| 摘要 |
An objective of the present invention is to provide a vacuum pump having a driving and driven screw member that does not require complex machining and has a simple structure to allow a coolant to flow into a space between screw wings to cool the screw wings. The vacuum pump according to the present invention comprises: a coolant suction hole to connect a lower portion of a screw installation space to a coolant flowing passage in a casing; a check valve installed on the coolant suction hole to allow fluid to flow from the coolant flowing passage to the screw installation space only; and a shutoff valve installed on a gas suction hole to allow gas to flow in or shut off gas. When the shutoff valve shuts off, a space between screw wings progresses in a vacuum state from the suction hole to draw the coolant from the coolant suction hole. |
