JPS6291676A - Micropump - Google Patents

Abstract

PURPOSE:To omit a stop valve and realize a compact size extensively, by arranging one or more piezoelectric bimorph elements parallel to the flow in an enclosed container furnished on the way of the flow, and causing a deflecting oscillation to them. CONSTITUTION:On the way of a fluid pipe line 4, is furnished a pump container 3, and at the entrance of the pump is arranged a slit plate 1. At the portion beside the opening of the slit plate 1, a piezoelectric bimorph element 2 is fixed standing square to the plate 1. The element 2 is composed of two sheets of piezoelectric ceramics 5 polarized in the direction of the arrow, to make it possible to generate a deflecting oscillation by applying an A-C electric field. The pumping is carried out by this deflecting oscillation, and a pair of piezoelectic bimorph elements operating in the reverse phases each other are necessary to furnish to get a further higher pumping efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure sensitive bimorph micropump applied to medical equipment and chemical analysis equipment.

(Prior art) Conventionally known micro pumps include mechanical ones that rotate an impeller, and ones that apply external pressure to vinyl pipes to deform them and squeeze them out. Ta. Alternatively, in a case that fully utilizes the piezoelectric Cera i-Kuku, a pair of identical surfaces of a rectangular rectangular container that performs all pump functions is installed in the middle of the flow path, and a piezoelectric bimorph diaphragm whose periphery is fixed with piezoelectric Boimorph elements is bent. It was designed to transport fluid by interlocking photography.

(Problems to be Solved by the Invention) However, conventional micropumps have the following problems. In all mechanical micropumps, the power section and the pump section are separate, so there is a limit to how far miniaturization can be achieved.

In addition, the flow rate can be controlled by slowing down the rotational speed of the impeller or by fully adjusting the force applied by a vinyl pipe, but in either case, it is difficult to control the flow rate completely accurately.

In addition, with piezoelectric bimorphs, the pump part and power part are integrated and can be made smaller, but when it comes to controlling the flow rate, for example, when transporting water, the controllable range is limited to lsom/minute. Put it away.

(Tth Means for Solving All Problems) The present invention has one or more piezoelectric bimorph elements arranged in a closed container provided in the middle of a flow path so as to run parallel to the flow. The micropump is further characterized in that one end of the piezoelectric bimorph element is fixed.

(Function) A slit plate is provided on the cross section of the inlet from the pipe to the pump section, and a piezoelectric bimorph element is fixed to this blind portion parallel to the flow. When a full AC voltage is applied to this bimorph element, flexural vibration motion is induced. This flexural vibration pushes away the surrounding fluid and realizes the function of a pump.

As described above, the micropump according to the present invention has a simple structure in which the power section and the pump section are integrated. In addition, there is no need for a backflow prevention valve as found in conventional piezoelectric bimorph pumps. Therefore, the size can be significantly reduced compared to the conventional one.

The flow rate can also be easily controlled by selecting the peak value of the drive wheel of the piezoelectric bimorph element and the frequency to easily select a wide range of flow rates. However, since the blur frequency for practical use is set at 50 to 60 Hz, only the i and H positive peak values are controlled. Now, in this case, the displacement δ at the tip of the piezoelectric bimorph diaphragm, which is closely related to the flow rate, is given by the following equation.

In this equation, K: proportionality constant + d31: piezoelectric constant, l: bimorph element length, t: bimorph element thickness V a Applied voltage Therefore, the displacement and voltage relationship ((with flow rate knee i,
, can be easily controlled.

(Example 1) FIG. 1 is a sectional view showing a complete example of the structure of the present invention.

A pump container 3 is formed in the middle of the fluid pipe line 4,
A slit plate 1 is arranged at the inlet of the pump section, and a piezoelectric bimorph element 2 is vertically fixed therein. As shown in FIG. 2, the element 2 consists of two piezoelectric ceramics 5 that are polarized in the direction of the arrow.
The other wire is connected so that an electric field acts in the opposite direction to the polarization. The piezoelectric ceramic used in this case is a conventionally known PZT ceramic. The piezoelectric ceramics 5
When an alternating electric field was applied to the element, the element began to undergo flexural oscillatory motion, acting as a pump. In principle, it is possible to realize the pump function with one piezoelectric bimorph element 2, but in order to further increase the efficiency of the pump, it is necessary to move another piezoelectric bimorph element in the opposite phase to the above. So, set it up. Furthermore, if a bare piezoelectric bimorph element is prepared, a larger flow rate can be controlled.

As mentioned above, the structure is very simple, so it is much smaller than conventional micro pumps, and the size of the pump part is 5.
Something of the order of X 5 X 3tα is realized.

(Example 2) The structure and other features were the same as in Example 1, but the piezoelectric bimorph element used was made of gold, conventionally known PZT-based piezoelectric ceramics, and a diaphragm made of constant elastic metal, etc. do. Even with this configuration, the same effects as in Example 1 were obtained.

(Effects of the Invention) As described above, since the pump part and the power part are integrated, the structure is simple and no check valve is required, so it is possible to significantly downsize the pump compared to the conventional one. , - Also, a wide range of flow rates can be easily controlled by the applied voltage value.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the overall configuration of a piezoelectric bimorph micropump according to the present invention, and FIG. 2 is a sectional view showing an example of a piezoelectric bimorph element. In the figure, 1 is a slit plate, 2 is a piezoelectric bimorph element, 3 is a pump container, 4 is a fluid conduit, and 5 is a piezoelectric ceramic. To Agent-11 Susumu Tsujiuchihara Etei 1
Illustration Z Diagram 5, Pressure Beak Spoof Lamix Showa Year, Month, Day 1, Incident Indication 1985 Patent Application No. 23025
No. 7 No. 2 Name of the invention, name Micropump 3 Relationship with the case of the person making the amendment Applicant 5-33-1 Shiba, Minato-ku, Tokyo (423) NEC Corporation Representative Tadahiro Sekimoto 4th Director 5 Column 6 of Detailed Description of the Invention in the Specification Subject to Amendment, Contents of Amendment (1) Page 3 of the Specification, Lines 16 to 18 [Also, the conventional...] Delete the J.

Claims (1)

[Claims] One or more piezoelectric bimorph elements are arranged parallel to the flow in a closed container provided in the middle of the flow path, and one end of the piezoelectric bimorph element is fixed. micro pump.