What are the types of pressure measuring instruments?

       There are many types of instruments used for pressure measurement, which can be roughly divided into the following types according to their conversion principles.      

      1.Liquid column pressure gauge           

      The liquid column pressure gauge is based on the principle of statics and converts the measured pressure into the height of the liquid column for pressure measurement. Such instruments include U-tube pressure gauges, single tube pressure gauges, and inclined tube pressure gauges. The commonly used pressure indicating liquids include alcohol, water, carbon tetrachloride, and mercury. The advantages of this type of instrument are simple structure, sensitive response, and accurate measurement; The disadvantage is that due to the limitation of liquid density, the pressure measurement range is relatively narrow, and when the pressure fluctuates violently, the liquid column is not easy to stabilize, and there are strict requirements for the installation position and posture. Generally, it is only used for measuring low pressure and vacuum, and is mostly used in laboratories. 

      2. Elastic pressure gauge           

The elastic pressure gauge measures the pressure by converting the measured pressure into the displacement of the element based on the principle of deformation of the elastic element under stress. Common types include spring tube pressure gauges, bellows pressure gauges, and diaphragm (or capsule) type pressure gauges. This type of pressure measuring instrument has a simple structure, is firm and durable, is inexpensive, works reliably, and has a wide measurement range. It is suitable for various production occasions such as low pressure, medium pressure, and high pressure, and is widely used in industry. However, the measurement accuracy of elastic pressure gauges is not very high, and most of them use mechanical pointer output, mainly for on-site indication at the production site. When remote transmission of signals is required, additional devices must be equipped.      

       3. Pressure sensors and pressure transmitters           

Pressure sensors and pressure transmitters utilize certain physical characteristics of objects to convert the measured pressure into various electrical signals through different conversion elements, and indirectly measure pressure based on the changes in these signals. According to the different conversion elements, pressure sensors and pressure transmitters can be divided into resistance type, capacitive type, strain type, inductive type, piezoelectric type, Hall plate, and other forms. The main characteristic of this type of pressure measuring instrument is that the output signal is easy to transmit remotely, and can be easily used in conjunction with various display, recording, and regulating instruments, thereby creating conditions for centralized pressure monitoring and control. It is widely used in production process automation systems.