Correct selection of pressure instruments
The correct selection of pressure instruments mainly includes determining the type, range, range, accuracy and sensitivity of the instrument, the size of the instrument, and whether it needs remote transmission and other functions, such as indication, recording, adjustment, alarm, etc.
The main basis for selecting pressure instruments:
1. The measurement requirements of the process, including range and accuracy. In the case of static test (or slow change), the maximum value of the measured pressure is selected to be two-thirds of the full scale value of the pressure gauge; in the case of pulsating (fluctuation) pressure, the maximum value of the measured pressure is to use the pressure gauge One-half of the full-scale value.
The accuracy levels of commonly used pressure detection instruments are 0.05, 0.1, 0.25, 0.4, 1.0, 1.5, and 2.5. They should be selected from the accuracy requirements of the production process and the most economical perspective. The maximum allowable error of the instrument is the product of the range of the pressure gauge and the percentage of accuracy level. If the error value exceeds the accuracy required by the process, the pressure instrument with a higher level of accuracy needs to be replaced.
2. The properties of the measured medium, such as state (gas, liquid), temperature, viscosity, corrosiveness, degree of pollution, flammability and explosiveness, etc. Such as oxygen meters, acetylene meters, with "oil-free" mark, dedicated to special media corrosion resistance pressure gauge, high temperature pressure gauge, diaphragm pressure gauge and so on.
3． Environmental conditions at the site, such as ambient temperature, corrosion, vibration, and humidity. Such as anti-vibration pressure gauges for vibration environmental conditions.
4． Suitable for staff observation. According to the location of the testing instrument and the lighting conditions, instruments with different diameters (outer dimensions) are selected.
