Technical article of pressure gauge

In the process of industrial process control and technical measurement, mechanical pressure gauge is widely used because of its high mechanical strength and convenient production The elastic sensitive element in mechanical pressure gauge has elastic deformation with the change of pressure The mechanical pressure gauge adopts spring tube (Bourdon tube), diaphragm, bellows and other sensitive elements and is classified according to this The measured pressure is generally regarded as relative pressure The general relative point is atmospheric pressure The elastic deformation of the elastic element under the action of the medium pressure is amplified by the gear transmission mechanism of the pressure gauge, and the relative value (high or low) of the pressure gauge relative to the atmospheric pressure will be displayed The pressure value in the measuring range is displayed by the pointer, and the indicating range of the dial is generally 270 degrees Classification of pressure gauge: pressure gauge can be divided into precision pressure gauge and general pressure gauge according to its measurement degree The measurement degree of precision pressure gauge is 0.1, 0.16, 0.25 and 0.4 respectively; the measurement degree of general pressure gauge is 1.0, 1.6, 2.5 and 4.0 respectively The pressure gauge is divided into general pressure gauge, pressure gauge and differential pressure gauge according to the different basis of indicating pressure General pressure gauge is based on atmospheric pressure; absolute pressure gauge is based on pressure zero; differential pressure gauge measures the difference between two measured pressures Pressure gauge is divided into vacuum gauge, pressure vacuum gauge, micro pressure gauge, low pressure gauge, medium pressure gauge and high pressure gauge according to its measuring range Vacuum gauge is used to measure the pressure value less than atmospheric pressure; pressure vacuum gauge is used to measure the pressure value less than and greater than atmospheric pressure; micro pressure gauge is used to measure the pressure value less than 60000 Pa; low pressure gauge is used to measure the pressure value between 0 and 6Mpa; medium pressure gauge is used to measure the pressure value between 10 and 60MPa; high pressure gauge is used to measure the pressure value above 100MPa The shell of the shockproof pressure gauge is made into a fully sealed structure, and the shell is filled with damping oil Because of its damping effect, it can be used in the measuring place of vibration or medium pressure (load) fluctuation in the working environment The pressure gauge with electric contact control switch can realize the function of sending alarm or control The pressure gauge with remote transmission mechanism can provide electrical signal (such as resistance signal or standard DC current signal) needed in industrial engineering The separator (chemical seal) used for diaphragm meter can isolate the measured medium from the instrument through the isolation diaphragm, so as to measure the pressure of the medium with strong corrosion, high temperature and easy crystallization The elastic element of pressure gauge the elastic sensitive element of mechanical pressure gauge produces elastic deformation with the change of pressure The mechanical pressure gauge adopts spring tube (Bourdon tube), diaphragm, bellows and other sensitive elements and is classified according to this The sensing elements are generally made of copper alloy, stainless steel or special materials Spring tube (Bourdon tube) can be divided into C-type tube, disc reed tube, spiral tube, etc Generally, the cold work hardening type material is adopted, which has high plasticity in the annealed state After cold work hardening and qualitative treatment by pressure processing, high elasticity and strength are obtained Under the pressure of the inner cavity, the spring tube can be easily transformed into the elastic displacement of the free end of the spring tube The measuring range of spring tube is generally 0.1MPa ~ 250Mpa Diaphragm sensing element is a circular diaphragm with waves The diaphragm itself is located between two flanges, or it is welded on the flange plate or its edge is clamped between two flange plates One side of the diaphragm is under the pressure of 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 magnitude of the pressure is indicated by a pointer Compared with bourdon tube, the transfer force of diaphragm is larger Since the edge of the diaphragm itself is fixed, 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 film can also be coated with a protective coating to improve corrosion resistance Use the opening flange, flushing, opening and other measures to measure the medium with high viscosity, unclean and crystallized by diaphragm pressure gauge The pressure measurement range of diaphragm pressure gauge is 1600pa ~ 2.5MPa The capsule sensing element consists of two pairs of diaphragms with circular wave cross-section The pressure of the measuring medium acts on the inner side of the capsule cavity, and the resulting deformation can be used to indirectly measure the pressure of the medium The size of the pressure value is indicated by a pointer Capsule pressure gauge is generally used to measure the micro pressure of gas, and has a certain degree of overpressure protection ability When several capsule sensors are stacked together, they will produce a large transfer force to measure the extremely small pressure The pressure measurement range of capsule pressure gauge is 250pa ~ 60000pa.