| 摘要 |
<p>A vacuum pump (10) includes a pump casing (56) having an inlet port (54a), an outlet port (54b), and pump chambers (50a-50f) defined therein, rotational shafts 60 having opposite ends rotatably supported by bearings (84a, 84b) on the pump casing (56) and extending longitudinally in the pump casing (56), and rotors (62a-62f) housed in the pump chambers (50a-50f) and coupled to the rotational shafts (60) for rotation in unison with the rotational shafts (60). The pump casing (56) has an atmosphere-vented compartment (52) defined therein which is held in fluid communication with the outlet port (54b) of the pump casing (56) and vented to the atmosphere.</p> |
