Miniature gas-liquid mixer with low power consumption

Abstract

The invention provides a low-power-consumption miniature gas-liquid mixer. An upper cover plate, a piezoelectric transducer, a first middle plate, a second middle plate and a lower cover plate are sequentially connected from top to bottom; a driving cavity is formed in the upper cover plate and the first middle plate; the piezoelectric transducer divides the driving cavity into an upper cavity and a lower cavity; a center hole is formed in the center of the piezoelectric transducer; the first middle plate is provided with a second chamber; the bottom plate is provided with a first cavity; a jet hole is formed in the first middle plate; a drainage hole is formed in the second middle plate; a mixing hole is formed in the lower cover plate. The device has the characteristics and advantages of low power consumption / driving noise, small size, easiness in integration and high mixing efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas-liquid mixing devices, and particularly relates to a low-power micro gas-liquid mixer. Background Art

[0002] A gas-liquid mixer is an indispensable device in industrial production. It can efficiently mix gas and liquid evenly, improving the reaction efficiency and product quality. For example, CN202110269022.8 discloses a gas-liquid mixer, including a diversion pipe, a receiver, a liquid inlet pipe, and a gas inlet pipe, which realizes efficient gas-liquid mixing through the change of the cross-sectional area of the fluid flow.

[0003] Currently, in the fields of fluid chemistry, water treatment, etc., reactions involving gas participation usually have poor effects. At the same time, the gas-liquid mixing device system is also developing towards the direction of integration, miniaturization, and portability. In order to make up for the deficiencies of the current gas-liquid mixer, it is necessary to develop a micro gas-liquid mixer that is easy to integrate, small in size, low in power consumption, and excellent in mixing effect. Piezoelectric drive has unique advantages such as low power consumption, high energy density, simple structure, and no electromagnetic interference, and it has broad prospects for constructing a micro gas-liquid mixer. Summary of the Invention

[0004] In order to achieve the energy-saving and miniaturization of the gas-liquid mixer, the present invention proposes a low-power micro gas-liquid mixer The present invention has the following structure, which is sequentially connected with an upper cover plate, a piezoelectric transducer, a first intermediate plate, a second intermediate plate, and a lower cover plate from top to bottom; a driving cavity is arranged in the upper cover plate and the first intermediate plate; the piezoelectric transducer divides the driving cavity into an upper cavity and a lower cavity; the upper cover plate, the first intermediate plate, the second intermediate plate, and the lower cover plate form the base of the gas-liquid mixer.

[0005] Further, a middle hole is arranged at the center of the piezoelectric transducer; the middle hole communicates the upper cavity and the lower cavity.

[0006] Further, the upper cover plate is provided with a liquid inlet and a gas inlet; the liquid inlet is connected to a conduit joint for liquid input; the gas inlet is connected to a conduit joint for gas input; the lower cover plate is provided with a mixing outlet, and the mixing outlet is connected to an output pipeline, and the mixing outlet is used for the output after gas-liquid mixing.

[0007] Further, the first intermediate plate is provided with a second chamber; the bottom plate is provided with a first chamber; the first chamber and the second chamber are cylindrical; the first chamber and the second chamber are coaxial; the first chamber and the middle hole are coaxial.

[0008] Further, a first channel is provided in the upper cover plate, the first intermediate plate, the second intermediate plate, and the lower cover plate; a second channel is provided in the upper cover plate, the first intermediate plate, and the second intermediate plate; the first channel communicates the liquid inlet with the first chamber; the second channel communicates the gas inlet with the second chamber.

[0009] Further, the first intermediate plate is provided with a jet hole; the jet hole communicates the lower chamber and the second chamber; the jet hole is coaxial with the middle hole.

[0010] Further, the aperture of the jet hole is larger than the aperture of the middle hole, and the aperture of the jet hole is not less than times the aperture of the middle hole.

[0011] Further, the second intermediate plate is provided with a drainage hole; the drainage hole communicates the second chamber with the first chamber; the drainage hole is coaxial with the jet hole.

[0012] Further, the drainage hole is a tapered hole, and the cross-sectional diameter of the drainage hole gradually decreases from the second chamber to the first chamber; the maximum cross-sectional diameter of the drainage hole is not less than the aperture of the jet hole.

[0013] Further, the lower cover plate is provided with a mixing hole; the mixing hole communicates the first chamber with the mixing outlet; the mixing hole is coaxial with the drainage hole.

[0014] Further, the mixing hole is composed of a tapered hole and a straight hole. The tapered hole part of the mixing chamber is close to the first chamber and is located above the straight hole part. The aperture of the straight hole part of the mixing hole is equal to the cross-sectional diameter of the large end of the tapered hole part of the mixing hole. The cross-sectional diameter of the mixing hole in the tapered hole part gradually increases from the first chamber to the mixing outlet. The minimum cross-sectional diameter of the mixing hole is not less than the minimum cross-sectional diameter of the drainage hole.

[0015] Further, the piezoelectric transducer is concentrically bonded by a piezoelectric wafer and a substrate; the diameter of the piezoelectric wafer is smaller than the diameter of the substrate.

[0016] Further, the periphery of the substrate is clamped by the upper cover plate and the first intermediate plate.

[0017] Further, the piezoelectric wafer faces the upper chamber.

[0018] Further, a matching layer is concentrically bonded to the substrate; the matching layer faces the lower chamber; the acoustic impedance of the matching layer is between that of the substrate and the working gas. The setting of the matching layer is beneficial to the propagation of the vibration sound energy of the piezoelectric transducer into the gas and improves the energy conversion efficiency.

[0019] Further, the outer diameter of the matching layer is not less than the outer diameter of the piezoelectric wafer; the outer diameter of the matching layer is smaller than the diameter of the substrate.

[0020] Further, the upper cavity is cylindrical with a cavity height of H1; the lower cavity is cylindrical with a cavity height of H2; the cavity height H1 of the upper cavity is less than the cavity height H2 of the lower cavity; the cavity height H1 of the upper cavity is not less than twice the maximum amplitude when the piezoelectric transducer works.

[0021] In the present invention, the piezoelectric transducer is driven by a controller, and the controller issues an alternating voltage signal to excite the piezoelectric wafer; the polarization direction of the piezoelectric wafer is vertical; the controller connects the positive and negative electrodes of the piezoelectric wafer through wires.

[0022] Preferably, 8 slot holes are circumferentially distributed on the substrate; the slot holes are fan-shaped through holes; cantilever beams are formed between adjacent slot holes; the arrangement of the slot holes divides the substrate into an outer support part and a central intermediate part, and the support part and the intermediate part are connected by cantilever beams; the piezoelectric wafer and the matching layer are both concentrically connected to the intermediate part; through the arrangement of multiple slot holes, the stiffness of the piezoelectric transducer is greatly reduced, which can effectively reduce its excitation voltage. At a small driving voltage, the piezoelectric transducer can obtain a large vibration amplitude. By matching a small driving voltage (not greater than 50V) with a large working frequency (>20kHz), the working life of the piezoelectric transducer will be greatly increased.

[0023] Further, a diaphragm is connected to the substrate at the slot holes, and the diaphragm is used for isolating the upper and lower ends of the slot holes, that is, ensuring that the upper cavity and the lower cavity are not connected at the slot holes.

[0024] Further, the driving frequency of the piezoelectric wafer is greater than 20kHz (ultrasonic frequency band). Under the drive of an alternating voltage signal with ultrasonic frequency, the piezoelectric transducer hardly emits driving noise, which can greatly reduce the driving noise pollution of the entire system.

[0025] Further, the cavity height of the second chamber is H3; the cavity height H3 of the second chamber is not greater than the cavity height H2 of the lower cavity.

[0026] Further, the cavity height of the first chamber is H4; the cavity height H4 of the first chamber is not greater than the cavity height H3 of the second chamber.

[0027] Driven by an alternating voltage signal with ultrasonic frequency, the piezoelectric transducer works in the second-order vibration mode. In the second-order vibration mode, there are 3 points with the maximum amplitude output on the piezoelectric transducer, and the 3 points with the maximum amplitude output are located at the center and both sides of the piezoelectric transducer respectively, where the center of the piezoelectric transducer has the maximum amplitude. In one working cycle, it can be specifically divided into a first working state and a second working state, which are specifically described as follows.

[0028] The first working state: The points with the maximum amplitude on both sides of the piezoelectric transducer vibrate downward, and the point with the maximum amplitude at the center vibrates upward. The piezoelectric transducer operates in the first vibration mode. High-pressure sound zones will be formed on both sides of the upper cavity near the center point with the maximum amplitude (it should be noted here that since the piezoelectric transducer has a central hole in the center and no ultrasonic waves are generated in the central region, no high-pressure sound zone is formed in the central region of the upper cavity). Under the action of the high-pressure sound zones, the fluid will flow from both sides of the upper cavity towards the center, and then spray downward along the central hole into the lower cavity, and a jet will be formed at the jet hole. It should be noted here that due to the fluid viscosity effect, vortices will be generated at the jet hole and near the wall of the central hole. Under the action of the vortices, a fluid flow opposite to the central flow direction will be formed at the jet hole and near the wall of the central hole).

[0029] The second working state: The points with the maximum amplitude on both sides of the piezoelectric transducer vibrate upward, and the point with the maximum amplitude at the center vibrates downward. The piezoelectric transducer operates in the second vibration mode. The first intermediate plate acts as a reflector. High-pressure sound zones will be formed on both sides of the lower cavity near the center point with the maximum amplitude (it should be noted here that since the piezoelectric transducer has a central hole in the center and the first intermediate plate is provided with a jet control, no ultrasonic waves are generated in the central region and there is no reflector, so no high-pressure sound zone is formed in the central region of the lower cavity). Under the action of the high-pressure sound zones, the fluid will flow from both sides of the lower cavity towards the center, and then spray upward along the central hole into the upper cavity, and a jet will be formed at the jet hole. It should be noted here that due to the fluid viscosity effect, vortices will be generated at the jet hole and near the wall of the central hole. Under the action of the vortices, a fluid flow opposite to the central flow direction will be formed at the jet hole and near the wall of the central hole).

[0030] Driven by the alternating voltage signal, the first working state and the second working state alternate. A high-speed and continuous jet will be formed at the center of the jet hole. Liquid is introduced into the first channel and gas is introduced into the second channel. The first chamber is filled with liquid and the second chamber is filled with gas. Under the action of the Venturi effect, the gas in the second chamber will be drained by the high-speed jet, and then a large-flow gas output will be formed at the drainage hole. It should be noted here that the drainage hole is in an inverted conical structure, which will cause the fluid to converge at the drainage hole and further increase the fluid velocity, which is beneficial to the subsequent gas-liquid mixing. The large-flow gas in the drainage hole is sprayed into the first chamber. Based on the Venturi effect, the gas sprayed from the drainage hole will carry the liquid into the mixing hole together in the first chamber. The mixing hole is in an inverted conical structure, and the mixing hole will produce an expanding flow effect. Combining with the bluff body, an expanding flow - contracting flow - expanding flow process can be achieved, which will greatly enhance the gas-liquid mixing effect.

[0031] Features and advantages: 1. Low power consumption and low noise: Driven by a piezoelectric transducer at ultrasonic frequency (low driving noise), combined with the upper cavity and lower cavity settings, the acoustic energy generated by the piezoelectric transducer is efficiently converted into fluid kinetic energy, with high energy conversion efficiency and power consumption as low as the milliwatt level; 2. Simple structure and easy integration: The overall structure is mainly composed of a piezoelectric transducer and a substrate, with a simple structure, suitable for system miniaturization and integration; 3. High mixing efficiency: Based on the Venturi effect, gas-liquid mixing is achieved through two jets, combined with the setting of an inverted conical blunt body in the mixing hole, enhancing the gas-liquid mixing effect. Description of the Drawings

[0032] Figure 1 is a schematic cross-sectional structure diagram of a preferred embodiment; Figure 2 is Figure 1 the first working state of the embodiment; Figure 3 is Figure 1 the second working state of the embodiment; Figure 4 is a cross-sectional view of a preferred embodiment of the substrate (22); Figure 5 is using Figure 4 the top view of the piezoelectric transducer (2) of the substrate (22) in; Figure 6 is Figure 5 the schematic C-C cross-sectional view of; Figure 7 is a preferred embodiment of the mixing hole (51); Wherein: 100 - substrate; 1 - upper cover plate; 2 - piezoelectric transducer; 20 - driving cavity; 200 - upper cavity; 201 - lower cavity; 21 - piezoelectric wafer; 22 - substrate; 220 - slot hole; 221 - middle part; 222 - support part; 223 - cantilever beam; 23 - matching layer; 24 - middle hole; 25 - diaphragm; 3 - first intermediate plate; 31 - jet hole; 4 - second intermediate plate; 41 - drainage hole; 5 - lower cover plate; 51 - mixing hole; 510 - blunt body; 11 - liquid inlet; 12 - gas inlet; 13 - mixing outlet; 110 - first channel; 111 - first chamber; 120 - second channel; 121 - second chamber; 300 - first vibration mode; 301 - second vibration mode. Detailed Embodiments

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. It should be noted that the orientation or positional relationship indicated by the terms "middle", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0036] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 The present invention provides a low-power micro gas-liquid mixer, which is successively connected with an upper cover plate 1, a piezoelectric transducer 2, a first intermediate plate 3, a second intermediate plate 4 and a lower cover plate 5 from top to bottom; a driving cavity 20 is arranged in the upper cover plate 1 and the first intermediate plate 3; the piezoelectric transducer 2 divides the driving cavity 20 into an upper cavity 200 and a lower cavity 201; the upper cover plate 1, the first intermediate plate 3, the second intermediate plate 4 and the lower cover plate 5 form the base body 100 of the gas-liquid mixer.

[0037] Furthermore, a middle hole 24 is arranged at the center of the piezoelectric transducer 2; the middle hole 24 communicates the upper cavity 200 and the lower cavity 201.

[0038] Furthermore, the upper cover plate 1 is provided with a liquid inlet 11 and a gas inlet 12; the liquid inlet 11 is connected to a conduit joint for liquid input; the gas inlet 12 is connected to a conduit joint for gas input; the lower cover plate 5 is provided with a mixing outlet 13, the mixing outlet 13 is connected to an output pipeline, and the mixing outlet 13 is used for the output after gas-liquid mixing.

[0039] Furthermore, the first intermediate plate 3 is provided with a second chamber 121; the bottom plate 5 is provided with a first chamber 111; the first chamber 111 and the second chamber 121 are cylindrical; the first chamber 111 and the second chamber 121 are coaxial; the first chamber 111 and the middle hole 24 are coaxial.

[0040] Furthermore, a first channel 110 is provided in the upper cover plate 1, the first intermediate plate 3, the second intermediate plate 4, and the lower cover plate 5; a second channel 120 is provided in the upper cover plate 1, the first intermediate plate 3, and the second intermediate plate 4; the first channel 110 communicates the liquid inlet 11 with the first chamber 111; the second channel 120 communicates the gas inlet 12 with the second chamber 121.

[0041] Furthermore, the first intermediate plate 3 is provided with a jet hole 31; the jet hole 31 communicates the lower chamber 201 with the second chamber 121; the jet hole 31 and the middle hole 24 are coaxial.

[0042] Furthermore, the aperture of the jet hole 31 is larger than the aperture of the middle hole 24, and the aperture of the jet hole 31 is not less than 3 times the aperture of the middle hole 24.

[0043] Furthermore, the second intermediate plate 4 is provided with a drainage hole 41; the drainage hole 41 communicates the second chamber 121 with the first chamber 111; the drainage hole 41 and the jet hole 31 are coaxial.

[0044] Furthermore, the drainage hole 41 is a tapered hole, and the cross-sectional diameter of the drainage hole 41 gradually decreases from the second chamber 121 to the first chamber 111; the maximum cross-sectional diameter of the drainage hole 41 is not less than the aperture of the jet hole 31.

[0045] Furthermore, the lower cover plate 5 is provided with a mixing hole 51; the mixing hole 51 communicates the first chamber 111 with the mixing outlet 13; the mixing hole 51 and the drainage hole 41 are coaxial.

[0046] Furthermore, the mixing hole 51 is composed of a tapered hole and a straight hole connected in sequence from top to bottom. The tapered hole part of the mixing chamber 51 is close to the first chamber 111 and is located above the straight hole part. The aperture of the straight hole part of the mixing hole 51 is equal to the cross-sectional diameter of the large end of the tapered hole part of the mixing hole 51. The cross-sectional diameter of the mixing hole 51 in the tapered hole part gradually increases from the first chamber 111 to the mixing outlet 13. The minimum cross-sectional diameter of the mixing hole 51 is not less than the minimum cross-sectional diameter of the drainage hole 41.

[0047] Further, the piezoelectric transducer 2 is concentrically bonded by a piezoelectric wafer 21 and a substrate 22; the diameter of the piezoelectric wafer 21 is smaller than that of the substrate 22.

[0048] Further, the periphery of the substrate 22 is clamped by the upper cover plate 1 and the first intermediate plate 3.

[0049] Further, the piezoelectric wafer 21 faces the upper cavity 200.

[0050] Further, a matching layer 23 is concentrically bonded to the lower surface of the substrate 22; the matching layer 23 faces the lower cavity 201; the acoustic impedance of the matching layer 23 is between that of the substrate and the working gas, and the setting of the matching layer 23 is conducive to the propagation of the vibration sound energy of the piezoelectric transducer 2 into the gas, improving the energy conversion efficiency; the material of the matching layer 23 is metal, for example, it is composed of aluminum alloy.

[0051] Further, the outer diameter of the matching layer 23 is not less than the outer diameter of the piezoelectric wafer 21; the outer diameter of the matching layer 23 is smaller than the diameter of the substrate 22.

[0052] Further, the upper cavity 200 is cylindrical, and its cavity height is H1; the lower cavity 201 is cylindrical, and its cavity height is H2; the cavity height H1 of the upper cavity 200 is smaller than the cavity height H2 of the lower cavity 201; the cavity height H1 of the upper cavity 200 is not less than twice the maximum amplitude when the piezoelectric transducer 2 works.

[0053] In the present invention, the piezoelectric transducer 2 is driven by a controller, and the controller issues an AC voltage signal to excite the piezoelectric wafer 21; the polarization direction of the piezoelectric wafer 21 is vertical; the controller is connected to the positive and negative poles of the polarization direction of the piezoelectric wafer 21 through a wire.

[0054] Further, the driving frequency of the piezoelectric wafer 21 is not less than 20 kHz (ultrasonic frequency band). Under the drive of the ultrasonic frequency, the piezoelectric transducer 2 hardly emits driving noise, which can greatly reduce the driving noise pollution of the entire system.

[0055] Further, the cavity height of the second chamber 121 is H3; the cavity height H3 of the second chamber 121 is not greater than the cavity height H2 of the lower cavity 201.

[0056] Further, the cavity height of the first chamber 111 is H4; the cavity height H4 of the first chamber 111 is not greater than the cavity height H3 of the second chamber 121.

[0057] Further, the aperture of the middle hole 24 does not exceed 1 mm. At this aperture, based on the surface tension of water, this can effectively prevent liquid from entering the upper cavity 201, thereby avoiding the short - circuit damage of the piezoelectric wafer 21.

[0058] Further, a waterproof coating, such as a silicone coating, is applied to the surface of the piezoelectric wafer 21.

[0059] Further, as Figure 7 shown, a blunt body 510 is provided at the center of the mixing hole 51.

[0060] Further, the blunt body 510 has an inverted conical structure, and the cross-sectional diameter of the blunt body 510 gradually decreases from top to bottom; the maximum cross-sectional diameter of the blunt body 510 does not exceed half of the minimum cross-sectional diameter of the mixing hole 51.

[0061] Preferably, as Figure 4 shown, eight slot holes 220 are circumferentially distributed on the substrate 22; the slot holes 220 are fan-shaped through holes; a cantilever beam 223 is formed between adjacent slot holes 220; the arrangement of the slot holes 220 divides the substrate 22 into an outer support portion 222 and a central intermediate portion 221, and the support portion 222 and the intermediate portion 221 are connected by the cantilever beam 223; the piezoelectric wafer 21 and the matching layer 23 are both concentrically connected to the intermediate portion; through the arrangement of the multiple slot holes 220, the stiffness of the piezoelectric transducer 2 is greatly reduced, which can effectively reduce its excitation voltage. At a small driving voltage, the piezoelectric transducer 2 can obtain a large vibration amplitude. By matching a small driving voltage (not greater than 50 V) and a large operating frequency (> 20 kHz), the working life of the piezoelectric transducer will be increased.

[0062] Further, as Figure 6 shown, a diaphragm 25 is connected to the substrate 22 at the slot holes 220, and the diaphragm 25 is used for isolating the upper and lower ends of the slot holes 220, that is, ensuring that the upper cavity 200 and the lower cavity 201 are not connected at the slot holes 220.

[0063] During the working process of the present invention, under the drive of an alternating voltage signal with an ultrasonic frequency, the piezoelectric transducer 2 operates in the second-order vibration mode. In the second-order vibration mode, there are three maximum amplitude output points on the piezoelectric transducer 2, and the three maximum amplitude output points are located at the center and both sides of the piezoelectric transducer 2 respectively, where the center of the piezoelectric transducer 2 has the maximum amplitude. Specifically, it can be seen in Figure 2 and Figure 3 the first vibration mode 300 and the second vibration mode 301. In one working cycle, it can be specifically divided into a first working state ( Figure 2 ) and a second working state ( Figure 3 ), and the specific description is as follows.

[0064] First working state: As Figure 2As shown, at the points with the maximum amplitude on both sides of the piezoelectric transducer 2, it vibrates downward, and at the point with the maximum amplitude at the center, it vibrates upward. The piezoelectric transducer 2 operates in the first vibration mode 300. High-pressure sound regions will be formed on both sides of the upper cavity 200 near the center maximum amplitude point (it should be noted here that since the piezoelectric transducer 2 has a middle hole 24 in the center and no ultrasonic waves are generated in the central region, no high-pressure sound region is formed in the central region of the upper cavity 200). Under the action of the high-pressure sound regions, the fluid will flow from both sides of the upper cavity 200 towards the center, and then spray downward along the middle hole 24 into the lower cavity 201, and a jet will be formed at the jet hole 31. It should be noted here that due to the fluid viscosity effect, vortices will be generated at the jet hole 31 and near the wall surface of the middle hole 24. Under the action of the vortices, a fluid flow opposite to the central flow direction will be formed at the jet hole 31 and near the wall surface of the middle hole 24.

[0065] Second working state: As Figure 3 As shown, at the points with the maximum amplitude on both sides of the piezoelectric transducer 2, it vibrates upward, and at the point with the maximum amplitude at the center, it vibrates downward. The piezoelectric transducer 2 operates in the second vibration mode 301. The first intermediate plate 3 acts as a reflector. High-pressure sound regions will be formed on both sides of the lower cavity 201 near the center maximum amplitude point (it should be noted here that since the piezoelectric transducer 2 has a middle hole 24 in the center and the first intermediate plate 3 is provided with a jet control 31, no ultrasonic waves are generated in the central region and there is no reflector, so no high-pressure sound region is formed in the central region of the lower cavity 201). Under the action of the high-pressure sound regions, the fluid will flow from both sides of the lower cavity 201 towards the center, and then spray upward along the middle hole 24 into the upper cavity 200, and a jet will be formed at the jet hole 31. It should be noted here that due to the fluid viscosity effect, vortices will be generated at the jet hole 31 and near the wall surface of the middle hole 24. Under the action of the vortices, a fluid flow opposite to the central flow direction will be formed at the jet hole 31 and near the wall surface of the middle hole 24.

[0066] Driven by an alternating voltage signal, the first working state and the second working state operate alternately, and a high-speed and continuous jet will be formed at the center of the jet hole 31. Liquid is introduced into the first channel 110 and gas is introduced into the second channel 120. The first chamber 111 is filled with liquid and the second chamber 121 is filled with gas. Under the action of the Venturi effect, the gas in the second chamber 121 will be drained by the high-speed jet, and then a large-flow gas output will be formed at the drainage hole 41. It should be noted here that the drainage hole 41 is of an inverted conical structure, which will cause the fluid to converge at the drainage hole 41 and further increase the fluid velocity, which is beneficial to the subsequent gas-liquid mixing. The large-flow gas in the drainage hole 41 is sprayed into the first chamber 111. Based on the Venturi effect, the gas sprayed from the drainage hole 41 will carry the liquid into the mixing hole 51 together in the first chamber 111. The mixing hole 51 is of an inverted conical structure, and the mixing hole 51 will produce an expansion flow effect. Combining with the bluff body 510, the expansion flow - contraction flow - expansion flow process can be realized, which will greatly enhance the gas-liquid mixing effect.

Claims

1. A low-power micro gas-liquid mixer, characterized by: An upper cover plate, a piezoelectric transducer, a first middle plate, a second middle plate and a lower cover plate are connected in sequence from top to bottom; a driving cavity is arranged in the upper cover plate and the first middle plate; the piezoelectric transducer divides the driving cavity into an upper cavity and a lower cavity; a middle hole is arranged in the center of the piezoelectric transducer; the middle hole connects the upper cavity and the lower cavity; a liquid inlet and a gas inlet are arranged in the upper cover plate; a mixing outlet is arranged in the lower cover plate; a second cavity is arranged in the first middle plate; a first cavity is arranged in the bottom plate; a first channel is arranged in the upper cover plate, the first middle plate, the second middle plate and the lower cover plate; a second channel is arranged in the upper cover plate, the first middle plate and the second middle plate; the first channel connects the liquid inlet with the first cavity; the second channel connects the gas inlet with the second cavity; The first intermediate plate is provided with a jet hole; the jet hole connects the lower chamber and the second chamber; the jet hole is coaxial with the middle hole; the first chamber and the second chamber are cylindrical; the first chamber is coaxial with the second chamber; the first chamber is coaxial with the middle hole; the second intermediate plate is provided with a drainage hole; the drainage hole connects the second chamber and the first chamber; the drainage hole is coaxial with the jet hole; the lower cover plate is provided with a mixing hole; the mixing hole connects the first chamber and the mixing outlet; the mixing hole is coaxial with the drainage hole; the upper chamber is cylindrical; the lower chamber is cylindrical; the cavity height H1 of the upper chamber is less than the cavity height H2 of the lower chamber; the aperture of the jet hole is larger than the aperture of the middle hole, and the aperture of the jet hole is not less than 3 times the aperture of the middle hole.

2. A low-power micro gas-liquid mixer as claimed in claim 1, characterized in that: The drainage hole is a conical hole, and the cross-sectional diameter of the drainage hole gradually decreases from the second chamber to the first chamber; the maximum cross-sectional diameter of the drainage hole is not less than the aperture of the jet hole.

3. A low-power consumption micro gas-liquid mixer as claimed in claim 1, characterized in that: The mixing hole is composed of a tapered hole and a straight hole connected in sequence from top to bottom; the cross-sectional diameter of the tapered hole portion of the mixing hole gradually increases from the first chamber to the mixing outlet; the minimum cross-sectional diameter of the mixing hole is not less than the minimum cross-sectional diameter of the drainage hole.

4. A low-power consumption micro gas-liquid mixer as claimed in claim 1, characterized in that: The piezoelectric transducer is formed by concentrically bonding a piezoelectric chip and a substrate; the diameter of the piezoelectric chip is smaller than the diameter of the substrate; the periphery of the substrate is clamped by the upper cover plate and the first intermediate plate; the piezoelectric chip faces the upper cavity.

5. A low-power consumption micro gas-liquid mixer as claimed in claim 4, characterized in that: A matching layer is concentrically bonded to the lower surface of the substrate; the matching layer faces the lower cavity; the acoustic impedance of the matching layer is between the substrate and the working gas; the material of the matching layer is metal; the outer diameter of the matching layer is not less than the outer diameter of the piezoelectric chip; and the outer diameter of the matching layer is less than the diameter of the substrate.

6. A low-power consumption micro gas-liquid mixer as claimed in claim 1, characterized in that: The cavity height H1 of the upper cavity is not less than twice the maximum amplitude of the piezoelectric transducer when it is working.

7. A low-power consumption micro gas-liquid mixer as claimed in claim 1, characterized in that: The height of the second chamber is H3; the height H3 of the second chamber is not greater than the height H2 of the lower chamber; the height of the first chamber is H4; the height H4 of the first chamber is not greater than the height H3 of the second chamber; the diameter of the middle hole does not exceed 1 mm.

8. A low-power consumption micro gas-liquid mixer as claimed in claim 3, characterized in that: A blunt body is arranged at the center of the mixing hole; the blunt body is an inverted cone structure, and the cross-sectional diameter of the blunt body gradually decreases from top to bottom; the maximum cross-sectional diameter of the blunt body does not exceed half of the minimum cross-sectional diameter of the mixing hole.

9. A low-power consumption micro gas-liquid mixer as claimed in claim 5, characterized in that: The substrate is provided with slots distributed around its circumference; the slots are fan-shaped through holes; cantilever beams are formed between adjacent slots; the arrangement of the slots divides the substrate into an outer supporting portion and a central middle portion, and the supporting portion and the middle portion are connected by the cantilever beam; the piezoelectric chip and the matching layer are both concentrically connected to the middle portion; a diaphragm is connected to the substrate at the slots, and the diaphragm is used for sealing and isolating the upper and lower ends of the slots.

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