SU1280585A1 - Method of preparing gas mixture for calibrating gas analyzers - Google Patents

Abstract

The invention relates to gas analysis methods and allows for improved calibration accuracy of gas analyzers. A multi-component calibration gas mixture is obtained from pure gases that are dispensed pulsed. The duration of the pulses set proportional to the volume concentration of the gas in the mixture. The start-up of gases is carried out so that the midpoints of the pulses for all gases coincide, and the interval between the pulses of the gas with the highest concentration is less than the duration of the pulses of the gas with the lowest concentration in the mixture. 1 ZP .. f-ly, 2 ill.

Description

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The invention relates to gas analysis, in particular, to methods for preparing a gas mixture for calibrating gas analysis systems, for example, gas analyzers of an automated blast-gas analysis system.

The purpose of the invention is to improve the accuracy of calibration.

FIG. 1 shows a simplified diagram of a device implementing the proposed method; in fig. 2 is a timing diagram explaining the method.

The device for dosing contains cylinders 1-4 with clean gases, balloon reducers 5-8, differential meters 9-11 with electrical output, controlled electrovalves 12-15, calibrated capillaries 16, receiver 17, booster 18, valve 19, timer 20, software-controlled device 21, gas analyzers 22-24 gas and electrical communication lines.

A multi-component gas mixture. Calibration is obtained from pure gases, for which the dosing of the volumetric amount of each gas from the cylinder to the receiver is pulsed at a constant and equal to the initial gas flow rate and temperature. The duration of a single dosing pulse is set to mixes. To ensure uniform mixing of single doses of pure gases, the dosing of each gas was started and mixed in the receiver at the same time according to a predetermined program, but so that the EL of the duration of a single dosing of gases coincided and the mixing time was, for example, an order of magnitude less than the calibration time. In order to ensure mixing of single doses of the mixture with a minimum time for preparing the calibration mixture, the time interval between subsequent gas dosages with the highest volume concentration in the mixture is set to no more than the duration of the gas dosing pulse with the lowest volume concentration.

A device for carrying out the proposed method of preparing a gas mixture works as follows.

In the initial state with the help of differential pressure gauges 9-11 with electrical output and balloon gearboxes 5-8

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installed in gas lines of communication equal to less than 0.2 kg / cm pressure, and calibrated capillaries 16 ensure constant and equal flow rates of pure gases at a constant temperature. Electrovalves 12-15 normally closed. The dosing of pure gases from cylinders 1-4 to the receiver 17 is started to mix and accumulate the mixture by applying voltage to the control circuits of the solenoid valves 12-15 from the corresponding outputs of timer 20. The duration of the control voltage pulse to each electro-valve is set with a high accuracy by a timer proportional to the volume concentration of the corresponding gas in the mixture. The timer is started by the control unit (including the microcomputer) according to a predetermined program.

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When pressure changes in gas

the lines of communication of CO, CO and Hg gases relative to the pressure in the nitrogen line, the corresponding error signals are sent to the corresponding timer bones in order to effect the correction of the duration of the dosage pulse.

To eliminate the inertia effect of the solenoid valves on the accuracy of gas metering, the condition is met - the Reynolds Re35 coefficient of the valve is significantly less than the Re coefficient of a calibrated capillary.

A receiver with a predetermined frequency is injected with a reproducible amount of the gas mixture. In order to ensure gas mixing, when the gas enters the receiver, the outputs of the calibrated capillaries are set differently, therefore, the flows of pure gases are cut at one point.

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When the pressure in the receiver is equalized with the pressure in the communication line with the gas cylinder, the pressure sensor 25 arrives at the input of the control unit. This signal from the corresponding output of the control unit to the valve 19 and the booster 18 receives the control voltage. In order to increase the homogeneity of the gas mixture, the latter from the receiver 17 is drawn in by the flow booster 18 and through the valve 19 enters the communication line to the inputs of calibrated gas analyzers 22-24.

1280585

The information output signals of the gas analyzers are fed to the corresponding inputs of the control unit and converted to digital form, they are then fed to the microcomputer of the control unit for analysis with programmed concentration values of the respective gases,

Claims (2)

11 The invention relates to gas analysis, in particular, to methods for preparing a gas mixture for calibrating gas analysis systems, for example, gas analyzers of an automated system for analyzing the top gas. The purpose of the invention is to improve the accuracy of calibration. FIG. 1 shows a simplified diagram of a device implementing the proposed method; in fig. 2 - times per diagram, explaining the method. The device for dosing contains cylinders 1-4 with clean gases, balloon reducers 5-8, differential meters 9-11 with electrical output, controllable solenoid valves 12-15, to capillaries 16, receiver 17, booster 18, valve 19, timer 20 , device 21 with programmed control, gas analyzers 22-24 gas and electric communication lines. A multi-component gas mixture. Calibration is obtained from pure gases, for which the dosing of the volumetric amount of each gas from the cylinder to the receiver is pulsed at constant and equal to the initial distance, the flow rate and temperature of the gases. The pulse duration of the unit dosing is set proportionally to the volume concentration. this gas in the mixture. To ensure uniform mixing of single doses of pure gases, the dosing of each gas was started and mixed in the receiver at the same time according to a predetermined program, but so that the EL of the duration of a single dosing of gases coincided and the mixing time was, for example, an order of magnitude less than the calibration time. In order to ensure mixing of single doses of the mixture with a minimum time for preparing the calibration mixture, the time interval between subsequent gas dosages with the highest volume concentration in the mixture is set to no more than the duration of the gas dosing pulse with the lowest volume concentration. A device for carrying out the proposed method of preparing a gas mixture works as follows. In the initial state, using differential pressure gauges 9-11 with electrical output and balloon reducers 5-8 5, the gas lines are set to less than 0.2 kg / cm of pressure, and calibrated capillaries 16 provide constant and constant temperatures equal costs of clean gases. Electrovalves 12-15 normally closed. The dosing of pure gases from cylinders 1-4 to the receiver 17 is started to mix and accumulate the mixture by applying voltage to the control circuits of the solenoid valves 12-15 from the corresponding outputs of timer 20. The duration of the control voltage pulse to each electro-valve is set with a high accuracy by a timer proportional to the volume concentration of the corresponding gas in the mixture. The timer is started by the control unit (including the microcomputer) according to a predetermined program. When the pressure in the gas lines of the CO, CO and Hg gases changes with respect to the pressure in the nitrogen line, the corresponding error signals are sent to the corresponding timer to correct the pulse duration of the dosing. To eliminate the influence of the inertia of the solenoid valves on the accuracy of gas metering, the condition Re coefficient of the Reynolds solenoid valve is observed is much smaller than the coefficient Re of a calibrated capillary. A receiver with a predetermined frequency is injected with a reproducible amount of the gas mixture. In order to ensure mixing of gases when they are introduced into the receiver, the outputs of the calibrated capillaries are installed in a different way; therefore, the flows of pure gases are dissected at one point. When the pressure in the receiver is equalized with the pressure in the communication line with the gas cylinder, the pressure sensor 25 arrives at the input of the control unit. This signal from the corresponding output of the control unit to the valve 19 and the booster 18 receives the control voltage. In order to increase the homogeneity of the gas mixture, the latter from the receiver 17 is drawn in by the flow booster 18 and through the valve 19 enters the communication line to the inputs of calibrated gas analyzers 22-24. The information output signals of the gas analyzers are fed to the corresponding inputs of the control unit and digitized, they are then fed to the microcomputer control units for analysis with programmed concentration values of the respective gases. Thus, the proposed method allows to automatically prepare multi-component gas mixtures according to the set program for calibration of gas analyzers (hydrogen, carbon monoxide, carbon dioxide) of the blast furnace analysis system; gas. Claim 1. Spospb preparation of the gas mixture for the calibration of gas analyzers. 12 5 including dosing and mixing of source gases, characterized in that, in order to improve calibration accuracy, gases are pulsed at constant pressures and temperatures so that the pulse midpoints coincide in time and the pulse duration. each gas is set proportional to its volume content in the mixture, 2. The method according to p. 1, about t l and h ay u and with the fact that the time interval between pulses of gas with the highest content in the mixture is set to less than the duration of the pulses of the component having the lowest content.