A piezoelectric micropump driven by dual piezoelectric and gas wheel type valve and pumping method

Abstract

The application discloses a piezoelectric micro-pump with double piezoelectric driving gas wheel type valve and a pumping method. The piezoelectric micro-pump comprises a pump body shell, a sandwich piezoelectric vibrator and two gas wheel type valves. The sandwich piezoelectric vibrator is fixed in the pump flow chamber of the pump body shell, and the pump flow chamber is divided into an air inlet cavity and an air outlet cavity. The pump body shell is provided with a series flow channel structure communicating the air inlet cavity and the air outlet cavity. The gas wheel type valve comprises a blocking layer, a diaphragm layer, a movable layer and a flow layer which are sequentially stacked along the air passing direction. A first flow hole is formed in the flow structure of the middle part of the flow layer; and a response hole is formed in the limiting structure of the middle part of the blocking layer. The application forms a rapid pressure feedback path through the response hole, realizes the rapid closing response of the valve piece, and makes the wheel type valve meet the response speed requirement of the gas pump. Meanwhile, the double piezoelectric driving elements in the sandwich piezoelectric vibrator help to improve the amplitude and reduce the input voltage.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric gas micropump technology, specifically relating to a dual-piezoelectric driven gas wheel valve piezoelectric micropump and a pumping method. Background Technology

[0002] Piezoelectric micropumps, as miniature fluid control devices that utilize piezoelectric vibration to drive gas, have been widely used in medical and nursing equipment, wearable electronic devices, portable gas circulation systems, and various microfluidic control platforms in recent years. Traditional piezoelectric micropumps typically use a monolithic piezoelectric vibrator in conjunction with a mechanical or diaphragm check valve to achieve unidirectional flow, but existing valve structures generally suffer from performance bottlenecks.

[0003] Specifically, for traditional wheel valves, the valve plate closure often relies solely on the elastic restoring force of the material itself or the natural pressure difference, lacking an effective rapid pressure-assisted feedback mechanism, resulting in slow valve closure speed and sluggish response, making it difficult to achieve precise fluid control under high-frequency operation.

[0004] Furthermore, the traditional staggered-hole one-way valve structure (which achieves unidirectional flow and closure through staggered vents on two diaphragm layers) relies on local deformation of the diaphragm to cover the staggered holes for sealing. This results in a long pressure transmission path and slow response during closure, and it is prone to fatigue cracking or plastic deformation under long-term high-frequency vibration, leading to seal failure. Additionally, after shutdown, incomplete diaphragm reset can easily create micro-leakage paths, resulting in poor pressure holding capacity and making it difficult to meet the stringent requirements of medical and portable device applications demanding high airtightness and pressure retention.

[0005] Besides the limitations of valve structures, some micropump solutions attempt to improve flow channel efficiency by fabricating micro-protrusions or micro-fluidic structures on vibrating substrates or barrier structures, such as the method of etching piezoelectric vibrating substrates proposed in existing technologies. However, the vibrating substrate itself is the core vibrating component of the piezoelectric micropump. Etching or slotting it not only presents significant processing difficulties and low yield rates but also inevitably weakens structural strength and fatigue life, significantly affecting the output stability and reliability of the micropump. Therefore, how to achieve efficient flow channel control without compromising the integrity of the vibrating substrate remains a problem that existing technologies struggle to solve.

[0006] On the other hand, traditional piezoelectric micropumps mostly use a single piezoelectric oscillator for driving, which requires a high excitation voltage to obtain high vibration energy. This is not conducive to integration into small portable devices. In addition, many electronic products have safety voltage requirements, and high voltage output poses certain risks. Therefore, how to maintain or even improve the output capability of the micropump while reducing the driving voltage has become another key technical challenge in the design of piezoelectric micropumps.

[0007] In summary, there is still an urgent need for a novel piezoelectric micropump system that combines the advantages of rapid opening and closing, high flow output, strong pressure holding performance, miniaturized structure, and low-voltage drive, in order to solve the technical problems of slow response, complex manufacturing, insufficient pressure holding performance, and high voltage dependence of traditional valve structures. This invention is based on the above technical needs and achieves a balance between high performance and high reliability through a novel wheel-type gas valve structure and dual piezoelectric element synergistic drive technology, significantly improving the overall performance of the micro gas drive device. Summary of the Invention

[0008] The purpose of this invention is to provide a dual-piezoelectric driven gas wheel valve piezoelectric micropump and its pumping method. This piezoelectric micropump is used in applications requiring high negative pressure and high flow rate gas output, such as breast pumps and eye massagers, to achieve more efficient and reliable gas driving performance. Through the collaborative driving method of the dual piezoelectric elements, the external excitation voltage can be significantly reduced while maintaining high output capacity. Only half the driving voltage of traditional piezoelectric oscillators is required to achieve comparable performance levels, keeping the overall driving voltage within a safe range for humans and making it easier to integrate into various terminal electronic products. Combined with an integrated modular gas wheel valve structure, it not only enhances the overall pressure holding effect while increasing pump pressure output and delaying pressure decay after shutdown, but also has advantages such as small size and easy assembly, enabling its widespread application in various micro gas control systems requiring unidirectional gas flow.

[0009] In a first aspect, the present invention provides a dual-piezoelectric driven gas wheel valve piezoelectric micropump, comprising a pump body housing. A pump flow chamber is provided within the pump body housing. The piezoelectric micropump further includes a sandwich-type piezoelectric vibrator and two gas wheel valves. The sandwich-type piezoelectric vibrator is fixed in the pump flow chamber, dividing the pump flow chamber into an inlet chamber and an outlet chamber. A series flow channel structure connecting the inlet chamber and the outlet chamber is provided within the pump body housing. The two gas wheel valves are respectively disposed between the inlet chamber and the inlet port, and between the outlet chamber and the outlet port.

[0010] The gas wheel valve includes a barrier layer, a diaphragm layer, a movable layer, and a flow passage layer stacked sequentially along the ventilation direction. One or more first flow passage holes are formed on the flow passage structure in the middle of the barrier layer; one or more response holes are formed on the limiting structure in the middle of the flow passage layer.

[0011] The active layer has a slotted structure that provides deformation space for the diaphragm layer. The diaphragm layer includes a central air-blocking section that aligns with the flow passage structure and the barrier layer limiting structure. When the gas wheel valve is closed, the central air-blocking section covers all first flow holes; when the gas wheel valve is open, the central air-blocking section covers all response holes. The diaphragm layer has a second flow hole surrounding the central air-blocking section. The flow passage layer has a third flow hole surrounding the limiting structure.

[0012] Preferably, the first flow orifice is aligned with the response orifice.

[0013] Preferably, the second flow passage on the diaphragm layer is aligned with the third flow passage on the flow passage layer. The area of ​​the third flow passage is larger than the area of ​​the second flow passage.

[0014] Preferably, the sandwich piezoelectric vibrator includes an intermediate counterweight layer, two support structures, and two driving elements stacked sequentially from the center to both sides. The outer peripheral edges of the two support structures are fixed by a pump flow chamber.

[0015] Preferably, the support structure includes a flexible substrate and two power supply lines; the driving element has an electrode in the central region and the peripheral region of the side of the corresponding support structure; the two electrodes are led out through the two power supply lines respectively.

[0016] Preferably, the pump body housing includes an inlet sealing housing and an outlet sealing housing that are spliced ​​and fixed together. Pump flow grooves are formed on opposite sides of both the inlet and outlet sealing housings. The two pump flow grooves together form a pump flow chamber; the outer connecting parts of the two supporting structures in the sandwich-type piezoelectric vibrator are sandwiched between the inlet and outlet sealing housings.

[0017] Preferably, the bottom surface of the pump flow channel is arc-shaped, causing the channel depth to gradually increase from the center to the edge. A support portion is provided at the center of the bottom surface of the pump flow channel. Two gas wheel valves are respectively fixed to the support portions of the two pump flow channels.

[0018] Preferably, the series flow channel structure includes a first series hole and a first air guide channel that are interconnected within the intake sealing housing, and a second series hole and a second air guide channel that are interconnected within the exhaust sealing housing. The first air guide channel and the second air guide channel are connected on opposite sides of the intake sealing housing and the exhaust sealing housing.

[0019] Preferably, the distance between the axis of the first series hole and the axis of the second series hole and the central axis of the pump channel is 63% to 70% of the radius of the pump channel.

[0020] Preferably, the outer peripheral surfaces of the inlet sealing shell and the outlet sealing shell are mainly cylindrical and have a protrusion structure. The first and second airflow channels are located within the protrusion structure.

[0021] Preferably, the outer peripheral edges of the opposite sides of the air inlet sealing shell and the air outlet sealing shell are respectively provided with a matching surrounding concave structure and a surrounding convex edge structure. The surrounding convex edge structure is sleeved on the periphery of the surrounding concave structure to form a mating positioning structure.

[0022] Secondly, the present invention provides a pumping method using a aforementioned dual-piezoelectric driven gas wheel valve piezoelectric micropump. The pumping method includes:

[0023] When excitation signals with the same frequency and phase are applied to two driving elements, the sandwich piezoelectric vibrator reciprocates under the superposition of the driving forces of the two driving elements. When the sandwich piezoelectric vibrator moves toward the outlet chamber, the pressure in the inlet chamber decreases and the pressure in the outlet chamber increases. External gas enters through the inlet port and passes through the corresponding gas wheel valve into the inlet chamber. The gas in the outlet chamber is pumped out from the outlet port through the corresponding gas wheel valve.

[0024] When the sandwich piezoelectric vibrator moves toward the inlet chamber, the pressure in the outlet chamber decreases and the pressure in the inlet chamber increases. Under the pressure in the response hole, the central gas-blocking part of the diaphragm layer attached to the flow layer in the gas wheel valve accelerates and moves toward the blocking layer, so that both gas wheel valves are closed. The gas in the inlet chamber flows toward the outlet chamber pressure through the series flow channel structure.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention constructs a gas wheel valve with a responsive orifice structure, enabling the valve body to perform unidirectional flow while simultaneously forming a rapid pressure feedback path through the responsive orifice. This allows for a rapid closing response of the valve plate, ensuring the wheel valve meets the response speed requirements of gas pumps. Furthermore, the wheel valve structure enhances the pump's pressure output performance and significantly improves the pressure holding capacity of the cavity, reducing the pressure decay rate after shutdown. It features small size, easy processing and embedding, and its modular structure is suitable for various micro gas circuit systems requiring unidirectional gas control, improving system integration and adaptability.

[0027] 2. This invention provides a sandwich-type piezoelectric oscillator with dual piezoelectric driving elements. By applying the same excitation signal to both piezoelectric driving elements, they produce a superimposed vibration effect, thereby significantly increasing the effective vibration amplitude of the piezoelectric oscillator. While ensuring high gas output performance, the external driving voltage is reduced, keeping the device's operating voltage within a safe range for humans. Simultaneously, the low-voltage drive facilitates the integration of the piezoelectric micropump with various portable electronic devices, improving the system's energy efficiency and applicability.

[0028] 3. This invention employs a dual-chamber, dual-one-way valve series design to achieve directional gas transport and effective pressure differential construction within the chambers. This structure not only delivers high flow rates and high negative pressure gas performance but also maintains residual pressure within the chambers after operation ceases, thus providing excellent pressure holding capability. Therefore, this invention is suitable for end products such as breast pumps and eye massagers that have stringent requirements for high negative pressure and pressure maintenance performance. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the cross-sectional structure of a piezoelectric micropump provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of a piezoelectric micropump package provided in an embodiment of the present invention.

[0031] Figure 3 The first exploded schematic diagram of the piezoelectric micropump provided in the embodiment of the present invention.

[0032] Figure 4 The second exploded schematic diagram of the piezoelectric micropump provided in the embodiment of the present invention.

[0033] Figure 5 This is an explosion diagram of the gas wheel valve in an embodiment of the present invention.

[0034] Figure 6 This is a schematic diagram of the working process of the gas wheel valve in an embodiment of the present invention.

[0035] Figure 7 This is a comparison diagram of the pressure holding capabilities of the gas wheel valve and the traditional misaligned orifice check valve structure in the embodiments of the present invention.

[0036] Figure 8 This is a schematic diagram of gas flow during the first half-cycle operation of the piezoelectric micropump provided in an embodiment of the present invention.

[0037] Figure 9 This is a schematic diagram of gas flow during the second half of the operation cycle of the piezoelectric micropump provided in an embodiment of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings.

[0039] like Figure 1 , 3 As shown in Figures 4 and 5, a dual-piezoelectric driven gas wheel valve piezoelectric micropump includes an inlet sealing housing 10, two gas wheel valves 20, a sandwich-type piezoelectric vibrator 30, and an outlet sealing housing 40. The inlet sealing housing 10 and the outlet sealing housing 40 are spliced ​​and fixed together. The two gas wheel valves 20 are respectively installed inside the inlet sealing housing 10 and the outlet sealing housing 40 to improve the unidirectional flow of the piezoelectric micropump's inlet and outlet. The sandwich-type piezoelectric vibrator 30 is sandwiched between the inlet sealing housing 10 and the outlet sealing housing 40.

[0040] The intake sealing housing 10 includes an intake port 100, an intake bearing portion 101, an intake protrusion 102, a first series hole 103, and a first airflow channel 104; the intake port 100 is provided on the upper side of the intake sealing housing 10 (specifically, the side facing away from the exhaust sealing housing 40). An intake pump groove is provided on the lower side of the intake sealing housing 10 (specifically, the side facing the exhaust sealing housing 40).

[0041] The bottom surface of the air intake pump channel is provided with an air intake protrusion 102. The air intake protrusion 102 is arc-shaped, so that the air intake pump channel has a structure in which the depth of the channel gradually increases from the center to the edge. The bottom surface of the air intake pump channel is provided with an air intake support part 101 of the channel structure. One of the gas wheel valves 20 is fixed in the air intake support part 101. The air intake pump channel and the air inlet 100 are unidirectionally connected through the air intake support part 101 and the corresponding gas wheel valve 20, so that the airflow can only enter the air intake pump channel from the air inlet 100 and cannot flow back. One or more first series holes 103 are provided at a position off-center on the bottom surface of the air intake pump channel. The air intake sealing shell 10 is provided with a first air guide channel 104. The first air guide channels 104 are spaced apart on one side of the air intake pump channel. The first series holes 103 are connected to the first air guide channels 104.

[0042] The exhaust sealing housing 40 includes an exhaust port 400, an exhaust bearing portion 401, an exhaust protrusion 402, a second series hole 403, and a second airflow channel 404; the exhaust port 400 is provided on the lower side of the exhaust sealing housing 40 (specifically, the side facing away from the intake sealing housing 10). An exhaust pump flow groove is provided on the upper side of the exhaust sealing housing 40 (specifically, the side facing the intake sealing housing 10).

[0043] The bottom surface of the outlet pump channel is provided with an inlet protrusion 402. The inlet protrusion 402 is arc-shaped, so that the outlet pump channel has a structure in which the depth of the channel gradually increases from the center to the edge. The bottom surface of the outlet pump channel is provided with an outlet bearing part 401 of the channel structure. One of the gas wheel valves 20 is fixed in the outlet bearing part 401. The outlet pump channel and the outlet 400 are unidirectionally connected through the outlet bearing part 401 and the corresponding gas wheel valve 20, so that the airflow can only flow from the outlet pump channel to the outlet 400 and cannot flow back. One or more second series holes 403 are provided at a position off-center on the bottom surface of the outlet pump channel. The inlet sealing shell 10 is provided with a second air guide channel 404. The second air guide channels 404 are spaced apart on one side of the outlet pump channel. The second series holes 403 are connected to the second air guide channels 404.

[0044] The inlet pump channel and the outlet pump channel are aligned with each other to form a complete pumping chamber. The inlet pump channel and the outlet pump channel are separated by a sandwich-type piezoelectric vibrator 30. The inlet pump channel in the inlet sealing housing 10 and the sandwich-type piezoelectric vibrator 30 together form an inlet chamber A, and the outlet pump channel in the outlet sealing housing 40 and the sandwich-type piezoelectric vibrator 30 together form an outlet chamber B. The ends of the first guide channel 104 and the second guide channel 404 are aligned together. The first series hole 103, the first guide channel 104, the second guide channel 404, and the second series hole 403 are connected in sequence to form a complete series flow channel structure, so that the inlet chamber A and the outlet chamber B are connected through the series flow channel structure.

[0045] The lower surface edge of the intake sealing housing 10 has a surrounding concave structure; the upper surface edge of the exhaust sealing housing 40 has a surrounding convex structure. The shapes of the surrounding concave structure and the surrounding convex structure are matched and can be fitted together. The surrounding concave structure makes the lower surface of the intake sealing housing 10 form a plug-type structure; the surrounding convex structure makes the upper surface of the exhaust sealing housing 40 form a slot-type structure. The surrounding convex structure on the exhaust sealing housing 40 is fitted onto the surrounding concave structure on the intake sealing housing 10. The surrounding concave structure and the surrounding convex structure together form a mating positioning structure to realize the positioning and installation of adjacent intake sealing housings 10 and exhaust sealing housings 40.

[0046] The initial distance between the center positions of the inlet pump channel and the outlet pump channel and the center position of the sandwich piezoelectric vibrator 30 is 0.3 mm. The distance between the axis of the first series hole 103 and the central axis of the inlet pump channel is 63% to 70% of the radius of the inlet pump channel. The distance between the axis of the second series hole 403 and the central axis of the outlet pump channel is 63% to 70% of the radius of the outlet pump channel.

[0047] The outer peripheral surfaces of the inlet sealing shell 10 and the outlet sealing shell 40 are mainly cylindrical and have protrusion structures. The first air guide channel 104 is located in the protrusion structure on the outer peripheral surface of the inlet sealing shell 10; the second air guide channel 404 is located in the protrusion structure on the outer peripheral surface of the outlet sealing shell 40. The presence of the protrusion structure allows the serial flow channel structure to be set without increasing the overall radial dimension of the entire shell, which helps to miniaturize the piezoelectric micropump. Multiple serial flow channel structures can be set. Each serial flow channel structure has a corresponding protrusion structure; the serial flow channel structure is the only gas flow path between the inlet chamber A and the outlet chamber B. Gas sequentially enters the serial flow channel structure from the inlet chamber A through the first serial hole, and then flows into the outlet chamber B, realizing directional transport between the chambers.

[0048] In some embodiments, the number of tandem flow channel structures is three; therefore, three protrusion structures are provided on the outer peripheral surfaces of both the inlet sealing housing 10 and the outlet sealing housing 40. Simultaneously, the protrusion structures can also provide circumferential positioning for the inlet sealing housing 10 and the outlet sealing housing 40, ensuring accurate alignment between the first airflow channel 104 and the second airflow channel 404.

[0049] The sandwich-type piezoelectric vibrator 30 includes an intermediate counterweight layer 33, two support structures 32, and two driving elements 31. The two support structures 32 are symmetrically arranged on both sides of the intermediate counterweight layer 33. The two driving elements 31 are symmetrically arranged on the opposite sides of the two support structures 32.

[0050] By symmetrically arranging the dual driving elements as described above, unidirectional excitation signals can be applied to the two driving elements 31, causing them to produce a synergistic superposition vibration effect, thereby significantly increasing the effective amplitude of the piezoelectric oscillator. While ensuring high gas output performance, this achieves the effect of reducing the external driving voltage, keeping the operating voltage within a safe range for the human body, and improving the integration and applicability of the device in portable electronic products.

[0051] The driving element 31 is a disc with a diameter of 18 mm. The driving element 31 is made of piezoelectric material, including but not limited to lead zirconate titanate (PZT) and aluminum nitride (AlN). The driving element 31 has two power supply areas, inner and outer, on its side near the supporting structure 32. Each power supply area is covered by an electrode. Driving the driving element 31 is achieved by inputting a driving signal to these two electrodes.

[0052] The intermediate counterweight layer 33 adopts the same circular plate structure as the driving element 31. The diameter of the intermediate counterweight layer 33 is the same as that of the driving element 31. The intermediate counterweight layer 33 is made of metal, such as stainless steel 430 or titanium. By adjusting the thickness of the intermediate counterweight layer, the overall driving frequency of the sandwich piezoelectric vibrator 30 is adjusted, so that the driving frequency is maintained above 20kHz (i.e., the ultrasonic range), thus reducing noise.

[0053] The support structure 32 is a flexible circuit board, including a PI substrate and two power supply lines disposed on the PI substrate. The two power supply lines are respectively connected to two electrodes on the drive element 31. The PI substrate and the two power supply lines are led out from the same position on the side of the pump housing.

[0054] The edge regions of the side of the support structure 32 are attached to the side of the inlet sealing housing 10 or the outlet sealing housing 40. In some embodiments, the edge regions of the two support structures 32 are pressed together by the inlet sealing housing 10 and the outlet sealing housing 40, so that the entire sandwich piezoelectric vibrator 30 is sandwiched between the inlet sealing housing 10 and the outlet sealing housing 40. In some other embodiments, a shim ring is provided between the edge regions of the two support structures 32. The thickness of the shim ring is equal to the thickness of the intermediate counterweight layer 33, so that the distance between the two support structures 32 in the outer region is equal to the distance between the two support structures 32 in the central region.

[0055] In some embodiments, the diameter of the sandwich piezoelectric vibrator 30 is selected in the range of less than or equal to 18 mm, and the natural frequency of the sandwich piezoelectric vibrator 30 is 18 kHz to 25 kHz.

[0056] like Figure 5 As shown, the gas wheel valve 20 includes a flow passage layer 21, a movable layer 22, a diaphragm layer 23, and a barrier layer 24. During manufacturing, the flow passage layer 21, the movable layer 22, the diaphragm layer 23, and the barrier layer 24 are stacked and fixed in sequence, with the barrier layer 24 serving as the load-bearing structure. The fixing method can be laser welding or adhesive bonding.

[0057] The barrier layer 24 serves as the inlet structure of the gas wheel valve, and a flow passage structure is provided at its center. The flow passage structure has several first flow holes 206, serving as the inlet for gas flow through the gas wheel valve. The movable layer 22 has a through-groove structure in its middle. This through-groove structure provides space for the diaphragm layer 23 to move, allowing it to move up and down under pressure within the valve body to control the opening and closing of the valve.

[0058] As the core component of the entire gas wheel valve, the diaphragm layer 23 deforms under the influence of gas pressure during device operation and undertakes the opening and closing of the valve.

[0059] The diaphragm layer 23 includes an outer ring structure, vibrating beams 203, and a central air-blocking portion 204. The outer peripheral edge of the central air-blocking portion 204 is connected to the inner peripheral edge of the outer ring structure by multiple vibrating beams 203. Adjacent vibrating beams 203 are spaced apart to form second flow holes 205. The second flow holes 205 are fan-shaped. In this embodiment, the diaphragm layer 23 is made of a thin film material, such as polyimide (PI), polyethylene terephthalate (PET), or polyethylene (PE).

[0060] In this embodiment, the central air-blocking part 204 is circular, while in some other embodiments, the central air-blocking part 204 may also be square or other regular geometric shapes.

[0061] The central air-blocking section 204 is aligned with the first flow orifice 206, and its area is sufficient to completely cover the entire first flow orifice 206 to ensure unidirectional gas flow and effective sealing. Under changes in the pressure difference across the central air-blocking section 204, it can move vertically. The vibrating beam 203 can constrain the central air-blocking section 204 and amplify its vibration amplitude and response time.

[0062] The flow layer 21 serves as the outlet structure of the gas turbine valve, and a limiting structure is provided at its center. Multiple response holes 202 are formed on the limiting structure. A third flow passage 201, surrounding the limiting structure, is also formed on the flow layer 21. The third flow passage 201 is fan-shaped. The number of third flow passages 201 on the flow layer 21 is the same as the number of second flow passages 205 on the diaphragm layer 23, and they are aligned. The area of ​​the third flow passage 201 on the flow layer 21 is larger than the area of ​​the second flow passages 205 on the diaphragm layer. The number of response holes 202 on the flow layer 21 is the same as the number of first flow passages 206 on the barrier layer 24, and they are aligned.

[0063] When the gas wheel valve 20 is in the closed state, the central gas-blocking part 204 adheres to the barrier layer 24, blocking all the first flow holes 206 on the barrier layer 24, thus preventing gas from passing through the gas wheel valve 20. When the gas wheel valve 20 is in the open state, the central gas-blocking part 204 adheres to the flow layer 21, blocking all the response holes 202 on the flow layer 21.

[0064] In some embodiments, the membrane layer is made of materials such as polyimide (PI), polyethylene terephthalate (PET), or polyethylene (PE).

[0065] like Figure 6 As shown in part (a), the gas wheel valve 20 is in the closed state in the initial state, and gas cannot pass through the valve.

[0066] like Figure 6 As shown in part (b), during the pumping process, when the pressure on the side of the barrier layer 24 away from the diaphragm layer 23 is greater than the pressure on the side of the flow passage layer 21 away from the diaphragm layer 23, the diaphragm layer 24 is displaced towards the flow passage layer 21 under pressure. Since there are multiple vibrating beams 203 on the diaphragm layer 23, after being compressed, the central gas-blocking part 204 of the diaphragm layer 23 quickly moves to the flow passage layer 21 and completely covers the response holes 202 on the flow passage layer 21. At this time, the first flow hole 206 on the barrier layer 24 opens, and gas can quickly flow out from the first flow hole 206 through the second flow hole 205 and then through the third flow hole 201.

[0067] like Figure 6As shown in section (c), when the pressure on the side of the barrier layer 24 away from the diaphragm layer 23 is less than the pressure on the side of the flow passage layer 21 away from the diaphragm layer 23, the diaphragm layer 23 moves towards the barrier layer 24 under the action of the pressure difference, and the valve begins to enter the closing process. Even with the central air-blocking part 204 in contact with the flow passage layer 21, the air pressure can still act directly on the central air-blocking part 204 through the response hole 202, allowing the diaphragm layer 23 to return to its normally closed position in contact with the barrier layer 24 more quickly. This effectively suppresses reverse leakage of external gas and prevents gas from flowing back into the pump chamber. Simultaneously, after the pump stops working, the above structure allows the valve to quickly return to a sealed state, thereby significantly improving the pressure holding capacity of the chamber and reducing the pressure decay rate after shutdown.

[0068] The gas wheel valve provided in this embodiment adopts a composite diaphragm structure of a central air-blocking part 204 and a vibrating beam 203, and the air pressure can be directly applied to the central air-blocking part 204 through the response hole 202, which makes the valve more pressure-sensitive and has a shorter closing time in the closing direction, thus overcoming the problem of slow closing speed of traditional wheel valves.

[0069] Compared to the traditional diaphragm-type one-way valve structure (which achieves one-way flow and closure through staggered vents on two diaphragm layers), this embodiment uses an integral central air-blocking part 204 to seal the first flow hole 206 on the barrier layer 24, which can effectively improve the pressure holding capacity. Figure 7 As shown, experimental results indicate that, under the same test conditions, the gas wheel valve 20 provided in this embodiment can increase the effective pressure holding time of the cavity by approximately one time compared to the diaphragm-type check valve structure. This significantly improves the airtightness and pressure holding capability of the micro-pump system in the shutdown state, thereby significantly enhancing the pressure holding performance of the pump cavity.

[0070] The working principle of the dual-piezoelectric driven gas wheel valve piezoelectric micro-pump in this embodiment is as follows:

[0071] like Figure 8As shown, by applying excitation signals in the same direction to the two driving elements on the sandwich piezoelectric vibrator 30, the two driving elements are driven synchronously, thereby causing the sandwich piezoelectric vibrator 30 to generate enhanced displacement in the same direction as a whole, thus obtaining amplified vibration amplitude. In the first half of the cycle, when the sandwich piezoelectric vibrator 30 vibrates towards the outlet chamber B, the volume of the inlet chamber A between it and the inlet sealing shell 10 is expanded, causing the air pressure in the inlet chamber A to drop below the outside air pressure. At this time, under the action of pressure difference, the diaphragm layer 23 inside the gas wheel valve 20 arranged on the inlet sealing shell 10 is subjected to pressure from the direction of the first flow hole 206 and moves towards the flow layer 21. The first flow hole 206 is opened, while the response hole 202 is covered, and the valve is thus opened. Outside gas enters the interior of the gas wheel valve 20 through the inlet 100, and enters the inlet chamber A through the first flow hole 206, the second flow hole 205, and the third flow hole 201. At the same time, the gas wheel valve 20 placed on the gas outlet sealing housing 40 is also in the open state under the action of pressure difference, and the gas in the gas outlet chamber B is discharged to the outside through the gas outlet 400.

[0072] like Figure 9 As shown, in the latter half of the cycle, when the sandwich piezoelectric vibrator 30 vibrates towards the inlet chamber A, its movement compresses the volume of inlet chamber A, while the volume of outlet chamber B on the outlet sealing shell 10 is simultaneously expanded. At this time, the air pressure in inlet chamber A rises to a level higher than that in outlet chamber B, and gas flows from inlet chamber A into outlet chamber B through the series flow channel structure under the pressure difference. Since the air pressure in inlet chamber A is greater than the external atmospheric pressure during this stage, the gas wheel valve 20 arranged on the inlet sealing shell 10, under the action of the pressure difference, has its internal diaphragm layer 23 subjected to pressure from the direction of the response hole 202, causing it to move towards the barrier layer 24. The first flow hole 206 is quickly covered, and the valve is thus closed, preventing gas from leaking back from the inlet port 100. At the same time, the air pressure in outlet chamber B is lower than the external atmospheric pressure, so the valve also remains closed, preventing external gas from flowing back into outlet chamber B through outlet port 400.

[0073] In summary, through the periodic reciprocating vibration of the piezoelectric vibrator, gas is sequentially introduced into the inlet chamber A, transported through the series flow channel structure, and finally output from the outlet chamber B, thus achieving a continuous and stable unidirectional pumping function.

Claims

1. A dual-piezoelectric driven gas wheel valve piezoelectric micropump, comprising a pump body housing; a pump flow chamber is provided inside the pump body housing; characterized in that: The piezoelectric micropump also includes a sandwich piezoelectric vibrator (30) and two gas wheel valves (20); the sandwich piezoelectric vibrator (30) is fixed in the pump flow chamber, dividing the pump flow chamber into an inlet chamber and an outlet chamber; the pump body shell is provided with a series flow channel structure connecting the inlet chamber and the outlet chamber; the two gas wheel valves (20) are respectively located between the inlet chamber and the inlet (100) and between the outlet chamber and the outlet (400); The gas wheel valve (20) includes a barrier layer (24), a diaphragm layer (23), a movable layer (22), and a flow passage layer (21) stacked sequentially along the ventilation direction; one or more first flow passage holes (206) are provided on the flow passage structure in the middle of the barrier layer (24); one or more response holes (202) are provided on the limiting structure in the middle of the flow passage layer (21). The active layer (22) has a through-groove structure that provides deformation space for the diaphragm layer (23); the diaphragm layer (23) includes a central air-blocking part (204) that aligns the flow passage structure of the flow passage layer (21) and the limiting structure of the barrier layer (24); the diaphragm layer (23) is made of polyimide; the diaphragm layer (23) has a second flow passage (205) surrounding the central air-blocking part (204); the flow passage layer (21) has a third flow passage (201) surrounding the limiting structure. When the gas wheel valve is closed, the central air-blocking part (204) covers all the first flow holes (206); when the gas wheel valve is open, the central air-blocking part (204) covers all the response holes (202). The sandwich piezoelectric vibrator (30) includes an intermediate counterweight layer (33), two support structures (32) and two driving elements (31) stacked sequentially from the center to both sides; the outer periphery of the two support structures (32) is fixed to the pump flow chamber; The series flow channel structure is the only gas flow path between the inlet chamber and the outlet chamber; the pump body shell includes a fixed inlet sealing shell (10) and an outlet sealing shell (40); pump flow grooves are provided on the opposite sides of the inlet sealing shell (10) and the outlet sealing shell (40); the two pump flow grooves together form the pump flow chamber; the outer connecting parts (322) of the two support structures (32) in the sandwich piezoelectric vibrator (30) are sandwiched between the inlet sealing shell (10) and the outlet sealing shell (40); the series flow channel structure includes interconnected sections inside the inlet sealing shell (10). The first series hole (103), the first air guide channel (104), and the second series hole (403) and the second air guide channel (404) are interconnected in the air outlet sealing shell (40); the first air guide channel (104) and the second air guide channel (404) are connected on the opposite sides of the air inlet sealing shell (10) and the air outlet sealing shell (40); the outer peripheral surface of the air inlet sealing shell (10) and the air outlet sealing shell (40) is mainly cylindrical and has a protrusion structure; the first air guide channel (104) and the second air guide channel (404) are located in the protrusion structure.

2. The dual piezoelectric driven gas wheel valve piezoelectric micropump according to claim 1, characterized in that: The first flow passage (206) is aligned with the response passage (202).

3. The dual piezoelectric driven gas wheel valve piezoelectric micropump according to claim 2, characterized in that: The second flow hole (205) on the diaphragm layer (23) is aligned with the third flow hole (201) on the flow layer (21); the area of ​​the third flow hole (201) is larger than the area of ​​the second flow hole (205).

4. The dual piezoelectric driven gas wheel valve piezoelectric micropump according to claim 1, characterized in that: The support structure (32) includes a flexible substrate and two power supply lines; the drive element (31) has an electrode in the central region and the peripheral region of the side of the corresponding support structure (32); the two electrodes are led out through the two power supply lines respectively.

5. A dual-piezoelectric driven gas wheel valve piezoelectric micropump according to claim 1, characterized in that: The bottom surface of the pump flow channel is arc-shaped, so that the depth of the pump flow channel gradually increases from the center to the edge; a bearing part is provided at the center of the bottom surface of the pump flow channel; two gas wheel valves (20) are respectively fixed on the bearing parts of the two pump flow channels.

6. A method for pumping air, characterized in that: Using a dual piezoelectric driven gas wheel valve piezoelectric micropump as described in claim 1; The pumping method includes: When excitation signals with the same frequency and phase are applied to the two driving elements, the sandwich piezoelectric vibrator (30) reciprocates under the superposition of the driving forces of the two driving elements. When the sandwich piezoelectric vibrator (30) moves towards the outlet chamber, the pressure in the inlet chamber decreases and the pressure in the outlet chamber increases. External gas enters through the inlet port (100) and enters the inlet chamber through the corresponding gas wheel valve (20). The gas in the outlet chamber is pumped out from the outlet port (400) through the corresponding gas wheel valve (20). When the sandwich piezoelectric vibrator (30) moves toward the inlet chamber, the pressure in the outlet chamber decreases and the pressure in the inlet chamber increases. The central gas blocking part (204) of the diaphragm layer (23) attached to the flow passage layer (21) in the gas wheel valve (20) moves towards the barrier layer (24) under the pressure in the response hole (202), so that both gas wheel valves (20) are closed. The gas in the inlet chamber flows to the outlet chamber pressure through the series flow channel structure.

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