Interpretation of common troubleshooting for stress testers-

Pressure tester is an instrument used for pressure resistance, pressure holding test and vacuum pressure holding test with helium and nitrogen as the test medium. Production workshop for leak testing.

Common Troubleshooting

1. Pointer is not at zero but on a certain scale on the dial

Pressurize the gauge and see that the pressure value changes from a certain time The main reason for this phenomenon is that the pressure gauge is usually used in a place where the vibration is relatively large, or the pressure gauge accidentally falls off, so that the pressure gauge is in the process of to return to zero, and the gap between the gear sector and the central shaft The method of eliminating this defect is to remove the needle and put the needle back in place.

As the pressure increases, the value indicated by the pressure gauge of the tubespring gradually increases or gradually decreases.

The error mentioned above 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 within the allowable range. When the error of the meter under test is positive and gradually increases with increasing pressure, move the adjusting screw outward to reduce the gear ratio.

2. Non-linear error

The indication error of the pressure gauge changes disproportionately with increasing 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 cooperation between the various components has changed. The way to troubleshoot this kind of failure is to change the angle between the sector gear and the tie rod.

The pThe pointer moves quickly in the first half and moves slowly in the second half, and the angle between the pull rod and the sector gear is reduced.

The pointer moves slowly in the first half, and moves quickly in the second half, and the angle between the pull rod and the sector gear is increased.

The adjustment of the angle between the traction rod and the toothed sector can be obtained by turning the movement. The specific method is to loosen the bottom plate fixing screws, rotate the movement to a suitable position, then tighten the bottom plate fixing screws, pressurize and recalibrate. The adjustment method is determined according to the specific error situation. Usually, the nonlinear error of the instrument is first adjusted to a linear error, and then the linear error is adjusted. For this reason, in general, when adjusting the anglebetween the pull rod and the sector gear, the position of the adjusting screw is also adjusted.

3. Hairspring torsion

Hairspring torsion is caused by man-made damage caused by overload during use, strong impact or self-disassembly . When in the normal position, it gives the center gear a linear and stable counter-clockwise restoring force. If the hairspring is twisted, this restoring force will disappear and there will be: (1) the pointer jumps, the value is unstable, and the grand chance error increases. (2) The zero position error is large. (3) System error increases. Ways to troubleshoot this type of failure: (1) Heavy disc hairspring. (2) Replace the hairspring.

4. Heavy wear on the tooth meshing surface and the corner of the mating shaft hole

Causes large numerical errors and instability, as well as pin jams. These damages are mainly due tos to the fact that the manometer is unstable in a fixed position. It is caused by long-term use under heavy load (such as an electric air compressor), so there is a large compensation or burr clogging in the pressure. transmission process, which makes the measurement value out of tolerance:

Remedy: (1) Replace The new accessory (2) adopts the removal cavity repair, and the damaged teeth can be adjusted to avoid damage to the tooth surface and continue to be used.

5. The needle does not return to zero

If the needle does not return to zero after increasing the pressure and then releasing the pressure, it means that the zero position of the watch increases the force in the direction of the restoring force. This force comes from the frictional resistance or the residual stress of deformation. Frictional resistance occurs mainly at the engaging parts of the connecting rodbalance spring and hinge. If the hairspring sticks or twists, the connecting rod hinge does not move well, and there are burrs in the meshed parts, the friction will increase sharply, and the pointer will not return to zero. These parts return to the normal state to eliminate the non-return phenomenon.

Prev: Interpretation of Application Notes for Steam Flow Meters-