Method and apparatus for testing underground pipes, carrying gas or liquid, for leakage

摘要

Hitherto, during the leak-testing of preferably gas-carrying pipes which are laid in the earth, a detector has been passed over the earth's surface in the area of the laid pipes and a connected measuring device has determined whether increased gas concentrations are present. This is logged in writing in the same way as the measuring section or the position. However, these written notes are very often incomplete or inaccurate, so that subsequent perusal of the log only gives an inaccurate overview of the test carried out. The novel method is intended to permit sure and reliable logging independent of personnel. According to the invention, the logging is now effected by a computer-controlled plotter which, independently of the inputs of an operator, automatically plots signals as a function of position and measured value at the start of and during the test. By markings which are provided in the area of the section to be tested and are firmly installed, signals can be picked up which are recorded in a corresponding log by the plotter and the pipe test carried out can be made exactly comprehensible at any time.