METHOD OF DETECTION OF LEAKAGE OF NATURAL GAS FROM GAS MAIN Russian patent published in 2003 - IPC

FIELD: analytical instrumentation engineering; methods of detection of leakage of natural gases from gas mains. SUBSTANCE: proposed method includes drawing sample of gas-and-air mixture near gas line, injecting this sample to flow of carrier gas, passing the sample through adsorbent column, followed by feeding the sample to detector after separation of methane, ethane and propane and measuring the time of detection and magnitudes of components of signals of methane, ethane and propane at detector outlet. Used as carrier gas is mixture of gases containing oxygen; adsorption of sample is effected on heated gas- sensitive adsorbing surface of detector sensor at simultaneous oxidation of methane, ethane and propane adsorbed on this surface; power of preheating of sensor is so selected that close magnitudes of electrical signals are obtained at detector output in analyzing the comparison sample of natural gas drawn directly from gas main; ratio of magnitudes of signals of components in sample of gas-and-air mixture is compared with ratio of these components in comparison sample; coincidence of said ratios is indicative of leakage of gas from this main. EFFECT: enhanced accuracy and selectivity of leak detection. 2 cl, 1 dwg