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Pressure Gauge The Principle Is Different
- Jun 16, 2017 -

Pressure gauge according to the working principle can be divided into liquid column, elastic type and sensor type 3 kinds.

(1). Liquid column, such as U-tube pressure gauge, pipe pressure gauge, etc., Pressure Gauge is based on the principle of fluid static pressure signal into a liquid column height signal, often use water, alcohol or mercury as a pressure gauge. Features: simple structure, Pressure Gauge intuitive readings, the signal can not be far away, suitable for low-pressure measurement, the upper limit of measurement does not exceed 0.1 ~ 0.2MPa; accuracy of ± 0.02% to ± 0.15%.

(2). Elastic type, such as the package tube pressure gauge, the pressure signal into a flexible component of the mechanical deformation of the amount of deflection in the way of output signal. But more cases require the signal to the control room, generally in the existing flexible dynamometer structure to increase the conversion components, you can achieve long-distance transmission of the signal. Pressure Gauge The elastic dynamometer signal is mostly used in the telemetry mode, that is, the deformation or displacement of the elastic element is converted into electrical signal output. Common conversion methods are potentiometer, Hall element type, inductive, differential transformer type. Industrial use of flexible pressure gauge.

(3). The principle of pressure sensor is the pressure signal into a certain electrical signal, common are: strain, piezoresistive, piezoelectric, capacitive.

A. Strain type: Strain element works based on the conductor and the semiconductor "strain effect", that is, when the conductor and semiconductor material mechanical deformation, the resistance will change.

B. Piezoresistive: Piezoresistive pressure sensor, also known as diffusion silicon pressure sensor, is based on the semiconductor piezoresistive effect. Pressure Gauge It is different from the strain sensor used in the body strain components, but with the integrated circuit technology directly on the silicon flat film made by a certain crystal orientation to the formation of diffusion varistor. Silicon flat film in the microwave deformation of a good elastic properties. The deformation of the diaphragm changes the resistance of the diffusion resistance.

C. Piezoelectric type: is the use of piezoelectric material piezoelectric effect of the measured pressure into electrical signals, it is commonly used in dynamic pressure detection sensor, Pressure Gauge not suitable for measuring slow changes in pressure and static pressure. Piezoelectric elements made of piezoelectric materials are subjected to pressure, and when the external force is removed, the charge disappears. In the elastic range, the amount of charge generated by the piezoelectric element is linearly related to the force.

D. Capacitive type: is the elastic component of the displacement is converted to the capacitance of the change in order to measure the diaphragm as a capacitor movable plate, which constitutes a variable capacitor with the fixed plate. When the measured pressure changes, the pressure diaphragm to produce displacement and change the distance between the two plates, measuring the corresponding capacitance changes, we can see the measured pressure value.