How is the vacuum calculated?
There are usually two methods for the identification of the degree of vacuum, one is to identify with absolute pressure (ie: absolute vacuum), and the other is to use relative pressure (ie: relative vacuum). The so-called "absolute pressure" means that the vacuum pump is connected to the detection container. After sufficient time has been continuously pumped, the pressure in the container does not continue to decrease and maintains a certain value. At this time, the gas pressure value in the container is the absolute pressure of the pump. If there is absolutely no gas in the container, the absolute pressure is zero, which is the theoretical vacuum state. In the actual case, the absolute pressure of the vacuum pump is between 0 and 101.325 KPa. The absolute pressure value needs to be measured with an absolute pressure meter. At 20 ° C and altitude = 0, the initial value of the meter is 101.325 KPa. In short, the air pressure identified by reference to "theoretical vacuum" is called "absolute pressure" or "absolute vacuum." The "relative vacuum degree" refers to the difference between the pressure of the object to be measured and the atmospheric pressure of the measurement site. Measured with a conventional vacuum gauge. In the absence of a vacuum, the initial value of the table is zero. When measuring vacuum, its value is between 0 and -101.325 KPa (generally expressed as a negative number). For example, a measured value of -30 KPa means that the pump can draw a vacuum of 30 KPa lower than the atmospheric pressure at the measurement site. The same pump is measured at different locations, and the relative pressure values may be different because the atmospheric pressures at different measurement locations are different, which is caused by different objective conditions such as altitude and temperature. In short, the air pressure identified by reference to "measuring location atmospheric pressure" is called "relative pressure" or "relative vacuum". The most common and scientifically important in the international vacuum industry is the use of absolute pressure marking; it is also widely used because of its simplicity in measuring relative vacuum, measuring instruments being very common, easy to buy and inexpensive. Of course, in theory, the two can be converted to each other. The conversion method is as follows: absolute pressure = air pressure at the measurement site - absolute value of relative pressure.
The industrial application of water ring vacuum pump is getting wider and wider, and the development trend is increasing
Horizontal vacuum belt filter operating procedure
