Pipeline pressure gauge parameters: 1, the instrument work ambient temperature of -40 ° C to 70 ° C; instrument work environment vibration conditions should be no more than GB4439 / T under the VH3 3, the pressure part of the instrument generally used to measure ceiling 3/44, relative humidity: less than 85%, temperature: when the ambient temperature deviation from 20 ° C ± 5 ° C, the instrument indication error is not greater than 0.04% / ° C. Pipeline pressure gauge pipe pressure gauge diaphragm pressure gauge for measuring a certain corrosive, non-solidification or crystallization of a fluid medium pressure or negative pressure. 6, the corrosion resistance can vary depending on the diaphragm material. Structural principle: the instrument from the measuring system (including the flange joint, corrugated diaphragm), transmission indicating mechanism (including connecting rod, gear transmission mechanism, pointer and dial) and housing (including case and cover ring). The instrument housing is splash-proof structure, with good tightness, it can protect its internal organs from contamination immersion. The principle role of the instrument is based on the deformation of the elastic element (diaphragm measuring system). In the the measured medium under pressure, forcing the diaphragm to produce the corresponding elastic deformation - displacement, by means of the link group by transmission of the transmission mechanism and to an enlarged, will be measured by the fixed gear on the pointer value on the dial instructions.