GB2387888A - Restraining device - Google Patents

Abstract

A device for securing a liner of a host pipe adjacent a branch thereof, the device comprising means for insertion in the branch and for gripping a boundary wall thereof, the means being adapted for use in branches of different diameter.

Description

1 2387888

RESTRAINING DEVICE

The invention relates to a restraining device, particularly to such a device for securing a liner of a host pipe in position in that pipe.

Underground pipes such as water mains are sometimes in need of repair, owing to leakage. This can be environmentally damaging, depending on the fluid carried in the pipe, and costly as it is wasteful of that fluid. This is particularly so in the case of water. It is costly and timeconsuming to excavate and replace an existing underground pipe with a new one, so the practice has arisen of lining such pipes with a plastic liner. This then has the disadvantage that for a branch, service connection, or "ferrule", say from a main into a dwelling, the liner can block off the ferrule against passage for say water from the main along the service connection to the dwelling, which would then be starved of supply.

Methods and systems have therefore been developed for perforating the liner at the entrance to the ferrule. This results in an annular area at the ferrule entrance which allows water to flow between the liner and the main, so tending to reduce flow to the ferrule, and also lifts the liner from the main, thus obviating the effectiveness of the liner and negating its function. A device has been developed for securing the liner to the main at the ferrule entrance the device which comprises a body which is adapted for self-support and for securing a liner adjacent the branch. A problem with such devices is that they are suitable for use only with ferrules of one particular bore size.

It is an object of the invention to seek to mitigate this problem.

According to the invention there is provided a device for securing a liner of a host pipe adjacent a branch thereof, the device comprising means for insertion in the branch and for gripping a boundary wall thereof, the means being adapted for use in branches of different diameter.

N Suitably, the means may comprise a plurality of members for gripping a boundary wall of a branch, each member being adapted for use in a branch of specified diameter. An embodiment of the invention is shown in the drawings, of which: Fig 1 shows schematically a side elevational view of a part of a device according to the invention; and Fig 2 shows schematically a plan view of the device of Fig 1 inserted in a branch of a host pipe.

Figs 1 and 2 show a part of a device 1 for securing a liner of a host pipe 2 adjacent a branch thereof comprising a shaft 3 for insertion in the branch (ferrule) 4, the shaft 3 being provided with three elements 5, 5, 5 for gripping a boundary wall of the branch 4. Each element 5, 5, 5 comprises two cross members 6 which have been mounted on the shaft 3 so that they are mutually perpendicular, and an equal portion of each cross member 6 projects from each side of the shaft 3. The cross members are made from springy stainless steel.

The length of each cross member 6 is different, and is selected such that each cross member 6 is suitable for gripping a boundary wall of a branch 4 of a particular bore size.

Fig 1 shows the shaft 3 inserted in a branch 4. Element 5 is too small to grip the boundary wall of the branch 4, and element is too large to grip the boundary wall of the branch 4. Element 5 is the correct size, and is a "sprag-fit" such that a small force is required to push the shaft 3 inwards, but a large force is required to pull it outwards.

It will be understood that a large number of modifications are possible.

Claims (1)

1. CLAIM 1. A device for securing a liner of a host pipe adjacent a branch

   thereof, the device comprising means for insertion in the branch and for gripping a boundary wall thereof, the means being adapted for use in branches of different diameter.