Patent ID: 6755611
Filing Date: 2004-06-29
Classification: F04D

Abstract:
A vacuum pump comprising:a casing having an inlet port and an inner wall portion gradually decreasing in diameter toward the inlet port; a rotor shaft mounted in the casing for undergoing rotation in a rotational direction about a rotational axis; exhaust means disposed between the rotor shaft and the casing for undergoing rotation with the rotor shaft about the rotational axis to discharge gas molecules which are taken in through the inlet port of the casing; a rotational member disposed between the inlet port and the exhaust means and mounted for undergoing rotation with the rotor shaft about the rotational axis, the rotational member having a generally conical-shaped surface gradually decreasing toward the inlet port; and a plurality of guiding blades disposed on the conical shaped surface of the rotational member for undergoing rotation with the rotational member about the rotational axis to impart an outward motion component in a radial direction to the gas molecules which are taken in through the inlet port, the guiding blades being disposed in the casing at a position corresponding to a space in the casing surrounded by the inner wall portion thereof.