SU1394112A1 - Chemiluminescent gas analyser - Google Patents

Abstract

The invention relates to gas analytical instrumentation. The goal is to increase accuracy. The gas analyzer contains a reaction chamber, one of the inputs of which is connected to an oyon generator, and a photoelectric receiver, the output of which is connected to an electronic amplifier with switching measurement subranges, in which the first position corresponds to the subrange with the minimum measured concentration, and the last one - with the maximum measured concentration nitric oxide. The ozone generator is equipped with an ozone output control device containing a switch, for example, a switch, for Koto, the first position corresponds to the minimum, and the last to the maximum concentration of the ozone output. In this case, the specified switch is located on the same axis with the switch subranges. 1 il. i (o

Description

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 The invention relates to gas analyzing instrumentation and can be used in the development of chemiluminescent gas analyzers.

 for measuring the content of nitric oxide in the surrounding atmosphere, technological and waste gases of industrial plants.

a measurement area in which the reading of the device 9 would not exceed its lower and upper measurement limits.

If the amount of azone entering the reaction chamber is constant on different subranges, then in the case of low concentrations of nitric oxide,

The aim of the invention is to increase the amount of honestly excess (unreacted) ozone so great that conditions are created for the interaction of excited nitrogen dioxide molecules with it to form higher oxides. As a result, the transformation function becomes non-linear in nature. The amount of excess ozone in chamber I can be reduced by introducing an azone generator into the generator and controlling the operating mode of the generator 4. At the same time, the switch 5 of the generator operating mode control device is located on the same axis as the switch 8 so that the lower measured nitric oxide concentration corresponds to a lower output ozone (the first position of the switches). The last position of the switch 5 corresponds to the maximum ozone output (the last position of the switches).

measurement accuracy by setting the linearity of the conversion function.

The drawing shows the proposed device.

The gas analyzer contains a reaction chamber 1 with two inlets 2 and 3 intended to introduce ozone into the chamber (inlet 2) and the analyzed gas mixture (inlet 3) containing nitric oxide. The input 2 of the reaction chamber is connected to the ozone generator 4, equipped with a generator operation control device made in the form of a controlled switch 5. At the translucent wall of the reaction chamber a photodetector 6 is located, the output of which is connected to an electronic amplifier. The output of the amplifier through the position switch 8 measurement subbands is connected to the recording device 9,

The gas analyzer works as follows

Under the influence of electrical voltage, an ozone generator 4 (for example, an electric discharge type) produces ozone from air or pure oxygen, which enters through the inlet. into the reaction chamber 1. Through the second inlet 3, the analyzed gas containing nitric oxide enters one way in the reaction chamber. A chemiluminescent reaction occurs between ozone and nitrogen oxide, resulting in the generation of excited nitrogen dioxide molecules, which emit optical radiation during the transition to a stationary state. The photodetector b under the influence of this radiation produces a photo outflow, which is amplified by an electronic amplifier 7 and is passed through a switch 8 subranges per recording device 9, calibrated in units of nitric oxide concentration.

Depending on the content of nitric oxide in the analyzed gas, switch 8 establishes such a subdia

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This level of ozone is so high that conditions are created for the interaction of excited nitrogen dioxide molecules with it to form higher oxides. As a result, the transformation function acquires a non-linear character. The amount of excess ozone in chamber I can be reduced by introducing an azone generator into the generator and controlling the operating mode of the generator 4. At the same time, the switch 5 of the generator operating mode control device is located on the same axis as the switch 8 so that the lower measured nitric oxide concentration corresponds to a lower output ozone (the first position of the switches). The last position of the switch 5 corresponds to the maximum ozone output (the last position of the switches).

Thus, the amount of excess unreacted ozone in the chamber in the first position of the switches is reduced, which reduces the rate of interaction of excited nitrogen dioxide molecules with ozone. The proportional supply of the amount of reagent gas depending on the concentration range of the measured gas in the proposed gas analyzer design reduces the side effects in the reaction chamber caused by excess ozone (for example, oxidation of the walls of the reaction chamber), thereby improving the linearity of the conversion. The reagent, depending on the measured concentrations, will be the ecoiomi flow rate of this reagent gas.

Claims (1)

Invention Formula A chemiluminescent nitrogen oxides gas analyzer containing a reaction chamber, one of the inputs of which is connected to an ozone generator, and the other to a channel with the analyzed gas 313941 as a mixture, on the side of the reaction chamber, there is a photodetector connected through an amplifier to a measurement subrange switch, the first position of which corresponds to the minimum signal, and the last (H) -sampled is the maximum signal of the measured concentration of nitric oxide, that is in order to improve accuracy by setting the conversion function to liiiioi. 24 the ozone generator is equipped with an ozone output control device, made in the form of a switch, in which the first position corresponds to the minimum and the last (N) -maximal concentration of ozone, while the switch is located on the same axis with the measurement subranges switch so that the position numbers of both switches identical in: all switch positions.