Principle and structure of a multi-chamber piezoelectric pump with large flow rate integrated into printed circuit board

Parametric simulation of multi-chamber piezoelectric pump proposed by authors shows that its flow rate is positively correlated with chamber compression ratio when height of chamber wall is not less than central deflection of circular piezoelectric unimorph actuator (CPUA). Therefore, in this paper, principle and structure of multi-chamber piezoelectric pump with novel CPUAs with three-layer structure are proposed and realized, so as to improve its chamber compression ratio, and then improve its flow rate. Its processing technology compatible with PCB processing technology is studied and its flow rate model is established. Central deflection of CPUA with three-layer structure and the flow rate characteristics are tested. Experimental results show that when the central deflection of CPUA with three-layer structure reaches the maximum value of 106.8 μm, the chamber compression ratio and flow rate of multi-chamber piezoelectric pump reach the maximum value of 50% and 3.11 mL/min, respectively. The maximum flow rate is increased by 622% compared to unimproved pump. By comparing experimental results with numerical and finite element simulation results, the realized multi-chamber piezoelectric pump has large flow rate and the established flow rate model can predict its flow rate.

Numerical simulation and experimental study on valveless piezoelectric pump with triangular obstacles

A valve less piezoelectric pump with triangular obstacles is designed and manufactured, which uses piezoelectric vibrator as power source. The working principle and theoretical flow rate of the valveless piezoelectric pump are analyzed, and its flow rate expression is derived. The flow resistance characteristics of triangular obstacles are simulated by numerical simulation. Based on the mass fraction distribution of liquid water, the forward and reverse flow resistance of triangular obstacles and the influence of triangular obstacles on pumping capacity are analyzed. Finally, two groups of test prototypes of the valveless pump are made by using the engraving machine, and the flow measurement test is carried out. The experimental results show that the valveless piezoelectric pump with triangular obstacles can realize the valveless pumping function, and the pumping flow per unit time increases with the increase of triangular obstacles in the channel, and decreases with the increase of the distance between triangular obstacles and the channel. When the driving voltage is 140V and the driving frequency is 10Hz, the maximum output flow of the piezoelectric pump is 16.26ml/min.

The characters exploration of a piezoelectric pump with fishtail-shaped bluffbody

This paper focuses on a new structure in the valveless piezoelectric pump, which has a combination structure of the conical flow channel and two fishtail-shaped bluffbodies in the chamber of the pump. The fishtail-shaped bluffbody is inspired by the shape of the swimming fish to diminish the backflow and optimize the performance of the pump. The performance is studied by changing the shape and size of the inlet and outlet, the bluff bodies’ height and the space between two bluff bodies. The results show that the 3 mm × 3 mm square inlet, 3 mm diameter round outlet, 3 mm height of bluffbodies, 6.8 mm pitch of bluffbodies has a best performance in all 10 prototypes, which implements a maximum flow rate of 87.5 ml/min at 170 V 40 Hz with a noise of 42.6 dB. This study makes a preliminary investigation and theoretical explanation for the subsequent optimization of this structure, improved the performance of the valveless piezoelectric pump, broaden the thinking of the design for the bluffbody for better performance of the valveless piezoelectric pump.

Advances in Valveless Piezoelectric Pumps

Piezoelectric pump design is regarded as a hot research topic in the microfluidic field, and has been applied in liquid cooling, precision machinery and other relevant domains. The valveless piezoelectric pump becomes an important branch of the piezoelectric pump, because it successfully avoids the problem of “pump-lagging of valve” during the valve piezoelectric pump processing. This paper summarizes the development of valveless piezoelectric pumps, and introduces some different configurations of valveless piezoelectric pumps. The structure and material of all kinds of valveless piezoelectric pumps are elaborated in detail, and also the output performance of the pump is evaluated and analyzed with the variations in flow rate and output pressure as reference. By comparing the flow of different types of valveless piezoelectric pumps, the application of valveless piezoelectric pumps is also illustrated. The development tendency of the valveless piezoelectric pump is prospected from the perspective of structure design and machining methods, which is expected to provide novel ideas and guidance for future research.

Valveless Piezoelectric Pump with Reverse Diversion Channel

In order to reduce backflow and improve output performance, a valveless piezoelectric pump with a reverse diversion channel was produced. The channel was designed based on the structure of the Tesla valve, which has no moving parts and can produce a high-pressure drop during reverse flow. Therefore, this special flowing channel can reduce the backflow of a valveless piezoelectric pump, which has the characteristic of one-way conduction. This work first revealed the relationship between the main structural parameters of the Tesla valve and the kinetic energy difference of liquid. Then, by using simulation software, the structure was verified to have the characteristics of effective suppression of the backflow of valveless piezoelectric pumps. Through setting multiple simulations, some important parameters that include the optimal height between the straight channels (H), the optimal angle (α) between the straight channel and the inclined channel, as well as the optimal radius (R) of the channel were confirmed. Finally, a series of prototypes were fabricated to test the output performance of this valveless piezoelectric pump. Comparing the experimental results, the optimal parameters of the Tesla valve were determined. The results suggest that when the parameters of the Tesla valve were H = 8 mm, α = 30°, and R = 3.4 mm, the output performance of this piezoelectric pump became best, which had a maximum flow rate of 79.26 mL/min with a piezoelectric actuator diameter of 35 mm, an applied voltage of 350 Vp-p, and a frequency of 28 Hz. The effect of this structure in reducing the return flow can be applied to fields such as agricultural irrigation.

Backstepping Sliding-Mode Control of Piezoelectric Single-Piston Pump-Controlled Actuator

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the intermittent oil supplying and position control precision is essential when designing the controller. In order to accurately control the output of the actuator, a backstepping sliding-mode control method based on the Lyapunov function is introduced, and the controller is designed on the basis of establishing the mathematical model of the system. The simulation results show that, compared with fuzzy PID and ordinary sliding-mode control, backstepping sliding-mode control has a stronger anti-jamming ability and tracking performance, and improves the control accuracy and stability of the piezoelectric pump-controlled actuator system.