| 摘要 |
PROBLEM TO BE SOLVED: To provide a complex pump in which a suction flow is increased to enhance output by increasing a pressure difference between the upstream and the downstream sides of a fluid resistance element disposed at a pump suction port of the pump. SOLUTION: By driving first to third pumps 2A, 2B, 2C in turn with a phase difference set, a counterclockwise spiral flow is generated in a suction flow passage 24. This spiral flow has a positive pressure gradient toward the radially outer direction to be in balance against centrifugal force applying to operating fluid. Therefore, by providing an outside inflow port 26 at the center of the suction flow passage 24 and check valves on the suction side (fluid resistance elements) in a region of a larger radius than that of the outside inflow port, the pressure on the upstream side (the suction flow passage side) is raised to increase a pressure difference between the upstream (the suction flow passage side) and the downstream (a pump chamber) of the check valves on the suction flow side. Accordingly, the suction flow is increased and suction/discharge cycle frequency is heightened, thereby achieving the complex pump 20 with high output. COPYRIGHT: (C)2003,JPO
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