Pressure gauges are now a vital measurement instrument in the safety production of enterprises because the parameters provided by the pressure gauge are directly related to important factors in production safety.
In natural gas pipeline transmission, the correct reading of the pressure gauge provides a certain degree of convenience to the station staff. However, as the pressure gauge ages, damage of varying degrees occurs in daily production.
We have analyzed the damage to the gauges through our work experience. A part of the damage to the pressure gauge is from the manufacturer’s quality problems. Another injury is caused by incorrect operation of the pressure gauge in the use process.
For this reason, we should correctly choose the correct pressure gauge and the operating procedures. We should also make the pressure value test more accurate in the process of use so that the life of the pressure gauge can be longer.
1. Causes of damage to pressure gauges
1.1 Quality problems
To obtain maximum profit from them, manufacturers use saving material costs and reduce labor costs in the manufacture of pressure gauges to reduce the manufacturing cost of pressure gauges. Thus, in the sale of pressure gauges to reduce the price to seize the market.
As material selection costs are reduced, labor costs are reduced, and other means, the manufactured pressure gauges will have various quality problems. The following issues generally occur when purchasing new pressure gauges.
1.1.1 Unqualified external quality
Qualified pressure gauges are generally selected from stainless steel, aluminum die castings and materials of even greater strength. However, such parts are more robust and complex, not easy to deformation, corrosion resistance strength, and other advantages.
Now to save costs, the choice of stainless steel and other materials are becoming thinner and thinner while also using lower-cost materials to replace, resulting in the pressure gauge now having much lower strength, shell deformation, etc.
This pressure gauge shell by a slightly larger external force, corrosive media will appear shell deformation, pressure gauge glass broken, shell corrosion and other severe cases.
1.1.2 Internal components quality problems
Spring pressure gauge internal components generally have a spring tube, tie rod, sector gear, main gear, pointer, dial, hairspring, and other organizations.
Due to cost reduction, the diameter of the spring tube is reduced, the wall becomes thin, and the material strength needs to be more. Therefore, it seriously affects the accuracy of the pressure gauge measurement. In addition, when the material selected for the movement decreases, the wear of the gears will increase, and the chance of damage will rise.
The quality of the dial causes the scale to be inaccurate, etc. A decline in the internal components’ quality directly affects the pressure gauge’s measurement accuracy. However, many pressure gauges can meet the process error requirements. However, when the pressure gauge reaches the limit of use, it will cause the pressure to exceed the load for a long time, resulting in damage to the indicator.
1.2 Causes of damage in use
1.2.1 Problems with the purchase of pressure gauges
When choosing the pressure gauge range, we should select a range that exceeds the operating capacity to reduce the chances of causing damage to the pressure gauge.
Pressure gauges are used in more corrosive liquids and gases in the field environment caused by severe corrosion. The internal components of the pressure gauge will appear to be deformation and damaged.
1.2.2 Problems in installation and dismantling
For accurate daily measurement of pressure gauges, we should calibrate them once every six months. During the calibration, we have to dismantle and install the pressure gauge.
When the pressure gauge is dismantled, the pressure gauge is relatively tight, and the dismantler is accessible to use brute force to disassemble it, which will cause damage to the threads at the pressure gauge connection.
In the installation process, the pressure gauge is pressed relatively quickly, significantly impacting the pressure gauge bellows and damaging it during the gear impact.
1.3 Problems with pressure gauges in operation
The pressure fluctuations of many pressure gauges are relatively large, causing the pressure gauge bellows to be prone to deformation and fracture, etc.
In pressure gauges, many pressure gauge seals age, causing water to enter the meter. After water ingress, the internal gears and bellows of pressure gauges become corroded. The degree of corrosion caused by the seriousness of the pressure gauge inaccurate measurement will also cause the pressure gauge bellows rust, and severe deformation can not be regular measurement use.
Many pressure gauges in the operation of the root valve at the emergence of sewage and other impurities. The presence of sewage and contaminants causes internal corrosion of the pressure gauge. At the same time, in winter operation, the pressure gauge is easy to cause freezing, causing the root of the pressure gauge to appear cracks and other phenomena.
2. Methods to reduce damage to pressure gauges
2.1 Quality requirements
When we buy pressure gauges, we must strictly control the quality and buy the brand and reputation of better pressure gauges as far as possible.
2.2 Correct model selection
We should choose the correct model according to the demand, the installation location and installation method of the site, and the connection method of the pressure gauge connector on the pressure gauge model chosen.
The installation direction of the pressure gauge is axial or radial, a pressure gauge with special requirements, or a standard pressure gauge.
2.3 Regular calibration
We should follow the requirements of the pressure gauge to be regularly calibrated, generally once every six months.
In the process of pressure gauge inspection, when dismantling the pressure gauge, we should pay attention to the operating procedures of the pressure gauge. In the pressure gauge pressure relief, our operation should be slow. When installing, we should follow the pressure gauge installation procedures. When stamping, we should stamp slowly.
2.4 Installation requirements
The pressure gauge should be installed in the surrounding environment -40 ~ 70 ℃, relative humidity is not more than 80%, and an altitude of less than 2000m. As the surrounding temperature increases or decreases, the error of the pressure gauge will become more prominent, so the pressure gauge is generally installed in the place of 15~25℃. If the temperature of the measured medium exceeds the use range of the pressure gauge, we should take appropriate measures to isolate it.
If the pressure gauge is installed in a vibrating pipeline, we should choose the anti-vibration pressure gauge as far as possible or take the corresponding preventive measures. On the other hand, if the pressure gauge is installed on a pipeline with significant impulses, we should choose a seismic pressure gauge, or increase the pressure lead pipe, buffer, etc.
Without affecting the premise of the use of the pressure table, we try to reduce the distance between the measured medium and the pressure table, the inner diameter of the pressure-led pipe, and the inner diameter of the pressure table as much as possible to prevent the actual value of the measured medium from being retarded and inaccurate.
2.5 Strengthen maintenance
We should strengthen the daily maintenance of the pressure gauge, regular inspection of the pressure gauge easy to corrode parts, for the measured medium corrosive strong isolation.
In pressure gauge maintenance, we should regularly carry out drainage. Mainly the surface of the pressure gauge is wiped, and the pressure gauge guide tube is regularly unblocked and purged periodically to prevent dirt blockage leading to inaccurate measurement. Strengthen the tour inspection, find the problem immediately take corresponding measures to ensure the accuracy of the pressure gauge measurement.
As an essential device for the detection of pressure values in the operation of production equipment, the accuracy of the measurement directly affects production safety. Therefore, relevant personnel should recognize the importance of daily maintenance and calibration of pressure gauges and develop appropriate measures in accordance with users’ requirements to increase pressure gauges’ service life.