How to distinguish the quality of pressure gauges

　　Pressure gauge is a commonly used instrument in industrial production, which mainly uses elastic components as sensitive components to test and indicate different ambient pressures. Pressure gauges are widely used in various industries, so it is very important to learn to identify the quality of pressure gauges.  

       1、 Visual inspection

       (1) Before receiving the pressure gauge, we should carefully observe its outer packaging and check whether the packaging box is clearly marked. 

       (2) After obtaining the pressure gauge, carefully observe whether the surface of the pressure gauge is uniform, smooth, and free of rust, and the weld should be smooth and free of cracks.

       (3) Check whether the reading part of the dial is clear and whether there are stains on the transparent cover. 

       (4) When there is no pressure on a pressure gauge with a stop pin, the pointer should be close to the stop pin. For pressure gauges without stop pins, the pointer should be at the zero position when there is no pressure.  

       (5) For liquid filled pressure gauges, the liquid should be clear and transparent without impurities, and its liquid level should be located at 1/3 to 1/4 above the center of the gauge case. 

       2、 Gauge            

       Select a suitable standard to verify its accuracy.    

       3、 Verification of indication error, return error, and tap displacement

      (1) Indication error: The calibration of the pressure gauge's indicator shall be conducted according to the graduation line marked with numbers. During the calibration, the pressure shall be gradually and steadily increased (or decreased). When the indicator reaches the upper detection limit, the pressure source shall be cut off, and the pressure shall be withstood for three minutes. Then, the calibration shall be conducted in a stable reverse order according to the original calibration point. 

      (2) Return error refers to the absolute value of the specified allowable error during boost (or buck) and boost (or boost) verification for the same point.      

      (3) Tap the displacement to check each calibration point. During boost (or decrease) and boost (or decrease) calibration, the indicator finger change caused by the lightweight case should not exceed 1/2 of the specified allowable absolute error value