1. The pointer is not at the zero position, but on a certain scale on the dial
Pressurize the pressure gauge, and find that its pressure value changes proportionally from a certain scale. The main reason for this phenomenon is that the pressure gauge is usually used in places with relatively large vibrations, or the pressure gauge is accidentally touched, causing pressure When the watch is returning to zero, the sector gear and the central shaft do not mesh for an instant. The way to troubleshoot this problem is to remove the pointer and reposition the needle.
As the pressure increases, the indication value of the spring tube pressure gauge gradually increases or gradually decreases.
The above-mentioned error is called linear error. The main reason is that the transmission ratio has changed. As long as the position of the adjustment screw is moved and the transmission ratio is changed, the error can be adjusted to the allowable range. When the error of the tested meter is positive and gradually increases with the increase of pressure, move the adjusting screw outwards to reduce the transmission ratio.
2. Non-linear error
The indication error of the pressure gauge changes disproportionately with the increase in pressure. This error is called nonlinear error. The main reason for this phenomenon is that the pressure gauge has been used for a long time, and the coordination between the components has changed. The way to troubleshoot this problem is to change the angle between the sector gear and the tie rod.
The pointer travels fast in the first half and slow in the second half. Adjust the angle between the lever and the sector gear.
The pointer moves slowly in the first half and fast in the second half. Increase the angle between the lever and the sector gear.
The angle adjustment between the pull rod and the sector gear can be achieved by rotating the movement. The specific method is to loosen the bottom plate fixing screws, turn the movement to the proper position, and then tighten the bottom plate fixing screws, and re-check the pressure. The adjustment method is determined according to the specific conditions of the error. Normally, the non-linear error of the instrument is adjusted to the linear error first, and then the linear error is adjusted. For this reason, in general, when adjusting the angle between the pull rod and the sector gear, the position of the adjusting screw is also adjusted.
3. The hairspring is twisted
The twisting of the balance spring is caused by man-made damage caused by overload or large impact or self-disassembly during use. When it is in the normal position, it gives a counterclockwise linear and stable restoring force to the central gear. If the balance spring is twisted, this restoring force will disappear, and there will be: (1) The pointer jumps, the value is unstable, and increases. Large accidental error. (2) The zero error is large. (3) The system error increases. The method to troubleshoot this kind of failure: (1) Rewind the balance spring. (2) Equipped with a hairspring.
4. The tooth meshing surface and the corners of the matching shaft hole are severely worn
Cause the numerical error to be large and unstable, and the phenomenon of pin stuck. This kind of damage is mainly caused by the long-term use of the pressure gauge under a fixed and unstable load (such as a power air compressor), so there is a large compensation or burr obstruction in the pressure transmission process, which makes the measurement value out of tolerance. :
Remedy: (1) Replace with new accessories (2) Take shrinkage repair, the damaged tooth can be adjusted to avoid the damaged tooth surface and continue to use.
5. The pointer does not return to zero
If the pressure is relieved after boosting, the pointer does not return to the zero position, indicating that the zero position of the meter has increased the force in the direction of the restoring force. This force comes from frictional resistance or residual tension from deformation. The frictional resistance mainly occurs at the meshing part of the hairspring connecting rod and hinge. If the hairspring sticks to the ring or twists, the connecting rod hinge does not move properly, and the meshing part has burrs, the friction will increase rapidly and the pointer will not return to the zero position. These parts return to the normal state to eliminate the phenomenon of non-return to zero.
