Rotary oil pumps are mechanical transport pumps. These pumps are widely used in many industries and are still most widely used vacuum pumps for good performance / price along with other useful features. Rotary oil pumps are produced in a wide range of pumping speeds from 1.5 m3 / h up to 1000 m3 / h. Depending on the application, they are designed with different pressure limits - typically from 0.5hPa to 0.001hPa. The rotary oil pump is used as the primary pump of the vacuum system. It can pump directly from the atmosphere and in conjunction with other types of pumps can be used to pump large volumes and to achieve high vacuum. The disadvantage of this type of vacuum pump is the possibility of back leakage of oil vapor into the vacuum equipment.
The base of the pump construction is hausing with eccentric bedding of a rotor with rotating blades. The pumps have either one-stage - a single-stage version or two stages - double-stage version. When the rotor rotates, molecules are transported from the input to the output and the gas is gradually compressed. The compressed gas is blown through the output valves through which a certain amount of oil gets into the system to lubricate the friction surfaces between the hausing and the rotor and between the blades and the hausing. The gas-ballast function is used for pumping of the condensable vapours. The oil filling of the pump is chosen according to the application from mineral oils to PFPE with regard to the nature and aggressiveness of the pumped gases.