The working principle and precautions of pressure sensors

Liquid level sensors are generally composed of pressure sensitive components and signal processing modules. According to different test pressure types, liquid level sensors can be divided into gauge pressure sensors, differential pressure sensors, and absolute pressure sensors. According to different structures and principles, it can be divided into: pressure resistance, pressure, capacitance, strain, vibration frequency, photoelectric, ultrasonic liquid level sensors, etc. The following introduces the working principle and precautions of the liquid level sensor.

Working principle of liquid level sensor

1. Piezoresistive liquid level sensor

Resistance Strain gauge is an important part of piezoresistive strain sensor. The working principle of metal resistance Strain gauge is that the strain resistance adsorbed on the base material changes with mechanical bending, commonly known as resistance strain effect.

2. Ceramic liquid level sensor

Based on the Piezoresistive effect, the pressure of the ceramic liquid level sensor directly acts on the front surface of the Ceramic membrane, causing the membrane to bend slightly. The thick film resistor is printed on the reverse side of the Ceramic membrane and connected to form a Wheatstone bridge. Due to the Piezoresistive effect of Varistor, the bridge generates a highly linear signal proportional to the pressure and a voltage signal proportional to the excitation voltage. According to the different pressure ranges, the standard signal calibration is 2.0/3.0/3.3mV/V, suitable for strain sensors.

3. Diffusion silicon pressure sensor

The working principle of diffusion silicon pressure sensors is also based on the pressure resistance effect. Using the principle of pressure resistance effect, the pressure of the medium to be measured directly acts on the sensor valve plate (stainless steel or ceramic), causing the membrane to produce a slight deviation proportional to the material pressure, causing a change in the sensor resistance value. Use electronic circuits to detect this change and convert and export the corresponding pressure gauge measurement signal.

4. Sapphire liquid level sensor

Adopting the working principle of strain resistance and selecting silicon sapphire as a semiconductor sensing element, it has unprecedented measurement characteristics. Therefore, semiconductor sensitive components made of silicon sapphire are not sensitive to temperature changes and have excellent working characteristics even in high-temperature environments; Sapphire has strong radiation protection characteristics; In addition, the silicon sapphire semiconductor sensing element does not have p-n drift.

5. Piezoelectric liquid level sensor

Piezoelectricity is the main working principle of piezoelectric sensors. Piezoelectric sensors cannot be used for static measurements. Due to external forces, the charge can only be stored when the circuit has infinite input impedance. The specific situation is not like this, as it determines that piezoelectric sensors can only measure dynamic stress.

Specification for the use of liquid level sensors

1. Avoid the accumulation of residues inside the catheter, and prevent the sensor from coming into contact with corrosive or overheated media.

2. When measuring gas pressure, the pressure tap should be set at the top of the step pipeline, and the sensor should also be installed at the upper end of the step pipeline to facilitate the accumulation of liquid and easy injection into the step pipeline.

3. When measuring liquid pressure, a pressure tap should be set on the side of the step tube to prevent slag accumulation.

4. The pressure conduit should be installed in areas with low temperature fluctuations.

5. When measuring liquid pressure, the sensor should avoid liquid impact (water hammer phenomenon) to prevent damage to the sensor due to overpressure.

6. When freezing occurs in winter, anti freezing measures must be taken and installed on outdoor sensors to prevent the liquid in the pressure inlet from losing the sensor due to the expansion of frozen volume.

7. When wiring, cross the cable over the waterproof joint or around the pipe, tighten the sealing nut to prevent precipitation from leaking into the transmitter casing through the cable.

8. When measuring steam or other high-temperature substances, a cooler such as a buffer tube (coil) should be connected, and the working temperature of the sensor should not exceed the limit.

If you have any purchasing needs for electronic components, please feel free to contact Chengyexing

Shenzhen electronic component IC chip supplier, one-stop BOM distribution company;

Can provide various electronic components (resistors, capacitors, inductors, switch connectors) for integrated circuit IC chips

If you cannot find the model you need, please contact us Chengyexing Company directly. The 50+purchasing team will be responsible for your needs and let us know the rest.

Service hotline: 134-3440-1267, 155-2178-1275