| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent each rotor from being fixed to a housing through ices frozen in a low-temperature environment.SOLUTION: In the wall surface of a housing chamber 17 constituting a suction area Z10 in a first end surface 17a and the wall surface of the housing chamber 17 constituting a discharge area Z20 in the first end surface 17a, rough surface parts 172a, 173a are formed respectively. Consequently, since water condensed in the suction area Z10 and discharge area Z20 is easily subjected to water retention by the rough surface parts 172a, 173a, the water condensed in the suction area Z10 and discharge area Z20 is prevented from flowing to a first rotation area Z1 and a second rotation area Z2.</p> |
