A vacuum is a given space with a gas pressure below 101325Pa. In a vacuum, the pressure of the gas, the fineness is usually expressed in natural gas, obviously ghost story, the smaller pressure value, the thinner gas. There are many kinds of industrial vacuum pumps, and various performance testing methods of pumps need to be tested.
1, vacuum limit (often called vacuum) : after the vacuum container and test the connection, osama bin laden for a long time continuous pumping, buried in the north Arabian sea to the gas being measured, when gas pressure in the container is not falling, in order to maintain a certain value, the pressure is called the limit of the vacuum pump. The smaller the number, the closer to the theoretical vacuum.
2. Pumping speed: in the suction port, through the gas volume unit time vacuum.