The storage conditions and periodic calibration techniques of gas sensor modules are crucial for ensuring their accuracy and extending their service life. The following is a detailed explanation of these two aspects:

　　1、 Storage conditions for gas sensor module

1. Avoid water environment:

Splashing or immersing sensors in water can cause a decrease in sensor sensitivity and even result in sensor damage and inability to function.

Under indoor usage conditions, slight condensation water can also have a certain degree of impact on sensor performance. If water condenses on the surface of the sensitive layer and remains for a period of time, the sensor characteristics will decrease.

Water freezing on the surface of the sensor can cause the sensor material layer to break and lose its sensitivity characteristics.

2. Avoid high concentration gases:

Regardless of whether the sensor is powered on or not, long-term placement in high concentration gas will affect the sensor characteristics. For example, placing the sensor in high concentrations of hydrocarbons or hydrogen for a long time, or directly spraying lighter gas towards the sensor, can cause damage to the sensor.

3. Avoid high voltage and polarity reversal:

When the voltage applied to the sensor module is too high (such as exceeding 5.5V), it will directly cause irreparable damage to the sensor module.

When the positive and negative polarities of the sensor are reversed, it can also cause damage to the sensor circuit.

4. Avoid acid-base environment and halogen pollution:

After the sensor is polluted by alkaline or acidic liquid spray, or exposed to halogens such as Freon, it will cause performance degradation and incorrect data.

Exposure of sensors to high concentrations of corrosive gases such as H2S, SO2, Cl2, HCl, etc. can not only cause corrosion or damage to the sensor module circuit and internal components, but also irreversible degradation of sensitive material properties.

5. Avoid exposure to volatile silicon compound vapors:

If the surface of the sensor adsorbs silicon compound vapor, the sensitive material of the sensor will be enveloped by silicon dioxide formed by the decomposition of silicon compounds, which suppresses the sensitivity of the sensor, and this damage is irreversible. Therefore, sensors should avoid exposure to silicone adhesives, hair gel, silicone rubber, putty, or other places where volatile silicone compounds are present.

6. Other precautions:

When sensors are stored for a long time without power, their resistance will undergo reversible drift, which is related to the storage environment. Therefore, the sensor should be stored in a sealed bag that does not contain volatile silicon compounds.

Sensors stored for a long time need to be powered on for a longer period of time before use to achieve stability. The longer the storage time, the longer the recommended aging time.

　　2、 Periodic calibration techniques for gas sensor modules

1. Pre mixed calibration gas method:

This is a popular method for calibrating gas sensors. Pre mixed calibration gases can be compressed and stored in gas cylinders at a certain pressure for easy on-site calibration.

When in use, a pressure regulator is required, consisting of a pressure controller, pressure gauge, and flow restriction hole, to ensure stable gas flow and pressure during the calibration process.

2. Cross calibration method:

When certain target gases are difficult to obtain or process, the cross calibration method can be used. Replace the target gas with an easily obtainable and processed gas for calibration.

For example, when calibrating ethane gas for LEL, since ethane is liquid at room temperature with low vapor pressure, 50% LEL methane gas can be used instead. However, it should be noted that the response factor of each sensor may vary, so when using the cross calibration method, it is necessary to refer to the response factor in the sensor manual for correction.

3. Gas mixing correction method:

For certain low concentration range gas monitors, calibration can be performed by diluting the available calibration gas.

This method requires ensuring that the diluted gas concentration is accurate and stable for accurate calibration.

4. Calibration cycle:

The calibration cycle should be determined based on the frequency of sensor usage, environmental conditions, and manufacturer's recommendations.

Generally speaking, it is recommended to calibrate sensors regularly to ensure their accuracy and reliability. The specific calibration cycle may vary depending on the sensor type and application scenario.

5. Calibration record:

During calibration, the calibration date, calibration results, calibration gas used, and any abnormal or faulty conditions should be recorded.

These records help track changes in sensor performance and take corrective measures when necessary.

Following appropriate storage conditions and periodic calibration techniques is crucial for ensuring the accuracy and extending the lifespan of gas sensor modules. By following these recommendations, you can improve the reliability and performance of gas sensor modules, thereby better meeting your application needs.