CN115822933A

CN115822933A - Piezoelectric jet pump

Info

Publication number: CN115822933A
Application number: CN202211664668.7A
Authority: CN
Inventors: 黄浩; 张起勋; 董景石; 罗煜; 王宇; 于敏泽; 丁肇辰; 李韬; 李俊杰; 班志天
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2022-12-23
Filing date: 2022-12-23
Publication date: 2023-03-21

Abstract

The present invention relates to a piezoelectric jet pump, comprising: the pump body, flexible diaphragm, inlet channel, piezoelectric vibrator, pump chamber, screw, valve, outlet channel, taper pin. The inlet channel is arranged at a pressure node of the piezoelectric vibrator; the outlet channel is arranged at the position with the maximum pressure at the upper part of the pump body; the piezoelectric vibrator is adhered to the flexible diaphragm; the valve adopts the mode of little valve array to improve natural frequency. The piezoelectric jet pump drives fluid by using an acoustic flow effect, and the principle is as follows: according to the acoustic flow effect, when ultrasonic waves generated by vibration of the piezoelectric vibrator are transmitted in fluid, the sound pressure changes along the gradient of the sound beam in the transmission direction, so that jet flow flowing from the piezoelectric vibrator to the outlet channel is formed, and the fluid is pumped. The flexible diaphragm is used for optimizing the sound pressure field and improving the output performance of the pump. The acoustic flow effect is enhanced by using a horn-shaped pump cavity with a high aspect ratio to generate larger jet flow. And the high-response valve rectification is used, so that better pumping is realized. The advantage of high energy density of the piezoelectric material is exerted.

Description

Piezoelectric jet pump

Technical Field

The invention relates to the field of microfluid driving, in particular to a piezoelectric jet pump.

Background

Microfluidic control systems have found wide application in the fields of micro-chemical analysis systems, electronic cooling systems, and portable medical systems. Designing a powerful microfluidic control system requires providing it with an efficient and reliable fluid delivery mechanism. With the development of science and technology, people have proposed the requirements of miniaturization, simple structure, no interference on independence of fluid samples, continuous and stable output, accurate control on flow and the like for miniature fluid control equipment, and the traditional pumps cannot meet the requirements. The piezoelectric pump manufactured according to the inverse piezoelectric effect has the advantages of simple structure, small volume, independence and no interference on fluid samples, low cost and the like, can well meet the requirements of human life, and is widely applied to the fields of medical appliances, computer chip heat dissipation, battery fuel transportation, auxiliary artificial heart pumps, avionic devices and the like.

The output performance of most existing piezoelectric pumps is limited by a valve, and the working frequency is low. Because the working frequency of the valve is low, the valve is easy to damage and has hysteresis when working in a high-frequency state, so that the performance of the piezoelectric pump is not excellent when working in the high-frequency state, and the advantage of high energy density of the piezoelectric material cannot be exerted. And the piezoelectric pump works in a low frequency state with inevitable pulsation problems and noise problems.

Disclosure of Invention

The invention provides a piezoelectric jet pump, which aims to solve the problems of pulsation and noise of the conventional piezoelectric pump and improve the performance of the pump. Based on the standing wave resonance principle, the flexible diaphragm is used for optimizing the sound pressure field and improving the output performance of the pump. Ultrasonic waves generated by the piezoelectric vibrator are focused through the horn-shaped pump cavity with high transverse-longitudinal ratio, high sound pressure is formed in the pump cavity, and the sound flow effect is enhanced; the valves of the micro valve array are used for rectification, so that better pumping is realized; the piezoelectric jet pump drives fluid by using the acoustic flow effect, improves the working frequency of the pump to the ultrasonic range, exerts the advantage of high energy density of piezoelectric materials, solves the problems of pulsation and noise, and realizes quick response and silence.

In order to achieve the purpose, the invention adopts the following technical scheme:

a piezoelectric jet pump comprising: the pump comprises a pump body (1), a flexible diaphragm (2), an inlet channel (3), a piezoelectric vibrator (4), a pump cavity (5), a screw (6), a valve (7), an outlet channel (8) and a taper pin (9). Wherein the piezoelectric vibrator (4) is adhered to the flexible diaphragm (2); the inlet channel (3) is arranged at a pressure node of the piezoelectric vibrator (4); the outlet channel (8) is arranged at the position with the maximum pressure at the upper part of the pump body (1); the valve (7) adopts a micro-valve array mode to improve the natural frequency and consists of an inlet layer, a valve clack layer and an outlet layer, wherein the middle of the outlet layer is sunken, and a little gap is formed between the middle of the outlet layer and the valve clack layer so as to facilitate the opening and closing of the valve clack; the valve (7) is arranged at the maximum pressure position of the pump body (1) through a taper pin (9) and can quickly respond to pressure change; the pump cavity (5) is in a horn shape with a high transverse-longitudinal ratio, is formed by connecting the pump body (1) and the flexible diaphragm (2) through a screw (6), and can focus ultrasonic waves generated by the piezoelectric vibrator (4).

When the ultrasonic pumping device works, the piezoelectric vibrator (4) vibrates to generate ultrasonic waves, and the ultrasonic waves can generate a sound flow effect when being transmitted in fluid, namely, the gradient change of sound pressure is generated along the sound beam transmission direction, so that jet flow flowing from the piezoelectric vibrator (4) to the outlet channel (8) is formed, and the pumping of the fluid is realized. Based on the standing wave resonance principle, the flexible diaphragm (2) is used for optimizing the sound pressure field and improving the output performance of the pump. Since the attenuation of ultrasound waves in a fluid decreases with increasing propagation distance, the acoustic flow effect is enhanced using a high aspect ratio horn-type pump chamber (5), producing a larger jet. The use of high response valve (7) commutation allows better pumping and the pumping rate of the fluid can be adjusted by adjusting the input sound pressure amplitude.

The piezoelectric jet pump has the advantages of small pulsation, no noise, small volume, large flow, high pressure and the like, and has high application potential in the fields of microfluid, phonochemistry, electronic cooling, mixing and the like.

Drawings

FIG. 1 is an isometric test pattern of a piezoelectric jet pump;

FIG. 2 is a schematic diagram of a piezoelectric jet pump;

FIG. 3 is an exploded view of a microvalve array valve structure;

fig. 4 is a schematic diagram of the operation of a piezoelectric jet pump.

Description of the reference numerals: 1-pump body, 2-flexible diaphragm, 3-inlet channel, 4-piezoelectric vibrator, 5-pump cavity, 6-screw, 7-valve, 7-1-inlet layer, 7-2-valve clack layer, 7-2-1-valve clack unit, 7-3-outlet layer, 8-outlet channel, 9-taper pin.

Detailed Description

In order to make the technical scheme and technical effects of the present invention more clearly understood, the present invention is further described in detail in the following through specific embodiments with reference to the attached drawings.

The specific structure and operation of a piezoelectric jet pump according to an embodiment of the present invention will be described with reference to fig. 1 to 4.

Referring to fig. 1-2, a piezoelectric jet pump, comprising: the pump consists of a pump body 1, a flexible diaphragm 2, an inlet channel 3, a piezoelectric vibrator 4, a pump cavity 5, a screw 6, a valve 7, an outlet channel 8 and a taper pin 9. The piezoelectric vibrator 4 is adhered to the flexible diaphragm 2; an orifice is formed at a pressure node of the piezoelectric vibrator 4 and is used as an inlet channel 3; an outlet channel 8 with a valve 7 is arranged at the maximum pressure position of the upper part of the pump body 1; the pump cavity 5 is in a horn shape with high transverse-longitudinal ratio, is formed by connecting the pump body 1 and the flexible diaphragm 2 through a screw 6, and can focus ultrasonic waves generated by the piezoelectric vibrator 4.

Referring to fig. 3, a piezoelectric jet pump, characterized in that: the natural frequency of the valve 7 is increased by means of a microvalve array; the valve 7 is arranged at the position with the maximum pressure at the upper part of the pump body 1 by a taper pin 9; the valve 7 of the micro valve array consists of an inlet channel layer, a valve clack layer and an outlet channel layer, wherein the middle of the outlet channel layer is sunken and has a certain gap with the valve clack layer so as to facilitate the opening and closing of the valve clack layer. The valve 7 can respond quickly to changes in differential pressure without limiting the performance of the pump. The valve 7 can be made of nickel, nickel-titanium alloy, stainless steel, polyester and other sheets with strong elasticity.

Referring to fig. 4, in operation, a sinusoidal signal is applied to the piezoelectric vibrator 4, the piezoelectric vibrator 4 vibrates to generate ultrasonic waves, and the ultrasonic waves generate an acoustic flow effect when propagating in a fluid, that is, gradient changes of sound pressure are generated in a sound beam propagation direction, so that a jet flow flowing from the piezoelectric vibrator 4 to the outlet channel 8 is formed, and pumping of the fluid is achieved. Based on the standing wave resonance principle, the flexible diaphragm 2 is used for optimizing the sound pressure field and improving the output performance of the pump. Since the attenuation of ultrasonic waves in the fluid decreases with increasing propagation distance, the use of a high aspect ratio horn-type pump chamber 5 enhances the acoustic flow effect, producing a larger jet. Using high response valve 7 commutation, better pumping is achieved and the pumping rate of the fluid can be adjusted by adjusting the input sound pressure amplitude.

Claims

1. A piezoelectric jet pump, characterized by: the piezoelectric jet pump drives fluid by using an acoustic flow effect, and the principle is as follows: according to the acoustic flow effect, namely when the piezoelectric vibrator (4) vibrates to generate ultrasonic waves and the ultrasonic waves are transmitted in the fluid, the sound pressure changes in a gradient manner along the transmission direction of the sound beams, so that jet flow flowing from the piezoelectric vibrator (4) to the outlet channel (8) is formed, and the pumping of the fluid is realized; based on the standing wave resonance principle, the flexible diaphragm (2) is used for optimizing the sound pressure field and improving the output performance of the pump; because the attenuation of ultrasonic waves in the fluid is reduced along with the increase of the propagation distance, the acoustic flow effect is enhanced by using the horn-shaped pump cavity (5) with high transverse-longitudinal ratio, and larger jet flow is generated; the high-response valve (7) is used for rectification, so that better pumping is realized; the piezoelectric jet pump includes: the pump body (1), the flexible diaphragm (2), the inlet channel (3), the piezoelectric vibrator (4), the pump cavity (5), the screw (6), the valve (7), the outlet channel (8) and the taper pin (9).

2. A piezoelectric jet pump according to claim 1, wherein: the inlet channel (4) is arranged at a pressure node of the piezoelectric vibrator (4); the outlet channel (8) is arranged at the position with the maximum pressure at the upper part of the pump body (1); the piezoelectric vibrator (4) is bonded on the flexible diaphragm (2).

3. A piezoelectric jet pump according to claim 1, wherein: the pump cavity (5) can focus ultrasonic waves generated by the piezoelectric vibrator (4).

4. A piezoelectric jet pump according to claim 1, wherein: the valve (7) adopts a micro-valve array mode to improve the natural frequency and consists of an inlet layer, a valve clack layer and an outlet layer; the valve (7) is arranged at the position with the maximum pressure at the upper part of the pump body (1) through a taper pin (9), and can quickly respond to pressure change; the valve (7) can be made of nickel, nickel-titanium alloy, stainless steel, polyester and other sheets with strong elasticity.