To provide a vacuum pump in which the operation is automatically stopped when the vacuum pressure becomes higher than the set vacuum pressure, and the operation is automatically started when the vacuum pressure becomes lower than the set vacuum pressure.
The insides of pistons 10a, 10b to be reciprocated in cylinders 9a, 9b on both sides of a main body block 2 are taken as vacuum chambers 12a, 12b, the outsides thereof are taken as driving chambers 13a, 13b, the vacuum chambers are communicated with an inlet port 6 for sucking air in a vacuum pressure chamber 5 through inlet check valves 15a, 15b, and they are communicated with an outlet port 7 for air through outlet check valves 16a, 16b. When driving fluid is supplied to and discharged from the driving chambers from a supplying port 3 for driving fluid through a governor 18 and a selector valve 17, the pistons are reciprocated, and pressure in the vacuum chamber is lowered to make vacuum pressure. When the vacuum pressure of the inlet port 6 becomes higher than set vacuum pressure set by the governor 18, supply of driving pressure fluid to the driving chambers is shut off by the governor 18, and a vacuum pump 1 is automatically stopped, on the other hand, when the vacuum pressure becomes lower than the set vacuum pressure, driving pressure fluid is supplied to the driving chambers by the governor 18, and the operation is automatically started.
YAMAJI MIKIO
FUKAMACHI KOICHI
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