Selection requirements for pressure gauges

The selection of pressure gauges mainly includes instrument type, range, accuracy and sensitivity, overall dimensions, and whether remote transmission and other functions are required, such as indication, recording, alarm, and control. The basis for selection is as follows:            

(1) Must meet the requirements of the process production process, including range and accuracy;           

 (2) The properties of the medium to be measured, such as temperature, pressure, viscosity, corrosivity, flammability, and explosiveness, must be considered;   

(3) Attention must be paid to the on-site environmental conditions under which the instrument is installed and used, such as ambient temperature, electromagnetic field, vibration, etc.      

When selecting a range, it should be noted that for stable conditions, the normal pressure should be at the upper limit of the scale; For pulsating pressure, the normal pressure should be at the upper limit of the scale; For high pressure pressures, the normal pressure should be below the upper limit of the scale.     

From the perspective of the properties of the medium being tested, corrosion-resistant diaphragm pressure gauges or corrosion-resistant materials for the parts in contact with the medium should be selected for highly corrosive media; Select a diaphragm pressure gauge for viscous, crystalline, and easily clogged media; Select pressure-resistant explosion-proof or intrinsically safe explosion-proof barriers according to the classification of explosive hazardous media; Special pressure instruments should be selected for measuring oxygen, ammonia, hydrogen, acetylene, hydrogen sulfide, and other media. 

From the perspective of the requirements for the output signal of the instrument, for situations where it is only necessary to observe the pressure change, a direct indicating instrument such as a bourdon tube or U-shaped liquid column type can be selected; For situations where it is necessary to remotely transmit pressure signals to the control room or other electric instruments, electrical pressure detection instruments or other instruments with electrical signal output should be selected, such as strain type pressure sensors, capacitive pressure sensors, etc; To detect rapidly changing pressure signals, electrical pressure detection instruments, such as diffused silicon pressure sensors, should be selected. 

From the perspective of the instrument operating environment, for environments with particularly high or low temperatures, sensitive elements with small temperature coefficients should be selected; For highly explosive environments, when using electrical pressure gauges, safety and explosion-proof pressure gauges should be selected.  

Each pressure gauge has its own characteristics and application range. After selecting a pressure gauge, it should also be installed correctly to avoid measurement errors caused by improper installation. The installation of pressure gauges must be carried out in strict accordance with the instructions for the use of pressure gauges.