Dry pump

Abstract

A dry pump comprising cylinders (31, 32, 33, 34, 35), pump chambers (11, 12, 13, 14, 15) respectively formed in the cylinders(31, 32, 33, 34, 35), partition walls (36, 37, 38, 39) each separating adjacent pump chambers (11, 12, 13, 14, 15) from each other, rotors (21, 22, 23, 24, 25) contained inside the pump chambers(11, 12, 13, 14, 15), rotor shafts(20a, 20b) which are the rotating shafts of the rotors (21, 22, 23, 24, 25), and refrigerant paths (38) formed inside the partition walls (36, 37, 38, 39) and allowing a refrigerant to flow therethrough.

Description

technical field [0001] This invention relates to volumetric displacement dry pumps. [0002] this application claims priority based on Japanese Patent Application No. 2008-263938 for which it applied on October 10, 2008, and uses the content here. Background technique [0003] A dry pump is used for exhaust. A dry pump has a pump chamber in which a rotor is accommodated in a pump body. A dry pump rotates a rotor in a pump body to compress and move exhaust gas, thereby decompressing and exhausting a closed space provided at a suction port (for example, refer to Patent Document 1). In particular, when exhausting to obtain a moderate vacuum or a good vacuum, a multistage dry pump is used in which a plurality of pump chambers are connected in series from an exhaust gas suction port to a discharge port (for example, refer to Patent Document 2). [0004] When the dry pump is running, the exhaust gas is compressed in the pump chamber to generate heat, and the temperature of the ...

AI Technical Summary

Problems solved by technology

As in the past, the structure that uniformly cools the entire pump body with a refrigerant etc. creates a temperature difference between the pump chambers, making it impossible to maintain a uniform temperature throughout the dry pump.

When a temperature deviation occurs inside the dry pump, there is a problem that the exhaust efficiency decreases due to local deformation and expansion of the dry pump.

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