Selection of Pressure Gauges (2)

5. Liquid filling

We have found in some environments with high mechanical vibrations that many pressure gauge dials are filled with liquid. In fact, the main function of these liquids is to increase resistance, effectively preventing the pointer of the pressure gauge from constantly vibrating, so that we can accurately read the pressure value. Usually used near pumps or in environments with severe vibrations.

6. Medium temperature

The maximum measurement medium temperature for copper alloy measuring elements is+60 degrees Celsius, while for stainless steel, it is+200 degrees Celsius; But if you choose a liquid filled shock resistant pressure gauge, the maximum temperature of the medium at this time can only reach+100 degrees; If the temperature is too high but it also needs to be shockproof, the method we use is a condenser tube.

7. Range range

Due to the fact that the pressure gauge displays the pressure value by measuring the deformation of the component and driving the pointer to rotate through an amplification mechanism, we should also pay attention when selecting the measurement range. The size of the upper limit value for pressure gauge measurement is designed based on the outer dimensions, stiffness, and nonlinear conditions of the spring tube. There are five series of upper limit values: 1 * 10n 1.6 * 10n 2.5 * 10n 4 * 10n 6 * 10n, where n is a positive integer, a negative integer, or zero. The accuracy of pressure gauges below 1/3 of the range is low and should not be used. When selecting the upper limit of measurement, in order to ensure the safe and reliable operation of the pressure gauge and maintain its service life, it should generally be greater than 1/3 of the maximum working pressure gauge. When selecting the range of use, according to the universality of load conditions, it is advisable to choose full range 1/3-2/3, because this range of use has high accuracy and can be used under both stable and fluctuating loads. The maximum range of use shall not exceed 3/4 of the full scale of the dial.

8. Connection size

Nowadays, due to the different thread standards in various countries, the main commonly used ones are M (metric system), G (British system) NPT (American system), R (more commonly used in Japan and South Korea), and so on.

9. Special instrument identification

When measuring special media such as viscosity or acid-base, stainless steel spring tubes, stainless steel movements, stainless steel shells, or phenolic shells should be selected. According to the different media tested, there should be a specified color code on the pressure gauge, and the name of the special medium should be indicated. For example, the oxygen gauge must be marked with the words "oil prohibited" in red.

Summary:

5. Liquid filling We have found in some environments with high mechanical vibrations that many pressure gauge dials are filled with liquid. In fact, the main function of these liquids is to increase resistance, effectively preventing the pointer of the pressure gauge from constantly vibrating, so that we can accurately read the pressure value. Usually used near pumps or in environments with severe vibrations.

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Time:

2023-06-29

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