Method of detecting leakage part of combined-layer pipe

Abstract

Abstract PURPOSE: To accurately detect the presence and position of a leakage part, by moving an insert into the inner pipe of a combined-layer pipe and transferring gas out of a space surrounded by the inner pipe and the insert, to the outside of the combined-layer pipe to detect the gas. CONSTITUTION: A hose 9 is extended into an inner pipe 2 so that an insert 6 is located in a manhole 18. Gas is introduced under pressure into a space 5 between the inner pipe 2 and an outer pipe 3 through a gas inlet port 16. The insert 6 is put in the inner pipe 2. The hose 9 is wound by a winder 10 provided in another manhole 19 to pull the insert 6 in the direction of an arrow A. As a result, air in a space B surrounded by both partition plates 6a, 6b is introduced into a discolorable liquid 12 in a tank 11 through a perforated hole 7, a suction hole 8 and the hose 9. If there is leakage through a part C of the inner pipe 2, the gas injected into the space 5 gushes into the inner pipe 2 through a heat retaining meaterial 4 and the leakage part C. When the leakage part C is located between the partition plates 6a, 6b, the gas is sucked by a pump 14 and introduced into the discolorable liquid 12 and discolors it. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Toshio Matsumura
• 👤 Hiroshi Kishigami

Bibliographic Details