GB2166826A

GB2166826A - Sealed pipe joint

Info

Publication number: GB2166826A
Application number: GB08428142A
Authority: GB
Inventors: Ian Roland Yarnell
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-11-07
Filing date: 1984-11-07
Publication date: 1986-05-14
Also published as: GB8428142D0

Abstract

A pipe joint formed by the male end portion of a first pipe section (10) and the female end portion of a second pipe section (20) is characterised by the male portion having a proximal annular channel (12A) housing a flexible sealing ring (16) and a distal inwardly directed step surface (14A), and by the female portion having an inwardly projecting flexible distal end part terminated by a proximally directed inner step surface (22A), the portions being so shaped and dimensioned that the distal end part of the female portion snaps over the step defined by the step surface (14A) of the male portion to compress the sealing ring (16) with a radial inward movement. <IMAGE>

Description

SPECIFICATION Sealed pipe joint This invention relates to the sealing of joints between pipe sections.

It is well-known to repair a damaged sewer by lining it with a plastics pipe having a number of pipe sections. It is also known to fracture an existing sewer from within to provide an enlarged duct which can accept a plastics pipe of corresponding diameter. The pipe sections may have threaded end portions so that they can be screwed together on site, or more conveniently, they may have "snap fit" joints. In many cases it is not necessary for sewer linings to be capable of remaining watertight under any great pressure, and adequate sealing can be achieved without special means. However, in certain situations, greater pressure resistance is required, as is the case for example when the sewer is in a region where there is a high water table, and water outside the sewer must be prevented from entering the pipe.

The present invention has as one of its objects the provision of a sealed pipe joint that allows the rapid assembly of pipe sections and can withstand the forces involved in locating the pipe inside a suitable underground duct. Accordingly, the invention provides a pipe joint in which one of the end portions of the pipe sections to be joined has a flexible sealing ring or the like housed in a channel extending around the pipe section, and has a snap fit feature between the sealing ring and the end of the respective pipe section. At least the end portions of the pipe sections are flexible, one female end portion having an inner step which is forced over the snap fit projection of a male end portion when the two pipe sections are pushed together.When the step snaps over the projection the outer part of the female end portion clamps onto the flexible sealing ring, compressing the ring against the base of the channel largely without sliding movement on the ring, as is the case with conventional O-ring joints. Thus, according to another aspect of the invention, a joint between two pipe sections is provided by locating a flexible sealing ring on a male end portion of a first pipe section, and by forming the outer surface of the said male end portion and/or the inner surface of a female end portion of a second pipe section so that part of the said female end portion compresses the sealing ring by a generally radially directed inward movement as the two pipe sections are fitted together.

A joint in accordance with the invention is illustrated by way of example in the accompanying drawing. In the drawing, which is a sectional view of a pipe wall in the region of the joint, the male end portion of a first pipe section 10 has a channel 12 bounded by a projecting annular step portion 14 which defines a step facing away from the end of the pipe section 10. The channel 12 has a stepped floor forming an inner groove 12A for a flexible O-ring 16 and an abutment surface 12B for limiting compression of the O-ring 16.

Both the channel floor 12A, 12B and the step portion 14 are conical, their outside diameters decreasing towards the end of the pipe section.

The female end portion of a second pipe section 20 has an inwardly projecting step portion 22 corresponding in length to the length of the channel 12, and a channel 24 located proximally relative to the end of the pipe section 20 corresponding in length to the length of the outwardly projecting step portion 14 of the first pipe section 10. The above described steps and channels formed in the two end portions provide a joint which "snaps" together when the two pipe sections are pushed together, the assembled joint being as shown in the drawing. The location of the O-ring is such that it is compressed only when the joint snaps together, the surface of the step portion 22 moving radially inwardly to compress the O-ring 16 as its inner edge 22A snaps over the inner edge 14A of the outwardly projecting step portion of the male end portion.The degree of compression may be determined, if required, by the engagement of the step portion 22 with the abutment surface 12B in the channel 12. Alternatively, the abutment surface 12B can be omitted so that the degree of compression depends on the elastic properties of the pipe material and the O-ring 16. It will be appreciated that, in the latter case, outside pressure (due, for example, in the case of an underground pipe, to a high water table) results in the O-ring 16 being further compressed.

The joint shown in the drawing, being a snap-fit joint, is particularly convenient for sewer repair since each pipe section can be joined to the next merely by applying compression to the pipe as a whole using a chain or cable running through the pipe from a remotely controlled duct enlarging device at the head of the pipe to a plate or other device placed over the rear end of the pipe, as described in my co-pending Applications No. 84 23678. A snap-fit joint as shown is also able to withstand the normal compressive and tensile loads placed on the joints during the conduit lining methods described in the co-pending application. Thus the present invention combines these advantages with the improved sealing properties provided by a flexible sealing ring.

The arrangement of the conical surfaces of the respective projecting step portions 14 and 24 of pipe sections is such that the leading edge of one or each of the pipe sections scrapes accumulated soil or other debris from the mating surfaces as the pipe sections are pushed together.

Claims

1. A pipe section having an end portion with an annular channel, a flexible sealing ring or the like housed in the channel, and, between the channel and the extreme end of the section, a snap fit feature.

2. A pipe section according to claim 1, wherein at least the end portion is made of a flexible plastics material.

3. A pipe section including (a) a male connector end portion having a recessed annular channel housing a flexible sealing ring or the like, and a proximally directed annular step surface located between the channel and the respective end of the pipe section, and (b) an opposite female connector end portion having a flexible distal part for compressing the sealing ring of the male connector end portion of an identical neighbouring pipe section, and an inner proximally directed step surface located proximally of the said distal part for engaging the step surface of the male connector end portion of the said neighbouring pipe section.

4. A pipe joint assembly comprising a male end portion of a first pipe section and a flexible female end portion of a second pipe section, and a flexible sealing ring located on an outwardly directed surface of the male end portion, wherein an inwardly directed surface of the female end portion and the said outwardly directed surface of the male end portion are so shaped and located that the said inner surface compresses the sealing ring against the said outer surface by a generally radially directed inward movement of the female end portion as the two pipe sections are fitted together.

5. A pipe section having a male end portion and a female end portion each of which is constructed and arranged substantially as herein described and shown in the drawing.