The correct selection and use of pressure measuring instruments is the primary prerequisite for correct and effective measurement and control of pressure parameters. The following are some researchers based on their previous design, installation, and debugging experience in the front line of metrology.
Selection of range
(1) When measuring the stable pressure, the maximum range of the general pressure gauge is close to or greater than 115 times the normal pressure measurement value.
(2) When measuring fluctuating pressure, the maximum range of the general pressure gauge is close to or greater than 2 times the normal pressure measurement value.
(3) When measuring the outlet pressure of the machine pump, the maximum range of the general pressure gauge should be close to the maximum pressure value at the outlet of the machine pump.
(4) When measuring high pressure pressure, the maximum range of the general pressure gauge should be greater than 1.7 times the maximum pressure measurement value.
(5) In order to ensure the accuracy of the pressure measurement value, the minimum pressure measurement value should be higher than 1/3 of the pressure measurement range.
Type selection
(1) The choice of indicating pressure gauge
A. When the pressure measurement is> 0.4MPa, a spring tube pressure gauge can be used.
B. When the pressure measurement is less than 0.04MPa, a bellows or bellows pressure gauge can be selected.
C. When measuring viscous, easy crystallization, corrosiveness, and solid particles, a diaphragm pressure gauge or attached chemical sealing device can be used.
D. For measuring steam or medium pressure higher than 60℃, stainless steel pressure gauge or condensing ring should be selected.
E. The pulsating pressure measurement should be attached with a damper or a seismic pressure gauge.
F. The dust collector should be installed when measuring the dust-containing gas.
G. A gas-liquid separator should be installed when measuring the pressure of a gas containing liquid.
H. Special pressure gauges should be used to measure certain chemical media: ammonia pressure gauges are used for pressure measurement of ammonia-containing media; oxygen pressure gauges are used for oxygen pressure measurement; acetylene pressure gauges are used for acetylene pressure measurement; pressure measurement of sulfur-containing media is used Sulfur-resistant pressure gauge.
I. High-pressure pressure gauges (>10MPa) should have pressure stagnation safety measures.
(2) Selection of long-distance pressure transmission instrument
A. For occasions requiring long-distance measurement or high measurement accuracy, a pressure sensor or pressure transmitter should be selected;
B. When the measurement accuracy is not high, you can choose the resistance type, inductance type, Hall effect type remote transmission pressure gauge;
C. Pneumatic base type pressure indicating regulator is suitable for on-site indicating adjustment;
D. Pressure transmitter and pressure quick shutoff should be selected reasonably according to the explosion-proof requirements of the installation site.
Selection of accuracy level
(1) Generally, pressure gauges, diaphragm pressure gauges and diaphragm pressure gauges should be used for 115 or 215 levels.
(2) Pressure gauges for precision measurement should be grade 014, grade 0125 or grade 0116.
Choice of external dimensions
(1) Pressure gauges installed on pipes and equipment, with a dial diameter of 100mm or 150mm.
(2) The pressure gauge installed on the instrument pneumatic pipeline and its auxiliary equipment has a dial diameter of 60mm.
(3) The pressure gauge is installed in the places where the illumination is low, the position is high, or the value is difficult to observe. The diameter of the dial is 150 or 200mm.
