Working principle: The rotor is installed in the pump chamber and rotates in the pump chamber. The rotor can extract, compress and discharge the pumped medium. The pumped medium is trapped between the pump cavity and the rotor, forming a closed cavity. The volume difference is used to achieve suction and exhaust between all levels, thus forming a vacuum negative pressure. During the compression process, the two rotors do not contact the pump cavity, so no lubricant or working fluid is required in the compression cavity.