| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a turbo dry pump which requires neither to upsize a dynamic pressure gas bearing nor to provide a cooling system for the bearing. SOLUTION: A communicating passage 7 is provided outside a pump housing 1 for communication between an inlet 1K and an outlet 1H of the turbo pump mechanism and is provided with an open/close valve 8 for opening and closing the passage. Fore and aft differential pressure of the turbo pump mechanism can be adjusted so as not to become equal to or higher than a specified pressure through the operation of this open/close valve 8. This open/close valve also serves as a regulating valve 8V, and a drive mechanism 16 is provided for driving the regulating valve 8V based on a signal output from an inverter circuit 11 controlling the rotation of a rotor 2, a main component of the turbo pump mechanism. Accordingly, the communicating passage is automatically opened and closed according to the rotational speed of the rotor 2, and an axial load on the rotor 2 can be adjusted to within an acceptable load of a foil bearing 5.</p> |
