Closed loop piezoelectric membrane pump and flow control method thereof

Abstract

The invention discloses a closed loop piezoelectric membrane pump and a flow control method thereof. The closed loop piezoelectric membrane pump comprises a piezoelectric vibrator, a flow sensor, a piezoelectric pump basal body, a circuit control module, a liquid inlet valve and a liquid outlet valve, wherein the liquid inlet valve and the liquid outlet valve are used for controlling the motion direction of fluid; the piezoelectric pump basal body is provided with a pipeline and a pump cavity formed in the piezoelectric pump basal body; the piezoelectric vibrator, the liquid inlet valve and the liquid outlet valve are all mounted on the piezoelectric pump basal body; the flow sensor and the piezoelectric pump basal body are integrated into a whole structure; a flow filter is arranged between a microchannel and the liquid outlet valve; the fluid uniformly flows into the flow sensor through controlling the pressure of the fluid by the flow filter. The closed loop piezoelectric membrane pump is small in size, high in precision of driving the fluid, and good in machinability and consistency.

Description

technical field [0001] The invention relates to a micro precision piezoelectric pump in the field of microfluid transmission and control, in particular to a closed-loop piezoelectric film pump and a flow control method thereof. Background technique [0002] A micropump is a typical microactuator, which plays the role of the power source of the microflow pumping process in the microflow control system, and has a wide demand in the fields of biomedicine, fine chemical industry, and pharmaceutical research. In recent years, piezoelectric pumps that use piezoelectric elements (piezoelectric sheets or piezoelectric stacks) as transducers for fluid transmission have the advantages of simple structure, small size, light weight, large driving force, low leakage, short response time, With the advantages of low energy consumption, no noise, no electromagnetic interference, etc., it is widely used in various micro fluid drive fields. [0003] The piezoelectric pump relies on the defor...

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Problems solved by technology

This method indirectly obtains the driving flow by detecting the deformation of the piezoelectric vibrator has the following problems: first, the flow change caused by the leakage zone of the valve during the deformation of the vibrator cannot be detected; second, the installation stress and deformation of the piezoelectric vibrator itself will cause cause detection error

Before that, I proposed the method of integrating the flow sensor and the piezoelectric film pump (patent application number: 201210050805.8, 201220072514.4). Since the pulsation wave generated by the piezoelectric film pump is not filtered by the external pipeline, although the accuracy of the pump can be improved, the Experiments have proved that there are the following problems: firstly, the detection control algorithm is difficult to implement, and secondly, the detection accuracy is greatly affected by the working state of the pump

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