| 摘要 |
PROBLEM TO BE SOLVED: To provide an ejector type vacuum pump capable of reducing an amount of cooling fluid to be supplied, by increasing heat radiation of circulated fluid.SOLUTION: An ejector type vacuum pump is composed of an ejector 1, circulation passages 2, 5, a liquid force-feeding pump 3, and a tank 4 disposed in the circulation passages 2, 5. The tank 4 is formed into the double cylindrical shape, and provided with an atmospheric air contact space 10 at its central portion. The atmospheric air contact space 10 is a cylindrical space penetrating through between upper and lower portions of the tank 4. By providing the tank 4 with the double cylindrical shape, and forming the atmospheric air contact space 10 kept into contact with the atmospheric air at a surface of the tank 4, at the central portion, a surface area of the tank 4 is increased, and an amount of heat radiation from th surface of the tank 4 to the atmospheric air is increased, thus an amount of the cooling fluid supplied to the tank 4 can be reduced. |
