The accuracy of precision pressure gauges is directly related to the safety of industrial production. The common problems of precision pressure gauges mainly include the following.
Due to long-term use and no zero limit, precision pressure gauges often show positive or negative over-tolerance. There are several reasons for the phenomenon of zero-point out-of-tolerance in precision pressure gauges:
1. The zero point out-of-tolerance caused by the problem of the spring tube: the elastic failure, elastic hysteresis and the accumulation of residual deformation of the spring tube will cause the performance of the spring tube to fail, resulting in the phenomenon of zero point out-of-tolerance.
2. Zero point out-of-tolerance caused by the separation of gear and toothing: There are two possibilities to cause the gear and toothing to disengage. One is caused by excessive pressure during the measurement of the precision pressure gauge, and the other is caused by precision. It is triggered by the rapid pressure relief of the pressure gauge.
3. Zero point out-of-tolerance caused by material problems of elastic elements: The reduction in the detection performance of the elastic element material itself and the decrease in fatigue strength will cause the zero point out-of-tolerance phenomenon.
4. Vibration-induced zero-point out-of-tolerance: During the use of the precision pressure gauge, the dial of the precision pressure gauge becomes loose due to vibration, which leads to the phenomenon of zero-point out-of-tolerance.
As the pressure increases or decreases, the precision pressure gauge always increases or decreases a fixed value (exceeding the tolerance). The error of the fixed value is mostly caused by the improper placement of the dial pointer or the looseness of the dial.
When the precision pressure gauge is working normally, tap the dial of the precision pressure gauge, and the pointer will not jump beyond the absolute value of the measured value. If the jump exceeds the absolute value of the measured value, the precision pressure gauge appears Tap the displacement fault.
The main reasons for tap displacement failure are as follows:
1. The hairspring problem: When the hairspring lacks sufficient tension, the precision pressure gauge is prone to tap displacement.
2. Friction between the transmission parts: the magnifying mechanism and the pointer are affected by the friction of the free end of the spring tube, and the phenomenon of jamming or excessively large or small tension occurs, which causes the tapping displacement failure.
3. Occlusion problem: When the sector gear and the central shaft are too tight or too loose, the phenomenon of tapping displacement is prone to occur.
4. Loose screws and pointers: When the screws or pointers are loose or between the pointer sleeve and pointer, it will cause tapping displacement.
Non-linear errors usually appear in the process of pressure increase and decrease. The pressure indication value error changes with the pressure value, and the error gradually changes from a positive error to a negative error or vice versa.