Constant temperature combustable gas concentration detector

Abstract

The constant temperature combustible gas concentration detector has bridge circuit comprising sensitive element and resistors, and compensating element, the constant temperature control loop comprising the bridge circuit, comparator and power regulator, the compensating circuit with the compensating element and with or without parallel expanding compensation resistor, and constant current power source circuit connected to the constant temperature control loop and the compensating circuit. The constant temperature control loop outputs detection signal V1, and the compensating circuit outputs compensating signal V0. The present invention has the advantages of high long-term stability, long service life, convenient intelligent treatment, wide detected combustible gas concentration range, etc.

Description

technical field [0001] The invention relates to a safety device for measuring the concentration of combustible gas, more specifically, relates to a constant temperature combustible gas concentration detection device. Background technique [0002] At present, the commonly used method for detecting the concentration of combustible gas is to use catalytic combustion gas sensor for detection. The catalytic combustion gas sensor usually consists of a sensitive element sensitive to combustible gas with a catalyst (hereinafter referred to as the sensitive element) and a compensating element without a catalyst that is not sensitive to combustible gas and has a temperature characteristic similar to that of the sensitive element (hereinafter referred to as Compensation element) to form an element pair, connect the sensitive element, compensation element and resistance to the bridge, and use the temperature of the sensitive element in the measured environment to change with the change ...

AI Technical Summary

Problems solved by technology

However, currently limited by production technology and process level, the temperature dispersion of the finished gas sensor pair is relatively large, and the existing detection method cannot perform secondary compensation for it, resulting in the detection device being unable to effectively control the zero drift, which directly affects the detection. accuracy of results

[0004] 2. The detection range is small

This limits the sensitive element to work only in low concentration combustible gas environment, and the detection range of combustible gas concentration is narrow

[0005] 3. Poor stability

Since the working temperature of the sensitive element fluctuates in a large range when detecting the concentration of combustible gas, the carbon deposit structure on the sensitive element due to incomplete combustion is very unstable, which will directly cause the drift of the zero point of the detection bridge and the change of detection accuracy

[0006] 4. High component damage rate

When the concentration of combustible gas in the detection environment is maintained at a high level, the existing detection method will keep the sensitive element working at a high temperature state, which will cause the evaporation and denaturation of the catalyst and aging, and make the sensitive element prematurely scrapped

In addition, although the sensitive components are protected in the application, since the monitoring of the concentration of combustible gases in the hazardous environment cannot be stopped, the detection device must intermittently restore the power supply to the sensitive components, so that when the concentration of combustible gases falls back to a level that is safe for the sensitive components Can continue to detect when in range

If the combustible gas concentration is still above the detection limit of the sensitive element at this time, every tentative power supply will damage the sensitive element, which will greatly reduce the service life of the element

[0007] 5. Unable to identify double-valued effects

Existing detection devices cannot recognize this double value effect, and will misjudge a higher combustible gas concentration value as a lower concentration value, which is extremely dangerous in practical applications

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