Difference between an air compressor and a vacuum pump?

What is the difference between an air compressor and a vacuum pump? Vacuum pumps are equipment that is used to create a vacuum. By analogy with a compressor, the pump decreases rather than increases the air pressure. The reduction occurs due to the removal of gas molecules in a special chamber. It makes up the air with their subsequent removal from the system. Thus, the density of the air mass and the pressure of the remaining gas are reduced. The operation of a vacuum pump is to convert mechanical energy supplied to the rotation shaft into pneumatic energy. It does this by pumping out the air that is inside the system. The amount of work performed by this device is equal to the amount of evacuated air and the level of pressure drop.

Pump vs compressor

  • the air pressure indicator, which is measured at the suction line, is lower than atmospheric and tends to decrease at a high vacuum level;
  • the difference between atmospheric and created pressure at the vacuum pump does not exceed 760 mm. mercury column, and for compressor equipment, this indicator ranges up to hundreds of atmospheres;
  • as the vacuum increases, the supplied amount of air decreases, as well as the pressure, while for the compressor, these indicators are constant;
  • when the vacuum increases, all the heat that is released as a result of operation is distributed inside the device, and there are no problems with its removal, unlike a compressor.

Sometimes, not one but two similar devices are used to create a vacuum. Auto mechanics use air compressor vacuum pump to get a maximum result. It is done to reduce the energy consumption for this work. For example, the air pressure in the first pump decreases to a particular value. Then this air is pumped into another pump, say a diaphragm pump. Due to a deeper vacuum, a significant decrease in pressure occurs.