At present, the application of Electrochemical sensor module is becoming more and more extensive. Driven by ubiquitous applications such as the Internet of Things. Its technological development direction has begun to develop towards miniaturization, integration, modularization, and intelligence. Among them, the industrial field is an application field of gas sensors. It is used to protect personnel and equipment from direct and indirect threats caused by dangerous gases. Whether using a portable gas alarm or a fixed gas detector. It may cause huge cost problems to ensure the safe operation of equipment within its service life. Users must have a deep understanding. In the industrial field, electrochemical gas sensor modules are more widely used. Here is a brief introduction to the relevant knowledge of electrochemical gas sensors.
Working principle of electrochemical gas sensor
In the small sensor, the electrode is wetted by an aqueous gel electrolyte (usually sulfuric acid: H2SO4). When the detected gas (such as carbon monoxide: CO, or hydrogen sulfide: H2S) enters the sensor and oxidizes or changes its concentration with the electrolyte. The working electrode generates a weak current under the action of the catalyst. The current is amplified by the amplifier connected to the sensor to display the gas concentration in the target area.
Factors affecting sensor life
Extreme temperatures can affect the life of the electrochemical sensor module. Generally, the equipment operating temperature range declared by the manufacturer usually varies from -30°C to +50°C. However, high-quality sensors can withstand temperatures exceeding this range in a short period of time. For example, there is no problem with sensors (such as H2S or CO) exposed to 60°C to 65°C for a short period of time (1~2 hours). However, repeated occurrences of extreme conditions will cause electrolyte volatilization, and may also cause zero baseline readings to move and slow response.
How to detect sensor failure?
In the past few decades, people have applied several patents and technologies on gas sensors. Although these technologies all claim to be able to detect the failure of the electrochemical sensor. But most techniques simply infer that the sensor is working under some kind of electrode stimulation. And it may only provide a false sense of security. The only reliable way to show that the sensor is working is to use a test gas and measure the sensor's response—that is, a quick test or a full calibration.