What pressure gauges are there
Pressure gauges can be divided into precision pressure gauges and general pressure gauges according to their measurement accuracy. Precision pressure gauges have measurement accuracy grades of 0.1, 0.16, 0.25, and 0.4 grades, and 0.05 grades; general pressure gauges have measurement accuracy grades of 1.0, 1.6, 2.5, and 4.0 grades, respectively.
Pressure gauges are divided into general pressure gauges , absolute pressure gauges , and differential pressure gauges according to the basis of their indicated pressure. General pressure gauges are based on atmospheric pressure; absolute pressure gauges are based on absolute zero pressure; differential pressure gauges measure the difference between two measured pressures.
Pressure gauges are divided into vacuum gauges , pressure vacuum gauges , micro pressure gauges , low pressure gauges , medium pressure gauges, and high pressure gauges according to their measurement ranges. Vacuum gauges are used to measure pressure values less than atmospheric pressure; pressure vacuum gauges are used to measure pressure values less than and greater than atmospheric pressure; micro-pressure gauges are used to measure pressure values less than 60,000 Pa; low pressure gauges are used to measure pressure values from 0 to 6 MPa ; Medium pressure gauge is used to measure the pressure value of 10 ~ 60MPa; High pressure gauge is used to measure the pressure value above 100MPa.
The pressure gauge is divided according to its display mode: pointer pressure gauge, digital pressure gauge
The housing of the seismic pressure gauge is made of a fully sealed structure, and the housing is filled with damping oil (mostly now filled with silicone oil). Due to its damping effect, it can be used in measuring places where the working environment is vibrating or the pressure (load) of the medium is pulsating.
The pressure gauge with electric contact control switch can realize alarm or control function.
The pressure gauge with remote transmission mechanism can provide electrical signals (such as resistance signals or standard DC current signals) required in industrial engineering.
The isolator (chemical seal) used in the diaphragm meter can isolate the measured medium from the instrument through the isolation diaphragm in order to measure the pressure of strong corrosion, high temperature, and easily crystallized media.
Elastic element of pressure gauge The elastic sensitive element in the mechanical pressure gauge is elastically deformed as the pressure changes. Mechanical pressure gauges use sensitive components such as spring tubes (bourdon tubes), diaphragms, capsules and bellows and are classified according to this. Sensitive components are usually made of copper alloy, stainless steel or special materials.
Spring tube (Bourdon tube) is divided into C-type tube, coil spring tube, spiral tube and other types. Generally, cold-work hardened material blank tubes are used, which have a high degree of plasticity in the annealed state, and obtains high elasticity and strength after cold working hardening and qualitative treatment. Under the pressure of the inner cavity of the spring tube, the elastic characteristics of the spring tube can be used to conveniently convert the pressure into the elastic displacement of the free end of the spring tube. The measuring range of spring tube is generally 0.1MPa ~ 250MPa.
The diaphragm sensitive element is a circular diaphragm with a wave. The diaphragm itself is located between the two flanges or welded on the flange or the edge is sandwiched between the two flanges. The diaphragm is under pressure from the measuring medium. In this way, the small bending deformation of the diaphragm can be used to indirectly measure the pressure of the medium. The amount of pressure is indicated by the pointer. Compared with Bourdon tube, the diaphragm has larger transmission force. Because the diaphragm itself is fixed around the edges, its vibration resistance is good. The diaphragm pressure gauge can achieve high over-pressure protection (for example, the diaphragm is attached to the upper flange). The diaphragm can also be added with a protective coating to improve corrosion resistance. Using open flanges, flushing, openings and other measures, diaphragm pressure gauges can be used to measure very viscous, unclean and crystalline media. The pressure measurement range of the diaphragm pressure gauge is 1600Pa ~ 2.5 MPa. The capsule sensitive element consists of two pairs of diaphragms with a circular wavy cross-section. The pressure of the measuring medium acts on the inside of the capsule cavity, and the resulting deformation can be used to indirectly measure the pressure of the medium. The magnitude of the pressure value is displayed by the pointer. Capsule pressure gauge is generally used to measure the micro pressure of gas, and has a certain degree of over-pressure protection. The stacking of several capsule sensitive elements will produce a large transmission force to measure extremely small pressures. The pressure range of the capsule pressure gauge is from 250Pa to 60000Pa.