GB2109078A

GB2109078A - Pipe joint

Info

Publication number: GB2109078A
Application number: GB08226860A
Authority: GB
Inventors: Keith Millward
Original assignee: Paragon Plastics Ltd
Current assignee: Paragon Plastics Ltd
Priority date: 1981-11-03
Filing date: 1982-09-21
Publication date: 1983-05-25
Also published as: GB2109078B

Abstract

A pipe joint comprising a female pipe part (10) for receiving a male pipe part (12) and also comprising a resilient sealing ring (14), the latter including a radially outer locating portion (16) and a fluid sealing portion (20). So that the joint will require a relatively low assembly force, there is formed a circumferential cavity (30) within the sealing ring and a passage communicating with said cavity through which a pressure of fluid within the male pipe part can flow to produce a sealing pressure within the ring. <IMAGE>

Description

SPECIFICATION Pipe joint The invention relates to pipe joints, particularly but not exclusively for use in water supply pipes.

Various kinds of pipe joints are known which comprise a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring, the latter including a radially outer locating portion capable of being received in a groove in the female pipe part and including also a fluid sealing portion connected integrally to said locating portion at one end, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is deflected radially outwards as the end of said male part enters said ring. However, such known pipe joints generally rely on the compression of the material of which the resilient sealing ring is made to produce a fluid tight joint.For this reason such joints are usually fairly difficult to assemble because they require a fair amount of force to enter the male pipe part into the resilient sealing ring. Furthermore, if the reaction from the compression of the ring material causes a localized necking of the male pipe part, this causes loss of compression in the ring material and an increased possibility of leakage. The invention aims to at least alleviate these drawbacks.

According to the invention, there is provided a pipe joint comprising a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring, the latter including a radially outer locating portion capable of being received in a groove in the female pipe part and including also a fluid sealing portion connected integrally to said locating portion at one end, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is deflected radially outwards as the end of said male part enters said ring, the arrangement also being such that when the fluid sealing portion of the ring has been fully deflected radially outwards by the male pipe part it contacts the radially outer locating portion at or in the region of its end remote from that at which it is integrally connected thereto so that there is formed a circumferential cavity within the sealing ring, there being at least one connecting passage communicating with said cavity through which a pressure of fluid within the male pipe part can flow to produce a sealing pressure between the ring and the surface of the male pipe part varying according to the fluid pressure within said male pipe part.The fluid sealing portion of the resilient sealing ring may have a lesser axial length than the radially outer locating portion so that the at least one connecting passage commun#cating with the cavity cannot be closed by the insertion of the sealing ring into the groove in the female pipe part. Alternatively, the fluid sealing portion of the resilient sealing ring may be the same length as the radially outer locating portion, the groove in the female pipe part being stepped so that there is provided an open annular pocket ensuring the cavity within the sealing ring remaining open to communicate with the interior of the male pipe part. In this latter case there may be a plurality of spaced slots which extend from the open end of the female pipe part and a slightly beyond the groove in which the sealing ring is received.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which:~ Figure 1 is a part sectional view of a pipe joint embodying the invention, Figure 2 is an end view of a resilient sealing ring forming a part of the joint, the ring being shown in its free condition, Figure 3 is a sectional view of the sealing ring on the line 3-3 in Fig. 2 but drawn to a very much enlarged scale, and Figures 4 to 8 are views which will presently be referred to when describing possible modifications.

Referring now to Fig. 1, the pipe joint there illustrated comprises a female pipe part 10 for receiving a male pipe part 12 and also comprises a resilient sealing ring 14 the latter including a radially outer locating portion 16 capable of being received in a groove 18 in the female pipe part and including also a fluid sealing portion 20 connected integrally to said locating portion at one end.

In Fig. 3 there is illustrated the cross sectional shape of the sealing ring in enlarged detail. It will be seen that the radially outer locating portion is provided with inclined side surfaces 22 corresponding to the inclination of the side walls of the groove 18 in the female pipe part. It will also be seen that the fluid sealing portion 20 is provided on its radially inner surface with a series of annular ribs 24; on its radially outer surface and substantially opposite the ribs 24 it is provided with an annular enlargement 26. The radially outer locating portion of the ring is provided with four equally spaced undercut grooves 28 which extend as shown from its free end almost to the region of its integral connection to the fluid sealing portion.

It will be seen that the female pipe part forming a part of the joint of Fig. 1 is in fact a double ended connector for joining together adjacent lengths of male pipe, a single length only being shown. The double ended connector is therefore provided with a groove 18 at each each end, the grooves containing respective seaing rings. The sealing ring at the right hand end of the connector is shown in its free condition; that at the left hand end of the connector is shown to have been deformed by the insertion of the male pipe part, the fluid sealing portion of the ring having been deflected radially outwards.In this fully deflected condition of the fluid sealing portion it contacts the radially outer locating portion at or in the region of its end remote from that at which it is integrally connected thereto, that it to say the annular enlargement 26 contacts the locating portion 1 6.

The arrangement is such that when the fluid sealing portion has been fully deflected and has contacted the locating portion, substantially as shown in chain-dotted lines in Fig. 3, there is formed a circumferential cavity 30 within the sealing ring. However, by virtue of the undercut grooves 28 in the radially outer locating portion of the ring, there are four connecting passages communicating with said cavity through which a pressure of fluid within the male pipe part can flow to produce a sealing pressure within the seal equal to the fluid pressure within said male pipe part.

Consequently, when the joint is in use there is always an effective seal against leakage and one which is virtually unaffected by any localised necking of the male pipe part. A further advantage is that when the joint is being assembled the absence of any sealing pressure within the sealing ring results in the male pipe part being able to be entered into the female pipe part with relative ease.

It will be seen from Figs. 1 and 3 that in the sealing ring described above the fluid sealing portion has a lesser axial length than the radially outer locating portion. In this way it is ensured that the four connecting passages communicating with the cavity within the sealing ring cannot be closed by the insertion of the sealing ring in its groove in the female pipe part. However, various modifications may be made. For example, in Fig. 4 there is illustrated an arrangement in which the fluid sealing portion is the same length as the radially outer locating portion, but in this case the groove in the female pipe part Is stepped as shown so that there is provided an open annular pocket 31 ensuring the cavity within the sealing ring remaining open to communication with the interior of the male pipe part.

In Figs. 5 and 6 there is shown a somewhat similar arrangement in that the groove in the female pipe part is stepped as in Fig. 4 but in addition there are four equally spaced slots 32 which extend from the open end of the female pipe part and extend as shown slightly beyond the groovy in which the sealing ring is received. Obviously, of course this is simply an alternative method of manufacture and the sealing function is exactly the same as before.

In a further possible modification which is shown in Figs. 7 and 8, the groove in the female pipe part is stepped as in Fig. 4 but in this case there are four equally spaced depression 34 in the side wall of the groove through which the cavity within the sealing ring can communicate with the interior of the male pipe part.

It will be understood that there will gener ally be sufficient clearance between the exter nal surface of the male pipe part and the bore of-the female pipe part for the pressure within the male pipe part to communicate with the groove in which the sealing ring is located.

However, the fluid path could be along axial grooves moulded or machined in the internal wall of the female pipe part if preferred.

Various other modifications could be made and it will be understood that the female pipe part need not necessarily be a double ended connector for joining together adjacent le#ngths of male pipe. On the contrary, the female pipe part could be formed as an enlarged end portion of a length of pipe the other end of which constitutes a male pipe part of the successive pipe joint. The detailed cross sectional shape of the resilient sealing ring could be varied in numerous ways. For example, the number and shape of the annular ribs 24 could be varied. The material of which the sealing ring may best be made can be determined by trial and experiment, but can be any synthetic or natural rubber of a composition appropriate to the application for which the pipe joint is intended.

Claims

1. A pipe joint comprising a female pipe part for receiving a male pipe part and also comprising a resilient sealing ring, the latter including a radially outer locating portion capable of being received in a groove in the female pipe part and including also a fluid s#ealing portion connected integrally to said -locating portion at one end, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is deflected radially outwards as the end of said male part enters said ring, the arrangement also being such that when the fluid sealing pprtion of the ring has been fully deflected radially outwards by the male pipe part it contacts the radially outer locating portion at or in the region of its end remote from that at which it is integrally connected thereto so that there is formed a circumferential cavity within the sealing ring, there being at least one connecting passage communicating with said cavity through which a pressure of fluid within the male pipe part can flow to produce a sealing pressure between the ring and the surface of the male pipe part varying accord ing to the fluid pressure within said male pipe part.

2. A pipe joint according to claim 1, in which the fluid sealing portion of the resilient sealing ring has a lesser axial length than the radially outer locating portion so that the at least one connecting passage communicating with the cavity cannot be closed by the insertion of the sealing ring into the groove in the female pipe part.

3. A pipe joint according to claim 1, in which the fluid sealing portion of the resilient sealing ring is the same length as the radially outer locating portion, the groove in the female pipe part being stepped so that there is provided an open annular pocket ensuring the cavity within the sealing ring remaining open to communicate with the interior of the male pipe part.

4. A pipe joint according to claim 3, in which there are a plurality of spaced slots which extend from the open end of the female pipe part and slightly beyond the groove in which the sealing ring is received.

5. A pipe joint constructed arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated by Figs. 1 to 3 or Fig. 4 or Figs. 5 and 6 or Figs. 7 and 8 of the accompanying drawings.