CN101424262A - Sawtooth shape flow passage one-way piezoelectric micropump - Google Patents

Abstract

The invention provides a unidirectional piezoelectric micropump with a zigzag channel. It includes a pump body, a pump cover and a driving device. The pump cover is provided with structures such as a pump cavity, fluid inlet and outlet zigzag flow channels, and the pump cover is provided with an inlet and an outlet. The pump body and the pump cover are bonded together to drive the pump. The device is bonded together by a PDMS piezoelectric film and a piezoelectric ceramic sheet, and the PDMS film and the pump body are bonded together by an irreversible bonding method. The micropump of the present invention is small in volume, simple in structure and convenient in operation, and is suitable for mass production, and has a relatively long service life because there are no moving parts. The product of the invention can be widely used in the fields of instrumentation, medical equipment, chemical analysis, medicine, food, aerospace and the like.

Description

A unidirectional piezoelectric micropump with zigzag channel

technical field

The invention relates to a one-way piezoelectric micropump with sawtooth flow channel.

Background technique

Micropumps and microvalves are the key executive components of microfluidic systems. Among them, valveless micropumps have been more and more widely studied in recent years because they reduce the friction and wear, fatigue damage and valve blockage of movable parts in valved micropumps. And application, become the most active branch in the research of microfluidic system. The research on valveless micropumps began in 1993. E.Stemme et al. in Sweden successfully used the conical expansion/contraction microvalve structure to make the first micropump. Subsequently, many scholars adopted different processing methods, driving methods, The pump body material and packaging method are similar to micropumps. Its working principle is based on the asymmetry of the expansion tube/contraction tube structure, the difference in resistance to the fluid, and the principle of different pressure losses in the expansion/contraction tube. Sweden Olsson et al. have done a detailed study on the structure and performance of the conical diffusion/contraction microvalve. Due to the simultaneous flow of fluid into and out of the pump chamber from the two microvalves, the micropump with this structure has a large flow loss and low efficiency. lower.

Contents of the invention

The object of the present invention is to provide a unidirectional piezoelectric micropump with a zigzag channel, which is stable in operation, high in efficiency and convenient for mass production.

The object of the present invention is achieved like this: a kind of zigzag channel one-way piezoelectric micropump, comprises pump body, pump cover and driving device, is characterized in that:

The pump body is provided with an inlet cavity, a pump chamber and an outlet cavity, and the pump cavity communicates with the inlet cavity and the outlet cavity by an inlet zigzag flow channel 5 and an outlet zigzag flow channel respectively;

The pump body is integrated with the pump cover, and the pump cover has an inlet and an outlet respectively connected to the inlet and outlet of the pump body;

The structure of the driving device is as follows: a piece of flexible film is pasted on the bottom of the pump body, the bottom of the flexible film is aligned with the bottom of the pump chamber, and a piece of piezoelectric ceramic is pasted.

The micro-channel adopts a special zigzag flow channel, and there is an optimal combination of structural parameters such as depth, minimum cross-sectional width, cone angle, expansion angle, and length (pitch) of the zigzag flow channel.

The pump cover material is Pyrex7740 glass or thick film photoresist SU-8;

The material of the pump body is silicon wafer or thick film photoresist SU-8;

The flexible film is a polydimethylsiloxane (PDMS) flexible film.

The present invention has the following obvious outstanding substantive characteristics and significant advantages:

The zigzag valveless micropump provided by the present invention has a simple structure, can be produced in batches using MEMS technology, and is easy to integrate in a microfluidic system; compared with a valved micropump, a valveless micropump has no movable valve part , which reduces the occurrence of clogging, is applicable to various liquids and liquids with solid particles, etc., and is more durable and reliable than valved micropumps. Compared with the traditional conical diffusion/constriction flow channel structure, the zigzag flow channel structure can greatly improve the performance of the micropump. The working voltage can be symmetrical or asymmetrical sine wave, square wave, triangular wave, etc. The invention has the advantages of small volume, simple structure, convenient operation, no moving parts and long service life, and can be widely used in the fields of instrumentation, medical equipment, chemical analysis, medicine, food and aerospace.

Description of drawings

Fig. 1 is a micropump structural representation of the present invention;

Fig. 2 is a sectional view at A-A place in Fig. 1;

Figure 3 and Figure 4 are schematic diagrams of the working principle of the present invention.

Fig. 5 is a structural diagram of a zigzag flow channel of the present invention;

Fig. 6 is a three-dimensional structure diagram of the zigzag flow channel of the present invention.

Detailed ways

In a preferred embodiment of the present invention, the working principle and structure of the present invention are further described in conjunction with the accompanying drawings: Referring to Fig. 1, the composition of the zigzag channel unidirectional piezoelectric micropump includes a pump body 1, an upper pump cover 8, a lower drive The PDMS flexible film 2 and the piezoelectric ceramic sheet 3 of the device have a pump chamber 4, an inlet chamber 6, an outlet chamber 10, an inlet zigzag flow channel 5 and an outlet zigzag flow channel 11 on the pump body; There are inlet 7 and outlet 9; the pump body 1 and the pump cover 8 are bonded together, the pump body 1 and the PDMS film 2 are bonded together by an irreversible pasting method, and the piezoelectric ceramic sheet 3 is fixed on the PDMS circular sink with an adhesive. In the tank, the binder is liquid PDMS. The pump cover 8 is made of Pyrex7740 glass or thick film photoresist SU-8. The pump body 1 is made of silicon wafer or thick film photoresist SU-8.

Referring to Fig. 3, Fig. 5 and Fig. 6, the main structural parameters of the zigzag flow channel 5, 11 in this embodiment include: depth H, width B, cone angle θ, diffusion angle α and length L, etc., the zigzag flow channel is in The expansion direction (the cross-sectional area gradually expands in the direction of fluid flow) and the contraction direction (the cross-sectional area gradually decreases in the direction of fluid flow) have different fluid resistances, resulting in different pressure losses. When the zigzag flow channel is placed asymmetrically The two sides of the pump cavity 4 of the micropump have been proved by specific tests that the micropump can achieve the purpose of pumping.

Referring to Fig. 3 and Fig. 4, the working principle of this embodiment:

When an AC sine wave signal is applied to both ends of the piezoelectric ceramic sheet wire, the micropump can realize the function of directional delivery, and the micropump can be divided into two half-cycles for analysis. When the piezoelectric ceramic sheet 3 moves downward, it drives the PDMS film 2 to move downward. At this time, the volume of the pump chamber 4 increases, and the micropump enters the "supply mode", and the fluid flows in from the zigzag inlet and outlet channels 5 and 11 at the same time. However, since the sawtooth-shaped inlet and outlet channels 5 and 11 are asymmetrically arranged on both sides of the pump cavity 4, the outlet channel 11 has a greater resistance to the fluid, so the flow that flows into the pump cavity 4 through the inlet channel 5 be greater than the flow inflow through the outlet. When the piezoelectric ceramic sheet 3 moves upward, it drives the PDMS film 2 to move upward. At this time, the volume of the pump chamber 4 decreases, and the micropump enters the "pump mode", and the fluid flows out of the pump chamber from the zigzag inlet and outlet channels 5 and 11 at the same time. 4. Since the zigzag inlet and outlet channels 5 and 11 are asymmetrically arranged on both sides of the pump chamber 4, the inlet channel 5 has greater resistance to the fluid, so the flow out of the pump chamber 4 through the outlet channel 11 is greater than that through the pump chamber 4. Inlet and outflow traffic.

In summary, after a working cycle of the micropump, the fluid flows into the pump chamber 4 from the inlet channel 5 and flows out of the pump chamber 4 from the outlet channel 11, realizing directional pumping.

Claims (5)

1. A zigzag flow channel unidirectional piezoelectric micropump, comprising a pump body (1), a pump cover (8) and a drive unit, is characterized in that: a. The pump body (1) has an inlet cavity (6), a pump chamber (4) and an outlet cavity (10), and the pump cavity (4) is connected with the inlet cavity (6) and the outlet cavity ( 10) are respectively communicated by an inlet zigzag flow channel (5) and an outlet zigzag flow channel (11); b. The pump body (1) is integrated with the pump cover (8), and the inlet (7) and outlet (9) on the pump cover (8) are respectively connected to the inlet (6) and Outlet mouth (10); c. The structure of the driving device is: a piece of flexible film (2) is pasted on the bottom of the pump body (1), and the bottom of the flexible film (2) is directly aligned with the bottom of the pump chamber (4), Paste a piezoelectric ceramic sheet (3). 2. The unidirectional piezoelectric micropump with zigzag channel according to claim 1, characterized in that the inlet zigzag channel (5) is in a diffuse shape along the direction from the inlet cavity (6) to the pump cavity (4), The outlet zigzag flow channel (11) is in a diffuse shape along the direction from the pump chamber (4) to the outlet chamber (10). 3. The unidirectional piezoelectric micropump with zigzag flow channel according to claim 1, characterized in that said flexible film (2) adopts polydimethylsiloxane film. 4. The unidirectional piezoelectric micropump with zigzag channel according to claim 1, characterized in that the material of the pump cover (8) is Pyrex7740 glass or thick film photoresist SU-8. 5. The unidirectional piezoelectric micropump with zigzag channel according to claim 1, characterized in that the material of the pump body (1) is silicon wafer or thick film photoresist SU-8.

Images