When measuring relatively stable pressure, the range should be 1.5 times the measured value; When measuring fluctuating pressure, the maximum range should be twice the measured value. The range of the pressure gauge should be selected appropriately, which can extend the service life of the instrument.
Selection of pressure gauge range:
When measuring stable pressure, the working pressure should not exceed 2/3 of the range.
When measuring pulsating pressure, the working pressure should not exceed 1/2 of the range.
When measuring high pressure, the working pressure should not exceed 3/5 of the range.
To ensure measurement accuracy, the working pressure should not be less than one-third of the range. According to the above principles, after calculating a value based on the maximum pressure being measured, select a value slightly larger than this value from the pressure gauge range series as the selected range.
Different pressure gauges should be selected for measuring different media and usage environments:
① For general media such as air, water, steam, oil, etc., a Y-shaped ordinary pressure gauge can be used, with a black casing. There are usually several common types of pressure gauges, including axial pressure gauges, radial pressure gauges, axial edge gauges, and radial edge gauges;
② Special pressure gauges are required for certain media, such as YA type ammonia pressure gauges for ammonia, with a yellow casing; The YO oxygen pressure gauge has a sky blue outer shell; Oxygen pressure gauges and acetylene pressure gauges should strictly prohibit oil. In case the gauge is contaminated with oil, a syringe can be used to inject carbon tetrachloride into the spring tube; Clean thoroughly before use.
③ For pressure measurement in highly corrosive media and corrosive gas environments, such as dilute hydrochloric acid, hydrochloric acid gas, etc., in addition to using isolation method for measurement, YB series all stainless steel pressure gauges can also be selected. However, all stainless steel pressure gauges are not suitable for environments with corrosive media such as chlorine, nitric acid, etc. YM series diaphragm pressure gauges can also be selected, with diaphragm materials including 0Cr7Nil2Mo2 (316), Monel alloy (Cu30Ni70), Hastelloy alloy (H276C), tantalum (Ta), and fluoroplastic (F4). Diangon.com can choose according to the measurement medium and fill it with appropriate working fluid such as glycerin or silicone oil according to the requirements of the measured medium. This type of instrument is widely used in the petrochemical industry, which adopts an indirect measurement structure and is suitable for measuring the pressure of liquids, gases, or media with high viscosity, easy crystallization, high corrosiveness, and high temperature, or media with solid suspended particles. There are various materials for isolation membranes to adapt to different measurement media.
