What is the reason for the displacement of the opening of the stainless steel pressure gauge?
In the verification process of stainless steel pressure gauge, there is a necessary inspection index, called tap displacement. Tap displacement refers to the pointer displacement caused by tapping the case at the same check point. The change in the two indicated values before and after shell tapping is the number of tapping displacements.
The purpose of checking tap displacement is to see if the pointer jumps or shifts, and to see if each part fits well.
To "tap" means to tap the side wall of the case with your fingers. Not suitable for hitting from the back of the case or with a hammer. The tap displacement number is not divided into "±", and the result is * value.
The pointer of the stainless steel pressure gauge in the normal state should swing counterclockwise after tapping the shell, otherwise it needs to have a tap displacement. Tap displacement is in many cases caused by friction between parts, with the exception of hairsprings. Parts are installed loose due to poor assembly, especially if the parts are installed too tightly. Tap displacement is usually caused by:
The hairspring is not tight enough or wide enough, or the ends of the hairspring are not tightened properly.
The friction of the gearbox parts will affect the resistance of the free end of the spring tube to the gearbox amplifying mechanism and pointer assembly. Commonly, the connecting rod is not flexible; the drive shaft is crushed; or the shaft is too tight to the hole.
The screw is loose somewhere, especially the adjustment screw is loose, which has a great impact.
Poor tooth engagement, loose or blocked teeth.
The main parts of the stainless steel pressure gauge, first the stainless steel pressure gauge part that can be seen from the outside, and then its internal structure, including the function of the device and its device will cause these failures, so that when the failure occurs, we can find the source of the problem as soon as possible , reduce the loss caused by failure. The external structure mainly includes the case, the watch glass, the pointer and the liquid receiving device. In the event of a leak, you can check the case for damage, leaks of wetted material, and then check the seal. Often, leaks are caused by these locations. If the index is not accurate enough, the pointer can be checked for bending and deformation faults. In addition, welded joints of wetted materials should also be checked, which are also prone to leaks.
The internal structure of the stainless steel pressure gauge is mainly composed of moving and elastic elements. If the pointer cannot be zeroed and the measurement value is inaccurate, most of it is caused by the elastic element, because long-term overpressure measurement may cause deformation of the elastic element, so that the pointer cannot be zeroed and the indication is inaccurate. When we're boosting in use, if the pointer isn't responding or isn't moving at zero, it's probably due to movement damage.
Installation of stainless steel pressure gauge:
1. The working environment temperature of the instrument is -40~70℃, and the relative humidity is not more than 80%. Deviations of 20.5°C from the normal operating temperature need to be included in the additional temperature error.
2. The instrument needs to be installed vertically, and try to keep it level with the measuring point. If the difference is too large, the additional error caused by the liquid column may not be taken into account when measuring the gas. During installation, the explosion-proof opening on the back of the box should be blocked to avoid affecting the explosion-proof performance.
3. The measurement range of the instrument in normal use: under static pressure, it does not exceed 3/4 of the upper limit of measurement, and under fluctuations, it does not exceed 2/3 of the upper limit of measurement.
