SU1410649A1 - Adsoprition analyzer of concentration of substances - Google Patents

Abstract

The invention can be used to control emissions of industrial plants and vehicles into the atmosphere, as well as in a number of technological processes. The aim of the invention is to increase the measurement accuracy. The device contains a radiation source, a working and a reference cell, an antiphase optical channel modulator and a modulator modulating optical channels with different frequencies, as well as an electronic measuring circuit including a narrowband amplifier with a controlled band. Use single channel. An electronic circuit with a controlled narrow-band amplifier as a compensating element eliminates the effect of changes in the transmission coefficient and amplification cycle, and the accuracy of measurements. 1 il. 1st S

Description

24-91 The invention relates to the field of analytical instrumentation and can be used to control emissions of industrial enterprises and road transport to the atmosphere, as well as in a number of technological processes.

The purpose of the invention is improving the accuracy of measurements.

In the drawing, a Q-device schematic diagram is shown.

The device contains a source of 1; , radiation, additional modulator .2, modulator 3, working 4 and supporting 5 cuvettes, optical system 6 for focusing radiation fluxes on the receiving area of the receiver,. reception-g. Nick 7 is radiated, 8-position sensor, additional modulator, preamplifier 9, narrowband. 20, the filter 10, the amplifier J i $ synchronous, the detector 12 and the device 13 for controlling the bandwidth of the narrow band filter, as well as the secondary device G4 ,. 25

The device works as follows.

The radiation from the source 1 by means of an additional modulator 2 is sequentially directed to the working and reference channels formed, respectively, by the working A and supporting 5 channels. With the help of the modulator 3, the radiation fluxes in the working and reference channels are modulated by different frequencies, - so that these frequencies are chosen to be higher than the modulation frequency of the source I radiation, which is obtained by using the auxiliary modulator 2. Next, the modulated Q fluxes by means of optical d-system 6 to receiver 7.

The output signal of the radiation receiver 7 is amplified by the preamplifier 9 and is fed to the input of the nodes dd of the band-pass filter 10, the central frequency of which coincides with the frequency modulation of the flow of one of the channels, for example, the working channel. In this case, the modulation frequency of the second radiation flux (in this example, the reference one) also falls into the passband of the narrowband filter 10. If necessary, the output signal of the narrowband filter 10 is amplified by an amplifier 11 and fed to the input of the synchronous detector 12 whose operation is performed at the frequency of the interruption of the radiation flux

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- Q

d

five

source I additional modulator 2 with the help of sensor number 8.

After a proper straightening and smoothing, the constant output voltage of the synchronous detector 12 is fed to the input of the device 13, with which the bandwidth of the narrowband filter 10 is adjusted so that the signal on the synchronous detector 12 is maintained-constant, for example, zero .

In the absence of an absorbing substance; In the work cell, the output signal from the 12 yc-i synchronous detector is turned on by a certain value, equal to zero for a given bandwidth of the narrow-band filter 10. The output signal of the device 13 will be corresponding-. zero concentration of the absorbing substance in the working cell. If an absorbing substance appears in the working cell, to maintain a constant output voltage of the synchronous detector 12 on the input of the device 13, a signal appears that detects a decrease in the passband of the narrowband filter 10. This control signal is a measure. the concentration of the absorbing substance in the working cuvette, and is controlled in the secondary device 14.

The device provides, by using one common electrpH7 measurement channel, and a narrow-band filter with adjustable bandwidth as a compensating element, eliminating the effect of changes in the gain of the amplifier path on the measurement accuracy. . -. .

Claims (1)

Invention Formula Absorption analyzer of concentrations of substances, containing an optically coupled radiation source, working for a reference cell, a modulator, a day-to-day modulation of the radiation fluxes in a working and reference cell with different frequencies, a radiation receiver and a preamplifier connected to it, sync - a rotary detector and a secondary device, characterized in that, in order to increase the measurement accuracy, 3 lA, an additional modulator, implemented with antiphase modulation of the radiation fluxes in the working and reference cells, the position sensor of the additional modulator, narrowband 1 dl and narrowband filter bandwidth control, with the preamplifier output connected to the narrowband input introduced into it. filter. 49 the output of which is connected to the input of the synchronous detector, the output of which is connected to the input, the bandwidth control device of the narrowband filter, the output of which is connected to the input of the secondary device and the control input of the narrowband filter, and the control input of the synchronous detector is connected to the position sensor modulator of the torus. .0 YU eleven 12 G4