CN103032296B - Piezoelectric stack pump based on disk type sensor valve - Google Patents

Abstract

The invention relates to a piezoelectric stack pump based on a disc-shaped sensor valve, which belongs to the field of microfluid transmission and control. The valve cover is installed on the pump cover, and the pump cover is installed on the pump body; an outlet valve and an inlet valve are bonded between the valve cover and the pump cover; both the outlet valve and the inlet valve are bonded by a ring piezoelectric film and a substrate , the base plate has a through hole; between the pump cover and the pump body, a pump chamber diaphragm is crimped, and the two sides of the pump chamber diaphragm are respectively installed with a piston and a top block through screws; the piston, the pump cover, the outlet valve and the inlet valve together form the pump chamber; the bolts crimp the piezoelectric stack driver on the top block through the anti-twist block; the piezoelectric stack, the outlet valve and the inlet valve are respectively connected to the electronic control unit through the wire group. Features and advantages: Use the one-way valve with sensing function to directly measure the output pressure and flow of the piezoelectric pump, so the structure is simple, the accuracy and reliability of the measurement accuracy are high, and it is suitable for liquids, gases, and gas-liquid mixtures, etc. Real-time monitoring during pumping of different media.

Description

Piezoelectric stack pump based on disc sensor valve

technical field

The utility model belongs to a piezoelectric pump used in the field of microfluid transmission control, in particular to a piezoelectric stack pump based on a disc-shaped sensor valve.

Background technique

Piezoelectric pumps have many advantages such as simple structure, small size, quick response, no electromagnetic interference, easy operation, good flow and pressure controllability, etc. etc. have broad application prospects, so its research and development has attracted extensive attention from scholars all over the world. In order to meet the application requirements in different fields, piezoelectric pumps with various structures have been proposed. Although the structure and performance of the proposed piezoelectric pumps are quite different, they all use the bending or stretching deformation of the piezoelectric vibrator under the action of an electric field to realize fluid drive. Because the fluid output by each working cycle of the piezoelectric pump is the volume change of the pump chamber caused by the deformation of the piezoelectric vibrator, it can realize precise control of flow and pressure, especially suitable for controlled drug release. However, in actual work, since the output flow and pressure of the piezoelectric pump are greatly affected by the working conditions, in addition to the driving voltage and frequency, the fluid viscosity, temperature and output pressure also have a greater impact on the actual output flow. Therefore, simply adopting the method of adjusting the driving voltage and frequency cannot obtain higher output accuracy. Flow and pressure measuring instruments still need to be used for monitoring in occasions requiring precise flow and pressure control, such as controlled release of drugs, chemical analysis, and fuel cells, which not only increases the cost of use, but also increases the volume, weight and complexity of the system, seriously This hinders the popularization and application of piezoelectric pumps in microelectromechanical systems and portable products.

In order to improve the output accuracy and controllability of piezoelectric pumps, reduce costs, and reduce the overall volume and weight of the system, people have proposed piezoelectric pumps with various structures, which can be realized without other pressure and flow measuring instruments. Automatic measurement of output flow and pressure, such as: Chinese patents 201110173933.7, 201110181209.9 and 201110181208.4, etc., which directly use the voltage generated by the deformation of the piezoelectric actuator to characterize the output performance of the piezoelectric pump, and Chinese patent 201220276952.2, etc. The output voltage of the pressure sensor in the pump chamber represents the output performance of the piezoelectric pump, etc. The measurement method adopted by the existing self-measurement piezoelectric pump mentioned above belongs to indirect measurement, and its measurement accuracy will decrease under some special working conditions, and even the measurement structure is completely invalid, such as: when transporting gas, liquid with large gas content , or the water-based liquid being transported is seriously gasified due to the increase in temperature, the pressure in the pump chamber decreases due to the increase in gas content, and the outlet valve cannot even be opened. Inductive voltage output, but the output flow of the pump may be very small or no fluid output at all; similarly, when the inlet and outlet valves themselves fail, or cannot be opened and closed normally, the measurement accuracy of the piezoelectric pump will also be reduced or even invalid. It can be seen that the existing self-measuring piezoelectric pump still has certain deficiencies in the accuracy and reliability of the measurement accuracy.

Contents of the invention

Aiming at the deficiencies in the accuracy and reliability of the measurement accuracy of the existing self-measuring piezoelectric pump, the utility model proposes a piezoelectric stack pump based on valve opening detection to realize output flow and pressure measurement, referred to as a piezoelectric stack pump based on Piezoelectric pump for disc sensor valves.

The technical scheme adopted by the utility model is: the valve cover is installed on the pump cover through screws, and the pump cover is installed on the pump body through screws; an outlet valve and an inlet valve are bonded between the valve cover and the pump cover, Both the outlet valve and the inlet valve are bonded by an annular piezoelectric film and a substrate, and the substrate has through holes; a pump chamber diaphragm is crimped between the pump cover and the pump body, The two sides of the chamber diaphragm are respectively installed with a piston and a top block through screws; the piston, the sealing ring installed on the piston, the pump cover, the outlet valve and the inlet valve together constitute the pump chamber; the bolts installed at the end of the pump body pass through the anti The twist block crimps the piezoelectric stack driver on the top block; the piezoelectric stack driver, the outlet valve and the inlet valve are respectively connected to the electronic control unit through the first wire group, the second wire group and the third wire group.

When the electronic control unit is turned on and enters steady-state operation, and the driving voltage increases from 0 to V ₀ , the piezoelectric stack driver begins to elongate and pushes the top block, pump chamber diaphragm and piston to the right, causing the pump chamber The volume of the pump decreases, the fluid pressure increases, and the increasing fluid pressure forces the outlet valve to open and the inlet valve to close, and the fluid is discharged from the pump chamber through the outlet valve. This is the discharge process; when the output voltage of the electronic control unit is reversed, that is When the voltage decreases from V ₀ to 0, the piezoelectric stack driver begins to shrink under the action of the diaphragm of the pump chamber, resulting in an increase in the volume of the pump chamber and a decrease in the fluid pressure in the chamber. The decreasing fluid pressure forces the inlet valve to open and the outlet valve to close , the fluid enters the pump chamber through the inlet valve, which is the suction process.

In the suction process and discharge process of the piezoelectric pump in the above embodiment, both the inlet valve and the outlet valve are alternately opened and closed, and voltage signals are generated, so the inlet valve and the outlet valve also have the function of sensors; because the inlet valve and the voltage value generated by the outlet valve, as well as the output flow and pressure of the piezoelectric pump are proportional to the opening of the valve, so the output pressure P and flow Q of the piezoelectric pump are the output voltage V _{g, c} and The function of the output voltage V _{g, r} of the inlet valve, the output voltage V _{g, c} of the outlet valve or the output voltage V _{g, r of} the inlet valve can be used to represent the output pressure and flow of the piezoelectric pump, that is, the pressure is P=k1| Vg|, the flow rate is Q=k2|Vg|, where k1 and k2 are the calibration coefficients of the piezoelectric pump output pressure and flow rate respectively, and Vg is the output voltage V _{g, c} of the outlet valve or the output voltage V _{g, r of} the inlet valve .

The features and advantages of the utility model are: the output pressure and flow of the pump are directly measured by using the one-way valve with sensing function without additional sensors, so the structure is simple, the accuracy and reliability of the measurement accuracy are high, and it is suitable for Real-time monitoring during the pumping process of different media such as liquid, gas and gas-liquid mixture.

Description of drawings

Fig. 1 is a structural sectional view of a piezoelectric stack pump discharging fluid in a preferred embodiment of the utility model;

Fig. 2 is a structural sectional view of a piezoelectric stack pump in a preferred embodiment of the utility model after sucking fluid;

Fig. 3 is A-A sectional view of Fig. 2;

Fig. 4 is the input voltage waveform of the piezoelectric stack pump in a preferred embodiment of the utility model;

Fig. 5 is the output voltage waveform of the outlet valve in a preferred embodiment of the utility model;

Fig. 6 is the output voltage waveform of the inlet valve in a preferred embodiment of the utility model;

Detailed ways:

The valve cover 2 is installed on the pump cover 4 by screws, and the pump cover 4 is installed on the pump body 10 by screws; an outlet valve 1 and an inlet valve 3 are bonded between the valve cover 2 and the pump cover 4, so that The outlet valve 1 is formed by bonding the annular piezoelectric film 1-2 and the substrate 1-1, and the inlet valve 3 is formed by bonding the annular piezoelectric film 3-2 and the substrate 3-1, and the substrate 1-1 and the substrate 1-1 are bonded together. 3-1 have through holes; a pump chamber diaphragm 8 is crimped between the pump cover 4 and the pump body 10, and a piston 7 and a top block 9 are respectively installed on both sides of the pump chamber diaphragm 8 through screws The piston 7 and the sealing ring 6 installed on the piston 7, the pump cover 4, the outlet valve 1 and the inlet valve 3 together constitute the pump chamber 5; The piezoelectric stack driver 11 is crimped on the top block 9; the piezoelectric stack driver 11, the outlet valve 1 and the inlet valve 3 communicate with the electric wire group 1 14, the wire group 2 17 and the wire group 3 16 respectively. Control unit 15 is connected.

When the electronic control unit 15 is turned on and enters steady-state operation, and the driving voltage increases from 0 to _V0 , the piezoelectric stack driver 11 starts to extend and pushes the top block 9, the pump cavity diaphragm 8 and the piston 7 to the right The movement causes the volume of the pump chamber 5 to decrease and the fluid pressure to increase. The increasing fluid pressure forces the outlet valve 1 to open and the inlet valve 3 to close. The fluid is discharged from the pump chamber 5 through the outlet valve 1. This is the discharge process; After the output voltage of the control unit 15 is reversed, that is, when the voltage decreases from V ₀ to 0, the piezoelectric stack driver 11 begins to shrink under the action of the diaphragm 8 of the pump chamber, so that the volume of the pump chamber 5 increases and the fluid pressure in the chamber decreases. , The decreasing fluid pressure forces the inlet valve 3 to open, the outlet valve 1 to close, and the fluid enters the pump chamber 5 through the inlet valve 3, which is the suction process.

In the suction process and discharge process of the piezoelectric pump in the above embodiment, both the inlet valve 3 and the outlet valve 1 are alternately opened and closed, and voltage signals are generated, so the inlet valve 3 and the outlet valve 1 also have the function of sensors ;Because the voltage value generated by the inlet valve 3 and the outlet valve 1, and the output flow and pressure of the piezoelectric pump are proportional to the opening of the valve, the output pressure P and flow Q of the piezoelectric pump are both of the outlet valve 1 The function of the output voltage V _{g, c} and the output voltage V _{g, r} of the inlet valve 3, the output voltage V _{g, c} of the outlet valve 1 or the output voltage V _{g, r} of the inlet valve 3 can be used to represent the output pressure of the piezoelectric pump and Flow, that is: pressure is P=k1|Vg|, flow is Q=k2|Vg|, where k1 and k2 are the calibration coefficients of the output pressure and flow of the piezoelectric pump, and Vg is the output voltage V of outlet valve 1 _{g, c} or the output voltage V _{g, r} of the inlet valve 3 .

Claims (1)

1. A piezoelectric stack pump based on a disc sensor valve, characterized in that: the valve cover is mounted on the pump cover by screws, and the pump cover is mounted on the pump body by screws; between the valve cover and the pump cover An outlet valve and an inlet valve are bonded; the outlet valve and the inlet valve are formed by bonding an annular piezoelectric film and a substrate, and the substrate has through holes; the pump cover and the pump body are crimped There is a diaphragm in the pump chamber, on both sides of the diaphragm in the pump chamber, a piston and a top block are respectively installed through screws; the piston, the sealing ring installed on the piston, the pump cover, the outlet valve and the inlet valve together constitute the pump chamber; The bolt at the end of the pump body crimps the piezoelectric stack driver on the top block through the anti-twist block; Wire group three is connected to the electronic control unit; the output pressure P and flow Q of the piezoelectric pump are represented by the output voltage V _g of the outlet valve or the inlet valve, that is, P=k ₁ |V _g |, Q=k ₂ |V _g |, Among them, k ₁ and k ₂ are the calibration coefficients of the piezoelectric pump output pressure and flow rate respectively.