Pump

Abstract

The invention provides a pump with high driving efficiency in which the number of mechanical switching valves is decreased to reduce pressure loss and increase reliability, and which is ready for high load pressure and high-frequency driving, and which increases the discharged fluid volume for one cycle of pumping. A circular diaphragm 5 arranged on the bottom of a casing 7 has the outer edge fixed to the casing 7. The diaphragm 5 includes a piezoelectric element 6 to move the diaphragm on the bottom surface thereof. The space between the diaphragm 5 and the top wall of the casing 7 serves as a pump chamber 3, wherein a suction channel 1 and a discharge channel 2 are opened to the pump chamber, the suction channel having a check valve 4 serving as a fluid resistive element and the discharge channel being always communicated with the pump chamber, even during the operation of the pump. In the pump, the activation of the piezoelectric element is controlled by a cycle control device so as to provide the cycle of the diaphragm in which the volume and the pressure of the discharged fluid of the pump are increased.

Description

technical field [0001] The present invention relates to a positive displacement pump which moves a fluid by changing the volume of a pump chamber by a plunger or a diaphragm, and more particularly relates to a pump with high reliability and a large flow rate. Background technique [0002] As a conventional pump of this type, a structure in which a check valve is provided between an inlet passage, an outlet passage and a volume-variable pump chamber is generally adopted. [0003] (For example, refer to Patent Document 1) [0004] In addition, as a pump structure for forming unidirectional flow by utilizing viscous resistance of fluid, there is a structure in which a valve is provided in the outlet passage, and when the valve is opened, the inlet passage has a higher fluid resistance than the outlet passage. (For example, refer to Patent Document 2) [0005] In addition, as a pump structure that improves the reliability of the pump without using a movable member in the valve...

AI Technical Summary

Problems solved by technology

[0010] However, there is such a problem in the structure described in Patent Document 1: check valves need to be installed in both the inlet passage and the outlet passage, and there will be a large pressure loss when the fluid passes through the two check valves.

However, in the structure described in Patent Document 2, there is a problem that it is difficult to realize a small and high output pump because it can only be driven at a low frequency as described above.

[0013] The structure described in Patent Document 3 has such a problem: in order to form a net flow rate of the fluid passing through the compression part in one direction due to the difference in the pressure drop caused by the direction of the liquid flow as the volume of the pump chamber increases and decreases, the flow rate increases with the pump outlet. The external pressure (load pressure) on the side increases, and the reverse flow increases, so that the pump cannot work under high load pressure

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