SU1056034A1 - Device for measuring oxygen concentration in gases - Google Patents

Abstract

TSLYA APPARATUS MEASURING OXYGEN CONCENTRATION IN GASES comprising tvordozlektrolitnuyu cell with electrodes as a sensitive and simultaneously zlementy snip temperature dates and upavl emy this sensor temperature controller cell, consisting of an amplifier, the generator operating frequency, .nagrevatel, unbalanced AC bridge and measuring It is characterized by the fact that, in order to improve the accuracy and increase the working life, the multivibrator and the switch are additionally introduced in the controller of the temperature, The input of the multivibrator is connected to the input of the amplifier, and the output is controlled by a switch circuit, the input of the switch is connected to the output of the amplifier, and the output is connected to a heater. About ate Ob about 00 4

Description

The invention relates to a gas guide (Lytic instrument making and can be used to measure oxygen concentration in gases. A device for measuring oxygen concentration in gases containing a solid electrolyte cell with electrodes and measuring device C 1} is known.} The disadvantage of this device is low measurement accuracy. The closest in technical essence to the invention is a device for measuring the concentration of oxygen in gases, containing a solid electrolyte cell with electrodes as h of a sensor element and at the same time a temperature sensor and a cell temperature control controlled by this sensor, consisting of an amplifier, an operating frequency generator, a heater, an unbalanced AC bridge, and a C2 3 measuring device. A disadvantage of the known device is the low accuracy of oxygen measurement in gases. The error arises due to the fact that when the maximum power is supplied to the heater from the power source to create the required working temperature of the cell in a solid electric Lyta are of microcracks and this reduces the accuracy of measurement degrades reliability and reduces RESOURCES operation. The aim of the invention is to improve the accuracy and increase the service life. This goal is achieved by the fact that in a device for measuring the concentration of oxygen in gases, containing a solid electrolyte cell With electrodes as a sensitive element and at the same time a temperature sensor and a temperature controller controlled by this sensor. cells consisting of an amplifier, an operating frequency generator, a heater. an unbalanced AC bridge and a measuring device; a multivibrator and a switch are additionally introduced into the temperature controller, the multivibrator input is connected to the amplifier input, and the output is controlled by the switch circuit of the switch, the switch input is connected to the amplifier output, and the output is connected to the heater. The drawing is a schematic image on the functional diagram of the device. The device contains a solid electrolyte cell 1 with electrodes 2, a temperature regulator consisting of an operating frequency generator 3, an amplifier 4, a multi-oscillator 5, a supply voltage switch 6, a heater 7 and an unbalanced AC bridge, the shoulders of which are formed by resistances 8-10 and a solid electrolyte cell 1 with electrodes 2 and measuring device 11. The device operates as follows. From generator 3, a voltage of at least I kHz is applied to the bridge, the variable resistance 0 of which serves to set the operating temperature of the solid electrolyte cell 1. At the initial moment when the device is switched on, the maximum unbalanced ac voltage offset from the diagonal is proportional to the electrical resistance of the solid electrolyte cell I concluded between the electrodes 2, which is a function of the operating temperature, is fed to the input of the amplifier 4 and the multivibrator 5. Reinforced This signal is then fed to the input of Kote yTaTbpa 6. Multivibrator 5 produces pulses with a varying duty cycle proportional to the change (decrease) of the unbalanced AC bridge, which is fed to the control circuit of the switch 6, i.e. The heater 7 at the initial moment receives the necessary minimum power to heat it. As the operating temperature increases, the duty cycle of the pulses decreases and the amount of energy supplied to the heater 7, i.e. There is a gradual increase in the operating temperature of the solid electrolyte cell 1, which excludes the possible thermal shock, which leads to the appearance of microcrescents in the solid electrolyte. When a predetermined operating temperature is reached, the order of FOO-HEO C to the heater 7 is supplied with the maximum power for heating it, at the same time the pulse duty cycle is maximum. When reaching equilibrium of the bridge switch 6 turns off the heater 7 from

310560344

source of supply voltage. In the distance, the electrodes 2, the solid electrolyte, when the temperature cell decreases, the emf is induced

the heater 7 is connected again, supplied to the measuring device 11

those. automatically maintained. and by the measured value of emf

Required working temperature. When about the value of oxygen concentration

measuring the concentration of oxygen in the sample gas.

Claims (1)

i DEVICE FOR MEASURING OXYGEN CONCENTRATION IN GASES, containing a solid electrolyte cell with electrodes as a sensing element and at the same time a temperature sensor and a cell temperature controller controlled by this sensor, consisting of an amplifier, an operating frequency generator, a heater, an unbalanced AC bridge and a measuring device, which differs in order to increase the accuracy and increase the service life, a multivibrator and a switch are additionally introduced into the temperature controller. a multivibrator is connected to the input of the amplifier, and the output is connected to the control circuit of the switch, the input of the switch is connected to the output of the amplifier, and the output to the heater.