| The structure of Double-actuator Piezo-pump is the simplest among the multi-actuator Piezo-pumps.It is very important to analyze the performance influence of the Double-actuator Piezo-pump, optimize the structure size,design a Double-actuator Piezo-pump with good output performance,offer a effective method for the turbulence of the liquid in the multi-actuator Piezo-pumps.The piezo-pump research has more than twenty years history,so it has a tremendous progress,such as the Co. thinXXSGmbH in Germany and Co.SIMI in Japan already have had products in market. As for the domestic research condition, related research of piezo -pump started lately, there is no products. By reading large numbers of papers and author's experience on the research, the research of the Piezo-pump overseas focus in the single-actuator single cavity pump, especially focus in the minisize Piezo-pump. In China,the research of the multi- actuator Piezo-pumps is developing based on the research of the single actuator Piezo-pumps.The two main development directions are below:one is the exact Piezo–pump,which is productd by the Micro-Processing technology,with the flux 10μl/min～10ml/min,mainly used in the chip laboratory, micro-analysis system, biomedical engineering(such as microinjected, disease examination analysis),even at unicellular monitor which need the flux at pl(1 pl=1/1,000,000,000,000L);the other is the big flux pump with the flux more than 1000 ml/min, the out press at 10～100kPa,and it can replace the traditional pump or used in situsituation that the traditional pump can't work, such as fuel battery supply, motor fuel supply, cooling of the chip. Moreover, for the Piezo-pump, beside pumping the low viscosity liquid such as water, the pumping high viscosity liquid or gas was no reported, this is very important in the future research.Based on the research of the design theory and structure optimization of the Double-actuator Piezo-pump , the author engaged some work below:1.Research of vibration characteristic of Piezoelectric actuatorIn order to predict the output performance of the Double-actuator Piezo-pump,in the situations of ignoring the influence of the glue line to the piezo-pump, establishing libration equation of circular piezoelectric actuator and cubage variety equation of cavity. The theory result indicate that establishing libration equation of circular piezoelectric actuator and cubage variety equation of cavity relate to the size of the actuator, performance parameter d 31of the ceramic wafer, driving voltage U. The result indicate that Drived by effective voltage 110V, the amplitude of center of ? 35mm single-actuator is 20.2 ?m ,the cubage variety of cavity is ?V =1.43x10-8m3;the amplitude of center of ? 35mm double-actuator is 50.49 ?m ,the cubage variety of cavity is ?V '=3.6x10-8m3 . Then, this thesis prove the theory derivation by static and dynamic test on the the amplitude of center.2.Research of design and work characteristic of check valveCheck valve is the key component which confirm the output performance of the piezo-pump ,the development of the check valve promotes the development of piezo-pump. Membrane valve is very popular for its simple structure, easy to open, high response frequency. According to the characteristic of the piezo-pump , the author designs and products three kinds of cut-off valves, cantilever valve, spiral plate valve, umbrella-shape rubber valve, analysised overflowing property and critical working conditions of the check valve.The experimentation show that the three kinds of valve start to work when the press reach 0.2kPa. The flow capacity of the umbrella-shape rubber valve is the best, those of cantilever valve is the worst.when set the three kinds of valves into the same structure of piezo-pump, self-absorbing capacity of the umbrella-shape rubber valve piezo-pump.is the best,those of cantilever valve piezo-pump is the worst.Then,did the simulation analysis of umbrella-shape rubber valve by the software ANASYS.3. Structure design and performance analysis of Double-actuator Piezo-pump with membrane valveAccording to the design theory of the Double-actuator Piezo-pump, the author develop the structure optimization design of Double-actuator Piezo-pump. The research of the Double-actuator Piezo-pump show that the more cavity initialization capacity,the worse self-absorbing capacity of pump. But a proper cavity initialization capacity could made the pump get the best output flow. The author also obtain the number of the suction holes and radius of the umbrella-shape rubber valve and spiral plate valve by experiment.When the valve hole radius of umbrella-shape rubber valve is r ? 3.2mm,suction holes=n=8,the suction performance is the best, the valve hole radius of spiral plate valve is r=2.75mm, the suction performance is the best. The experiment also show that tandem pump three valves structure is better than those of two valves.The author expatiated the reason of cavitation give birth to in the pump,we must make sure that the pressure ratio on the two sides of the vlalve p1/p2<3.5 for avoid producing cavitation in the pump. Cavitation may lead to abscission and cauterization of actuator metal plate .Aiming at the factors that affect the performance of double-actuator piezo-pump, such as drive method of actuator electrical signal,high of cavity, author product many kinds of Piezo-pump ,choose water as transmission medium,use bimorph actuator, experimentalize with sine alternating current 110V.With regard to double-actuator single cavity pump, with the synchronous drive on actuator, working frequency band of pump less than 250Hz,the optimal frequency is around 60Hz,at that time the flux is more than 500ml/min. With the synchronous drive on actuator, working frequency band of pump is more wide, which can reach to 400Hz,when the pressure output is more than 100kPa. The cavity initialization capacity may affect the output of the pump, which reach to 2501.2 mm3,the output is pretty good.The length of the outlet pipe may affect optimal working frequency of the pump. Prolong the length of the loulet pipe, the optimal working frequency of the pump will diminish, the output flux will diminish.The using of flexible support on actuator will diminish optimal working frequency of the pump, without influence of the flux output.In the face of double-actuator pump in series, the output performance of pump is affected by chamber initialization capacity and valve number,which is best when the chamber initialization capacity is 1900 mm3 and with three valves,the max output flux can reach to 1100ml/min.When the working frequency of the pump is less than 400Hz,the max output pressure is 100kPa.In the face of double-actuator pump in parallel, analysis the influence which cavity initialization capacity,drive method of actuator,the different kinds of valve onto it.When cavity initialization capacity is 1135 mm3, paralleled pumps get the best output performance,the max output flux is 1350ml/min, when the working frequency of the pump is less than 400Hz, the max output. Pressure is 40kPa.Compare with the cantilever valve paralleled pumps, spiral plate valve paralleled pumps,the umbrella-shape rubber valve paralleled pump's performance is best in the experiment.4. Experimental Study of Double-actuator Piezo-pump with membrane valve driving gas and liquid with different viscosity.The author did the experimental study of Double-actuator Piezo-pump with membrane valve driving gas and liquid with viscosity higher than water, the result of the experiment indicate that driven by the effective working voltage 110v sinusoidal current, double-actuator tandem pump and paralleled pump can drive max viscosity 234.6 mPa.s glycerine solution,when the the max output flux is 30ml/min. comparing with the driven by liquid, Piezo-pump driven by synchronous electric signal is much than those driven by induction electric signal;the max gas output pressure of Piezo-pump is 7.8kPa; The output gas performance is affected by the cavity initialization capacity,the litter the cavity initialization capacity,the better the output gas performance.If we take the three kinds structure double-actuator Piezo-pump with the same cavity initialization capacity in a experiment, in aspect of output flux , synchronous parallel pump is the best, induction tandem pump is the worst;in the aspect of output pressure, induction tandem pump is the best, synchronous parallel pump is the worst.Based on the research of Double-actuator Piezo-pump , author offered a effective method for the turbulence of the liquid in the double-actuator Piezo-pumps, showed clearly direction of the research on the multi-actuator Piezo-pumps, such as Three- actuator Piezo-pump ,four-actuator Piezo-pump.This paper funded by―863 programe‖Investigation on Multi-chamber Mini-Piezo-Pump‖(number 2002AA404250)and innovation fund for technology based firms program― computer chip water cooling system with piezo-pump‖(number04C26222210064), investigated a kind of piezo-pump with valve which has the characteristics of working stabilized, low noise ,great flow(1000ml/min), high and accurate out pressure(100kPa).Base on the research above, the theory of Piezoelectric drive and the structure design of the Double-actuator Piezo-pump , experimental study were developed. |
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