| 摘要 |
PURPOSE:To prevent thrust force from occurring as well as to make high-speed rotation performable in an easy manner, by making the transfer directions of gas to be transferred by two-paired screws with each other. CONSTITUTION:A sense of movement of gas to be led into a compression chamber P1 from a suction port 42 and a sense of movement of gas to be led into another compression chamber P2 from a suction port 43 are made into the sense opposed with each other. Therefore, the pressure inside both compression chambers P1 and P2 is symmetrically set up with each other in consequence so that thrust force to produced in both paired screws is offset with each other so that generation of the thrust force is prevented. Therefore, high-speed rotation is thus attainable without complicating a structure of bearings and the like.
|
