AU658311B2

AU658311B2 - Female end socket of a pipe

Info

Publication number: AU658311B2
Application number: AU41679/93A
Authority: AU
Inventors: Andre Lagabe
Original assignee: Pont a Mousson SA
Current assignee: Pont a Mousson SA
Priority date: 1989-05-23
Filing date: 1993-07-01
Publication date: 1995-04-06
Anticipated expiration: 2010-05-22
Also published as: FR2647520A1; ES2032720T1; FR2647520B1; ZA903940B; EP0399940A1; OA09177A; AU4167993A; RU2015441C1; ATE81715T1; MX171616B; EP0399940B1; EG19313A; DK0399940T3; GR3006040T3; JPH0341264A; ES2032720T3; DE69000395T2; BR9002393A; MA21847A1; DE69000395D1

Abstract

Seal 1, for the connection of a pipe with a male end and a pipe with a fitting, comprising an anchoring structure 2 of thickness A and a sealing body 3 of thickness E, in which the anchoring structure 2 is constituted by an anchoring bead 5 of height H, radially external, and an annular foot 10 for radially internal compression, the H/E ratio being greater than 0.2. Application to the production of a sealing joint between two hollow-spun pipes.

Description

Regulatdon 3.2

AUSTRALIA

Patents Act 1952 COMEPLETE SPECIFCATIlON FOR A STANDARD PATENT

(ORIGINAL)

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Name of Applicant: Pont-a-Mousson SA Actual Inventor(s): Andrd Lagabe Address for Service: Invention Title: DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Female end socket of a pipe The following statement is a full description of this invention, including the best method of performing it known to us: 930628,p:~opermab,55M2.div,1 BACKGROUND OF THE INVENTION This invention concerns a female end socket of a pipe for use in housing an annular sealing ring made of an elastomer for use in a joint connecting the male and female ends of pipes, and to a joint formed from the ring and socket. The ring comprises a compression body and an annular heel piece projecting radially from the exterior surface of the ring.

This ring is designed to be radially compressed between interior surface of the female pipe socket and the exterior surface of a male pipe.

A sealing ring of this type must be able to provide complete water-tightness, considering the dimensional tolerances of the pipes to be connected, the offset position S" of one pipe in relation to the other, and the pressure of the fluid circulating in the pipeline. These requirements, which presuppose a sufficiently large sealing ring, are supplemented by another, opposing requirement dictating that the stresses caused when the male pipe end is inserted into the female socket be limited to non-deterrent values, thereby establishing the requirement that the size of the ring be restricted.

French patent No. 2,554,205 describes a sealing ring of the kind described above, in which the anchoring heel is extended internally and radially on the interior surface of the ring by an annular compression foot. Accordingly, the anchoring function of the ring in the socket is performed independently of the water-tightness function, the anchoring function being provided by the combination of the heel and the foot, while the water-tightness function is performed by the compression body which is extended toward the bottom of the socket by the anchoring structure.

930628,p:\operkab,55826.div,1 -2- Even though this ring makes it possible to provide watertightness within the pressure and dimensional tolerance ranges for which it was built, nevertheless problems arise under certain circumstances. Indeed, when pipes are laid at construction sites, not only are they sometimes axially offset in relation to each other, but they may also embody angular deviations possibly exceeding 100. Furthermore, while the values of the dimensional manufacturing tolerances are uniform for all manufacturers of centrifuged pipes, they are not .1 0 specified for the same average female socket and male endpiece diameters.

Consequently, the problem lies in the manufacture of a water-tight sealing ring of the kind described above, which is able to accommodate the dimensional tolerances involved in the manufacture of centrifuged pipes, wherever they come from.

SUMMARY OF THE INVENTION An object of the present invention is to provide a female end socket of a pipe for use in housing an annular sealing ring made of an elastomer. The ring includes an anchoring structure and a sealing body which works by radial compression, the anchoring structure being composed of an anchoring heel located on an exterior surface of the ring and projecting radially outwardly, and of an annular compression foot.

Another object of the invention is the provision of a water-tight joint made up of the ring and the socket.

According to the present invention there is provided a female end socket of a pipe for use in housing an annular sealing ring made of elastomer and having an axis X-X, for a pipe joint, intended to be radially compressed between the inner surface of the end socket and the outer surface of the spigot end of another pipe to be connected, the sealing ring comprising: 93D628,p:\oper\mab,55826.div,2 -3a sealing body having an annular thickness E, having a cylindrical outer surface with diameter D2; and an anchoring structure axially displaced from the sealing body, formed by an anchoring heel with a cylindrical outer surface of diameter D1 projecting radially outward in relation to the sealing body.

The anchoring structure is connected to the sealing body by a link structure having a frustoconical surface with its cone opening towards the sealing body, whereof it extends the cylindrical outer surface. This frustoconical surface of the sealing body is connected to the cylindrical outer surface of the anchoring heel by a planar face, or by a slightly frustoconical face whereof its cone diverges towards the sealing body, perpendicular to the axis X-X, and by a concave curved surface of arcuate section. The said planar face and the said curved surface form a cheek whereof the radial height H is such that the ratio between the height H and the annular thickness E of the sealing body is greater than 0.2.

The socket of the invention comprises, following an entry collar, an interior surface including a groove having a diameter extended along the direction of the axis by a convex structure connected to a cylindrical surface having a diameter smaller than the diameter of the groove. This interior surfce of the socket comprising the groove, convex structure and cylindrical surface has a profile corresponding respectively to that of the outer surface of the anchoring heel, the frustoconical surface and the cheek of the link structure, and the outer surface of the sealing body.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: .i Figure 1 is a partial axial cross-section of a water-tight sealing ring for use with a female end socket according to the invention; 950118,q:\oper\gjn,41679-93.18,3 -4- Figure 2 is a partial axial cross-section of the female socket of a pipe to be connected designed to house the sealing ring of Figure 1; and Figure 3 illustrates a water-tight joint comprising the sealing ring and the socket of Figures 1 and 2 respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated in Figure 1, a sealing ring 1 on the axis 10 X-X comprises an anchoring structure 2 with axial length L2 and a sealing body 3 with axial length L3 which extends the anchoring structure 2 along the axis X-X, and an intermediate connecting structure 4 with axial length L4 which joins the anchoring structure 2 to the sealing body 3.

The axial length L2 of the anchoring structure 2 accounts for 25% to 35% of the total axial length Ll of the ring.

Further, the volume of the anchoring structure represents between 30% and 40% of the total volume of the sealing ring.

The ring 1 has a radially external surface comprising an •anchoring heel 5 of the anchoring structure 2. This heel, which has a cylindrical outer surface and a diameter DI, is connected to a tapered surface 6 of the connecting structure 4 by a surface 7 which is either flat or slightly tapered, the taper converging toward the sealing body 3 and having a height perpendicular to the axis X-X of the ring, and by a curved surface 8 which, in this embodiment, has an arc-shaped section of radius R.

The tapered surface 6 is extended along the axis by a cylindrical surface 9 of the sealing body 3. As shown in Figure 1, the taper of the surface 6 opens toward the sealing body 3, the surfaces 6, 7, and 8 forming a concave surface, and the surfaces 7 and 8 forming a cheek having height H equal to and, therefore, an internal diameter equal to Dl-2H.

As also illustrated in Figure 1, diameter D2 of the 930628,p:opermab,55826v,4 cylindrical surface 9 of the sealing body is less than Dl and greater than D1-2H.

The ring has an annular foot 10 on its interior surface constituting a radial interior extension of the anchoring heel opposite the latter. The annular foot 10 is composed of an internal cylindrical surface 11 having a diameter Dll, and of a tapered inlet surface 12 connected to the anchoring heel 5 by a slightly tapered surface 13. The taper of the 10 surface 12 converges toward the sealing body 3 and has at its vertex a half-angle of between 400 and 48°, an advantageous arrangement as will be seen below. The tapered surface 13 opens toward the sealing body 3 and has a half-angle at its S..vertex of more than On its internal surface proximate the annular foot the sealing body 3 has a tapered surface 14 with a half-angle at its vertex of approximately 40° and a taper opening toward the anchoring structure 2, followed by a second interior cylindrical surface 15 having an interior diameter D12 and ending in a tapered surface 17 having a half-angle at its vertex of between 100 and 200, and a taper opening toward the anchoring structurc 2. The interior diameter D12 of the interior surface 15 is less than the diameter D11 of surface 11 of the annular foot The transverse surface of the end of the sealing body 3 opposite the surface 13 of the anchoring structure 2 has an axially projecting lobe 16, and two surfaces 25 and 26 flanking the lobe. The surface 26, in combination with surface 17, forms a small triangular lip 18, and the surface which is either flat or slightly tapered and perpendicular to the axis X-X, connects with the exterior cylindrical surface 9 of the sealing body 3.

An annular groove 19 between the annular foot 10 and the sealing body 3 on the interior surface of the ring, connects 930628,p:\opermab,55826.div,5 -6the interior surface 11 of the foot to the interior tapered surface 14 of the sealing body, and constitutes the interior radial boundary of the connecting structure 4. As illustractd in Figure 1, the ridge formed by the surface 11 of the foot and the annular groove 19 is located in a straight line with the surface 7 which laterally delimits the anchoring heel The ratio between the minimum thickness e of the ring in a straight line with the groove 19 and the curved surface 8 0 and the height H of the anchoring heel 5 is between 1.3 and It has been shown, contrary to the description in the French '205 patent, that, especially in the case of maximum offsetting and angular deviation between the two pipes to be connected, it is necessary to maintain a sufficient height H of the anchoring heel 5. It has been demonstrated, more particularly, that the ratio between the height H of the anchoring heel and the thickness E of the sealing body must S. 20 be greater than 0.2 to ensure that the anchoring effect provided by the heel in combination with the annular foot remains sufficient. The preferred H/E ratio ranges between 0.25 and 0.38.

Furthermore, in order to maintain reasonable rates of compression of the ring which prevent the premature wearing out of its elastomer composition, while providing effective water-tightness within the range of tolerances which the 1 fitting must accommodate, it has been shown that, if A represents the thickness of the ring along the line joining the heel 5 and the foot 10, it is necessary, first, that the A/E ratio range between 0.80 and 1, and preferably between 0.85 and 0.95, and, second, that the ratio D11-D12/2E be greater than 0.18, and preferably between 0.2 and 0.3.

93628,p\oper\mab,5582.iv,6 -7- As illustrated in Figure 2, a sealing ring of the type described above is designed to be mounted inside of a female socket 30 of a pipe requiring connection. The socket 30 has, at its inlet end following a collar 31, a coaxial groove 32 comprising a slightly tapered surface 33 extended toward the bottom of the socket by a cylindrical surface 34 having a diameter D31 and ending, in an interior radial direction, in a slightly tapered or flat surface 35. The latter is extended toward the bottom of the socket by a convex curve 36 and a 10 tapered surface 37 which connects with a cylindrical surface 38 having a diameter D32 smaller than the diameter D31 of the cylindrical surface 34. The taper of the surface 37 opens out oo o toward the bottom of the socket 30, and the interior surface of the socket thus has a shape which corresponds to the exterior profile of the ring. At the inner limit of the socket, the cylindrical surface 38 ends in a radial stop 39 which limits the length L of the surface 38.

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As shown in Figure 3, a sealing ring 1 of the type 20 described above is designed to be mounted in the female socket of a pipe T1 in which the anchoring heel 5 fits into the groove 32 of the socket, and surfaces 6, 7, 8 and 9 of the ring come into contact with the corresponding surfaces 35, 36, 37, and 38 of the socket. As described in the French '205 patent, the male end 40 of a pipe T2 is then inserted into the socket 30, causing the compression of the annular foot 10 and, in consequence pushing the anchoring heel 5 into the groove 32 of the socket. Accordingly, the sealing ring is rendered stable in the socket, thereby avoiding any movement of the anchoring heel when the male end 40 is being inserted, and; in consequence, avoiding any movement of the ring toward the bottom of the socket.

The shape peculiar to the socket 30 is a function of the requirement described above pertaining to the height H of the anchoring heel and to the centrifuged casting process.

Indeed, if a sealing body 3 is connected directly to the 930628,pkoperkmab,55826.div,7 anchoring heel 5 as described in the French '205 patent, the exterior diameter of the anchoring heel, taking its height H into account, becomes such that the thickness of the socket along a line passing through the groove 32 becomes insufficient to impart any effective mechanical strength to the socket. Therefore, a sufficient height H of the heel in relation to the thickness E of the sealing body 3 should be provided, while avoiding a corresponding reduction of the thickness of the socket on a line with its groove 32. This was achieved through the provision of an anchoring heel "uncoupled" from the sealing body 3 by surfaces 6, 7, and 8 of the intermediate structure 4, without which the height of the heel 5 would be merely equal to (Dl D2)/2.

Furthermore, the specific value of the half-angle at the vertex of the tapered surface 12 of the foot 10 makes it possible to insert a male end of one pipe into the female socket of another pipe with angular deviations between the pipe axes of more than 100, as well as when the male end to se". 20 be inserted has an excessively imperfect edge chamfer, or none at all. Moreover, the stop 39 limits the excessive insertion of the sealing ring into the bottom of the socket 0* Additionally, the relative volume of the anchoring structure 2 in relation to the total volume of the ring makes it possible to prevent the fitting from being ejected from the socket when highly-pressurized fluids circulate in the pipeline. Finally, by working in conjunction with each other, the tapered surface 13 of the ring and the tapered surface 33 of the socket allow the anchoring heel 5 to be fully inserted into the groove 32.

Thus, the sealing ring and the socket according to the invention allow the formation of a water-tight joint which accommodates all manufacturing tolerances of the centrifuged pipes, while at the same time allowing the male end of a pipe to be fitted into the female socket of another pipe positioned 930628,p:oper~mab,55826.div, -9at an angular deviation of more than 100, while preventing the ring from being ejected from the socket and while maintaining non-deterrent insertion stresses.

The invention has been described by way of example only and modifications are possible within the scope of the invention.

00 0: 93G628,p:\oper\mab,55W2.div,9

Claims

1. A female end socket of a pipe for use in housing an annular sealing ring made of elastomer and having an axis X-X, for a pipe joint, intended to be radially compressed between the inner surface of the end socket and the outer surface of the spigot end of another pipe to be connected, the sealing ring comprising: a sealing body having an annular thickness E, having a cylindrical outer surface with diameter D2; and an anchoring structure axially displaced from the sealing body, formed by an anchoring heel with a cylindrical outer surface of diameter D1 projecting radially outward in relation to the sealing body, the anchoring structure being connected to the sealing body by a link structure having a frustoconical surface with its cone opening towards the sealing body, whereof it extends the cylindrical outer surface, the said frustoconical surface of the sealing body being connected to the cylindrical outer surface of the anchoring heel by a planar face, or by a slightly frustoconical face whereof its cone diverges towards the sealing body, perpendicular to the axis X-X, and by a concave curved surface of arcuate section, the said planar face and the said curved surface forming a cheek whereof the radial height H is such that the ratio between the said height 20 H and the annular thickness E of the sealing body is greater than 0.2, o wherein the socket comprises, following an entry collar, an interior surface including a groove having a diameter extended along the direction of the axis by a convex structure connected to a cylindrical surface having a diameter smaller than the diameter of the groove, and wherein said interior surface of the socket comprising said groove, convex structure and cylindrical surface has a profile corresponding respectively to that of the outer surface of the anchoring heel, the frustoconical surface and the cheek of the link structure, and the outer surface of the sealing body. 950118,q:\oper\gin,41679-93.18,10 11

2. A female end socket of a pipe substantially as hereinbefore described with reference to the drawings. Dated this 28th day of June, 1993 PONT-A-MOUSSON S.A. by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s) *oo 0 0:0. *se. .00.0

066. 950118,q:\oper~gr2,41679-93.18,11