Closing down burning crude oil natural gas supply pipes - using slide valve with cutting edges, and providing access to underground pipe by digging shaft, does not use sealants and existing installation can be reused

摘要

A means of shutting off flow in crude oil or natural gas feed pipes where fires or other damage prevents the use of the well head shut off valves. The method and appts. claims to enable the existing well head valve and pipe to be put into use again, once the fire has been extinguished. The novelty is the use of a slide valve which does not pass all the way through the pipe and dispenses with pipe sealants or concrete. An access shaft is dug at a safe distance from the well head, down to the feed pipe, and a working chamber made around the feed pipe. The pipe is weakened by cutting a groove into the outer pipe coating around approx. half of the circumference. Strengthening and sealing shells are clamped around the pipe for a length of about 4 times the diameter of the pipe. Flanges on the sides of the strengthening shells allows attachment of a slide valve with hardened cutting edges. The slide valve is at least as wide as the pipe inner diameter, but not wider than the outer diameter. A slot in one half of the strengthening shell is positioned over the groove cut into the pipe. The slide valve is bolted to the clamped strengthening shell at right angles to the pipe. A hydraulic powered ram forces the cutting edge into the groove cut into the pipe. Diametrically opposite the slide valve and ram, a tail pipe section acts as a collection chamber for material pressed or extruded from the pipe. ADVANTAGE - Enables existing pipe work to be used again once well head fire has been extinguished or other repair work carried out. Does not use pipe sealants. Work can be carried out in safety.