The application of pressure gauges is extremely common, covering almost all industrial processes and scientific research fields. It can be found everywhere in the fields of heating network, oil and gas transportation, water and gas supply systems, car maintenance factories, and sales markets. Especially in the industrial process control and technical measurement process, due to the mechanical pressure gauge's sensitive elastic component having characteristics such as high mechanical strength and convenient production, the application of mechanical pressure gauges is becoming more and more widespread. Therefore, pressure gauge product failures may occur in practical applications.
Below, we will briefly introduce 7 common pressure gauge failures, their causes, and solutions:
When the pressure of the pressure gauge is released, the pointer cannot return to zero
If the pointer is bent or loose, it can be corrected with tweezers and then hit hard if there is no error.
If the torsional force of the wire is insufficient, disengage the center gear from the sector gear, rotate the center gear shaft counterclockwise, and increase the wire reaction torque. If the problem cannot be solved, please contact the technician of industrial gauge manufacturers in time.
The pointer of the pressure gauge jumps or stagnates and does not rotate
There is friction between the pointer and the driving gear. Adjust the clearance of the driving gear.
The surface glass or dial rub against each other. The pointer can be corrected by thickening the gasket below the glass or enlarging the pointer hole.
The center gear shaft is bent, the shaft diameter is eccentric, or there is no match. You can remove the gear and straighten it with a wooden mallet or a flat-nose pliers; if there is dirt in the meshing part of the two gears, you can remove the two gears and clean them.
If the active screw between the connecting rod and the sector gear is not active or the active screw is loose, reduce the thickness of the connecting rod with a file.
The pressure gauge only exceeds the tolerance limit at a certain verification point
When you find out which scale exceeds the tolerance limit, stop at that scale. Check the fitting of the parts at the scale point, whether the driving shaft hole is blocked, and whether the connecting rod is flexible; exclude the damaged or foreign matter at the meshing point, etc.
When there is a positive or negative error at a point, it is often due to dirt and burrs at the meshing point; when there is a negative error, it is mainly due to tooth wear or tooth damage. If the teeth are severely damaged, they should be replaced with new ones. When there are no new parts to replace, if the center wheel has broken teeth, the meshing position can be changed to avoid transmission. If the sector wheel has broken teeth, it cannot be adjusted and must be replaced with a new one.
During the use of the pressure gauge, the indication value is unstable, and the pressure drops significantly
At this time, first, check whether there is gas leakage at the connection between the pressure gauge and the pressure gauge calibrator. If there is no oil leakage and the calibrator is intact, it means that the diaphragm tube is leaking oil. Remove the dial for further inspection.
The base itself has water bubbles, which will gradually seep after long-term use. Bases of the same specifications need to be replaced, and low-pressure measurement can be repaired.
Long-term fatigue of the diaphragm tube or leaks at the two end seal parts may occur under the action of pulse pressure. The two seal parts can be repaired or re-tightened. If it is broken, the diaphragm tube will be scrapped.
The tested medium corrodes the diaphragm tube for a long time, causing leaks. A corrosion-resistant pressure gauge must be selected, and the diaphragm tube must be replaced when necessary.
Due to the quality problems of the diaphragm tube, there are obvious cracks or ruptures. It is necessary to replace the same specification diaphragm tube and take corresponding protective measures.
Improper selection of specifications will cause fatigue fractures when the measured pressure approaches the upper limit of the gauge pressure. Therefore, you should choose a pressure gauge with appropriate specifications carefully. If the diaphragm tube breaks, replace the same specification tube.
The pressure indication of the pressure gauge is uneven or incorrect
The diaphragm tube deforms and fails, and the displacement is not proportional to the pressure. The diaphragm tube needs to be replaced.
The transmission ratio of the free end of the diaphragm tube, sector gear and wheel rod is improperly adjusted and needs to be rechecked and adjusted.
The combination position of the gear clip and the base plate is incorrect. The connecting screws should be loosened, and the clip plate should be driven counterclockwise.
The displacement of the pointer is uneven, which causes the tension of the pendulum wire to be tightened forward or backward unevenly. Adjust the balance of the pendulum wire to rotate the center gear.
During pressurization, the pointer of the pressure gauge jumps, stagnates, or significantly deteriorates
There is friction in the indication transmission mechanism. The instrument needs to be disassembled to check the meshing of the transmission mechanism and perform the necessary treatment. In some cases, using a contact gauge that does not rely on springs or moving parts can be a more robust solution to avoid mechanical failures.
The measurement error of the pressure gauge of the test instrument always increases or decreases by a fixed value
Based on the characteristics of this error, we can draw the conclusion that the error will increase or decrease by the same amount with the increase of pressure. Therefore, the reading of the pointer is always a fixed value different from the standard display value within the entire measurement range. This is a system error caused by incorrect installation of the pointer. Don't worry, because this type of error is easy to adjust, you only need to restart it for adjustment.