Some important knowledge that must be mastered when using a pressure gauge.
If you don’t know the usage of the pressure gauge very well when you are using it, it should be difficult to guarantee its correct use. In many cases, its performance is very important to everyone’s usage, so I hope everyone will be able to use it. Strictly follow the correct method to operate, the following is some specific content.
The pressure gauge has reliable performance and good adaptability. At present, it is mainly used in petroleum, chemical, chemical fiber, dyeing, pharmacy, and soda food industries to complete the measurement of the pressure of various fluid media on the pressure gauge. Some pressure gauges are specifically used to measure the pressure of liquids and gases that are highly corrosive, high viscosity, easy to crystallize, easy to solidify, or high temperature.
In addition, for the measurement of the pressure of some media containing particulate solid floating matter, it is often necessary to use a pressure gauge for detection. When the pressure of the measuring medium acts on the diaphragm, the diaphragm is deformed and compresses the sealing fluid of the pressure gauge pressure measurement system. Therefore, for a certain stroke pressure, if the rigidity of the diaphragm is small enough, and P is also small, the pressure of the diaphragm pressure gauge formed by the pressure measuring system of the diaphragm pressure gauge can be regarded as equal to the pressure of the measuring medium.
1. Regarding the temperature characteristics of the pressure gauge:
Since the sealing liquid is used inside the pressure gauge, and the sealing liquid is a medium that transmits pressure, when the temperature changes, it will cause the volume of the sealing liquid to change. In this way, when the pressure of the medium is actually measured, It is often affected by temperature, especially for pressure gauges with small ranges.
2. Regarding the corrosion resistance of the pressure gauge:
In the actual measurement operation, some working environments of shock-resistant pressure gauges may be corrosive, or the measured medium is corrosive. Then, at this time, it is necessary to use a pressure gauge with corrosion resistance. As far as the table is concerned, its corrosion resistance can be ensured by appropriately selecting the materials of the diaphragm, flange, and sealing gasket in contact with the measuring medium.
3. Regarding the connection form of the pressure gauge and the equipment:
At present, when using pressure gauges, the connection methods mainly include three forms, namely threaded connection, flange connection, and sanitary interface.
Specific methods for judging the accuracy level of the pressure gauge.
The accuracy grade of the seismic pressure gauge is expressed as the percentage of the allowable error to the pressure gauge range. It is generally divided into seven grades: 0.5, 1, 1.6, 2, 2.5, 3, 4 (the boiler does not need 3 and 4 Level), the smaller the value, the higher the accuracy.
For example, for a pressure gauge with a precision of 2.5 MPa with a dial range of 0～2.5MPa, the allowable error between the pressure value indicated by its pointer and the actual pressure value of the measured medium shall not exceed 2.5MPa×2.5%=±0.0625MPa. When the pressure gauge indicates that the pressure is 0.8MPa, the actual air pressure is between 0.7375 and 0.8625MPa.
1. Selection of precision pressure gauge grades:
According to national regulations: the grading accuracy of the standard pressure gauge cannot be greater than one-third of the grading accuracy of the tested pressure gauge.
If the grade of the pressure gauge that needs to be calibrated is 1.6, then the grading accuracy of the standard pressure gauge should be less than 0.5-grade precision pressure gauge, and the country has clear regulations on the grading accuracy of precision pressure gauges, so choose 0.4 precision The pressure gauge is fine.
2. Selection of precision pressure gauge range:
Stainless steel pressure gauge.
The precision pressure gauge is a more precise instrument. When in use, try not to exceed two-thirds of the range of the precision pressure gauge.
If the pressure gauge level required for verification is 1.6, the range is 0-10 kg, and the pressure unit is converted to MPa, it is 1MPa, then the range of the selected precision pressure gauge is 1 divided by two-thirds, Equal to 1.5MPa, and there is no precision pressure gauge of 1.5Mpa in the standard range of the precision pressure gauge specified by the country, the precision pressure gauge of the similar range is selected, that is, 0-1.6MPa.
