Two stage screw type vacuum pump with motor in-between the stages
AssigneeEbara Corporation
InventorsKiyoshi Yanagisawa, Kozo Matake, Yoshinori Ojima, Yasushi Hisabe
Life of this patent
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Abstract
A screw type dry vacuum pump having dual shafts is disclosed, whereby the process gas is transported through three compartments, a gas admittance pump section, a central drive motor section, and a gas discharge pump section. By placing the drive motor in the center of the pump, it becomes possible to design a pump having the dual shafts supported only at one end, thus enabling to mount the rotors at the free ends of the pump which are closed with end plates which can be removed easily for servicing the pump sections. Synchronous operation of the dual shaft pump by magnetic coupling enables to lower power consumption and to extend the range of operable pressures.
Claims9
A displacement type vacuum pump, having a pair of parallel drive shafts rotating in opposite directions within a casing, and a pair of screw rotor having screw threads thereon mounted on each of said drive shafts, said screw threads mating with each other for transporting and exhausting a gas trapped in a space formed by said casing, comprising:
- first pump section having a pair of drive shafts rotating in opposite directions within first casing, and a pair of screw rotors having screw threads thereon mounted on each of said drive shafts, said screw threads mating with each other for transporting and exhausting a gas trapped in said first casing;
- second pump section having a pair of drive shafts rotating in opposite directions within second casing, and a pair of screw rotors having screw threads thereon mounted on each of said drive shafts, said screw threads mating with each other for transporting and exhausting a gas trapped in said second casing;
- and a motor section mounted between said first pump section and said second pump section for driving said pair of drive shafts of said first pump section and said second pump section.
Dependencies are inferred from the claim text.