Piezoresistive pressure transmitter as below picture is characterized by its small size and simple structure. The sensitivity coefficient of diffusion resistance is dozens of times that of metal strain gauge, and can directly measure small pressure changes. In addition, piezoresistive pressure transmitters also have good dynamic response and low hysteresis, which can be used to measure pulsating pressures of several thousand Hertz or even higher. This is a relatively rapid development, very widely used pressure transmitter.
Capacitive pressure transmitter adopts differential capacitance as detection element, which mainly includes measurement and conversion amplification. The differential signal is converted into differential capacitor signal by the central pressure sensing diaphragm and the left and right curved capacitor plate, and the central pressure sensing diaphragm forms a capacitor with the left and right curved capacitor plate respectively. The differential pressure causes the central pressure sensing diaphragm to produce displacement, so that the distance between the movable electrode and the left and right fixed electrodes is no longer equal, forming a differential capacitance, and the relative change value of the differential capacitance is linear with the differential pressure. Due to the mechanical transmission mechanism without lever inside the whole capacitive differential pressure transmitter, it has the characteristics of high precision, high stability and high reliability, and its accuracy level can reach 0.2, which is a kind of transmitter commonly used in industry.
The piezoelectric pressure transmitter uses the piezoelectric effect of the piezoelectric material to convert the measured pressure into an electrical signal. It is a commonly used sensor in dynamic pressure detection, and is not suitable for measuring slowly changing pressure and static pressure. The vibration frequency pressure transmitter uses the relationship between the resonant frequency of the pressure sensing element itself and the pressure to detect the pressure by measuring the change of the frequency signal. This kind of sensor has a variety of forms such as vibrating drum, vibrating string, vibrating film, quartz resonance, etc. The instrument has small size, output frequency signal, good repeatability and vibration resistance. High precision, suitable for gas measurement.
Application:
Pressure transmitters are widely used in various industrial fields, such as petroleum, chemical, metallurgy, electric power, pharmaceutical, water treatment, etc., for measuring and controlling the pressure of various fluids to ensure the stability and safety of the process.
They can measure a wide range of pressures from tiny to extremely high, with high precision, high stability, high reliability and long life. In addition, according to the different measurement principles and application scenarios, pressure transmitters can also be divided into a variety of types, such as differential pressure transmitters (used to measure the difference between two pressures), absolute pressure transmitters (used to measure the absolute pressure relative to vacuum), gauge pressure transmitters (used to measure the pressure relative to atmospheric pressure) and so on.
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