| 摘要 |
The invention relates to the area of electric measurements and can be used in coal-producing mines, in the systems for control of worked-out gases of combustion engines or in like complex systems where there is an especially important problem of monitoring of concentration of secondary harmful, explosive and fire-dangerous products of production. A method for the control of changes of gas medium integral composition is based on measurement of changes of phase incursion of micro-wave signal at its repeated propagation by closed waveguide structure through which environmental air is passed as well. Through control of the total length of the waveguide structure that acts as a measuring line and the adjustment frequency of bandpass low-frequency filter that separating the informative low-frequency signal it is possible to obtain different sensitivity of the system as a whole. According to the method it is a variable parameter. This makes it possible to carry out general calibration as to specific type of controlled substance with known value of its dielectric permittivity, for instance combustible, explosive-dangerous and/or toxic gases. Due to use of waveguide structure in which air flow from environment circulates the need in use of additional repeaters remote from measuring block is completely excluded. The method provides increase of accuracy of control of changes of integral composition of air and simplification of the system that functions by the claimed method. |
