The correct use of pressure gauges is also of great help to all walks of life. Correctly grasping the tips of using the pressure gauge can reduce the occurrence of failures.
When the applied pressure reaches the measurement upper limit of the pressure gauge and the value of the pressure gauge, if the pointer of the pressure gauge still does not move or moves little, it means that the pressure is not transmitted to the spring tube. First check whether the sealing gasket connected to the pressure gauge calibrator blocks the passage at the joint. If there is no problem with the connection, it proves that the inside of the pressure gauge is blocked and should be cleaned. When we use pressure gauges, we often encounter the following problems.
1. After the pressure is removed, the pointer of the pressure gauge cannot return to the low point
1) If the pointer is bent or loose, it can be corrected with tweezers and tightened after calibration.
2) The torque of the hairspring is insufficient, the engagement of the central gear and the sector gear can be disengaged, and the shaft of the central gear can be rotated counterclockwise to increase the reaction torque of the hairspring.
2. The pointer of the pressure gauge jumps or is sluggish and does not rotate
1) There is friction between the pointer and the transmission gear. Adjust the transmission gear meshing clearance. There is friction when the watch glass or the dial meet. The pointer can be corrected by thickening the gasket under the glass or enlarging the pointer shaft hole.
2) The central gear shaft is bent, the shaft diameters are not concentric, and do not match. The gear can be removed and straightened with a mallet or straightened with flat pliers.
3) There is dirt at the meshing part of the two gears, and the two gears can be removed for cleaning.
4) The movable screw between the connecting rod and the sector gear does not move or the movable screw is loose, and the thickness of the connecting rod can be thinned with a file.
3. Only one verification point of the pressure gauge is out of tolerance
1) On which scale is found to be out of tolerance, and on which scale to stop. Check the coordination of the components on the scale point, whether the drive shaft hole is blocked; whether the connecting rod is flexible;
2) When a positive error occurs at a certain point, it is often due to dirt and burrs at the meshing point of the teeth; when a negative error occurs, it is mostly due to shape damage or damage to the teeth. If the teeth are seriously damaged, they should be replaced with new ones. When there is no new part to replace, the center wheel has damaged teeth to change the meshing position, so that the damaged teeth can avoid the transmission. If the sector wheel has damaged teeth, it cannot be repaired and must be replaced with a new one.
4. When the pressure gauge is in use, the indication value is not stable, and the pressure drops significantly: at this time, first check whether there is oil leakage at the connection between the pressure gauge and the pressure gauge calibrator. If there is no oil leakage and the checker is intact, it means that there is leakage inside the spring tube, and the scale plate should be removed for further inspection.
1) There are sand holes in the machine base itself, which will gradually leak after long-term use. The base of the same specification needs to be replaced, and the welding can be repaired by measuring low pressure.
2) Long-term exposure to pulse pressure, spring tube fatigue or leakage at both ends of the seal. The two sealing parts can be repaired or re-tightened, and the spring tube will be scrapped if it is broken.
3) Long-term corrosion by the measured medium, the spring tube will cause leakage. It is necessary to choose a pressure gauge with corrosion resistance, and replace the spring tube if necessary.
4) Due to the quality of the spring tube, there are obvious cracks or ruptures. It is necessary to replace the high-quality spring tube of the same specification and take corresponding protective measures.
5) The selected specifications are improper, the measured pressure is close to the upper limit of the gauge, and the long-term pressure will cause fatigue and rupture. The pressure gauge of the appropriate specification should be carefully selected, and if the spring tube is broken, the tube of the same specification should be replaced.
5. The error of the indicated value of the pressure gauge is uneven
1) The deformation of the spring tube fails, and the displacement is not proportional to the pressure, so the spring tube needs to be replaced.
2) The transmission ratio between the free end of the spring tube and the sector gear and wheel rod is improperly adjusted, and it needs to be inspected and adjusted again.
3) The joint position of the gear splint and the bottom plate is wrong. The combination screw should be loosened to drive the splint counterclockwise.
4) The size of the pointer displacement, resulting in the forward or backward, the spring is not the same tightness, you can adjust the tightness of the hairspring, and rotate the central gear.
6. During the process of pressurization, the pointer of the pressure gauge jumps, sluggish, and changes greatly. It indicates that there is friction in the transmission mechanism, and the instrument must be disassembled to check the meshing condition of the transmission mechanism and perform necessary treatment.
7. The error of the tested meter of the pressure gauge always increases or decreases by a fixed value: According to the characteristics of this error, we can draw a conclusion: the error of the tested meter increases or decreases by the same amount as the pressure increases. In the whole measurement range, the pointer reading always differs from the standard indication by a certain fixed value. This is a system error caused by incorrect pointer installation. We don't need to worry too much. Because it is very easy to adjust this error, just start the needle again to adjust.