RU94025670A - Method of testing of composition of gas mixture and liquid media - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: method is intended for testing of compositions of gas mixtures and liquid media in technological processes as well as for emission of harmful gas mixtures into atmosphere and stowage discharge. Tested medium is passes (fills) periodically and continuously with composition known at the moment of first measurement. Short-term acoustic sinusoidal oscillations with known parameters are excited in it through waveguide 3. They are converted into electric signals by means of pickup 5, amplified by amplifier 7 and amplitude Uof this signal is measured and converted into code with the aid of converter 15. Oscillation period Tis measured and converted into code with the use of threshold device 10 flip-flop 11, clock generator 20 and converter 16. Temperature Tof medium in waveguide is measured and converted with the help of pickup 6, converters 13, 14 and clock generator 20. Then sound velocity a,, rate of change of acoustic pressure (dP/dt)for moment of transition by voltage of electric signal through zero are computed. Further on short-term sinusoidal oscillations are periodically excited, time intervals Δt between excitation moments, signal amplitude U, oscillation period T, temperature T, of medium are measured. Sound velocity a, rate of change of acoustic pressure (dP/dt), are calculated. Starting from second measurement one judges about change of composition of medium by calculation by rate of change of volumetric fractions of components of medium (dα/dt). If (dα/dt)= 0 = 0 one judges about constancy of composition. If (dα/dt)≠ 0 0 value of rate of change of volumetric fractions Δαis computed for all n components of medium and if= 0 one judges about invariability of number of components (n-const) and if0 one judges about appearance of new components. Two threshold values (U, U) of voltages are isolated across growing section of change of signal with the aid of two-threshold unit 9. Duration of interval τ, corresponding to these threshold values is measured and rate of change of acoustic pressure (dP/dt)within this interval is calculated by expressionwhere Kis gain factor of pickup 5, Kis gain factor of amplifier 7. EFFECT: expansion of application field of method, simplified design of device used for testing, increased accuracy and timeliness of test. 3 cl, 2 dwg

Claims (1)

Usage: to control the composition of gas mixtures and liquid media in technological processes, as well as the emission of harmful gas mixtures into the atmosphere and the discharge of wastewater. Objective: expanding functionality, simplifying the device, increasing the accuracy and efficiency of control. The inventive periodically and continuously pass (fill) the controlled medium, with the composition known at the time of the first control measurement, through the waveguide 3, with known parameters, excite short-term acoustic sinusoidal oscillations in it, convert them into electrical signals by sensor 5, amplify by amplifier 7 and measure the amplitude of this signal is U <Mv> m0 <D> and it is converted into code by the converter 15, the oscillation period T <Mv> 0 <D> is measured and converted into code using the threshold device 10, trigger 11 of the clock a radiator 20 and a transducer 16, measure and convert the temperature T into a code $\genfrac{}{}{0ex}{}{\text{°}}{\text{o}}$ medium in the waveguide using the sensor 6, converters 13,14 and the clock generator 20, after which the speed of sound a <Mv> 0 <D>, the rate of change of acoustic pressure (dP / dt) <Mv> 0 <D> for the moment of transition are calculated voltage of the electric signal through a zero value, then periodically excite short-term sinusoidal oscillations, measure the time intervals Δt between the moments of excitation, the amplitude of the signal U <Mv> mk <D>, the oscillation period T <Mv> to <D>, the medium temperature T $\genfrac{}{}{0ex}{}{\text{°}}{\text{to}}$ , calculate the speed of sound a <Mv> to <D>, the rate of change of acoustic pressure (dP / dt) <Mv> to <D>, while, starting from the second measurement, judge the change in the composition of the medium by calculation (dα _i / dt) _{to the} rate of change in volume fractions of the components of the medium, in this case, if (dα _i / dt) _k = 0, the composition is constant, when (dα _i / dt _k ) ≠ 0, for all n components of the medium, the change in volume fractions Δα _i and, if in this case

, judge about the invariability of the number of components (n - const), and when

judge the appearance of new components. On the growing section of the signal change, two threshold voltage values U <Mv> p1 <D>, U <Mv> p2 <D> are distinguished using a two-threshold device 9, the duration of the interval τ _nc corresponding to these threshold values is measured, and the rate of change of the acoustic (dP / dt) <Mv> to <D> the pressure in this interval by the expression:

where K <Mv> d <D> is the transmission coefficient of the sensor 5, K <Mv> y <D> is the gain of the amplifier 7. 1 c. and 1 z.p. f-ly, 2 ill.