Explanation of Professional Terminology for Gas Detectors
Gas detector response time
The response time represents the response speed of the gas sensing element to the detected gas. In principle, the faster the response, the better. That is, as soon as the gas sensing element contacts the measured gas or the concentration of the gas changes, the device resistance value immediately changes to its determined resistance value. But in reality, it always takes some time to reach a stable value. The response time (tres) is defined as the time required for the component to reach a stable resistance value of 90% at this concentration after contact with the gas being measured. It is defined as the response time, commonly represented by tres.
Gas detector recovery time
Unlike the response time, the recovery time represents the desorption rate of the gas sensor to the detected gas, also known as desorption time. Similarly, we also hope that this time will be as soon as possible. The recovery time trec is defined as the time required for the component to detach from the detected gas and return to 10% of its resistance value in normal air. It is defined as the recovery time, represented by trec.
Gas sensors and their classification
Sensors refer to devices or devices that can be measured according to regulations and converted into usable output signals according to certain rules, usually composed of sensitive components and conversion components. Among them, sensitive components refer to the part of the sensor that can directly sense or respond to the measured part; The conversion element refers to the part of a sensor that can convert the measured signal sensed or responded by the sensitive element into an electrical signal suitable for transmission or measurement.
Gas sensors mainly include semiconductor sensors (resistive and non resistive), insulator sensors (contact combustion and capacitive), electrochemical sensors (constant potential electrolysis, Gavanni cell type), as well as infrared absorption sensors, quartz oscillation sensors, fiber optic sensors, thermal conductivity sensors, surface acoustic wave sensors, gas chromatography methods, etc.
Zero drift
Zero drift refers to the phenomenon where the reading of a gas detector is greater than (positive drift) or less than zero (negative drift) when used for a period of time or applied to a new environment in clean air or without this gas.
