PURPOSE: To enable continuous operation without using lubricating oil by operating a vacuum pump when a discharge pump dischares water, and cooling frictional heat in a slidably movable part of the vacuum pump while introducing outside air when the discharge pump is evacuated into vacuum for priming of water. ;CONSTITUTION: When a discharge pump is operated, since an eccentric shaft 2 rotates inside of a casing 1 through a pulley 4, a vane 5 of a rotor 3 projects, and the inside of the casing 1 is put in a pressure reduced condition. As a result, the inside of the discharge pump is evacuated into vacuum for priming of water, and water discharge is started. At the same time, since outside air is sucked from plural air intake ports 9 and is introduced into clearances between the rotor 3 and both end plates 1a and 1b, frictional heat is cooled by these sliding motion. Thereby, a temperature rise caused by frictional heat of a vacuum pump is restrained without using lubricating oil, and the vacuum pump is operated for required time to conduct sufficient priming for the discharge pump. Pollution by the lubricating oil can be also eliminated.;COPYRIGHT: (C)1994,JPO&Japio
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