JPS6483881A - Vacuum pump - Google Patents

Abstract

PURPOSE:To transfer heat to the vicinity of a gas discharge port form a stator via shaft sealing gas and prevent a reaction product from sticking thereto by installing a pipe line between the stator fixed to the inside of a housing and an upper case of the housing, and passing the shaft sealing gas through the inside of this pipe line. CONSTITUTION:A rotor 1 is driven by a motor 2, and, gas is inhaled out of an inlet port 3A and compressed while it is discharged out of a discharge port 3B. In this case, shaft sealing gas is inhaled out of an inlet 6A of an upper case 5 while being passed through a shaft seal pipe line 8 arranged in a space surrounded by a stator 4 and the upper case 5, and it is discharged out of an outlet 6B of the upper case 5. Afterward, the shaft sealing gas is injected into the rotor 1 from a filler hole 6C by way of a support 9, and then it is discharged out of the discharge port 3B. The shaft sealing gas is heated by heat of the stator 4 to be produced at the time of gas compression, while temperature in and around the discharge port 3B is raised. A reaction product is thus prevented from sticking to spots in and around the discharge port 3B.