CN103016317A - Three-cavity valveless piezoelectric pump based on wall-attachment effect - Google Patents

Abstract

The invention relates to the field of microfluid transmission and control and micromechanical technology, in particular to a three-cavity valveless piezoelectric pump based on the Coanda effect. It includes a jet control element, characterized in that: the jet control element is composed of a three-way pipe and three direct-flow pipes, wherein the three-way pipe is a three-way structure composed of a converging cone pipe and two identical shunt pipes, and the two shunt pipes One end of the pipe communicates with the end with a larger cross-sectional area of the confluence cone, and the other end communicates with the inlet and outlet chambers respectively. One end of the three straight pipes is respectively connected with three lower pump chambers, and the other end meets and communicates with the smallest cross-section of the confluence cone. The control element is symmetrical about the center line of the conical pipe. The invention has the beneficial effects of simple structure, easy miniaturization, high pump volume efficiency, and bidirectional fluid delivery.

Description

A kind of three chamber Valveless piezoelectric pumps based on wall attachment effect

Technical field

The present invention relates to microfluid transmission and control and micro mechanical technology field, refer in particular to a kind of three chamber Valveless piezoelectric pumps based on wall attachment effect.

Background technique

Piezoelectric pump is a kind of of mechanical type Micropump, belongs to displacement pump, is widely used in that the medicine trace transports, cell separation, electronic product (such as CPU) cooling, the injection of fuel trace, chemical microanalysis, Flows transfer twist the fields such as control; Foundation has or not valve structure, and piezoelectric pump can be divided into has valve piezoelectric pump and Valveless piezoelectric pump two classes, and Valveless piezoelectric pump does not have one-way valve structures, processing is simple, be easy to microminiaturization, and flowing medium can not be cut off because of valve arrangement, avoid some sensitive medias to be affected; Most of Valveless piezoelectric pump structures are to connect two special construction stream pipes at pump chamber, utilize the differences in flow resistance that flows on the special construction stream pipe both direction to produce the pumping effect, and common special construction stream pipe has conical pipe, tesla pipe, three-way pipe etc.; Because the differences in flow resistance of special construction stream pipe is little, the volumetric efficiency of the type Valveless piezoelectric pump is lower, and throughput direction can't change, limited the application of Valveless piezoelectric pump, the hydrocontrolling element that utilizes wall attachment effect to change jet direction has simple in structure, the characteristics that are easy to control get final product the deflection flow direction by the pressure of regulating the jet both sides, can be applied to developing the Valveless piezoelectric pump of two-way conveying.

Summary of the invention

The objective of the invention is deficiency low for existing Valveless piezoelectric pump volumetric efficiency, unidirectional pumping, provide a kind of based on the wall attachment effect design simple in structure, volumetric efficiency is high, can realize three chamber Valveless piezoelectric pumps of two-way conveying.

The technical solution used in the present invention is: comprise the pump housing, pump cover and three piezoelectric vibrators, the pump housing and pump cover bonding, three piezoelectric vibrators are fixed in the pump cover top, be provided with three upper pump chambers on the pump cover, an import and an outlet, be provided with three lower pump chambers corresponding to upper pump chamber on the pump housing, snout cavity, outlet plenum and hydrocontrolling element; Three lower pump chambers are communicated with respectively with three upper pump chambers, the turnover oral cavity is communicated with the import and export of pump respectively, it is characterized in that: hydrocontrolling element is comprised of a three-way pipe and three DC tube, the three-port structure that formed by conflux Taper Pipe and two identical ram's hornss of three-way pipe wherein, the end that one end of two ram's hornss and the Taper Pipe sectional area that confluxes are larger is communicated with, the other end is communicated with the turnover oral cavity respectively, one end of three DC tube connects respectively three lower pump chambers, the other end crosses and is communicated with the Taper Pipe smallest cross-sectional of confluxing, and hydrocontrolling element is centrosymmetric about the Taper Pipe center line that confluxes.

The span of the Taper Pipe smallest cross-sectional of confluxing width a is 40 μ m to 1mm, and the Taper Pipe length L of confluxing is 2 to 10 times collecting pipe smallest cross-sectional width, and the Taper Pipe cone angle confluxes

Being that angle between two DC tube adjacent in 20 ° to 60, three DC tube that cross is identical, is 30 ° to 90 °, and all the other parameters of structural dimension are conventional value.

When the piezoelectric vibrator distortion diminishes pump chamber, this pump is in discharge process, can regulate respectively the flow of two DC tube in three-way pipe both sides by the amount of deformation of regulating respectively two piezoelectric vibrators that are distributed in the three-way pipe both sides, the jet that two plume amounts are different converges with another jet along the Taper Pipe direction of confluxing in the Taper Pipe that confluxes, cause the Taper Pipe two side areas pressure that confluxes different, wall attachment effect occurs and change jet direction, fluid is close to conflux Taper Pipe one side and is flowed out from one of them ram's horns, when the piezoelectric vibrator distortion makes pump chamber become large, this pump is in suction process, the flow that flows into pump chamber from two ram's hornss is basic identical, and the difference of flow is the pump discharge of one-period on the ram's horns both direction.

The invention has the beneficial effects as follows: simple in structure, be easy to microminiaturization, the volumetric efficiency of pump is high, and can realize two-way conveying fluid.

Description of drawings

Fig. 1 is structure sectional view of the present invention;

Fig. 2 is plan view of the present invention;

Fig. 3 is A-A sectional drawing among Fig. 1;

Fig. 4 is I partial enlarged drawing among Fig. 3;

Fig. 5 is B-B sectional drawing among Fig. 2;

Fig. 6 is C-C sectional drawing among Fig. 2;

Discharge process fundamental diagram when Fig. 7 is working state I of the present invention;

Suction process fundamental diagram when Fig. 8 is working state I of the present invention;

Discharge process fundamental diagram when Fig. 9 is working state II of the present invention;

Suction process fundamental diagram when Figure 10 is working state II of the present invention;

Figure 11 is the speed vector figure of embodiment 1 in discharge process;

Figure 12 is the speed vector figure of embodiment 1 in suction process;

Figure 13 is ram's horns 18 in embodiment's 1 one-period, 19 air-quantity chart;

Figure 14 is embodiment 1 physical dimension;

1,7,10. piezoelectric vibrator among the figure:; 2, pump chamber on 21,22.; 3. pump cover; 4,11,14. times pump chambers; 5. hydrocontrolling element; 6. the pump housing; 8, the 9. import and export of pump; 12,13. turnover oral cavities; 15,16,20. DC tube; The Taper Pipe 17. conflux; 18,19. ram's hornss.

Embodiment

Shown in Fig. 1,2,3,4,5,6, the present invention includes the pump housing 6, pump cover 3 and three piezoelectric vibrators 1,7,10, the pump housing 6 and pump cover 3 bondings, three piezoelectric vibrators 1,7,10 are fixed in pump cover 3 tops by binder, process pump chamber 2,21,22 on three at pump cover, the import and export 8,9 of two pumps process three lower pump chambers 4,11,14, two turnover oral cavities 12,13 and hydrocontrolling element 5 at the pump housing; Lower pump chamber 4 is communicated with upper pump chamber 2, lower pump chamber 11 is communicated with upper pump chamber 21, lower pump chamber 14 is communicated with upper pump chamber 22, turnover oral cavity 12,13 respectively with import and export 8,9 and be communicated with, hydrocontrolling element 5 be one by conflux Taper Pipe 17 and two identical ram's hornss 18,19 three-port structures that form and three DC tube 15,16,20; One end of ram's horns 18 and ram's horns 19 crosses and is communicated with the larger end of Taper Pipe 17 sectional areas that confluxes, the other end is communicated with snout cavity 12 and outlet plenum 13 respectively, the end that DC tube 15, DC tube 16 are connected with DC tube connects respectively lower pump chamber 4, lower pump chamber 11 and lower pump chamber 14, the other end crosses and is communicated with Taper Pipe 17 smallest cross-sectional of confluxing, and hydrocontrolling element 5 is centrosymmetric about Taper Pipe 17 center lines that conflux.

When the present invention works, load respectively synchronous alternating voltage and make three piezoelectric vibrators 1,7,10 synchronous vibrations, if piezoelectric vibrator 1 is identical with the Oscillation Amplitude of piezoelectric vibrator 7, the Oscillation Amplitude of piezoelectric vibrator 10 is less, is the working state I; If piezoelectric vibrator 1 is identical with the Oscillation Amplitude of piezoelectric vibrator 10, the Oscillation Amplitude of piezoelectric vibrator 7 is less, is the working state II.

Piezoelectric vibrator 1,7,10 vibration downwards is discharge process, upper pump chamber 2,21,22 volumes reduce, fluid is discharged via hydrocontrolling element 5 from lower pump chamber 4,11,14, piezoelectric vibrator 1,7,10 upwards vibration is suction process, upper pump chamber 2,21,22 volumes increase, and fluid flows into lower pump chamber 4,11,14 from the external world via hydrocontrolling element 5; If under the in running order I, in the discharge process in the hydrocontrolling element 5 mobility status as shown in Figure 7, the flow in DC tube 15 and the DC tube 16 is

, the flow in the DC tube 20 is less, for

, since wall attachment effect, the deflection that flows in the Taper Pipe 17 that confluxes ram's horns 19 1 sides, and via ram's horns 19 outflows, the segment fluid flow in the ram's horns 18 is entrainmented and enters ram's horns 19 simultaneously, flow is

, the total discharge that flows out from ram's horns 19 is Mobility status is as shown in Figure 8 in the hydrocontrolling element 5 in the suction process, because piezoelectric vibrator 1,7,10 upwards vibration is identical with the amount of deformation of vibration downwards, flow in the DC tube 15,16,20 is identical during respectively with discharge process, and flow direction is opposite, identical with the flow that ram's horns 19 flows into collecting pipe via ram's horns 18, for

The pump discharge of one-period is the difference of flow on ram's horns 18 or ram's horns 19 both directions, namely

If under the in running order II, in the discharge process in the hydrocontrolling element 5 mobility status as shown in Figure 9, the flow in DC tube 15 and the DC tube 20 is

, the flow in the DC tube 16 is less, for

, since wall attachment effect, the deflection that flows in the Taper Pipe 17 that confluxes ram's horns 18 1 sides, and via ram's horns 18 outflows, the segment fluid flow in the ram's horns 19 is entrainmented and enters ram's horns 18 simultaneously, flow is

, the total discharge that flows out from ram's horns 18 is In the suction process in the hydrocontrolling element 5 mobility status as shown in figure 10, it is similar to the working state I to flow, identical with the flow of ram's horns 19 inflow collecting pipes via ram's horns 18, for

, the pump discharge of working state II one-period also is

, it is opposite that working state II and working state I are compared throughput direction, and pump discharge is identical.

 

Embodiment 1: present embodiment is liquid numerical simulation, and shown in Figure 14 is the physical dimension of present embodiment, specifically is of a size of: the Taper Pipe 17 smallest cross-sectional width a that conflux are 150 μ m, cone angle

Be 32 °, length L is 700 μ m, and the angle in the DC tube that three cross between adjacent two DC tube is identical, is 90 °; Ram's horns 18,19 width

,

Be 235 μ m, angle

Be 32 °, DC tube 15,16,20 width

, ,

Be 100 μ m, pipeline depth h is 100 μ m; Replace upper pump chamber 2,21,22 and lower pump chamber 4,11,14 volume-variation because of piezoelectric vibrator 1,7,10 generation of vibrations with the velocity boundary conditions of sinusoidal variations, frequency is 100Hz, DC tube 15,16,20 maximum mean velocity are respectively 10m/s, 10m/s, 1m/s, flowing medium is water, uses the SST turbulence model.

Figure 11 and shown in Figure 12 be respectively embodiment at the speed vector figure of discharge process and suction process, wall attachment effect occurs in discharge process, ram's horns 18 in the suction process, 19 velocity flow profile are more or less the same; Ram's horns 18 in shown in Figure 13 is embodiment's one-period, 19 instantaneous flow, the pump discharge that can be calculated this embodiment is 67.6%.

Claims (2)

1. A three-cavity valveless piezoelectric pump based on the Coanda effect, including a pump body, a pump cover and three piezoelectric vibrators, the pump body and the pump cover are bonded, and the three piezoelectric vibrators are fixed above the pump cover. The cover is provided with three upper pump chambers, one inlet and one outlet, and the pump body is provided with three lower pump chambers corresponding to the upper pump chamber, the inlet chamber, the outlet chamber and the jet control element; the three lower pump chambers and the three The upper pump chambers are connected respectively, and the inlet and outlet chambers are respectively connected with the inlet and outlet of the pump. It is characterized in that: the jet control element is composed of a three-way pipe and three direct-flow pipes, and the three-way pipe is composed of a confluence cone pipe and two identical A three-way structure composed of shunt pipes, one end of the two shunt pipes communicates with the end with a larger cross-sectional area of the confluence cone, and the other end communicates with the inlet and outlet chambers respectively, and one end of the three direct-flow pipes connects to three lower pump chambers, and the other end Intersect and communicate with the minimum cross-section of the confluence cone, and the jet flow control element is symmetrical about the center line of the confluence cone. 2. A three-cavity valveless piezoelectric pump based on the Coanda effect as claimed in claim 1, wherein the value range of the minimum cross-sectional width a of the confluence cone is 40 μm to 1 mm, and the length L of the confluence cone is 2 to 10 times the minimum section width of the manifold, the cone angle of the manifold

20° to 60°, and the included angle between two adjacent straight pipes among the three intersecting straight pipes is the same, ranging from 30° to 90°.

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