GB2172358A

GB2172358A - Branch pipe connector

Info

Publication number: GB2172358A
Application number: GB08506858A
Authority: GB
Inventors: Peter Bond; Andrew Bowler
Original assignee: R J FABRICATIONS Ltd
Current assignee: R J FABRICATIONS Ltd
Priority date: 1985-03-16
Filing date: 1985-03-16
Publication date: 1986-09-17
Also published as: GB2172358B; GB8506858D0

Abstract

A connector comprising a threaded body 1, a sealing ring 10 mounted on the body, and a collar 8 within which the sealing ring is received and a flat washer 9. The washer defines a flat surface generally perpendicular to the axis of the body which surface contacts one axial side of the sealing ring. A nut 7 is supported on the threaded body so as to contact the flat surface of the collar. The collar further comprises a single cylindrical inner surface intended to engage with the radially outer surface of the sealing ring. <IMAGE>

Description

SPECIFICATION Connector The present invention relates to a connector and in particular to a connector for making a branch connection to a pipe of the type used for example in gas distribution networks.

Branch connectors of various types have been known for many years some of which can only be installed when the pipe to which the connection is to be made is empty and others of which can be used to make branch connections to pipes containing fluid under pressure using appropriate installation equipment. The present invention has application to both types of connector but is particularly suitable for use in making connections to pipes containing fluid under pressure.

A prior art connector has been used comprising a threaded body intended to be screwed into a threaded aperture in the pipe to which a connection is to be made, a resilient sealing ring supported on the threaded body, a rigid collar arranged around the sealing ring and defining a flat surface intended to be located on the side of the sealing ring remote from the pipe to which the connection is to be made, and a nut intended to be tightened onto the threaded body so as to press the collar and thus the sealing ring against the pipe to which the connection is to be made.

In the prior art device the rigid collar has been formed with a side wall defining an undercut into which a corresponding flange on the sealing ring is received. This ensures that the sealing ring cannot be pulled loose from the collar. Furthermore the inner surface of the collar is tapered on either side of the undercut so as to improve compression of the sealing ring as the nut is tightened home.

It is difficult to form the undercut and conical surfaces required in the known collar and as a result the prior art device is relatively expensive. It has nevertheless been thought necessary to use an expensive collar of this type to achieve the required sealing effect.

It is an object of the present invention to provide an improved connector which comprises a collar and sealing ring which are easy to manufacture.

According to the present invention there is provided a connector comprising a threaded body, a sealing ring mounted on the body, a collar within which the sealing ring is received, the collar defining a flat surface generally perpendicular to the axis of the body and intended to contact one axial side of the sealing ring, and a nut supported on the threaded body so as to contact the flat surface of the collar, wherein the collar further comprises a single cylindrical inner surface intended to engage with the radially outer surface of the sealing ring.

The collar is particularly easy to manufacture as no undercut is required on the inner surface of the collar which contacts the peripheral surface of the sealing ring.

The collar may be defined by two or more separable components. If the collar is manufactured from two components it can comprise a simple short length of tube defining the cylindrical inner surface and a washer intended to bear against one end of the tube. The end of the tube remote from the washer may be pressed inwards to define a tapering surface. As an alternative to the two component structure, the collar may comprise a cupshaped washer a first portion of which defines the cylindrical inner surface and a second portion of which defines an annular inner surface intended to bear against the sealing ring.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 illustrates the structure of a conventional connector; and Figures 2, 3, 4 and 5 illustrate respective embodiments of the present invention.

Referring to Figure 1, the prior art connector comprises a tubular threaded body 1 intended to be screwed into a threaded aperture in a pipe (not shown). A resilient sealing ring 2 having a cylindrical outer surface 3 and a conical outer surface 4 is received within a collar 5 defining an undercut 6 mating with the conical surface 4 of the sealing ring. The sealing ring and collar are screwed onto the threaded body.

In use the threaded body is screwed into the pipe to which a connection is to be made and a nut 7 is then tightened onto the threaded body so as to force the collar 5 and the sealing ring 2 into contact with the outer curved surface of the pipe.

The sealing ring 2 is then compressed ensuring a good seal between the threaded member 1 and the pipe body.

The manufacture of the collar 5 with its undercut 6 is a relatively expensive process and as a result the collar 5 represents a substantial proportion of the total cost of the connector. A collar of the type illustrated in Figure 1 has previously been thought necessary to ensure good engagement between the collar and the sealing ring 2 and to ensure good compression of the ring 2 as the nut 7 is tightened up.

Referring now to Figure 2, the threaded body 1 and nut 7 are identical to those of the conventional connector illustrate in Figure 1. The collar 5 of Figure 1 is replaced however by a simple tubular member 8 and a simple flat washer 9. A sealing ring 10 is pushed into the tube 8 and the nut 7 is then tightened up forcing the washer 9 into contact with one end of the tube 8. Thereafter the use of the connector is identical to that of the conventional connector illustrated in Figure 1.

In contrast to the arrangement of Figure 1, the embodiment of the invention illustrated in Figure 2 is cheap to produce as the tube 8 and washer 9 are extremely cheap to produce. The total cost of a connector is reduced significantly as a result. Surprisingly it has been found in practice that the tube 8 and sealing ring 10 remain in engagement with each other in all normal circumstances. Furthermore as the nut 7 is tightened up despite the fact that there are no conical surfaces on the tube 8 the sealing ring nevertheless forms a good seal as it is compressed against the outer surface of the pipe to which the connection is to be made.

Referring now to Figure 3, a second embodiment of the invention is illustrated which is similar to that of Figure 2 except for the fact that instead of a separate tube 8 and washer 9 a single piece collar 11 is provided. The collar 11 is structurally exactly equivalent to the combination of a cylindrical tube and a flat washer. The performance of the collar 11 is substantially exactly the same as that of the collar formed by the tube 8 and washer 9 in the embodiment of Figure 2.

If it is desired to provide a tapering surface on the collar to increase the radial compression on the sealing ring this can be achieved by using a structure such as that illustrated in Figure 4. In the arrangement of Figure 4, the collar is a two-part structure comprising a simple flat washer 12 and a cup-shaped member having a cylindrical portion 13 and a conical portion 14. The cup shaped member may be formed by cutting a short length of steel tube and simply pressing in the edge of one end to form the tapering conical portion 14. The sealing ring has a cylindrical outer surface 15 and a conical end surface 16 to correspond with the internal shape of the cup-shaped member defined by portions 13 and 14.

As the nut 7 is tightened the washer 12 forces the sealing ring into the cup-shaped member and the cooperating conical surfaces of the cup-shaped member and sealing ring increase the radial compression on the sealing ring. The sealing ring projects through the end of the conical portion 14 into firm contact with the outside of the pipe to which the connection is being made. Thus with the arrangement of Figure 4 by using a two-part collar one can effectively obtain the same radial compression as is obtained using the complex undercut collar of Figure 1.

Figure 5 illustrates an embodiment of the invention which is similar to that of Figure 4 in that the collar comprises a flat washer 12 and a cup-shaped member having a conical portion 14. In contrast to the embodiment of Figure 5 however the sealing ring has end faces supporting annular ridges 17 and has a groove 18 around its circumference. This form of sealing ring comprises the sealing effect in use and also assists in retaining the cup-shaped member on the sealing ring.

Claims

1. A connector comprising a threaded body, a sealing ring mounted on the body, a collar within which the sealing ring is received, the collar defin ing a flat surface generally perpendicular to the axis of the body and intended to contact one axial side of the sealing ring, and a nut supported on the threaded body so as to contact the flat surface of the collar, wherein the collar further comprises a single cylindrical inner surface intended to engage with the radially outer surface of the sealing ring.

2. A connector according to claim 1, wherein the collar is defined by two or more separable components.

3. A connector according to claim 2, wherein the collar comprises a short length of tube defining the cylindrical inner surface and a washer intended to bear against one end of the tube.

4. A connector according to claim 3, wherein the end of the tube remote from the washer is pressed inwards to define a tapering surface.

5. A connector according to claim 1, wherein the collar comprises a cup-shaped washer a first portion of which defines the cylindrical inner surface and a second portion of which defines an annular inner surface intended to bear against the sealing ring.

6. A connector substantially as hereinbefore described with reference to Figure 2, Figure 3, Figure 4 or Figure 5 of the accompanying drawings.