| 摘要 |
<p>The pump has a pumping stage in which a gas to be pumped circulates between gas intake inlet and gas delivery outlet. The stage includes a stator (19) whose inner space is formed by an outer wall includes two root type rotors, where the rotors rotate in synchronized manner in inverse direction to drive the gas from the inlet towards the outlet. A drain duct has an inlet (41) connected to a drain fluid inlet and an outlet (43) emerging in the inner space of the stator. Guiding grooves (54, 55) for guiding the drain fluid are arranged in a front surface (49) of the stator.</p> |
