1. Piezoresistive force sensor

The resistance strain gauge is one of the main components of the piezoresistive strain sensor. The working principle of the metal resistance strain gauge is the phenomenon that the strain resistance adsorbed on the substrate changes with mechanical deformation, commonly known as the resistance strain effect.

2. Ceramic pressure sensor

The ceramic pressure sensor is based on the piezoresistive effect. The pressure acts directly on the front of the ceramic diaphragm, causing the diaphragm to deform slightly. The thick film resistor is printed on the back of the ceramic diaphragm and connected to form a Wheatstone bridge. Due to the piezoresistive effect of the piezoresistive resistor, the bridge generates a highly linear voltage signal that is proportional to the pressure and also proportional to the excitation voltage. Depending on the pressure range, the standard signal is calibrated to 2.0/3.0/3.3 millivolts, which can be compared with the strain sensor.

3. Diffused silicon pressure sensor:

The working principle of the diffused silicon pressure sensor is also based on the piezoresistive effect. Based on the principle of piezoresistive effect, the pressure of the measured medium acts directly on the diaphragm (stainless steel or ceramic) of the sensor, causing the diaphragm to produce a micro-displacement proportional to the medium pressure, resulting in a change in the resistance value of the sensor. Electronic circuits are used to detect this change and convert and output a standard measurement signal corresponding to the pressure.

4. Sapphire pressure sensor:

Based on the principle of strain resistance, silicon sapphire, as a semiconductor sensitive element, has incomparable metrological characteristics. Therefore, semiconductor sensors made of silicon sapphire are insensitive to temperature changes and have good working characteristics even under high temperature conditions; sapphire has strong radiation resistance; in addition, silicon sapphire semiconductor sensors have no p-n drift.

5. Metrological detection piezoelectric pressure sensor:

The piezoelectric effect is the main working principle of piezoelectric sensors. Piezoelectric sensors cannot be used for static measurement, because the charge after the external force is saved only when the loop has infinite input impedance. This is not the case in reality, so it is decided that piezoelectric sensors can only measure dynamic stress.

03

Installation problem

Correct installation

Usually, the damage of high-temperature melt pressure sensors is caused by improper installation position. If the sensor is forcibly installed in a hole that is too small or irregular, the vibrating membrane of the sensor may be damaged by impact. Choosing the right tool to process the mounting hole is conducive to controlling the size of the mounting hole. In addition, appropriate installation torque is conducive to forming a good seal, but if the installation torque is too high, it is easy to cause the high-temperature melt pressure sensor to slip. To prevent this phenomenon, the sensor is usually threaded before installation.

1. Correct installation method of pressure sensor:

(1) Verify the frequency response value of the pressure sensor under normal atmospheric pressure and standard temperature conditions through appropriate instruments.

(2) Verify the correctness of the pressure sensor code and the corresponding frequency response signal.

2. Determine the specific installation location

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

(1) The pressure sensor must be installed along the cable, preferably at the cable joint.

(2) Each cable should be equipped with at least 4 pressure sensors, and the distance between two pressure sensors close to the telephone exchange should not exceed 200 meters.

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

(4) Each cable should be installed with a branch point. If the two branch points are close to each other (less than 100 m), only one branch point can be installed.

(5) When the cable laying method (overhead and underground) changes, a cable should be installed

(6) For cables without branches, since the cable program of the baseline is consistent, the installation spacing of the pressure sensor is not more than 500m, and the total number of pressure sensors is not less than 4.

(7) In order to determine the fault point of the pressure sensor, in addition to installing the pressure sensor at the starting point, another pressure sensor should be installed 150~200 meters away from the starting point. Of course, in the design, economic and technical factors must be considered, and pressure sensors are not required in places where they are not needed.

Check the size

If the mounting hole size is not appropriate, the threaded part of the high-temperature melt pressure sensor is easy to wear during the installation process, which not only affects the sealing performance of the equipment, but also makes the sensor unable to fully function, and may even cause safety hazards. Only suitable mounting holes can avoid thread wear (thread industry standard 1/2-20UNF2B). The mounting hole can usually be detected by the mounting hole measuring instrument and adjusted appropriately.