Abstract: Method for increasing the smoothness of the free surface area of a PFA film, provided on a component by sequentially exposing it to a temperature higher than its melting temperature so as to melt at least the free surface area, lowering the temperature to solidify the melted portion, remelting the free surface area by exposing it to a temperature of at least the PFA melting temperature and again lowering the temperature. The PFA film may be provided on Al2O3, Ni or NiF2 film.

Abstract: Method for increasing the smoothness of the free surface area of a PFA film, provided on a component by sequentially exposing it to a temperature higher than its melting temperature so as to melt at least the free surface area, lowering the temperature to solidify the melted portion, remelting the free surface area by exposing it to a temperature of at least the PFA melting temperature and again lowering the temperature. The PFA film may be provided on Al2O3, Ni or NiF2 film.

Abstract: There is provided a gas exhaust pump system capable of suppressing the inclusion of a seal gas into a process gas. The gas exhaust pump system has a main and sub pumps. The main pump has a screw rotor, a rotating shaft, a holding unit, a lubricating oil supply path, a seal housing for covering a periphery of a non-held portion by the holding unit with a predetermined gap formed with an outer periphery of the rotating shaft, a seal member interposed between the rotating shaft and the seal housing, a seal gas supply path for supplying a seal gas to the gap, and a seal gas exhaust path for exhausting the seal gas from the gap to the outside of the main pump. The sub pump is configured to reduce a pressure in the seal gas exhaust path.

Abstract: In a gas exhaust pump, there is provided a rotation mechanism that can ensure safe rotation and can greatly reduce the usage of a seal gas. A rotation mechanism of the present invention is formed of a rotating shaft and a seal housing. Between the rotating shaft and the seal housing, there is provided a predetermined gap. On at least one of an outer surface of the rotating shaft and an inner surface of the seal housing, there is provided a PFA film. As to a PFA film on a surface of at least one of the rotating shaft and the seal housing, after coating with PFA the wall surface of the rotation mechanism member defining at least the gap, followed by melting and remelting processes, the PFA film is formed to have a high smoothness on its free surface.

Abstract: There is provided a stator that can ensure safe rotation even if a width of a gap between a screw rotor and a stator is particularly smaller than that of a conventional one and can greatly increase a pumping performance of a pump. A stator of the present invention is formed of a metal and a PFA film is provided on an inner wall surface of a top end surface of a screw rotor. After coating the inner wall surface with PFA, followed by melting and remelting processes, the PFA film is formed to have a high smoothness. The stator is placed with a gap between the inner wall surface and the top end surface. If the PFA film of the present invention is provided in a predetermined manner, the width of the gap can be made significantly smaller than that of a conventional one.

Abstract: There is provided a screw rotor that can ensure safe rotation and can greatly increase a pumping performance of a pump. The screw rotor is placed with a gap between a top end surface of a tooth of a screw portion and an inner wall surface of a stator. A PFA film is provided on the top end surface. If the PFA film of the present invention is provided in a predetermined manner, the width of a gap between a free surface of the PFA film and the inner wall surface of the stator can be made significantly smaller than that of a conventional one, so that the pumping performance is greatly improved. After coating at least the top end surface of the screw rotor with PFA, followed by melting and remelting processes, the PFA film is formed to have a high smoothness on its free surface.