Triboelectric self-sensing piezoelectric micro valve and flow monitoring method

Abstract

A triboelectric self-sensing piezoelectric micro valve, comprising a housing (1), a piezoelectric vibrator (2) and a friction sensing unit (3). The housing (1) is provided with a liquid inlet (11) and a liquid outlet (12); the piezoelectric vibrator (2) and the friction sensing unit (3) are arranged in the housing (1); the piezoelectric vibrator (2) is arranged at the liquid inlet (11); the friction sensing unit (3) comprises a first power generation unit (31) and a second power generation unit (32) arranged opposingly; the first power generation unit (31) is fixedly connected to an inner wall of the housing (1); the second power generation unit (32) is fixedly connected to the piezoelectric vibrator (2); the piezoelectric vibrator (2) is used for driving the second power generation unit (32) to contact or move away from the first power generation unit (31); the piezoelectric vibrator (2) deforms under the action of a driving voltage to open the liquid inlet (11) and make the second power generation unit (32) contact the first power generation unit (31) so as to generate a first electrical signal; or the piezoelectric vibrator (2) deforms under the control of the driving voltage to close the liquid inlet (11) and make the second power generation unit (32) move away from the first power generation unit (31) so as to generate a second electrical signal. A flow monitoring method, applied to the triboelectric self-sensing piezoelectric micro valve. In this way, self-sensing flow monitoring can be realized, and by integrating the friction sensing unit and the piezoelectric vibrator, the space utilization rate is improved, thereby facilitating the miniaturization and integration of a device.

Description

A triboelectric self-sensing piezoelectric microvalve and flow monitoring method Technical Field

[0001] This application relates to the field of liquid flow monitoring technology, and in particular to a triboelectric self-sensing piezoelectric microvalve and a flow monitoring method. Background Technology

[0002] Liquid flow valves typically control fluid flow through mechanical or electronic means. For example, the flow rate can be adjusted by changing the valve opening, thus achieving flow monitoring and control. Valves come in various actuation methods, such as electromagnetic, electrostatic, and thermal actuation. Electromagnetic actuation is susceptible to external environmental interference and has high power consumption. While electrostatic actuation offers fast response and low power consumption, its highly nonlinear control characteristics are unfavorable for proportional control. Thermal actuation is easily affected by fluid changes and has poor stability. Furthermore, valves are sensitive to the viscosity and temperature of the medium. For high-viscosity media, the accuracy of flow regulation is significantly affected. Therefore, there is an urgent need for a triboelectric self-sensing piezoelectric microvalve with high precision. Summary of the Invention

[0003] This application provides a triboelectric self-sensing piezoelectric microvalve and flow monitoring method that combines piezoelectric ceramics with triboelectric nanogenerators, proposing a novel triboelectric self-sensing piezoelectric microvalve capable of self-sensing flow monitoring with micro-liter-level accuracy. Furthermore, integrating the triboelectric sensing unit with the piezoelectric oscillator improves space utilization and facilitates the miniaturization and integration of the device.

[0004] On one hand, an embodiment of this application provides a triboelectric self-sensing piezoelectric microvalve comprising a housing, a piezoelectric vibrator, and a triboelectric sensing unit. The housing has an inlet and an outlet, and the piezoelectric vibrator and the triboelectric sensing unit are disposed within the housing. The piezoelectric vibrator is disposed at the inlet. The triboelectric sensing unit includes a first power generation unit and a second power generation unit disposed opposite to each other. The first power generation unit is fixedly connected to the inner wall of the housing, and the second power generation unit is fixedly connected to the piezoelectric vibrator. The piezoelectric vibrator is used to drive the second power generation unit to contact or move away from the first power generation unit. Under the action of a driving voltage, the piezoelectric vibrator deforms to open the inlet and causes the second power generation unit to contact the first power generation unit to generate a first electrical signal; or, under the control of a driving voltage, the piezoelectric vibrator deforms to close the inlet and causes the second power generation unit to move away from the first power generation unit to generate a second electrical signal.

[0005] In the above embodiments, a triboelectric sensing unit is combined with a piezoelectric vibrator. The piezoelectric vibrator acts as a switch, controlling the liquid flow time by controlling its deformation and driving the triboelectric sensing unit. Without affecting the normal operation of the piezoelectric vibrator, the voltage amplitude change and frequency pulse count are obtained by monitoring the electrical signal generated by the triboelectric sensing unit, thus determining the actual response time of the piezoelectric vibrator switch. This enables real-time flow monitoring, improving the accuracy of flow monitoring to the micro-level. Furthermore, when the piezoelectric vibrator malfunctions, the triboelectric sensing unit will not generate an electrical signal. By monitoring changes in the electrical signal generated by the triboelectric sensing unit, it is possible to detect whether the piezoelectric vibrator is abnormal, such as damaged, facilitating timely equipment maintenance by the user. The triboelectric self-sensing piezoelectric microvalve of this application has a simple structure and small size, and can be applied to scenarios such as drug injection and biopharmaceutical mixing.

[0006] In one embodiment, the first power generation unit and the second power generation unit are spaced apart by a preset distance, the preset distance being 1 mm.

[0007] In one embodiment, the first power generation unit includes a nylon film layer and a first electrode layer stacked together, the first electrode layer being located between the housing and the nylon film layer.

[0008] In one embodiment, the second power generation unit includes an FEP film layer, which is fixedly connected to the surface of the piezoelectric vibrator facing the first power generation unit.

[0009] In one embodiment, the piezoelectric vibrator includes a stacked ceramic layer and a second electrode layer, with the second power generation unit mounted on the side of the ceramic layer opposite to the second electrode layer.

[0010] In one embodiment, the second power generation unit includes an EFP film layer and an insulating adhesive layer, the insulating adhesive layer being disposed between the EFP film layer and the piezoelectric vibrator.

[0011] In one embodiment, the insulating adhesive layer completely covers the ceramic layer in the orthogonal projection of the piezoelectric vibrator.

[0012] In one embodiment, the insulating adhesive layer and the EFP film layer have the same shape and area, and are bonded together.

[0013] In one embodiment, the orthographic projection of the first power generation unit onto the second power generation unit is entirely within the second power generation unit.

[0014] In one embodiment, the cross-sections and areas of the first power generation unit, the second power generation unit, and the ceramic layer are exactly the same, all being circular or all being square. Along the stacking direction, the orthographic projection of the first power generation unit onto the second power generation unit completely coincides with the second power generation unit, and the orthographic projection of the second power generation unit onto the ceramic layer completely coincides with the ceramic layer.

[0015] In one embodiment, the first power generation unit and the second power generation unit have the same cross-sectional shape, and the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit.

[0016] In one embodiment, the first power generation unit has a circular cross-section, the second power generation unit has a square cross-section, the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit, the ceramic layer is circular, and the second power generation unit is tangentially disposed within the ceramic layer.

[0017] In one embodiment, the first power generation unit has a square cross-section, the second power generation unit has a circular cross-section, and the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit.

[0018] In one embodiment, the housing includes a body and a cover, the cover being fastened to the body to form a receiving cavity, the first power generation unit being mounted on the cover, and the piezoelectric vibrator being mounted on the body.

[0019] In one embodiment, the triboelectric self-sensing piezoelectric microvalve further includes a first sealing ring and a second sealing ring. The body is provided with a first mounting groove, in which the first sealing ring is installed. The cover is provided with a second mounting groove, in which the second sealing ring is installed. The first sealing ring and the second sealing ring are coaxially arranged.

[0020] In one embodiment, the triboelectric self-sensing piezoelectric microvalve further includes a flexible gasket, which is fixedly installed on the side of the piezoelectric vibrator facing the liquid inlet; when the piezoelectric vibrator deforms to open the liquid inlet, the flexible gasket moves away from the liquid inlet along with the piezoelectric vibrator; or, when the piezoelectric vibrator deforms to close the liquid inlet, the flexible gasket adheres to the liquid inlet.

[0021] On the other hand, embodiments of this application also provide a flow monitoring method applied to the above-mentioned triboelectric self-sensing piezoelectric microvalve. The flow monitoring method includes: sending a driving signal to the piezoelectric vibrator to cause the piezoelectric vibrator to deform in order to open or close the inlet; adjusting the deformation of the piezoelectric vibrator by controlling the voltage of the driving signal to control the flow velocity v of the liquid; monitoring the first electrical signal and the second electrical signal generated by the triboelectric sensing unit in real time to obtain the actual time t1 when the piezoelectric vibrator opens the inlet; and obtaining the liquid flow rate through the triboelectric self-sensing piezoelectric microvalve based on the actual time t1 when the inlet is opened and the flow velocity v of the liquid.

[0022] In one embodiment, sending a driving signal to the piezoelectric vibrator to cause the piezoelectric vibrator to deform in order to open or close the liquid inlet includes: sending a first square wave signal to the piezoelectric vibrator, and controlling the time t2 for the piezoelectric vibrator to open the liquid inlet by the duty cycle of the first square wave signal.

[0023] In one embodiment, real-time monitoring of the first electrical signal and the second electrical signal generated by the friction sensing unit to obtain the actual time t1 when the piezoelectric vibrator opens the liquid inlet includes: converting the first electrical signal and the second electrical signal into a second square wave signal, and obtaining the actual time t1 when the piezoelectric vibrator opens the liquid inlet through the duty cycle of the second square wave signal. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the structure of a triboelectric self-sensing piezoelectric microvalve provided in an embodiment of this application;

[0025] Figure 2 is an exploded view of a first power generation unit and cover provided in an embodiment of this application;

[0026] Figure 3 is an exploded view of a second power generation unit and a piezoelectric vibrator provided in an embodiment of this application;

[0027] Figure 4 is an exploded view of a triboelectric self-sensing piezoelectric microvalve provided in an embodiment of this application;

[0028] Figure 5 is a top view of the body provided in an embodiment of this application;

[0029] Figure 6 is a flowchart of a traffic monitoring method provided in an embodiment of this application.

[0030] Figure label:

[0031] 1-Housing; 2-Piezoelectric vibrator; 3-Friction sensing unit; 11-Inlet; 12-Outlet; 31-First power generation unit; 32-Second power generation unit; 311-Nylon film layer; 312-First electrode layer; 321-FEP film layer; 322-Insulating adhesive layer; 21-Ceramic layer; 22-Second electrode layer; 101-Cover; 102-Body; 1011-Through hole; 4-First sealing ring; 5-Second sealing ring; 1021-First mounting groove; 1012-Second mounting groove; 13-First chamber; 14-Second chamber; 6-Flexible gasket; 00-Screw. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of the application is provided in conjunction with the accompanying drawings and embodiments.

[0033] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more” unless the context clearly indicates otherwise.

[0034] References to “an embodiment” or “a specific embodiment” as used in this specification mean that one or more embodiments of this application include a particular feature, structure, or characteristic described in connection with that embodiment. The terms “comprising,” “including,” “having,” and variations thereof mean “including, but not limited to,” unless otherwise specifically emphasized.

[0035] In related technologies, piezoelectric ceramics are materials capable of converting electrical energy and mechanical energy into each other, exhibiting both piezoelectric and inverse piezoelectric effects. When a voltage is applied, it generates mechanical vibration; conversely, when mechanical pressure is applied, it generates voltage. Piezoelectric ceramics possess advantages such as high sensitivity, high precision, and high stability, and are widely used in sensors, actuators, vibrators, and other fields.

[0036] A square wave is a periodic waveform at a specific frequency, characterized by a sudden change in amplitude between positive and negative half-cycles of equal amplitude. Square waves are characterized by periodicity, high frequency, and high precision, and are widely used in digital circuits, communication systems, control systems, and other fields.

[0037] Combining piezoelectric ceramics with square waves allows for the use of square wave signals as drive signals to enable periodic reversal switching actions of the piezoelectric ceramic sheet, thus achieving more precise measurement and control. However, while square wave drive signals can control the switching action of the piezoelectric ceramics, environmental factors such as medium viscosity and temperature can cause deviations between the actual deformation time of the piezoelectric ceramic response and the deformation time of the drive signal, resulting in errors in flow monitoring.

[0038] To address the aforementioned issues, this application provides a triboelectric self-sensing piezoelectric microvalve and a flow monitoring method that employs a combination of triboelectric and piezoelectric methods to monitor flow rate, thereby resolving the technical problem of low flow rate accuracy when using liquid flow valves.

[0039] Figure 1 is a schematic diagram of the structure of a triboelectric self-sensing piezoelectric microvalve provided in an embodiment of this application. As shown in Figure 1, the triboelectric self-sensing piezoelectric microvalve provided in this embodiment of the application is installed in a fluid pipeline. The triboelectric self-sensing piezoelectric microvalve includes a housing 1, a piezoelectric vibrator 2, and a triboelectric sensing unit 3. The housing 1 has an inlet 11 and an outlet 12, and liquid in the pipeline can enter the housing 1 through the inlet 11 and flow out of the housing 1 through the outlet 12. The piezoelectric vibrator 2 and the triboelectric sensing unit 3 are both disposed in the housing 1. The triboelectric sensing unit 3 includes a first power generation unit 31 and a second power generation unit 32 disposed opposite to each other. The first power generation unit 31 is fixedly connected to the inner wall of the housing 1, and the second power generation unit 32 is fixedly connected to the surface of the piezoelectric vibrator 2 facing the first power generation unit 31. The piezoelectric vibrator 2 is used to drive the second power generation unit 32 to contact or move away from the first power generation unit 31. The piezoelectric vibrator 2 is disposed at the inlet 11, and the piezoelectric vibrator 2 deforms upon receiving an externally applied driving voltage. The deformation includes two actions: bending away from the inlet 11 and bending towards the inlet 11. When the piezoelectric vibrator 2 bends away from the inlet 11, a gap is created between the piezoelectric vibrator 2 and the inlet 11, opening the inlet 11 and allowing liquid in the fluid pipe to enter the housing 1 and then flow out of the housing 1 from the outlet 12. When the piezoelectric vibrator 2 bends towards the inlet 11, it contacts the inlet 11, closing the inlet 11. During the deformation process, when the piezoelectric vibrator 2 bends away from the inlet 11, it can drive the second power generation unit 32 to approach and contact the first power generation unit 31. The gap between the first power generation unit 31 and the second power generation unit 32 gradually decreases until they make contact, resulting in triboelectric charging and electrostatic coupling, generating a first electrical signal. When the piezoelectric vibrator 2 bends towards the inlet 11, it moves the second power generation unit 32 away from the first power generation unit 31, gradually increasing the gap between them and causing a change in potential, generating a second electrical signal. During continuous operation, the piezoelectric vibrator 2 repeatedly opens and closes the inlet 11, while the triboelectric sensing unit 3 outputs alternating current pulse signals, forming a square wave.

[0040] In the above embodiments, the triboelectric sensing unit 3 can specifically be a triboelectric nanogenerator. Based on triboelectric charging and electrostatic coupling effects, the triboelectric nanogenerator can convert mechanical energy into electrical signals to achieve intelligent sensing. The two power generation units of the triboelectric sensing unit 3 generate electrical signals during contact and separation, and the voltage amplitude change and frequency pulse count can be obtained from these signals. The triboelectric sensing unit 3 is combined with a piezoelectric vibrator 2, which acts as a switch. The piezoelectric vibrator 2 can control the liquid flow time by controlling its deformation, and it can also drive the triboelectric sensing unit 3. Without affecting the normal operation of the piezoelectric vibrator 2, by monitoring the electrical signals generated by the triboelectric sensing unit 3, the voltage amplitude change and frequency pulse count are obtained, thus determining the actual response time of the piezoelectric vibrator 2 switch. This enables real-time flow monitoring, improving the accuracy of flow monitoring to the micro-level, thereby enhancing the precision of flow monitoring.

[0041] Furthermore, when the piezoelectric vibrator 2 malfunctions, the triboelectric sensing unit 3 will not generate an electrical signal. By monitoring changes in the electrical signal generated by the triboelectric sensing unit 3, it is possible to detect whether the piezoelectric vibrator 2 is malfunctioning, such as being damaged. This facilitates timely maintenance of the equipment by the user. The triboelectric self-sensing piezoelectric microvalve of this application has a simple structure and small size, and can be applied to scenarios such as drug injection and biopharmaceutical mixing.

[0042] The core power generation principle of triboelectric nanogenerators (TENGs) originates from the friction between the surfaces of objects of different materials, specifically categorized into four basic forms: vertical contact separation, horizontal sliding, single electrode, and independent layer. The triboelectric sensing unit 3 of this application employs the single-electrode power generation form. A triboelectric nanogenerator mainly consists of two basic components: a friction material and an electrode. The friction material is the core component of the triboelectric nanogenerator, typically composed of two materials with different triboelectric properties. When these two materials come into contact, charge separation occurs due to electron transfer. When the two materials separate, a potential difference is generated, and the charge is transferred to the external circuit through the electrode to form a current. The specific structure and materials of the triboelectric sensing unit 3 of this application are described below:

[0043] Figure 2 is an exploded view of the first power generation unit and cover provided in one embodiment of this application, and Figure 3 is an exploded view of the second power generation unit and piezoelectric vibrator provided in one embodiment of this application. As shown in Figures 2 and 3, in one embodiment, the first power generation unit 31 has a thin structure, including a nylon film layer 311 and a first electrode layer 312 stacked together, with the first electrode layer 312 located between the housing 1 and the nylon film layer 311. The first electrode layer 312 can specifically be a copper electrode layer. The second power generation unit 32 also has a thin structure, including an FEP film layer 321. The FEP film layer is fixedly connected to the surface of the piezoelectric vibrator 2 facing the first power generation unit 31. Specifically, when installing the FEP film layer 321, it can be bonded to the piezoelectric vibrator 2 through an insulating adhesive layer 322. The insulating adhesive layer 322 is located between the piezoelectric vibrator 2 and the FEP film layer 321. The FEP film (perfluoroethylene propylene film) is a material copolymerized from tetrafluoroethylene and hexafluoropropylene.

[0044] The nylon film layer 311 and the FEP film layer 321 are two material layers with different triboelectric properties. During the process of contact and separation, a potential difference is generated. The charge is transferred to the external circuit through the first electrode layer 312 to form an electrical signal. The flow rate is monitored by monitoring this electrical signal.

[0045] In one embodiment, along a direction perpendicular to the piezoelectric vibrator 2, the orthogonal projection of the first electrode layer 312 onto the nylon film layer 311 completely coincides with the nylon film layer 311.

[0046] In one embodiment, the first power generation unit 31 and the second power generation unit 32 are spaced apart by a preset distance when not in operation. This preset distance can be 1 mm. Setting the distance between the first power generation unit 31 and the second power generation unit 32 to 1 mm effectively reduces the volume of the friction sensing unit 3, thereby reducing the size of the triboelectric self-sensing piezoelectric microvalve and enabling its application in some micro-scale scenarios. Furthermore, this distance allows the friction sensing unit 3 to output a stable current, improving monitoring accuracy. It also reduces frictional damage to the membrane layer when the friction sensing unit 3 is not in operation, extending the service life of the nylon membrane layer 311 and the FEP membrane layer 321.

[0047] In one embodiment, the piezoelectric vibrator 2 is also a thin structure, capable of deforming and bending under the action of the reverse piezoelectric effect when receiving a voltage signal. It includes a stacked ceramic layer 21 and a second electrode layer 22. The second power generation unit 32 is mounted on the side of the ceramic layer 21 opposite to the second electrode layer 22, i.e., the FEP film is adhered to the surface of the ceramic layer 21. Specifically, the second electrode layer 22 can be a copper electrode layer.

[0048] All of the above-mentioned stacking directions are perpendicular to the piezoelectric vibrator 2.

[0049] To prevent the charge on the ceramic layer 21 from transferring to the EFP film layer 321 and affecting the electrical signal generated by the tribological sensing unit 3, in one embodiment, the second power generation unit 32 further includes an insulating adhesive layer 322 disposed between the EFP film layer 321 and the ceramic layer 21 of the piezoelectric vibrator 2. The insulating adhesive layer 322 isolates the EFP film layer 321 from the ceramic layer 21, preventing the charge on the ceramic layer 21 from transferring to the EFP film layer and causing monitoring errors.

[0050] In one embodiment, the insulating adhesive layer 322, projected onto the piezoelectric vibrator 2, completely covers the ceramic layer 21. Therefore, the EFP film layer 321 or the nylon film layer 311 cannot come into contact with the ceramic layer 21. This reduces the influence of the piezoelectric vibrator 2 on the friction sensing unit 3, thereby improving the accuracy of the electrical signal generated by the friction sensing unit 3.

[0051] In one embodiment, the insulating adhesive layer 322 and the EFP film layer 321 have the same shape and area, and are bonded together to facilitate the assembly of the second power generation unit 32. The nylon film layer 311 and the first electrode layer 312 have the same shape and area, and are bonded together to facilitate the assembly of the first power generation unit 31.

[0052] In one embodiment, the orthographic projection of the first power generation unit 31 onto the second power generation unit 32 is entirely within the second power generation unit.

[0053] The cross-section and area settings of the first power generation unit 31 and the second power generation unit 32 can be configured in the following ways:

[0054] In one embodiment, the first power generation unit 31, the second power generation unit 32, and the ceramic layer 21 have identical cross-sections and areas, all being circular or all being square. Along the stacking direction, the orthographic projection of the first power generation unit 31 onto the second power generation unit 32 completely coincides with the second power generation unit 32, and the orthographic projection of the second power generation unit 32 onto the ceramic layer 21 completely coincides with the ceramic layer 21. During assembly, the first power generation unit 31, the second power generation unit 32, and the ceramic layer 21 can be coaxially arranged. The second power generation unit 32 overlaps with the ceramic layer 21, and the first power generation unit 31 and the second power generation unit 32 overlap when in contact.

[0055] In the above embodiments, the first power generation unit 31 and the second power generation unit 32 are completely overlapped when in contact, which is the ideal state of assembly. However, in the actual assembly process, due to the influence of the assembly process, the first power generation unit 31 and the second power generation unit 32 have certain assembly errors, resulting in the first power generation unit 31 and the second power generation unit 32 not being completely overlapped when in contact. Therefore, the area of ​​the second power generation unit 32 can also be set to be larger than the area of ​​the first power generation unit 31, so that the second power generation unit 32 isolates the piezoelectric vibrator 2 from the first power generation unit 31, thereby reducing the influence of the piezoelectric vibrator 2 on the friction sensing unit 3.

[0056] In another embodiment, the first power generation unit 31 and the second power generation unit 32 have the same cross-sectional shape, the area of ​​the second power generation unit 32 is larger than the area of ​​the first power generation unit 31, and the orthographic projection of the first power generation unit 31 onto the second power generation unit 32 is completely located within the second power generation unit 32.

[0057] Alternatively, in another embodiment, the first power generation unit 31 has a circular cross-section, the second power generation unit 32 has a square cross-section, the area of ​​the second power generation unit 32 is larger than the area of ​​the first power generation unit 31, and the orthographic projection of the first power generation unit 31 onto the second power generation unit 32 is completely located within the second power generation unit 32. The ceramic layer 21 is circular, and the second power generation unit 32 is tangentially disposed within the ceramic layer 21.

[0058] Alternatively, in another embodiment, the first power generation unit 31 has a square cross-section, and the second power generation unit 32 has a circular cross-section. The area of ​​the second power generation unit 32 is larger than the area of ​​the first power generation unit 31, and the orthographic projection of the first power generation unit 31 onto the second power generation unit 32 is completely located within the second power generation unit 32.

[0059] The area mentioned above refers to the area of ​​the respective surfaces of the first power generation unit 31 and the second power generation unit 32 on the side where they are in contact with each other.

[0060] Figure 4 is an exploded view of a triboelectric self-sensing piezoelectric microvalve provided in one embodiment of this application. As shown in Figure 4, in one embodiment, the housing 1 includes a body 102 and a cover 101. The cover 101 and the body 102 are fastened together to form a receiving cavity. The first power generation unit 31 is installed on the cover 101, and the piezoelectric vibrator 2 is installed on the body 102. The cover 101 and the body 102 are respectively provided with corresponding threaded holes, and the cover 101 and the body 102 can be connected and fixed by screws 00.

[0061] In one embodiment, the cover 101 is provided with a through hole 1011, which does not overlap with the first power generation unit 31. The through hole 1011 allows cables connected to the friction sensing unit 3 and the piezoelectric vibrator 2 to pass through.

[0062] In one embodiment, the housing 1 can be a cylinder, a square prism, or a polygonal prism.

[0063] Figure 5 is a top view of the main body provided in one embodiment of this application. Referring to Figures 1, 2, 4, and 5, in one embodiment, the triboelectric self-sensing piezoelectric microvalve further includes a first sealing ring 4 and a second sealing ring 5. The bottom of the main body 102 is provided with a first mounting groove 1021, in which the first sealing ring 4 is installed. The cover 101 is provided with a second mounting groove 1012, located on the periphery of the first power generation unit 31, in which the second sealing ring 5 is installed. The first sealing ring 4 and the second sealing ring 5 can be coaxially arranged. The piezoelectric vibrator 2 is located between the first sealing ring 4 and the second sealing ring 5. After the cover 101 is fastened to the main body 102, the first sealing ring 4 and the second sealing ring 5 can press and fix the piezoelectric vibrator 2. Because the first sealing ring 4 and the second sealing ring 5 are coaxially arranged, the piezoelectric vibrator 2 can be subjected to even force.

[0064] The piezoelectric vibrator 2 divides the housing 1 into a first chamber 13 and a second chamber 14. The first sealing ring 4, the piezoelectric vibrator 2, and the bottom of the body 102 together form the first chamber 13, which is a sealed chamber. The inlet 11 and outlet 12 are both located at the bottom of the housing 1. When the piezoelectric vibrator 2 opens the inlet 11, liquid enters the first chamber 13 through the inlet 11. Once the first chamber 13 is full, the liquid flows out through the outlet 12. The cover 101, the second sealing ring 5, and the piezoelectric vibrator 2 together form the second chamber 14, which is completely isolated from the first chamber 13, preventing liquid from entering the second chamber 14 and causing a short circuit.

[0065] Referring to Figure 1, in one embodiment, the triboelectric self-sensing piezoelectric microvalve further includes a flexible gasket 6, which is fixedly installed on the side of the piezoelectric vibrator 2 facing the inlet 11. When the piezoelectric vibrator 2 deforms to open the inlet 11, the flexible gasket 6 moves away from the inlet 11 along with the piezoelectric vibrator 2. Alternatively, when the piezoelectric vibrator 2 deforms under the control of the controller to close the inlet 11, the flexible gasket 6 adheres to the inlet 11. At this time, the flexible gasket 6 deforms under the pressure of the inlet 11 and the piezoelectric vibrator 2, blocking the inlet 11 and improving the sealing of the first chamber 13.

[0066] In one embodiment, the aforementioned triboelectric self-sensing piezoelectric microvalve may further include a controller, a data acquisition unit, a data processor, and a display panel (not shown in the figure). The controller is used to send a drive signal to the piezoelectric vibrator 2, and the data acquisition unit is used to acquire the first and second electrical signals emitted by the triboelectric sensing unit 3. The data processor is used to analyze and convert the first and second electrical signals to obtain flow data, and then sends the flow data to the display panel for display. The controller, data acquisition unit, data processor, and display panel are all conventional modules, and their specific structures will not be described in detail here.

[0067] Figure 6 is a flowchart of a flow monitoring method provided in an embodiment of this application. As shown in Figure 6, an embodiment of this application also provides a flow monitoring method applied to the triboelectric self-sensing piezoelectric microvalve in any of the above embodiments. The flow monitoring method includes the following steps:

[0068] S1: The controller sends a drive signal to the piezoelectric vibrator 2, causing the piezoelectric vibrator 2 to deform and open or close the liquid inlet 11. The piezoelectric vibrator 2 acts as the switch of the triboelectric self-sensing piezoelectric micro-valve, controlling the inflow of liquid.

[0069] Specifically, when the piezoelectric vibrator 2 does not receive a drive signal, it is in a non-operating state, and the friction sensing unit 3 does not generate an electrical signal. When a drive signal is input, the piezoelectric vibrator 2 bends and deforms away from the liquid inlet 11, and the flexible gasket 6 moves with the piezoelectric vibrator 2. At this time, the liquid inlet 11 is open, and liquid begins to flow in. The liquid enters the first chamber 13 through the liquid inlet 11 and flows out through the liquid outlet 12 after filling the first chamber 13. At this time, the gap between the FEP film layer 321 and the nylon film layer 311 becomes smaller until they come into contact, and triboelectric charging and electrostatic coupling effects occur, generating the first electrical signal. After that, the piezoelectric vibrator 2 remains in a continuously open state. When the time t2 for the piezoelectric vibrator 2 to open the liquid inlet 11 ends, the piezoelectric vibrator 2 bends towards the liquid inlet 11, the flexible gasket 6 seals the liquid inlet 11, the liquid stops flowing in, and the liquid inlet 11 is closed. At this point, the gap between the FEP film layer 321 and the nylon film layer 311 increases, causing a change in potential and generating a second electrical signal. Afterward, the piezoelectric vibrator 2 remains in a continuously off state, completing one cycle. During continuous operation, the piezoelectric vibrator 2 cycles between these two actions. When the driving signal stops, the piezoelectric vibrator 2 returns to its non-deformable state when it is not in operation.

[0070] In step S1, a drive signal is sent to the piezoelectric vibrator 2 to cause the piezoelectric vibrator 2 to deform in order to open or close the liquid inlet 11. This includes sending a first square wave signal to the piezoelectric vibrator 2 and controlling the time t2 for the piezoelectric vibrator 2 to open the liquid inlet 11 by the duty cycle of the first square wave signal.

[0071] A square wave is a non-sinusoidal waveform. A square wave signal refers to a signal in which voltage or current rapidly switches between two specific levels within each cycle, typically switching between a maximum and a minimum value. The duty cycle of a square wave signal refers to the ratio of the time the signal is at a high level to the total time of the cycle. Specifically, the duty cycle is the proportion of time the signal is at a high level within a cycle. A 50% duty cycle for a square wave means that the signal is at a high level for half the time and at a low level for the other half of the complete signal cycle. In this application, the width of the duty cycle in the waveform of the first square wave signal is equal to the opening time t2 of the inlet 11. The opening time t2 of the inlet 11 can be controlled by adjusting the duty cycle of the first square wave signal.

[0072] S2: The deformation of the piezoelectric vibrator 2 is adjusted by controlling the voltage of the drive signal to control the flow rate v of the liquid.

[0073] Specifically, the driving signal can be a voltage signal, and the piezoelectric vibrator 2 can change its deformation according to different voltage signals. For example, increasing the voltage increases the deformation of the piezoelectric vibrator 2, thereby increasing the valve opening, and correspondingly increasing the liquid flow rate per unit time (i.e., increasing the flow velocity). In other words, the flow velocity can be controlled by the driving signal; the flow velocity v under a fixed voltage is a fixed value, and the flow velocity is uniform.

[0074] S3: Real-time monitoring of the first and second electrical signals generated by the friction sensing unit 3 to obtain the actual opening time t1 of the piezoelectric vibrator 2 at the liquid inlet 11.

[0075] Since there is a deviation between the controlled opening time t2 and the actual opening time t1 of the piezoelectric vibrator 2, the actual opening time t1 of the piezoelectric vibrator 2 can be obtained more accurately by monitoring the electrical signal of the friction sensing unit 3, thereby improving the accuracy of flow monitoring.

[0076] In step S3, the first and second electrical signals generated by the friction sensing unit 3 are monitored in real time to obtain the actual opening time t1 of the piezoelectric vibrator 2 at the liquid inlet 11. This includes: the data acquisition unit collects the first and second electrical signals, which are then processed by the data processor to generate a second square wave signal. The actual opening time t1 of the piezoelectric vibrator 2 at the liquid inlet 11 after the response is obtained through the second square wave signal.

[0077] S4: Based on the actual opening time t1 of the inlet 11 and the liquid flow rate v, the liquid flow rate Q through the triboelectric self-sensing piezoelectric micro-valve is obtained: Q = t1 × v.

[0078] This application presents a triboelectric self-sensing piezoelectric microvalve and flow monitoring method that combines piezoelectric ceramics with triboelectric nanogenerators, proposing a novel triboelectric self-sensing piezoelectric microvalve capable of self-sensing flow monitoring. Integrating the triboelectric sensing unit 3 with the piezoelectric vibrator 2 improves space utilization, facilitates miniaturization and integration of the device, and achieves micro-level flow monitoring accuracy.

[0079] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A triboelectric self-sensing piezoelectric microvalve, characterized in that, It includes a housing, a piezoelectric vibrator, and a triboelectric sensing unit, wherein, The housing has a liquid inlet and a liquid outlet, the piezoelectric vibrator and the friction sensing unit are disposed in the housing, and the piezoelectric vibrator is disposed in the liquid inlet; The friction sensing unit includes a first power generation unit and a second power generation unit arranged opposite to each other. The first power generation unit is fixedly connected to the inner wall of the housing, and the second power generation unit is fixedly connected to the piezoelectric vibrator. The piezoelectric vibrator is used to drive the second power generation unit to contact or move away from the first power generation unit. The piezoelectric vibrator deforms under the action of the driving voltage to open the liquid inlet and bring the second power generation unit into contact with the first power generation unit to generate a first electrical signal; or, the piezoelectric vibrator deforms under the control of the driving voltage to close the liquid inlet and move the second power generation unit away from the first power generation unit to generate a second electrical signal.

2. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The first power generation unit and the second power generation unit are spaced apart by a preset distance, which is 1 mm.

3. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The first power generation unit includes a nylon film layer and a first electrode layer stacked together, with the first electrode layer located between the housing and the nylon film layer.

4. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The second power generation unit includes an FEP film layer, which is fixedly connected to the surface of the piezoelectric vibrator facing the first power generation unit.

5. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The piezoelectric vibrator includes a ceramic layer and a second electrode layer stacked together, and the second power generation unit is installed on the side of the ceramic layer away from the second electrode layer.

6. The triboelectric self-sensing piezoelectric microvalve according to claim 5, characterized in that, The second power generation unit includes an EFP film layer and an insulating adhesive layer, wherein the insulating adhesive layer is disposed between the EFP film layer and the piezoelectric vibrator.

7. The triboelectric self-sensing piezoelectric microvalve according to claim 6, characterized in that, The insulating adhesive layer completely covers the ceramic layer in the orthogonal projection of the piezoelectric vibrator; Alternatively, the insulating adhesive layer and the EFP film layer have the same shape and area, and are bonded together.

8. The triboelectric self-sensing piezoelectric microvalve according to claim 6, characterized in that, The orthographic projection of the first power generation unit onto the second power generation unit is entirely within the second power generation unit.

9. The triboelectric self-sensing piezoelectric microvalve according to claim 8, characterized in that, The cross-sections and areas of the first power generation unit, the second power generation unit, and the ceramic layer are exactly the same, all being circular or all being square. Along the stacking direction, the orthographic projection of the first power generation unit onto the second power generation unit completely coincides with the second power generation unit, and the orthographic projection of the second power generation unit onto the ceramic layer completely coincides with the ceramic layer. Alternatively, the first power generation unit and the second power generation unit have the same cross-sectional shape, and the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit; Alternatively, the first power generation unit has a circular cross-section, the second power generation unit has a square cross-section, the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit, the ceramic layer is circular, and the second power generation unit is inscribed within the ceramic layer. Alternatively, the first power generation unit has a square cross-section, the second power generation unit has a circular cross-section, and the area of ​​the second power generation unit is larger than the area of ​​the first power generation unit.

10. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The housing includes a body and a cover, the cover being fastened to the body to form a receiving cavity, the first power generation unit being installed in the cover, and the piezoelectric vibrator being installed in the body.

11. The triboelectric self-sensing piezoelectric microvalve according to claim 10, characterized in that, The triboelectric self-sensing piezoelectric micro-valve further includes a first sealing ring and a second sealing ring. The body is provided with a first mounting groove, in which the first sealing ring is installed. The cover is provided with a second mounting groove, in which the second sealing ring is installed. The first sealing ring and the second sealing ring are coaxially arranged.

12. The triboelectric self-sensing piezoelectric microvalve according to claim 1, characterized in that, The triboelectric self-sensing piezoelectric microvalve also includes a flexible gasket, which is fixedly installed on the side of the piezoelectric vibrator facing the liquid inlet. When the piezoelectric vibrator deforms to open the liquid inlet, the flexible pad moves away from the liquid inlet along with the piezoelectric vibrator; or, when the piezoelectric vibrator deforms to close the liquid inlet, the flexible pad adheres to the liquid inlet.

13. A flow monitoring method, applied to the triboelectric self-sensing piezoelectric microvalve as described in any one of claims 1 to 12, characterized in that, include: A driving signal is sent to the piezoelectric vibrator to cause the piezoelectric vibrator to deform, thereby opening or closing the liquid inlet; The deformation of the piezoelectric vibrator is adjusted by controlling the voltage of the driving signal to control the flow rate v of the liquid; the first and second electrical signals generated by the friction sensing unit are monitored in real time to obtain the actual time t1 when the piezoelectric vibrator opens the liquid inlet. The liquid flow rate through the triboelectric self-sensing piezoelectric microvalve is obtained based on the actual opening time t1 of the inlet and the liquid flow rate v.

14. The flow monitoring method according to claim 13, characterized in that, Sending a drive signal to the piezoelectric vibrator to cause it to deform in order to open or close the liquid inlet includes: sending a first square wave signal to the piezoelectric vibrator, and controlling the time t2 for the piezoelectric vibrator to open the liquid inlet by the duty cycle of the first square wave signal.

15. The flow monitoring method according to claim 13, characterized in that, Real-time monitoring of the first and second electrical signals generated by the friction sensing unit to obtain the actual time t1 when the piezoelectric vibrator opens the liquid inlet includes: converting the first and second electrical signals into a second square wave signal, and obtaining the actual time t1 when the piezoelectric vibrator opens the liquid inlet through the duty cycle of the second square wave signal.

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