There are many types of pressure gauges,

There are many types of pressure gauges, which not only have general (ordinary) pointer indication type, but also digital type; There are not only conventional types, but also special types; There are not only contact types, but also remote transmission types; There are not only vibration-resistant types, but also seismic types; There are not only diaphragm types, but also corrosion-resistant types. The range of pressure gauges is complete. It has not only regular series, but also digital series; There are not only ordinary media application series, but also special media application series; There are not only switch signal series, but also remote signal series, etc., all of which are derived from practical needs and have successively constituted a complete series. The specifications and models of the pressure gauge are complete, and the structure is perfect. From the nominal diameter, there are Φ40mm, Φ50mm, Φ60mm, Φ75mm, Φ100mm, Φ150mm, Φ200mm, Φ250mm, etc. From the point of view of installation structure type, there are direct installation type, embedded type and embossed type, of which the embedded type is divided into radial embedded type and axial embedded type, and the convex type also has radial convex type and axial convex type. Direct mounting type is further divided into radial direct mounting type and axial direct mounting type. Among them, the radial direct installation type is the basic installation type, and generally refers to the radial direct installation type when the installation structure type is not specified. Considering the stability of its own support, the axial direct mounting type is generally only selected on pressure gauges with a nominal diameter of less than 150mm. The so-called flush and convex pressure gauges are what we often call edge (mounting ring) pressure gauges. The axial flush type is both axial forward with edge, radial flush type refers to radial forward with edge, and radial convex type (also called wall mounted) refers to the radial rear edge pressure gauge. From the perspective of the measurement domain and the range section, the positive pressure range is divided into the micro pressure range section, the low pressure range section, the medium pressure range section, the high pressure range section, and the ultra-high pressure range section, and several kinds of measurement ranges (instrument range) are subdivided into each range section. There are 3 types of negative pressure (vacuum gauge) in the negative pressure range (vacuum); A pressure gauge with positive and negative pressure is a type of pressure gauge that spans a measuring area. Its standard name is pressure vacuum gauge, and it is also called vacuum pressure gauge. It can measure both positive and negative pressures. The classification of accuracy classes for pressure gauges is very clear. Common accuracy grades include 4, 2.5, 1.6, 1, 0.4, 0.25, 0.16, 0.1, etc. The accuracy level should generally be marked on its dial, and its identification also has corresponding provisions, such as "(1)" indicates that its accuracy level is grade 1. For some pressure gauges with very low accuracy levels, such as those under grade 4, and some do not need to measure their accurate pressure values, but only need to indicate the pressure range, such as the pressure gauge on fire extinguishers, the accuracy level can not be identified.