There are many kinds of pressure measurement products
, which can be roughly divided into the following types according to their conversion principle.
According to the principle of statics, the liquid column pressure gauge converts the measured pressure into the height of the liquid column for pressure measurement. These instruments include U-tube manometer, single tube manometer, inclined tube manometer, etc. Commonly used pressure indicator liquids are alcohol, water, carbon tetrachloride, and mercury. The advantages of this kind of instrument are a simple structure, sensitive reaction, and accurate measurement. The disadvantage is that they are limited by liquid density, narrow range of pressure measurement. When the pressure fluctuates sharply, the liquid column is not stable, and there are strict requirements for installation position and posture. It is generally and only used to measure low pressure and vacuum, mostly used in the laboratory.
The elastic pressure gauge transforms the measured pressure into the displacement of the element to measure the pressure, according to the principle of force and deformation of the elastic element. Common types are Bourdon tube pressure gauge, bellows pressure gauge, diaphragm (or diaphragm box) pressure gauge. This kind of pressure gauge has a simple structure, strong durability, low price, reliable operation, and a wide measuring range. It is suitable for low, medium and high-pressure production occasions and most widely used pressure gauge in industry. However, the measurement accuracy of the elastic pressure gauge is not very high, and most of them use mechanical pointer output, mainly used for the on-site indication in the production site. When signal transmission is required, additional devices must be equipped.
and pressure transmitters
use some physical characteristics of the object to convert the measured pressure into various electrical signals through different conversion elements, and indirectly measure the pressure according to the changes of these signals. Pressure sensor and pressure transmitter can be divided into resistance type, capacitance type, strain type, inductance type, a piezoelectric type, Hall plate and so on. The most important characteristic of this kind of pressure measuring instrument is that the output signal is easy to transmit, and it can be used with various display, recording and adjusting instruments conveniently, thus creating conditions for centralized monitoring and control of pressure. Therefore, it is widely used in the production process automation system.