Vacuum pumps are devices that are used to remove gas molecules from sealed volumes, leaving behind a partial vacuum. Different pumps have different performances and this includes the pumping speed. Pumping speed is the rate flow per volume of the pump, at the inlet. However, the type of gas being pumped as well as its chemical composition will greatly determine the speed.

Generally, vacuum pumps may be categorized into three main techniques, depending on the principles used while pumping. The first one is the Momentum transfer, also known as molecular pumps. These use jets of dense fluids or high-speed blades that rotate and in the process eliminate the gas molecules in the chamber. The second type is the Positive displacement, which makes use of a simple mechanism. This includes expending a cavity repeatedly, which allows the gases to flow in from the chamber. The cavity is then sealed off and exhausted to the atmosphere. The third category is the Entrapment pumps, which capture gases in solid states.

vacuum pumps are just like any other air pump, only that it is used for sucking, instead of blowing. They are used in industries and even in hospitals and specific uses.