MEASURING SYSTEM FOR LEAKS LOCALIZATION AND GAS CONTAMINATION ANALYSIS AT GAS PIPELINE SECTION

摘要

FIELD: measurement technology.;SUBSTANCE: invention relates to means of monitoring gases based on semiconductor sensor cells for detecting gas mixtures and can be used to measure concentration of gases in atmosphere of premises of industrial enterprises, tunnels, etc. Principle of operation of the system for determining location of gas leaks with measurement of gas content is based on recording changes in resistance of gas-sensitive sensors (sensors of gas mixtures) when exposed to gas. Measuring system is a loop consisting of parallel gas-sensitive sensors, conductivity of which varies when exposed to gas mixtures. Signal passing along the gas-sensitive sensor circuit, which registered presence of the gas mixture, is supplied to the integral detector with a counting-and-arithmetic device, the functional purpose of which is determination of the gas leakage location with measurement of the level of gas content. Distinctive feature of the declared system, in the method of location of gas leakage and measurement of gas content level. Periodic series of stepped pulses with linear increase in amplitude passes through a chain of a gas-sensitive sensor, which detected presence of a gas mixture. Since the conductivity of the gas-sensitive sensor is proportional to the concentration level of the gas mixture, the amplitude value of the stepped pulses at the end of the circuit section will always be less than the reference value. Integral amplitude detector together with counting-and-arithmetic device calculates arithmetic difference of number of stages of reference and analyzed signals. Calculated difference is proportional to the concentration level of the gas mixture. Thus, the disclosed system measures the concentration level of the gas mixture. Periodic series of stepped pulses with linear increase in amplitude, passing along the gas-sensitive sensor circuit, which detected presence of gas mixture, will always be delayed by time of arrival at the input of the analyzed signal of the phase detector relative to reference pulses. Phase shift is proportional to the distance to which the gas-sensitive sensor is removed. Integral phase detector together with counting-and-arithmetic device calculates value of phase shift. Calculated value will be proportional to the distance to which the gas-sensitive sensor is removed. Thus, the declared system locates the gas leak.;EFFECT: design of a system which enables to determine the location of a gas leak with measurement of the level of gas content of sections of gas pipelines laid in soils, in tunnels or in complex configurations.;1 cl, 2 dwg