Hydrogen pressure sensorThe hydrogen concentration is mainly measured by detecting the electrical physical quantity by using the functional relationship between the electrical properties of the material and the hydrogen concentration. According to the different working principles, hydrogen pressure sensors can be divided into resistive and non-resistive.

1) Resistive hydrogen sensor

The resistive hydrogen sensor is mainly a semiconductor metal oxide hydrogen sensor. When the semiconductive metal oxide adsorbs oxygen, the resistivity will increase significantly. When a reducing gas, such as hydrogen, reduces oxygen in the metal oxide chemisorption layer, the resistivity will change accordingly. The hydrogen concentration can be detected by detecting a change in resistance.

Most semiconductor metal oxide sensors use tin oxide as the sensitive material, the average response time is 4S to 20s, and the measurable hydrogen concentration range is 10ppm to 20ppm. The selectivity of hydrogen production using a single metal oxide is not high. In order to improve the selectivity, a metal material having good selectivity to hydrogen, such as palladium, platinum, or the like, may be doped.

The resistive hydrogen sensor has fast response speed and long service life, up to 10 years. However, it has poor selectivity to hydrogen and is easily interfered by other reducing gases, such as methane, carbon monoxide, alcohols, etc.

2) Non-resistive hydrogen sensor

Non-resistive hydrogen sensors mainly use material capacitance or potential barrier to form a certain functional relationship with hydrogen concentration. According to the working principle and structure of the sensor, it is divided into Schottky diode type and field effect type

Tubular

At present, Schottky diode sensors have been widely used. The basic principle of the Schottky two-stage tubular hydrogen sensor is to deposit a very thin layer of metal on the semiconductor to form a "Schottky junction". When hydrogen comes into contact with the Schottky junction, it adsorbs on the metal surface with catalytic properties and rapidly catalytically decomposes into h. H through the metal lattice gap, diffusion to the metal-semiconductor interface, due to the existence of h, a certain bias voltage is applied to the sensor, the characteristic curve of the semiconductor diode drift, the sensor detects the hydrogen concentration by detecting the change of voltage or capacitance.

Hydrogen pressure sensorIt has the advantages of simple structure, easy miniaturization and easy integration. However, the temperature required for its work is high, energy consumption is increased, and electric sparks are easily generated during the working process, so it is not suitable for hydrogen concentration detection in flammable and explosive places.

At present, hydrogen pressure sensors are widely used in various industries. The correct installation of the sensor contributes greatly to its service life. I will introduceHydrogen pressure sensorInstallation Tips:

1. Preparation before installation:

(1) First, under the premise of normal atmospheric pressure and standard temperature, check the frequency response value of the pressure sensor.

(2) Verify the correctness of the encoding and response frequency echo signal of the pressure sensor.

2. Applicable to equipment orientation:

In order to determine the product number and installation position of the pressure sensor, it is necessary to consider each inflatable part of the inflatable net.

(1) The installation skills of the pressure sensor should be carried out along the cable, and the device should be installed at the cable discussion place.

(2) More than four pressure sensors are installed on the installation cable. The distance between two pressure sensors close to the telephone office should not exceed 200 meters.

(3) Install one at the beginning and one at the end of the cable.

(4) A branch point for installing cables should be installed. If the branch point is less than 100m, one can be installed.

Jiangmen Hengmin Intelligent Control Instrument Co., Ltd. is a pressure transmitter manufacturer, mainly engaged in oil pressure sensors, wall-mounted boiler water pressure sensors, urea pump pressure sensors, hydrogen pressure sensors, pressure calibrators, automobile pressure sensors, water pump pressure sensors, water pressure Sensors, intelligent pressure controllers, high pressure sensors and other products. Our company found in the research industry production activities that with the increasing popularity of the Internet of Things and intelligent manufacturing concepts, the demand for pressure sensors in my country has grown rapidly in recent years. In response to the needs of the era of intelligent manufacturing, our company has developed high-precision testing instruments and special production system equipment for pressure sensor manufacturers to help sensor manufacturers greatly reduce the labor intensity of testing, reduce the number of workers, improve product quality, improve production efficiency and reduce production costs.