For industrial production, precision pressure gauges or digital pressure gauges are suitable for applications requiring precise measurement. Pressure transmitters should be selected for remote transmission or control requirements. Properly selecting the pressure gauge's range can extend its service life.
1. Ordinary pressure gauges can be used for air, water, steam, oil, etc., and have a black casing. For certain media, pressure gauges are required; for example, ammonia pressure gauges are used for ammonia and have a yellow casing; oxygen pressure gauges are used for oxygen and have a sky-blue casing. Oxygen and acetylene pressure gauges must be strictly oil-free. If the Bourdon tube is contaminated with oil, carbon tetrachloride can be injected into the Bourdon tube with a syringe for cleaning before use.
2. All-stainless steel pressure gauges are used for measuring the pressure of highly corrosive media and corrosive gases, such as dilute hydrochloric acid and hydrochloric acid gas. Isolation is also possible. However, all-stainless steel pressure gauges are not suitable for environments with external corrosive media, such as chlorine and nitric acid. Diaphragm pressure gauges can also be selected. Isolation diaphragms are available in various materials, such as Monel alloy, Hastelloy, tantalum, and fluoroplastics. The appropriate material can be selected based on the medium being measured.
3. Some isolation instruments employ an indirect measurement structure. Depending on the properties of the measured medium, a working fluid, such as glycerin or silicone oil, is filled into the gauge or capillary tube to transmit pressure. These instruments are suitable for measuring the pressure of liquids, gases, or media containing solid suspended matter that have high viscosity, are prone to crystallization, are highly corrosive, or have high temperatures. For applications with significant vibration, YN vibration-resistant pressure gauges or marine pressure gauges should be selected.
4. For applications requiring remote transmission, alarms, and interlocking, pressure transmitters should be selected to transmit the measured pressure as a current signal to the display instrument or DCS card. Pressure transmitters have a wide measuring range and are more flexible in use; pressure resistance and corrosion resistance are key considerations.
5. Electrical contact pressure gauges should use magnetically assisted electrical contact devices. These offer stable and reliable operation, high contact power, and internal damping devices to resist medium pulsation or mechanical vibration. For explosion-proof environments, explosion-proof electrical contact pressure gauges should be selected.
6. Diaphragm pressure gauges can be used for on-site micro-pressure measurement. Diaphragm pressure gauges are only suitable for measuring the minute pressure of gaseous or liquid media that are not corrosive to copper and copper alloys.
