Portable gas detection instruments are mainly divided into two types from the detection principle: diffusion type and pump type. The so-called portability means that it is designed for convenience, mobile and flexible. When selecting, we should consider what kind of portable instrument is suitable for its application range.
The portable gas detection instrument shall have the following functions:

1. The display is clear and can accurately display the current gas concentration.

3. It has sound, light and vibration prompt for gas exceeding the standard.

4. Rechargeable lithium battery or replaceable battery is used for power supply to provide long-term endurance.

5. The weight and volume of the equipment are basically different from those of many portable gas detection instruments, so we should consider the appropriate volume and weight according to our own application methods and characteristics.

The working principles of portable gas detection instruments include diffusion sampling and pumping sampling, which are mainly characterized by the following points.

1. The diffusion type consumes less power, and the equipment volume can be made smaller. The detected gas is similar to the human olfactory mode, and the gas concentration is detected after contacting the sensor according to the gas diffusion.

2. Pumping type, because of pumping and sampling according to the work of the air pump, the power consumption and volume will certainly increase, but because of the pumping and sampling of the air pump, it can achieve fast and accurate gas detection. It is more suitable to use pumping sampling detection conditions, such as detecting the gas concentration in the pipeline and the gas concentration in the sealed space, which are basically based on the pumping gas detection instrument to carry out the detection work more conveniently.