| 摘要 |
PROBLEM TO BE SOLVED: To make an efficient operation at a safety temperature without using water by a method wherein a second vacuum pump inlet connection part of a rotary piston pump which is equipped with a cooling air inlet port for limited suction of outside air at atmospheric pressure and has a precooled inlet, is connected to an outlet of a first vacuum pump, and specified desorption pressure is generated with a vacuum pump stand. SOLUTION: Air is alternately fed to adsorption apparatuses 1, 2 connected in parallel with an air blower 3, and exhausted alternately from the adsorption apparatuses 1, 2. Then, for suction of a portion which is rich in nitrogen, vacuum pumps 13, 14 are provided, and a vacuum pump stand 12 generating a desorption pressure of 300 to 500 millibar is used. Simultaneously with opening and closing of generated matter send out valves 25, 26, an air valve 8 or an air valve 9 to be combined with the specific adsorption apparatus 1 or the adsorption apparatus 2 is opened, and connected to the vacuum pump stand 12. An outlet of the first vacuum pump 13 receiving compressed air cooled with an air cooler 32 from the air blower 3 is connected to an inlet of the second vacuum pump 14. Thereby, a cooling air inlet port of the pump 14 mixes cold air in suction air, and the operation can be carried out without using water with excellent energy efficiency. |
