| 摘要 |
PURPOSE:To make a good efficiency obtainable, with a state of overcompression and reverse flow compression prevented at the full operation vacuum, by means of installing an elastically flexible plate-shape valve unit, big enough for fully enclosing delivery ports, to the air in-out cylinder of the pump. CONSTITUTION:As a degree of vacuum increases after operating the pump, an elastically flexible plate-shape valve unit 10, installed to an air in-out cylinder 6 and big enough for fully enclosing delivery ports 5...., is going to close the delivery ports 5 from the lower stage, that is, successively in the order of 5a, 5b, 5c..., and, when reaching the prescribed degree of high vacuum, closes all delivery ports 5 except the delivery port 5e at the topmost stage, or closes, with a delivery port 5 at the top stage near the topmost delivery port 5e only excepted, the lower stage delivery ports 5 than said port. In this way, the plate-shape valve unit 10, functioning to open the delivery port 5 only required and to close the rest, can prevent the pump from overcompression and reverse flow compression, thus capable of obtaining a good pump efficiency. |
