Quality Requirements for Pressure Gauges

1. The spring tube of a general pressure gauge has a specific cross-sectional shape (commonly flat round and approximately oval), bent into a 'C' shape, and must meet certain elasticity requirements. If the spring tube is too small, it will affect the accuracy level of the pressure gauge.

2. If the reading of the pressure gauge exceeds the allowable error, the adjustment screw for the gauge's reading should be adjusted. If the gauge does not have an adjustment screw, it can only be deemed unqualified.

3. The scale numbers and symbols on the pressure gauge dial should be complete and clear. The scale on the dial should be evenly distributed, generally covering a central angle of 270°. The pointer of the pressure gauge should extend into all scale lines, and the width of the pointer's indicating end should not exceed 1/5 of the minimum scale interval. The distance between the pointer and the plane of the scale should be within 1 to 3 mm for gauges with an outer diameter of over 200 mm (including 200 mm), and within 2 to 4 mm for those with an outer diameter of 200 mm.

4. For pressure gauges with a stop pin, the pointer should be close to the stop pin when there is no pressure or in a vacuum, and the 'scale reduction' should not exceed the specified allowable error.

5. The casing of the pressure gauge should protect the internal components from contamination, and the gauge should be equipped with a safety hole, which must have a dust-proof device.

6. For digital pressure gauges, the overall structural rationality, selected materials, aging process of electronic components, and long-term stability should be considered.