Vacuum pressure gauge working principle and use precautions

Vacuum pressure gauges are based on atmospheric pressure and are used to measure instruments that are less than atmospheric pressure. The vacuum pressure gauge is used to measure the negative pressure of non-crystalline and non-solidified liquids and gases that are not corrosive to steel, copper and copper alloys, and have no danger of explosion. It is widely used in the measurement of vacuum degree in petroleum, chemical, metallurgy and other industrial processes.

Working principle of vacuum pressure gauge

The working principle of the vacuum pressure gauge is that the pressure of the medium acts directly on the diaphragm of the sensor, causing the diaphragm to produce a micro displacement proportional to the pressure of the medium, so that the resistance of the sensor changes, and the electronic circuit detects this change and converts it. A standard signal corresponding to this pressure is output.

Vacuum manometer range

The vacuum pressure gauge range is -0.1MPa~0.

How to select the range of the pressure gauge:

1. When using a pressure gauge to measure stable pressure, the maximum working pressure should not exceed 2/3 of the range;

2. Use a pressure gauge to measure the pulsating pressure, and the maximum working pressure should not exceed 1/2 of the range;

3. When using a pressure gauge to measure high pressure, the maximum working pressure should not exceed 3/5 of the range. In order to ensure the measurement accuracy, the minimum working pressure should not be lower than 1/3 of the measuring range. According to this principle, after calculating a value according to the measured maximum pressure, select a measurement range slightly larger than this value from the product catalog of the pressure gauge.

4. It should be selected according to the working pressure of the boiler. The limit value of the scale range should be 1.5~3.0 times of the working pressure, preferably 2 times.

Air pressure vacuum fuctions

There are many kinds of vacuum pressure gauges. Most of the functions of vacuum pressure gauges are two aspects, one is to measure the pressure of the fluid in the container or pipeline, and the other is to measure the degree of vacuum. It should be noted that the vacuum pressure gauge also has a certain measurement range. Under static pressure, it does not exceed 3/4 of the upper limit of measurement, and under fluctuations, it should not exceed 2/3 of the upper limit of measurement. When measuring vacuum, all the vacuum part is used.

How to use a vacuum pressure measurement?

Install the valve on the pressure point on the pipeline or vacuum pump, and then install the vacuum gauge on the valve. The other end is connected to the equipment that needs to be evacuated. Open the valve and start the vacuum pump. At this time, the pointer of the pressure gauge swings counterclockwise, shifting from the 0 scale to the -0.1 direction. The pointer is at -0.1, which is close to vacuum, but not equal to vacuum.

The outer ring reads in red, corresponding to the red unit PSI. The inner circle is read in black, corresponding to the black unit MPa. Turn off the vacuum pump for a period of time, the pointer does not shift, and it can be used normally.

Precautions for the use of vacuum pressure gauges

1. The meter must be vertical: use a 17mm wrench to tighten it during installation, and the case should not be twisted; collisions should be avoided during transportation;

2. The instrument should be used in the ambient temperature of -25~55℃;

3. The vibration frequency of the working environment is less than 25HZ, and the amplitude is not more than 1mm;

4. During use, due to the high ambient temperature, the indication value of the instrument does not return to zero or the indication value is out of tolerance, the sealing rubber plug on the upper part of the case can be cut off to make the inner cavity of the instrument communicate with the atmosphere;

5. The use range of the instrument should be between 1/3 and 2/3 of the upper limit;

6. When measuring corrosive media, media that may crystallize, and media with high viscosity, an isolation device should be added;

7. The instrument should be checked frequently (at least once every three months), and if any fault is found, it should be repaired in time.