| 摘要 |
Since many valves are used, pressure loss is large, resulting in low reliability of a pump. Even when the period of increasing and decreasing the volume of a pump chamber is long, and a piezoelectric element is used as an actuator that drives a diaphragm, a driving operation cannot be performed at a high frequency, or a proper flow rate cannot be realized under a high load pressure. In accordance with the invention, the combined inertance value of an entrance passage used to make working fluid flow into a pump chamber is smaller than the combined inertance value of an exit passage used to make the working fluid flow out from the pump chamber. A fluid resistance member is provided at the entrance passage in which fluid resistance when the working fluid flows into the pump chamber is smaller than fluid resistance when the working fluid flows out of the pump chamber.
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