling - Google Patents

Abstract

The joint device for two pipes (T1, T2) comprises a male end and a socket respectively comprising bearing devices (3, 11). The bearing device of the socket is defined by a flange (3) and the bearing device of the male end is defined by a bearing ring (11). The bearing ring (11) is constituted by an incomplete open ring comprising an opening and having sufficient elasticity to be made of variable diameter, this ring remaining open once the joint is locked by virtue of a spacing device (25) interposed between the two radial faces (24) of the said opening. <IMAGE>

Description

SPECIFICATION Joint device between cast-iron pipes comprising a male end and a socket The present invention relates to a joint device or locked joint between two cast-iron pipes comprising a male end and a socket which may have an angular deviation one with respect to the other.

More particularly, the invention relates to a locked joint of the type described in French Patent Application Number 78 31994 published under Number 24 41121.

In this aforementioned prior patent, a mass of metal balls or shot is housed inside the socket of one of the pipes in a deformable space closed on all sides by an L-section ring sliding with radial clearance in the opening of an inlet flange of the socket and in the cylindrical base of the cavity of the socket. This Lsection ring bears on a split metal ring itself bearing on a weld bead integral with the male end, whereas the gasket is interposed between the male end and the socket in the vicinity of the bottom of the socket and of the end face of the male end.

In this prior patent, due to its capacity for deformation, the mass of balls allows a slight angular deviation of one of the pipes with respect to the other whilst preserving axial locking of the joint, even after its assembly. In this prior patent, the aforesaid L-section ring is split along a narrow slit to be welded after its assembly. This split ring, serving to enclose the mass of metal balls or shot inside the socket, is introduced into its housing in the socket by contraction until it has a sufficiently small diameter to cross the inlet flange of the socket. When this crossing has been effected, the contraction of the ring is released, which allows the ring to expand freely and to reassume its diameter in the free state which is greater than the diameter of the said inlet flange.Then, the said ring is made rigid by welding to each other its terminal edges which constituted the slit. The slit is thus eliminated.

The result is that in the case of an incident on the pipe and in the case of the necessity of examining the locked assembly of pipes, it is necessary to cut this ring with a view to removing it and to have access to the inside of the socket. There is a danger that this cutting with a saw and/or blow torch may damage the cast-iron pipes.

Moreover, this ring which is split at the time of assembly and is therefore able to contract and expand solely at the time of assembly and is then made rigid after assembly, does not make it possible to see the annular space housing the metal balls or shot. Finally, according to this prior patent, the metal balls or shot are introduced through a radial orifice passing right through the socket.

The applicant has tackled the problem of providing a locked joint of the type described in this preceding patent but which is improved with a view to allowing, in the case of need, dismantling of the said ring without cutting it into several sections and without any risk of damaging the pipes, making it easier to see the inner space housing the metal shot in the socket and allowing the introduction of this metal shot into the socket without perforating the wall of the socket.

The present invention relates to a locked joint which resolves this problem.

According to the invention, the locked joint, for cast-iron pipes of large diameter, comprises a male end and a socket, the male end and the socket comprising bearing devices in facing relationship, the bearing device of the socket being defined by an inner flange of the latter and the bearing device of the male end being defined by a bearing ring pressed by an inner face against a radial shoulder of the said male end, an incompressible mass, constituted by a granular material, being contained in an annular space which is impervious to the said granular material and formed by the inner surface of the socket and the outer surface of the bearing ring, the said joint being characterised by the fact that the said bearing ring is constituted by an incomplete open ring comprising an opening and having sufficient elasticity to be of variable diameter, the said ring remaining open once the joint is locked by virtue of mechanical spacing means interposed between the two radial faces of the said opening.

Further features and advantages will become apparent on reading the ensuing description, made with reference to the accompanying drawings given solely by way of non-limiting example.

Figure 1 is a partial view in longitudinal section of the locked joint according to the invention, in the case of maximum clearance constituted by a minimum outer diameter of the male end and a maximum angular deviation of the male end with respect to the socket.

Figure 2 is a view similar to Fig. 1 illustrating the locked joint according to the invention in the case of a maximum outer diameter of the male end.

Figure 3 is a sectional view illustrating the ring of the locked joint according to the invention.

Figure 4 is a front view of the ring of the locked joint according to the invention.

Figure 5 is a partial view in perspective with cutaway illustrating the device for locking the ring of the locked joint according to the invention.

Figure 6 is a partial sectional view of the device for spacing and locking the ring of the locked joint according to the invention.

As can be seen more particularly in Figs. 1 and 2, the locked joint according to the inven tion is constituted by a socket 1 of a pipe T1 and a male end 2 of a pipe T2, of outer diameter D, penetrating inside the said socket 1, the two pipes T1 and T2 being coaxial with the axis XX in Fig. 2 and slightly deflected by an angle a one with respect to the other in Fig. 1.

At its end, the socket 1 comprises an inner flange 3, defined by radial walls 4 and 5, perpendicular to the axis XX, of inner diameter D1, defining a cylindrical opening 6 of diameter D1 and on the axis XX. The socket 1 also comprises a shoulder 7, defining a circular opening 8, of diameter d clearly less than D1 and greater than the outer maximum diameter D of the male end 2. Thus, inside the socket 1, the flange 3 and shoulder 7 define with an inner cylindrical face 10 on the axis XX of the socket 1, of diameter D2 greater than D1, a recess 9.

Housed beyond the shoulder 7, adjacent the bottom of the socket 1 is a gasket G of known type comprising an anchoring heel and with a radially compressed sealing body.

Thus, the tightness of the joint is ensured by the radial compression of this gasket between the inner surface of the socket 1 and the outer surface of the male end 2. A radial compression gasket has been shown in this case, but other types of gasket, such as for example alveolar gaskets or gaskets comprising lips, may also be used.

Located between the male end 2 and this socket 1, inside the recess 9 are bracing devices constituted by a ring 11 and a radial shoulder 12 (bearing ring) bearing axially on the male end 2, for example through the intermediary of a weld 14 integral with the said male end 2. This radial shoulder 12 (bearing ring) is constituted by a split metal ring.

In the example illustrated in Figs. 1 and 2, this ring 12, pressed by its inner cylindrical surface 13 against the outer surface of the pipe T2 is limited in its axial sliding movement, adjacent the bottom of the socket 1, along the pipe T2, by the weld bead 14. In another embodiment, this ring 12 could be located inside an annular groove machined on the outer surface of the pipe T2. The outer diameter D3, greater than D, of this ring 12, mounted on the male end 2, is still less, even in the case of a maximum outer diameter of the pipe T2 on which it bears, than the inner diameter D1 of the opening 6.Moreover, the ring 12 comprises a surface 15, cooperating by abutment with the ring 11, this surface 15 being curved, having a very great radius of curvature, thus very close to a frustum of a cone and situated adjacent the opening of the socket when the ring 12 is mounted on the male end 2. The ring 11 is illustrated separately in Figs. 3 and 4.

As shown in Fig. 4, the ring 11 is constituted by an incomplete open ring, comprising two radial faces 24. The elasticity of this ring is sufficient to make it possible to obtain a variable diameter of this ring. If one wishes to reduce the stiffness of the latter, it is possible to provide notches 30 distributed regularly on the outer surface of this ring. The opening, constituted by the spacing of the radial faces 24, is sufficient to allow the interposition of mechanical means for spacing the radial faces 24 of the said opening.

As shown in Figs. 1, 2 and 3, the ring 11 has a general L-shaped section. The radial branch of the L, inside the socket 1, is defined by two annular radial surfaces 16 and 17, connected to each other by a cylindrical surface 18 on the axis XX, in contact with the face 10 of the socket 1; the face 16 has a height h corresponding to the height H of the flange 3. The longitudinal side of the L, on the axis XX, is thus perpendicular to the radial branch of the L and limited by two cylindrical surfaces 19 and 20 on the axis XX, the cylindrical surface 19 being pressed against the surface 6 of the flange 3.

The perpendicular surfaces 17 and 20 of the ring 11 are connected to each other by a frustoconical surface 21 bearing on the curved surface 15 of the ring 12. The total radial height E of the ring is still less than (D1-D)/2 even in the case of a maximum outer diameter of the male end 2.

Thus and as shown in Figs. 1 and 2, the faces 16 and 19 of the ring 11 and the faces 5 and 10 of the socket 1 define an annular space 22 inside which is situated an incompressible granular material 23. This granular material 23 may be constituted in particular by iron shot or stainless steel balls, whereof the grain size, depending on the manufacturing and assembly tolerances of the locked joint, is of the order of 1.5 to 2.5 mm. It is also possible to use sand.

As shown in Figs. 1 and 2, the volume of this annular space 22 depends on the outer diameter of the male end 2 and on the angular deviation of the male end 2 with respect to the socket 1.

The device for keeping the surface 19 of the ring 11 against the surface 6 of the socket 1 will now be described. The latter is constituted by a spacing device 25 interposed between the two radial faces 24 of the ring.

Once the said ring 11 has been pressed by the surfaces 18 and 19 against the surfaces 10 and 6 of the socket 1 and by its surface 21 against the curved surface 15 of the ring 12, the surface 19 of the ring 11 thus having a diameter dl corresponding to the diameter D1 of the surface 6 of the socket 1 and the two edges 24 thus having a spacing e (Fig.

4), this spacing device imparts a tangential force to the ring 11, which prevent the two radial faces 24 from moving towards each other, thus preventing the diameter dl of the surface 19 from decreasing and consequently keeping the surfaces 6 and 19 and 18 and 10 in contact.

According to the preferred embodiment, illustrated in Figs. 5 and 6 (in which the same reference numerals designate the same parts as in the preceding figures), this spacing device is constituted by a screw-jack 25 of known type, of adjustable length which, by each of its ends, bears roughly perpendicularly on each of the radial faces 24 of the ring 11, a plate 26 for closing off the annular space 22 being able to be interposed between each end of the said jack 25 and each end 24 of the ring 11. As shown in Fig. 6, this screwjack is constituted for example by two screwthreaded rods 28 with reverse threads connected by a double nut 29 with two reverse threads whereof the rotation in one direction causes the two rods 28 to move away from each other bringing about a spacing of the two radial faces 24.Each plate 26 is provided with a hole 27 for supplying the space 22 with granular material 23.

The assembly of the locked joint according to the invention will now be described.

After having passed the ring 11 beyond the weld bead 14, the ring 12 is placed behind and against the weld bead 14 by pressing the surface 13 of the ring 12 against the outer surface of the male end 2. Then the ring 11 is moved towards the ring 12 and the ring 11 is restrained by virtue of a binding cable surrounding the surface 19 of the said ring 11 until the diameter of the surface 18 is less than the diameter of the surface 6 and the diameter of the face 20 is less than the outer diameter D3 of the ring 12. Then the ring 11 is placed against the ring 12 by directing its opening, formed by the two radial faces 24 along the upper generatrix.

Once these operations have been carried out, the male end 2 and the ring 11 are introduced inside the socket 1 in the recess 9.

Then the ring 11 is released by removing the binding cable. After this, the jack 25 and two plates 26 are placed against the radial edges 24 of the ring 11 and due to the spacing of the two radial faces 24 by virtue of the jack 25, the surfaces 18 and 19 of the ring 11 are pressed moderately against the surfaces 6 and 10 of the socket 1. Once this has been carried out, the ring 11 is pushed against the ring 12, the surfaces 21 and 15 are then in contact over their entire periphery. The bracing devices are thus in position and it is possible to tighten the ring 11 firmly against the inner surface of the socket 1 by carrying out tightening of the jack 25, i.e. operating it in order to separate the two radial faces 24 of the ring 11 to the maximum extent.

The annular space 22 may then be supplied with granular material 23 through the two orifices 27 in the plates 26 according to a known device such as that described for example in French Patent Number 2 441 121.

Locking of the joint is then completed. If one wishes to dismantle the locked joint, it is sufficient to release the jack 25, in order to allow the radial faces 24 of the ring 11 to move towards each other elastically, the ring 11 then contracts naturally and the granular material 23 escapes from the annular space 22. The ring 11 may then be restrained once more and removed from its housing, the joint is thus unlocked.

Thus, by virtue of a ring 11 formed by an open and incomplete ring whereof the ends are able to be moved apart or towards each other, one provides a locked joint which is easy to assemble, does not require the use of any special assembly device, prevents the drilling of the socket in order to supply the annular space 22 with granular material 23 and in addition can be dismantled easily.

Moreover, this device makes it possible to produce a locked joint for cast-iron pipes comprising a male end and socket which may be coated with an epoxy resin without the locking device in any way impairing this coating.

Finally, owing to the opening of the ring 11, it is possible to inspect the inside of the socket easily once the joint is assembled and locked.

Claims (5)

1. Joint device between pipes comprising a male end and a socket, the male end and the socket comprising bearing devices in facing relationship, the bearing device of the socket being defined by a flange inside the latter and the bearing device of the male end being defined by a bearing ring pressed, by an inner face, against a radial shoulder of the said male end, an incompressible mass, constituted by a granular material, being contained in an annular space, which is impervious to the said granular material and formed by the inner surface of the socket and the outer surface of the bearing ring is constituted by an incomplete open ring comprising an opening and having sufficient elasticity to be of variable diameter, the said ring remaining open once the joint is locked by virtue of a spacing device interposed between the two radial faces of the said opening.

2. Joint device according to Claim 1, wherein the spacing device is constituted by a screw-jack with two screw threaded rods of reverse thread and a nut with two reverse threads.

3. Joint device according to Claim 1 or 2, wherein two bearing plates are respectively interposed between each of the two radial faces of the opening in the bearing ring and the spacing device.

4. Joint device according to Claim 3, wherein each bearing plate is provided with an orifice making it possible to supply the annular space with granular material.

5. Joint device between two pipes sub stantially as hereinbefore described with reference to the accompanying drawings.