CN103644105B - A kind of Archimedes spiral pipe Valveless piezoelectric pump - Google Patents

Abstract

The invention discloses an Archimedes solenoid valveless piezoelectric pump, which comprises a pump body and a pump cover. The pump body has an inlet buffer chamber, an outlet buffer chamber, an inlet flow pipe, an outlet flow pipe and the lower half of the pump chamber. Part, the inlet flow pipe and the outlet flow pipe have the same structure and are coaxially arranged and equidistant from the center of the pump chamber. The flow pipe centerline is symmetrically arranged and connected by a split pipe. The Archimedes spiral flow pipe has a good property of a linear transition of the curvature radius. When the fluid flows in it, it is subjected to a uniform lateral force, the flow is stable, the vibration is small, and the energy consumption is low. ,efficient.

Description

An Archimedes solenoid valveless piezoelectric pump

technical field

The invention relates to the technical fields of microfluid transmission and control and micromechanics, in particular to an Archimedes solenoid valveless piezoelectric pump.

Background technique

Piezoelectric pump is a kind of mechanical micropump, which belongs to positive displacement pump. It is widely used in the fields of micro-transportation of drugs, cell separation, cooling of electronic products, micro-injection of fuel, chemical micro-analysis, and transition control of pipeline flow. At present, piezoelectric pumps are mainly divided into two types: valved piezoelectric pumps and valveless piezoelectric pumps. Valveless piezoelectric pumps have no movable valves, and have a simple structure, which is more suitable for miniaturization and miniaturization, and can meet the needs of high-frequency applications. Work requirements, overcome the shortcomings of valved piezoelectric pumps that cause noise when the flow is interrupted, and have good anti-fatigue performance, avoiding some sensitive media from being affected. Most valveless piezoelectric pumps connect two special-structure flow tubes with the pump chamber, and use the difference in flow resistance when the fluid flows in different directions along the special-structure flow tubes to produce pumping effects. The common special-structure flow tubes are tapered tubes , tesla tube, vortex tube, tee tube, etc.

The conical tube has a simple structure and is easy to design and process, but its difference in forward and reverse flow resistance is small, resulting in low efficiency of the micropump; Tesla tubes are also called special-shaped tubes, and their main structure is composed of straight channels and curved channels , when the fluid reciprocates, due to the difference in the length of the flow channel and the inertial effect of the fluid, the net flow in the outlet direction is generated, but the difference in forward and reverse flow resistance is also very small, and the net flow obtained by the micropump in one working cycle is limited; The essence of the vortex tube is to add a series of triangular or circular vortex areas on the wall of the two-dimensional plane conical tube. These triangular vortex areas form a vortex channel together with the conical flow tube, but the existence of the vortex surface increases. This increases the difficulty of making the flow channel, and the forward and reverse flow resistance of this flow tube is very large, which makes the micropump consume a lot of energy and low efficiency; the three-way tube includes "Y" type tube and "V" type tube, etc., " Y"-shaped pipe consists of a confluence pipe and two diversion pipes to form a "Y" shape. The confluence pipe and the diversion pipe are rectangular pipes with equal cross-section. (shrinkage) shunt tube, the three-way tube reduces the forward flow resistance to a certain extent, and increases the reverse flow resistance, so that the micropump can obtain a higher net flow along the forward direction in one working cycle, but the straight line The design of the pipe wall makes the friction loss larger when the fluid flows, and the energy consumption is higher. The Chinese invention patent application with the publication number CN102230465A discloses an Archimedes spiral flow tube valveless piezoelectric pump. A first Archimedes screw is arranged between the lower cover and the upper cover of the valveless piezoelectric pump. A line flow tube and a first communication groove, one end of the Archimedes spiral flow tube is connected to the fluid inlet provided on the pump body, and the other end is connected to the pump chamber; one end of the first communication groove is connected to the pump chamber, The other end is connected with the fluid outlet; the first Archimedes spiral flow tube is an Archimedes spiral flow tube with the fluid inlet as the center and the starting point counterclockwise. The flow tube of this kind of structure uses the overall Archimedes spiral structure flow tube, the flow channel is too long, and the loss of the fluid along the forward and reverse directions is very large when the fluid flows in the curved flow tube. The secondary flow is formed on the surface, which increases the local resistance and causes the loss of the secondary flow, and the direct communication groove used has no flow resistance characteristics, so the efficiency of the micropump is low. In addition, the structure is relatively complicated, which is not conducive to integration and miniaturization.

The ancient Greek mathematician and mechanics Archimedes made a detailed discussion on the geometric properties of the plane equidistant spiral in his treatise "On the Spiral", which is called "Archimedes spiral". Later mathematicians discovered chain spiral, Fermat spiral, logarithmic spiral, hyperbolic spiral, cylindrical spiral, conical spiral, etc. The solenoid flow tube has superior structural characteristics and good hydrodynamic properties, which is conducive to integrated layout, and is widely used in energy, warships, submarines, space stations, ship power, petrochemical, aerospace, electronic cooling and cryogenic technology and other fields .

Contents of the invention

The purpose of the present invention is exactly to propose a kind of Archimedes solenoid valveless piezoelectric pump in order to avoid the deficiencies in the above-mentioned technology, and it is mainly aimed at the existing problems of existing valveless piezoelectric pumps such as flow turbulence, viscous A new type of Archimedes solenoid valveless piezoelectric pump with small scale, stable flow, low energy consumption, high efficiency, and low vibration due to adverse effects such as large resistance and easy separation of the boundary layer, and expanded the spiral flow tube technology at the same time The scope of application in the field of microfluidic machinery.

The technical scheme adopted by the present invention is: including a pump body and a pump cover, the pump cover has a pump inlet, a pump outlet and the upper half of the pump chamber, and the pump body has an inlet buffer chamber, an outlet buffer chamber, an inlet flow pipe, and an outlet flow pipe As in the lower part of the pump chamber, the inlet flow pipe and the outlet flow pipe have the same structure and are coaxially arranged and equidistant from the center of the pump chamber. One end of the inlet flow pipe communicates with the inlet buffer chamber, the other end communicates with the pump chamber, and one end of the outlet flow pipe It is connected with the pump chamber, and the other end is connected with the outlet buffer chamber. The inlet buffer chamber and the outlet buffer chamber are respectively connected with the pump inlet and the pump outlet. The inlet flow pipe and the outlet flow pipe are composed of an Archimedes spiral flow pipe and a The center line of the Archimedes spiral flow tube is symmetrically arranged and connected to the shunt tube. The small end of the Archimedes spiral flow tube in the inlet flow tube is connected with the inlet buffer chamber, and the large end is connected with the pump chamber; The small end of the Archimedes spiral flow tube is connected to the pump cavity, and the large end is connected to the outlet buffer cavity; the second and third flow tubes are straight tubes with the same geometric structure and size, and the central axes of the two are in line with the Archimedes The central axis of the spiral flow pipe is parallel and symmetrical; one end of the second shunt pipe communicates with the first shunt pipe, and the other end communicates with the pump chamber; one end of the third shunt pipe communicates with the fourth shunt pipe, and the other end communicates with the pump chamber; The first and fourth shunt tubes are semicircular tubes with the same geometric structure and size, and both are symmetrical to the center line of the Archimedes spiral flow tube and are respectively connected with the big ends of the Archimedes spiral flow tube.

The contour of the horizontal cross-section of the Archimedes spiral flow tube is given by the Archimedes spiral equation The determined segment of the Archimedes spiral with wrap angle φ of 45°, constant =0.1, polar angle =0~2610°; the length of the Archimedes spiral flow tube is 1200μm~3000μm, the height is 80μm~150μm, the minimum cross-sectional width of the small end is 120μm~180μm, and the radius of the fillet at the small end is 50μm~80μm.

The beneficial effects of the present invention are: the present invention organically combines the solenoid flow tube technology with the piezoelectric pump technology, adopts the flow tube structure of the combination of the spiral flow tube and the shunt tube whose outline is the Archimedes helix, and is different from the traditional diffusion Compared with the shrink tube valveless piezoelectric pump and the three-way tube valveless piezoelectric pump, the Archimedes spiral flow tube has a good property of linear transition of the radius of curvature, and the fluid flows in it under a uniform lateral force. Stable, small vibration, low energy consumption, high efficiency; when the fluid flows forward along the inlet flow pipe (outlet flow pipe), the shunt pipe plays a suction role to a certain extent, thereby controlling the separation of the boundary layer and preventing flow separation. Reduce the loss, reduce the forward flow resistance, and increase the flow through the flow tube; when the fluid flows in the reverse direction along the inlet flow tube (outlet flow tube), the reasonable application of the shunt tube with a certain inclination angle relative to the flow direction and the wall surface, Discrete longitudinal vortices can be generated, which can disrupt the flow of the main flow to a certain extent, increasing the reverse flow resistance and reducing the flow through the flow tube, so that a higher net flow can be obtained along the forward flow direction in one working cycle , improves the efficiency of the valveless piezoelectric pump; at the same time, the pump can work at a higher frequency, has a strong ability to prevent electromagnetic interference, and the flow is easy to control. It can be applied to biochips, microfluidic chips, miniature full analysis systems and clinical applications. Drug micro-infusion system and other fields.

Description of drawings

Fig. 1 is a front sectional view of the overall structure of an Archimedes solenoid valveless piezoelectric pump according to the present invention;

Fig. 2 is the A-A direction sectional view of Fig. 1;

Fig. 3 is a partial enlarged view of I in Fig. 2;

Figure 4 is an enlarged view of the geometry of the inlet flow pipe 7 or the outlet flow pipe 9 in Figure 2;

Fig. 5 is the B-B direction sectional view of Fig. 2;

Fig. 6 is a partial enlarged view of M in Fig. 5;

Fig. 7 is a schematic diagram of the Archimedes spiral under the polar coordinate system used by the present invention;

Fig. 8 is a working principle diagram of the suction process of the inlet flow pipe 7 in the present invention;

Fig. 9 is a working principle diagram of the discharge process of the inlet flow pipe 7 in the present invention;

Fig. 10 is a working principle diagram of an Archimedes solenoid valveless piezoelectric pump suction process according to the present invention;

Fig. 11 is a working principle diagram of an Archimedes solenoid valveless piezoelectric pump discharge process according to the present invention;

In the figure: 1. Pump inlet; 2. Pump cover; 3. Piezoelectric vibrator; 4. Pump chamber; 5. Pump outlet; 6. Inlet buffer chamber; 7. Inlet flow tube; 8. Pump body; 9. Outlet flow Tube; 10. Outlet buffer cavity; 11. Archimedes solenoid; 12, 13, 14, 15. Splitter tube.

detailed description

Referring to Fig. 1, Fig. 2 and Fig. 5, a kind of Archimedes solenoid valveless piezoelectric pump of the present invention comprises pump body 8, pump cover 2 and piezoelectric vibrator 3, and the material of pump body 8 is silicon chip , the material of the pump cover 2 is glass, the pump inlet 1, the pump outlet 5 and the upper half of the pump cavity 4 are processed on the pump cover 2 by laser processing technology, and the inlet is processed on the pump body 8 by using a dry etching process. The buffer chamber 6, the outlet buffer chamber 10, the inlet flow pipe 7, the outlet flow pipe 9 and the lower half of the pump chamber 4, the inlet flow pipe 7 and the outlet flow pipe 9 have the same structure and are arranged coaxially, and are arranged with the center of the pump chamber 4, etc. One end of the inlet flow pipe 7 communicates with the inlet buffer chamber 6, the other end communicates with the pump chamber 4, one end of the outlet flow pipe 9 communicates with the pump chamber 4, and the other end communicates with the outlet buffer chamber 10, and the inlet buffer chamber 6 and the outlet buffer chamber The cavity 10 is respectively connected to the pump inlet 1 and the pump outlet 5, the pump body 8 and the pump cover 2 are closely bonded by anodic bonding process, and the piezoelectric vibrator 3 is fixed and bonded directly above the pump cover 2 with an adhesive.

Referring to Fig. 2 and Fig. 3, the inlet flow pipe 7 and the outlet flow pipe 9 are connected by an Archimedes spiral flow pipe 11 and a shunt pipe arranged symmetrically with respect to the center line of the Archimedes spiral flow pipe 11, Wherein, the shunt pipe 13 and the shunt pipe 14 are arranged symmetrically with respect to the center line of the Archimedes spiral flow pipe 11, and the central axes of the shunt pipe 13 and the shunt pipe 14 are parallel to the central axis of the Archimedes spiral flow pipe 11 One end of the shunt pipe 13 communicates with the shunt pipe 12, and the other end communicates with the pump chamber 4; one end of the shunt pipe 14 communicates with the shunt pipe 15, and the other end communicates with the pump chamber 4. The shunt pipe 12 and the shunt pipe 15 are arranged symmetrically with respect to the centerline of the Archimedes spiral flow pipe 11, and the shunt pipe 12 and the shunt pipe 15 are connected with the big end of the Archimedes spiral flow pipe 11 respectively; the shunt pipe 13 The geometric structure dimensions of the branch pipe 14 are the same, and the geometric structure dimensions of the branch pipe 12 and the branch pipe 15 are the same. The small end of the Archimedes spiral flow tube 11 of the inlet flow tube 7 communicates with the inlet buffer chamber 6 , and the small end of the Archimedes spiral flow tube 11 of the outlet flow tube 9 communicates with the pump chamber 4 .

Referring to Fig. 4, Fig. 6 and Fig. 7, the contour line of the horizontal cross section of the Archimedes spiral flow tube 11 is determined by the Archimedes spiral equation The determined Archimedes spiral segment MN with a wrap angle φ of 45°, where the constant is 0.1, the polar angle is 0~2610°; the length of the Archimedes spiral flow tube 11 1200μm~3000μm, height 80μm~150μm, the minimum section width of the small end 120μm~180μm, small end nozzle fillet radius 50 μm ~ 80 μm; the flow tubes 13 and 14 are direct current tubes, the distance between their central axis and the central axis of the Archimedes spiral flow tube 11 410μm~900μm, length 400μm~1000μm, width for ,high Height with Archimedes spiral flow tube 11 Same; shunt pipes 12, 15 are semicircular pipes, the distance from the center of its circle to the central axis of Archimedes spiral flow pipe 11 270μm~560μm, inner semicircle radius 110μm~250μm, outer semicircle radius 170μm~420μm.

Referring to Fig. 8, Fig. 9, Fig. 10 and Fig. 11, the working principle of an Archimedes solenoid valveless piezoelectric pump according to the present invention is: an alternating voltage signal (sinusoidal or rectangular wave signal), the piezoelectric vibrator 3 will bend and deform and vibrate up and down with the voltage frequency, and the vibration drives the fluid flow in the pump chamber 4; the movement of the piezoelectric vibrator 3 can be divided into upward displacement motion and downward displacement motion , the flow process in the pump chamber 4 is correspondingly divided into a suction process and a discharge process. When the piezoelectric vibrator 3 vibrates upward, the volume of the pump chamber 4 increases, and the pressure in the pump chamber 4 decreases and is lower than the external pressure, so that the fluid flows into the pump from the pump inlet 1 and the pump outlet 5 through the inlet flow pipe 7 and the outlet flow pipe 9 At this time, the piezoelectric pump is in the suction state. Due to the difference in the flow resistance coefficients of the inlet flow pipe 7 and the outlet flow pipe 9 in the forward and reverse directions, the flow of the pump inlet 1 flowing into the pump chamber 4 through the inlet flow pipe 7 Greater than the flow rate flowing into the pump chamber 4 from the pump outlet 5 through the outlet flow pipe 9 , since both the inlet flow pipe 7 and the outlet flow pipe 9 adopt the flow pipe structure of the combination of the spiral flow pipe 11 whose outline is the Archimedes helix and the shunt pipes 12, 13, 14, 15, so in the suction process , when the fluid flows through the Archimedes spiral flow tube 11 from the inlet buffer chamber 6, the flow is stable, the energy loss is small, and the four shunt tubes 12, 13, 14 and 15 can lead the fluid to be stagnated on the wall surface of the Archimedes spiral flow tube 11 into the pump chamber 4, and play a suction effect to a certain extent, and this suction effect can make the Archimedes spiral flow The fluid in the boundary layer of the pipe 11 overcomes the effect of the reverse pressure difference and continues to flow to the pump chamber 4, thereby preventing the separation of the boundary layer to a certain extent and achieving the effect of reducing viscous frictional resistance, so that it flows into the pump chamber through the inlet flow pipe 7 4 traffic increase, and at the same time due to the sudden expansion effect, a pair of vortices formed at the outlet of the Archimedes spiral flow tube 11 moves to the center of the pump chamber 4 under the action of the fluid passing through the four shunt tubes 12, 13, 14, and 15. During the process, the dissipation of the vortex becomes slow, the vortex decreases, and the effective range increases, thereby further inhibiting or delaying the occurrence of flow separation; similarly, the fluid flows from the outlet buffer chamber 10 through the Archimedes spiral flow tube 11 , compared with the straight wall surface flow tube (diffusion/shrink tube), the Archimedes spiral flow tube 11 has greater resistance to flow, and when the fluid flows through the four split tubes 12, 13, 14, 15, it can generate The vertical vortex of the vertical vortex has a certain disturbing effect on the mainstream, making the reverse flow resistance increase, and the flow through the flow tube Further reduced, the total inflow of the piezoelectric pump during the suction process is ; When the piezoelectric vibrator 3 vibrates downward, the volume of the pump chamber 4 decreases, and the pressure in the pump chamber 4 increases and is greater than the external pressure, so that the fluid passes through the inlet flow pipe 7 and the outlet flow pipe 9 on both sides of the pump chamber 4 by The pump inlet 1 and the pump outlet 5 flow out of the pump chamber 4. At this time, the piezoelectric pump is in the discharge state. This process is opposite to the pump suction process. The pump chamber 4 passes through the inlet flow tube 7 and the flow discharged from the pump inlet 1 Less than the flow discharged from the pump outlet 5 by the pump chamber 4 through the outlet flow pipe 9 , the total outflow of the piezoelectric pump during the discharge process is In the present invention, the vibration amplitude of the piezoelectric vibrator 3 is constant in the suction process and the discharge process, and the flow rate flowing into the pump cavity 4 is equal to the flow rate flowing out of the pump cavity 4, which is denoted as , then there is , a discharge process and a suction process constitute a cycle, and the pumping flow rate of a cycle is the difference between the flow rate that flows out of the pump chamber 4 through the outlet flow pipe 9 and the flow rate that flows into the pump chamber 4 , or the difference between the flow rate flowing into the pump chamber 4 through the inlet flow pipe 7 and the flow rate flowing out of the pump chamber 4 , then the pumping flow in one cycle for:

,

This value is greater than zero. Therefore, in a working cycle of the valveless piezoelectric pump, the flow that flows into the pump chamber 4 through the inlet flow pipe 7 during the suction process is greater than the discharge flow during the discharge process, while the outlet flow pipe 9 is just the opposite, that is, in The flow rate flowing into the pump chamber 4 during the suction process is smaller than the discharge flow rate during the discharge process, finally realizing the one-way flow of the fluid and completing the pumping function.

Claims (3)

1. an Archimedes spiral pipe Valveless piezoelectric pump, comprise the pump housing (8) and pump cover (2), pump cover (2) there is pump inlet (1), upper half part of pump discharge (5) and pump chamber (4), the pump housing (8) there is import buffer cavity (6), outlet buffer cavity (10), inlet flow tube (7), lower half portion of outlet flow pipe (9) and pump chamber (4), inlet flow tube (7) is identical with outlet flow pipe (9) structure and coaxially arranged and equidistant with pump chamber (4) center of circle, inlet flow tube (7) one end is communicated with import buffer cavity (6), the other end is communicated with pump chamber (4), outlet flow pipe (9) one end is communicated with pump chamber (4), the other end is communicated with outlet buffer cavity (10), import buffer cavity (6) is communicated with pump inlet (1) and pump discharge (5) respectively with outlet buffer cavity (10), it is characterized in that: described inlet flow tube (7) is communicated with composition by an Archimedean spiral flow pipe (11) with the ram's horns be arranged symmetrically with relative to Archimedean spiral flow pipe (11) center line with outlet flow pipe (9), the small end of the Archimedean spiral flow pipe (11) in inlet flow tube (7) is connected with import buffer cavity (6), large end is connected with pump chamber (4), the small end of the Archimedean spiral flow pipe (11) in outlet flow pipe (9) is connected with pump chamber (4), large end is connected with outlet buffer cavity (10), second, third ram's horns (13,14) is DC tube that geometric structure diamete is identical and both central axis are symmetrical relative to the centerline axis parallel of Archimedean spiral flow pipe (11), second ram's horns (13) one end is communicated with the first ram's horns (12), the other end is communicated with pump chamber (4), 3rd ram's horns (14) one end is communicated with the 4th ram's horns (15), the other end is communicated with pump chamber (4), the first, the 4th ram's horns (12,15) is semicircular pipe that geometric structure diamete is identical and both are symmetrical relative to Archimedean spiral flow pipe (11) center line and through with the large end of Archimedean spiral flow pipe (11) respectively.

2. a kind of Archimedes spiral pipe Valveless piezoelectric pump according to claim 1, is characterized in that: the profile line of the level cross-sectionn of Archimedean spiral flow pipe (11) is by spiral of Archimedes equation the cornerite φ determined is the spiral of Archimedes section of 45 °, constant =0.1, polar angle =0 ~ 2610 °; The length of Archimedean spiral flow pipe (11) is 1200 μm ~ 3000 μm, is highly 80 μm ~ 150 μm, and the smallest cross-sectional width of small end is 120 μm ~ 180 μm, and small end mouth of pipe fillet radius is 50 μm ~ 80 μm.

3. a kind of Archimedes spiral pipe Valveless piezoelectric pump according to claim 2, is characterized in that: the distance of the central axis of second, third ram's horns (13,14) and the central axis of Archimedean spiral flow pipe (11) is 410 μm ~ 900 μm, length be 400 μm ~ 1000 μm, width is , height is identical with the height of Archimedean spiral flow pipe (11); The first, the center of circle of the 4th ram's horns (12,15) is 270 μm ~ 560 μm to the distance of the central axis of Archimedean spiral flow pipe (11), and interior semicircle radius is 110 μm ~ 250 μm, and outer semicircle radius is 170 μm ~ 420 μm.