Pressure gauges are checked every year. In this case, it is established how the operating parameters of the device correspond to the declared characteristics. To perform this operation, many methods have been developed, among which the following are most widely used:
- using a hydraulic press;
- using a metrological stand;
- through the calibrator.
Each of them has both strengths and weaknesses. To begin with, we will consider the theoretical basis on the basis of which the manometers are calibrated, and then we will consider each of them individually.
Theoretical basis
Any modern science is based on comparison, and metrology in this regard is no exception. A pressure gauge is a device that measures pressure. According to the established rules, calibration of pressure gauges should be carried out every year. For example, the previous time this operation was performed in the first quarter of this year, which means that the next time it should be performed from January to March. Its essence lies in the fact that the readings of 2 devices are compared: our meter
pressure, which is checked, and the second, especially accurate. If the difference in values between them is insignificant, then the device is suitable for further operation. Otherwise, he is rejected and it is forbidden to work with him.
Press
In the first case, the calibration of the pressure gauge is performed on a special hydraulic press. It includes a set of weights, 2 manometers and the press itself. In the process of performing such an operation, pressure is created with the help of weights, it is transmitted to measuring instruments. For example, a load weighing 1 kilogram is set, then both devices should show this value taking into account the error. That is, a certain deviation is allowed. The medium used here is oil. This method cannot be used to check oxygen manometers; in all other cases, this method has proven itself well and is often used.
Stand
The following gauge calibration technique is very similar to the previous one. There are also two dial gauges. The pressure is provided by a special pump, then the readings are compared and on their basis a conclusion is made regarding the suitability or inoperability of a particular device. As a medium
air is used (that is, oxygen devices can also be checked).
Calibrator
This method differs from that described in the previous paragraph in that the calibrator is a mobile device. Therefore, in this way they check the measuring means in place. The pressure generator is the same pump that creates air pressure. But the manometer readings are compared with a special electronic meter with a high accuracy class.
Conclusion
Calibration of pressure gauges is an important operation, which allows not only to provide the necessary level of quality of technological processes, but also their high safety. The first method described is simple and reliable, but not always applicable. In the second way, most pressure gauges are checked today. If this operation can be done only at the installation site, then there is simply no alternative to the third option.