METHOD OF DETECTION OF LOCAL LOSS OF TIGHTNESS Russian patent published in 1995 - IPC

FIELD: measurement technology. SUBSTANCE: space between pipe-line and shell is blown through with ballast gas with flow rate G₁. Calibrated flow of test gas with value Q_t is fed into specified space at start of tested section. Time interval from moment of start of feed up to moment when gas analyzer starts to register test gas in this space at end of tested section is recorded as well as value of steady-state increment of signal of gas analyzer. Feed of calibrated flow is stopped, pipe-line is blown through with ballast gas under working pressure to which flow rate G₂ corresponds with G₂< G₁. Then blowing through of pipe-line with ballast gas is discontinued. Simultaneously with stopping of blowing through of pipe- line with ballast gas with flow rate G₂ test gas with flow rate G₃ is fed with G₂< G₃< G₁. After lapse of time ^∧t feed of test gas into pipe-line is stopped. Simultaneously with stopping of feed of test gas into pipe-line with flow-rate G₃ ballast gas with flow rate G₄ is fed into it with G₃< G₄< G₁. Times of start of growth of signal of gas analyzer (signal from forward front of test gas), intervals of time of growth of signal of gas analyzer from background up to steady-state (maximum) value and value of steady-state increment of signal of gas analyzer as well as times of start of fall of signal of gas analyzer (signal from rear front of test gas) and intervals of time of fall of signal of gas analyzer from steady-state (maximum) to background value are recorded. Coordinate of point of loss of tightness is determined by relation of measured time intervals and its value by relation of measured steady-state increments of signal of gas analyzer. EFFECT: improved efficiency of detection of multiple posses of tightness. 1 dwg