Underground coal mine dust concentration sensor based on surface acoustic waves

Abstract

The invention discloses an underground coal mine dust concentration sensor based on surface acoustic waves, which comprises a piezoelectric substrate, a first interdigital transducer, a second interdigital transducer, a graphene layer and a circuit board, and is characterized in that the first interdigital transducer and the second interdigital transducer are arranged on the piezoelectric substrate at an interval; the graphene layer is arranged on the piezoelectric substrate and used for adsorbing dust, the circuit board is used for transmitting a radio frequency electric signal to the first interdigital transducer, and the second interdigital transducer is used for receiving a surface acoustic wave generated by the piezoelectric substrate, converting the surface acoustic wave into an electric signal and transmitting the electric signal to the circuit board. According to the invention, real-time monitoring of coal mine dust concentration can be realized, abnormal conditions can be found in time, and guarantee is provided for mine safety production. The surface acoustic wave sensor is very sensitive to the change of dust concentration and can accurately detect tiny change. Compared with a traditional optical and electrical dust detection method, the surface acoustic wave technology is high in anti-electromagnetic interference capacity and is more suitable for being used in a complex mine environment.

Description

Technical Field

[0001] The present invention relates to the technical field of dust concentration sensors, and in particular to an underground coal mine dust concentration sensor based on surface acoustic waves. Background Art

[0002] Coal mines, as a vital geological resource, play a crucial role in energy supply and industrial production. However, during the mining process, drilling operations often generate large amounts of coal dust. This dust not only poses a serious threat to miners' health, causing occupational diseases such as pneumoconiosis and respiratory illnesses, but can also cause dust explosions under certain concentrations and conditions, endangering mine safety. Therefore, the detection and control of coal mine dust has become a crucial component in ensuring safe mine production. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention proposes an underground coal mine dust concentration sensor based on surface acoustic waves.

[0005] An underground coal mine dust concentration sensor based on surface acoustic waves according to an embodiment of the present invention includes a piezoelectric substrate, a first interdigital transducer, a second interdigital transducer, a graphene layer, and a circuit board. The first interdigital transducer and the second interdigital transducer are arranged on the piezoelectric substrate at intervals along the length direction of the piezoelectric substrate. The graphene layer is arranged on the piezoelectric substrate and located between the first interdigital transducer and the second interdigital transducer to absorb dust.

[0006] The circuit board is electrically connected to the first interdigital transducer and the second interdigital transducer respectively. The circuit board is used to transmit a radio frequency electrical signal to the first interdigital transducer so that the first interdigital transducer excites the piezoelectric substrate to produce mechanical vibration and generate surface acoustic waves. The second interdigital transducer is used to receive the surface acoustic waves generated by the piezoelectric substrate and convert them into electrical signals and transmit them to the circuit board. The circuit board is also used to process the electrical signals sent by the second interdigital transducer and judge the changes in dust concentration based on the changes in the electrical signals.

[0007] In some embodiments, the graphene layer, the first IDT, and the second IDT are located on the same side of the piezoelectric substrate.

[0008] In some embodiments, the graphene layer is a porous graphene layer.

[0009] In some embodiments, the first interdigital transducer includes a first bus electrode and a plurality of first interdigital electrodes, the first bus electrode extends along the length direction of the piezoelectric substrate, the plurality of first interdigital electrodes are arranged on the first bus electrode at intervals along the length direction of the first bus electrode, and the first interdigital electrodes extend along the width direction of the piezoelectric substrate.

[0010] In some embodiments, the underground coal mine dust concentration sensor based on surface acoustic waves of an embodiment of the present invention also includes a first reflection grating, the first reflection grating includes a first bus bar and a plurality of first bar electrodes, the first bus bar extends along the length direction of the piezoelectric substrate and is arranged at intervals with the first bus electrode, the plurality of first bar electrodes are arranged on the first bus bar at intervals along the length direction of the piezoelectric substrate, the first bar electrode extends along the width direction of the piezoelectric substrate, and the first bar electrodes and the first finger electrodes are arranged alternately in sequence.

[0011] In some embodiments, the second interdigital transducer includes a second bus electrode and a plurality of second interdigital electrodes, the second bus electrode extends along the length direction of the piezoelectric substrate, the plurality of second interdigital electrodes are arranged on the second bus electrode at intervals along the length direction of the second bus electrode, and the second interdigital electrodes extend along the width direction of the piezoelectric substrate.

[0012] In some embodiments, the underground coal mine dust concentration sensor based on surface acoustic waves of an embodiment of the present invention also includes a second reflection grating, the second reflection grating includes a second bus bar and a plurality of second bar electrodes, the second bus bar extends along the length direction of the piezoelectric substrate and is arranged at intervals with the second bus electrode, the plurality of second bar electrodes are arranged on the second bus bar at intervals along the length direction of the piezoelectric substrate, the second bar electrode extends along the width direction of the piezoelectric substrate, and the second bar electrodes and the second interdigitated electrodes are arranged alternately in sequence.

[0013] In some embodiments, the underground coal mine dust concentration sensor based on surface acoustic waves of an embodiment of the present invention also includes a base plate and a protective cover, wherein the protective cover is detachably covered on the base plate, and a protective cavity is defined between the protective cover and the base plate, and the protective cover has a plurality of dust holes arranged at intervals, and the piezoelectric substrate and the circuit board are arranged in the protective cavity.

[0014] In some embodiments, a wire hole is provided on the protective cover, and the wire hole is used for the power cord to enter the protective cavity.

[0015] In some embodiments, the underground coal mine dust concentration sensor based on surface acoustic waves of an embodiment of the present invention also includes a first support frame and a second support frame, the first support frame and the second support frame are arranged on the bottom plate at intervals and are located in the protective cavity, the piezoelectric substrate is arranged on the first support frame, and the circuit board is arranged on the second support frame.

[0016] When the underground coal mine dust concentration sensor of the embodiment of the present invention is in use, when the circuit board transmits a radio frequency electrical signal to the first interdigital transducer, the alternation of the first interdigital transducer will stimulate the piezoelectric substrate to periodically expand and contract. In this process, surface acoustic waves are generated, and the generated surface acoustic waves propagate along the length direction of the piezoelectric substrate, and the surface acoustic waves pass through the porous graphene layer. If there is dust in the air, the dust will diffuse into the inside of the porous graphene layer and be consistent with the dust concentration in the air. At this time, the surface acoustic wave signal will attenuate, and the attenuation amplitude is proportional to the dust concentration. When the attenuated surface acoustic wave signal passes through the second interdigital transducer, the surface acoustic wave signal is converted into a radio frequency electrical signal and transmitted to the circuit board. At this time, the circuit board can obtain the current dust concentration in the air by monitoring the changes in the radio frequency electrical signal.

[0017] The underground coal mine dust concentration sensor of the embodiment of the present invention can realize real-time monitoring of coal mine dust concentration, detect abnormal conditions in a timely manner, and provide protection for mine safety production. The surface acoustic wave sensor is very sensitive to changes in dust concentration and can accurately detect tiny changes. Compared with traditional optical and electrical dust detection methods, surface acoustic wave technology has strong resistance to electromagnetic interference and is more suitable for complex mine environments. The present invention is not easily affected by environmental factors such as temperature and humidity in the mine, and provides more stable measurement results. Surface acoustic wave sensors usually have the characteristics of low power consumption, which is conducive to long-term operation in energy-limited environments such as underground. Graphene, as a sensitive material, has good chemical stability and mechanical strength, which can ensure the long-term stability of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the dust concentration sensor according to an embodiment of the present invention.

[0019] Figure 2 is a cross-sectional view of a dust concentration sensor according to an embodiment of the present invention.

[0020] Figure 3 Schematic diagram of the internal structure of the dust concentration sensor according to an embodiment of the present invention.

[0021] Figure 4 Schematic diagram of the installation of the piezoelectric substrate according to an embodiment of the present invention.

[0022] Figure 5 This is a working flow diagram of the dust concentration sensor according to an embodiment of the present invention.

[0023] Reference numerals:

[0024] 100. Dust concentration sensor; 1. Piezoelectric substrate; 2. First interdigital transducer; 201. First bus electrode; 202. First interdigital electrode; 3. Second interdigital transducer; 301. Second bus electrode; 302. Second interdigital electrode; 4. Graphene layer; 5. Circuit board; 6. First reflector; 601. First bus electrode; 602. First bar electrode; 7. Second reflector; 701. Second bus electrode; 702. Second bar electrode; 8. Bottom plate; 9. Protective cover; 901. Dust hole; 902. Wire hole; 10. Protective cavity; 11. First support frame; 12. Second support frame. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0026] like Figures 1 to 5 As shown, an underground coal mine dust concentration sensor 100 according to an embodiment of the present invention includes a piezoelectric substrate 1, a first IDT 2, a second IDT 3, a graphene layer 4, and a circuit board 5. The first IDT 2 and the second IDT 3 are arranged on the piezoelectric substrate 1 at intervals along the length of the piezoelectric substrate 1. The graphene layer 4 is arranged on the piezoelectric substrate 1 and located between the first IDT 2 and the second IDT 3 to absorb dust.

[0027] The circuit board 5 is electrically connected to the first IDT 2 and the second IDT 3. The circuit board 5 transmits radio frequency (RF) signals to the first IDT 2, causing it to excite the piezoelectric substrate 1 to generate mechanical vibrations and surface acoustic waves (SAWs). The second IDT 3 receives the SAWs generated by the piezoelectric substrate 1, converts them into electrical signals, and transmits them to the circuit board 5. The circuit board 5 also processes the electrical signals transmitted by the second IDT 3 and determines changes in dust concentration based on the changes in the electrical signals.

[0028] The piezoelectric substrate 1 utilizes the piezoelectric effect to generate mechanical vibrations when a voltage is applied to the substrate, and vice versa. The piezoelectric substrate 1 is a key component for generating and receiving surface acoustic waves (SAWs). The first IDT 2 excites the SAWs by applying a radio frequency (RF) signal to the piezoelectric substrate 1, causing them to generate corresponding mechanical vibrations, thereby forming SAWs on the surface of the piezoelectric substrate 1. The second IDT 3, located in the SAW propagation path, receives the propagating SAWs and converts them into electrical signals. Graphene, due to its excellent physical properties, such as its high specific surface area and good adsorption properties, is used to absorb coal mine dust. A graphene layer 4 is located between the first and second IDTs 3. As the SAWs pass through the graphene layer 4, their propagation speed changes due to the adsorption of dust. The circuit board 5 controls signal transmission and reception and processes the electrical signals from the second IDT 3. By analyzing the changes in the electrical signals, the dust concentration can be determined.

[0029] Specifically, when the underground coal mine dust concentration sensor 100 of the embodiment of the present invention is in use, when the circuit board 5 transmits a radio frequency electrical signal to the first interdigital transducer 2, the alternation of the first interdigital transducer 2 will stimulate the piezoelectric substrate 1 to periodically expand and contract. In this process, surface acoustic waves will be generated, and the generated surface acoustic waves will propagate along the length direction of the piezoelectric substrate 1, and the surface acoustic waves will pass through the porous graphene layer 4. If there is dust in the air, the dust will diffuse into the inside of the porous graphene layer 4 and be consistent with the dust concentration in the air. At this time, the surface acoustic wave signal will attenuate, and the attenuation amplitude is proportional to the dust concentration. When the attenuated surface acoustic wave signal passes through the second interdigital transducer 3, the surface acoustic wave signal is converted into a radio frequency electrical signal and transmitted to the circuit board 5. At this time, the circuit board 5 can obtain the current dust concentration in the air by monitoring the changes in the radio frequency electrical signal.

[0030] The underground coal mine dust concentration sensor 100 of the embodiment of the present invention can realize real-time monitoring of coal mine dust concentration, detect abnormal conditions in a timely manner, and provide protection for mine safety production. The surface acoustic wave sensor is very sensitive to changes in dust concentration and can accurately detect small changes. Compared with traditional optical and electrical dust detection methods, surface acoustic wave technology has strong resistance to electromagnetic interference and is more suitable for complex mine environments. The present invention is not easily affected by environmental factors such as temperature and humidity in the mine, and provides more stable measurement results. Surface acoustic wave sensors usually have the characteristics of low power consumption, which is conducive to long-term operation in energy-limited environments such as underground. Graphene, as a sensitive material, has good chemical stability and mechanical strength, which can ensure the long-term stability of the sensor.

[0031] In some embodiments, the graphene layer 4 , the first IDT 2 , and the second IDT 3 are located on the same side of the piezoelectric substrate 1 .

[0032] Placing all components on the same side of the piezoelectric substrate 1 can simplify the overall structure of the sensor and reduce manufacturing costs and complexity. Arranging components on the same side is conducive to the integration of the sensor with other electronic components, and helps to develop a miniaturized, integrated detection system. Since the propagation path of the surface acoustic wave on the piezoelectric substrate 1 is shorter, the attenuation and reflection of the signal may be reduced, thereby improving the detection efficiency and accuracy of the sensor. Placing components on the same side of the piezoelectric substrate 1 may make the maintenance and replacement of the sensor more convenient. The graphene layer 4 and the interdigital transducer are on the same side, which helps to reduce signal interference caused by spatial distribution and improve the quality of the signal. The layout on the same side may help to improve the heat dissipation performance of the sensor, because graphene has good thermal conductivity, which helps to dissipate heat quickly.

[0033] In some embodiments, the graphene layer 4 is a porous graphene layer 4 .

[0034] Porous graphene has a higher specific surface area, which means it provides more active sites for dust particle adsorption, thereby improving sensor sensitivity. The porous structure facilitates gas flow and mass transfer, accelerating the diffusion of dust particles to the surface of the graphene layer 4 and improving detection speed. The porous graphene layer 4 reduces the propagation resistance of surface acoustic waves and signal attenuation, thereby increasing the strength of the signal received by the sensor. By adjusting the pore size and distribution of the porous graphene, selective adsorption of dust particles of specific sizes can be achieved, increasing the selectivity and accuracy of detection.

[0035] In some embodiments, the first interdigital transducer 2 includes a first bus electrode 201 and a plurality of first interdigital electrodes 202, the first bus electrode 201 extends along the length direction of the piezoelectric substrate 1, the plurality of first interdigital electrodes 202 are arranged on the first bus electrode 201 at intervals along the length direction of the first bus electrode 201, and the first interdigital electrodes 202 extend along the width direction of the piezoelectric substrate 1.

[0036] like Figure 3 and Figure 4 As shown, the first bus electrode 201 is an electrode extending along the length direction of the piezoelectric substrate 1, which serves to collect electrical signals. The bus electrode is usually wider and can provide a stable current supply. A plurality of interdigitated electrodes 202 are arranged at intervals along the length direction of the first bus electrode 201, and each first interdigitated electrode 202 extends along the width direction of the piezoelectric substrate 1. These electrodes form a series of staggered "fingers", which can excite or receive surface acoustic waves on the piezoelectric substrate 1 when voltage is applied. The design of the interdigitated electrodes can effectively convert electrical signals into mechanical energy, thereby exciting surface acoustic waves on the piezoelectric substrate 1. The staggered arrangement of multiple interdigitated electrodes can increase the area for exciting or receiving surface acoustic waves and improve the energy conversion efficiency.

[0037] In some embodiments, the underground coal mine dust concentration sensor 100 of the present invention further includes a first reflector 6, which includes a first busbar 601 and a plurality of first bar electrodes 602. The first busbar 601 extends along the length of the piezoelectric substrate 1 and is spaced apart from the first busbar electrodes 201. The plurality of first bar electrodes 602 are spaced apart along the length of the piezoelectric substrate 1 on the first busbar 601. The first bar electrodes 602 extend along the width of the piezoelectric substrate 1, and the first bar electrodes 602 and the first interdigitated electrodes 202 are arranged alternately.

[0038] The first reflector 6 is a component used to control the propagation and reflection of surface acoustic waves. It consists of a first busbar 601 and a plurality of first grid electrodes 602. The first reflector 6 is provided to enhance the reflection efficiency of the surface acoustic wave, allowing more acoustic waves to be reflected back to the transducer, thereby increasing the strength of the detection signal. By precisely designing the spacing and width of the first grid electrodes 602, the propagation path of the surface acoustic wave on the piezoelectric substrate 1 can be controlled, avoiding unnecessary energy loss. The structure of the first reflector 6 helps to improve the directionality of surface acoustic wave propagation and reduce energy loss caused by beam diffusion.

[0039] In some embodiments, the second interdigital transducer 3 includes a second bus electrode 301 and a plurality of second interdigital electrodes 302, the second bus electrode 301 extends along the length direction of the piezoelectric substrate 1, the plurality of second interdigital electrodes 302 are arranged on the second bus electrode 301 at intervals along the length direction of the second bus electrode 301, and the second interdigital electrodes 302 extend along the width direction of the piezoelectric substrate 1.

[0040] like Figure 3 and Figure 4 As shown, the second bus electrode 301 is an electrode extending along the length direction of the piezoelectric substrate 1, which serves to collect electrical signals. The bus electrode is usually wider and can provide a stable current supply. A plurality of second interdigitated electrodes 302 are arranged at intervals along the length direction of the second bus electrode 301, and each second interdigitated electrode 302 extends along the width direction of the piezoelectric substrate 1. These electrodes form a series of staggered "fingers", which can excite or receive surface acoustic waves on the piezoelectric substrate 1 when voltage is applied. The design of the interdigitated electrodes can effectively convert electrical signals into mechanical energy, thereby exciting surface acoustic waves on the piezoelectric substrate 1. The staggered arrangement of multiple interdigitated electrodes can increase the area for exciting or receiving surface acoustic waves and improve the energy conversion efficiency.

[0041] In some embodiments, the surface acoustic wave-based underground coal mine dust concentration sensor 100 of the embodiments of the present invention further includes a second reflector 7, which includes a second busbar 701 and a plurality of second bar electrodes 702. The second busbar 701 extends along the length of the piezoelectric substrate 1 and is spaced apart from the second busbar electrodes 301. The plurality of second bar electrodes 702 are spaced apart along the length of the piezoelectric substrate 1 on the second busbar 701. The second bar electrodes 702 extend along the width of the piezoelectric substrate 1, and the second bar electrodes 702 and the second interdigitated electrodes 302 are alternately arranged.

[0042] The second reflector grating 7 is a component used to control the propagation and reflection of surface acoustic waves. It consists of a second busbar 701 and multiple second grid electrodes 702. The second reflector grating 7 is designed to enhance the reflection efficiency of surface acoustic waves, allowing more acoustic waves to be reflected back to the transducer, thereby increasing the strength of the detection signal. By precisely designing the spacing and width of the second grid electrodes 702, the propagation path of the surface acoustic waves on the piezoelectric substrate 1 can be controlled, avoiding unnecessary energy loss. The structure of the second reflector grating 7 helps improve the directionality of surface acoustic wave propagation and reduce energy loss caused by beam spread.

[0043] In some embodiments, the surface acoustic wave-based underground coal mine dust concentration sensor 100 of the present invention further includes a base plate 8 and a protective cover 9. The protective cover 9 is detachably mounted on the base plate 8, and a protective cavity 10 is defined between the protective cover 9 and the base plate 8. The protective cover 9 has a plurality of spaced dust holes 901, and the piezoelectric substrate 1 and the circuit board 5 are disposed within the protective cavity 10.

[0044] The base plate 8 is the base of the sensor, providing stable support and serving as the mounting interface of the sensor. The protective cover 9 is detachably mounted on the base plate 8, forming a protective cavity 10 between the base plate 8 and the protective cover 9. The design of the protective cover 9 can protect the sensitive components inside the sensor from being affected by the external environment. The enclosed space defined between the protective cover 9 and the base plate 8 is used to accommodate sensitive components such as the piezoelectric substrate 1 and the circuit board 5. The protective cover 9 is designed with a plurality of dust holes 901 arranged at intervals. These holes allow air and dust to pass through, but at the same time can prevent larger particles from directly impacting the internal components of the sensor.

[0045] The design of the protective cover 9 and base plate 8 creates a protective chamber 10 for the sensor, effectively protecting internal components from the effects of coal and rock in the mine environment, ensuring long-term stable operation of the sensor. The removable design of the protective cover 9 makes maintenance and replacement of the sensor's internal components more convenient and quick. The dust hole 901 allows air flow, reduces pressure differentials, and also blocks larger particles to prevent damage to the sensor.

[0046] In some embodiments, a wire hole 902 is provided on the protective cover 9 , and the wire hole 902 is used for the power line to enter the protective cavity 10 .

[0047] Wire hole 902 is a hole in the protective cover 9 specifically used for inserting a power cord or other cables. Wire hole 902 is designed to be larger than the diameter of the power cord to ensure that the power cord can pass through easily. The design of wire hole 902 makes the installation and maintenance of the power cord easier and more convenient. Technicians can easily pass the power cord through the hole and connect it to the circuit board 5 inside the sensor. The provision of wire hole 902 helps maintain the closedness of the protective cavity 10, preventing other harmful substances from entering the protective cavity 10, thereby protecting the internal electronic components and improving the safety and reliability of the system.

[0048] In some embodiments, the surface acoustic wave-based underground coal mine dust concentration sensor 100 of the present invention further includes a first support frame 11 and a second support frame 12. The first support frame 11 and the second support frame 12 are spaced apart and arranged on the bottom plate 8 and located within the protective cavity 10. The piezoelectric substrate 1 is arranged on the first support frame 11, and the circuit board 5 is arranged on the second support frame 12.

[0049] like Figure 2 As shown, the first support frame 11 is located in the protective cavity 10 and is used to support and fix the piezoelectric substrate 1. The design of the first support frame 11 usually takes into account the size and shape of the piezoelectric substrate 1 to ensure stable placement. The second support frame 1 is also located in the protective cavity 10 and is used to support and fix the circuit board 5. The design of the second support frame 12 also needs to take into account the size and layout of the circuit board 5. The first support frame 11 and the second support frame 12 are arranged at intervals on the base plate 8, which not only ensures the independence of each component, but also facilitates circuit wiring and maintenance.

[0050] The support frame design enhances the stability of the piezoelectric substrate 1 and circuit board 5, preventing damage caused by vibration or impact during transportation or installation. Using two support frames to separate the piezoelectric substrate 1 and circuit board 5 reduces electromagnetic interference between them and facilitates maintenance and replacement of each. The spaced-apart arrangement of the support frames provides greater flexibility in the sensor's internal layout, helping to optimize circuit routing and surface acoustic wave propagation paths.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are 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 understood as limiting the present invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0053] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0054] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0056] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An underground coal mine dust concentration sensor based on surface acoustic wave, characterized in that: include: Piezoelectric substrate; a first interdigital transducer and a second interdigital transducer, wherein the first interdigital transducer and the second interdigital transducer are arranged on the piezoelectric substrate at intervals along the length direction of the piezoelectric substrate; a graphene layer, the graphene layer being provided on the piezoelectric substrate and located between the first IDT and the second IDT, and being used for absorbing dust; A circuit board is electrically connected to the first IDT and the second IDT, respectively. The circuit board is used to transmit a radio frequency electrical signal to the first IDT so that the first IDT excites the piezoelectric substrate to generate mechanical vibrations and surface acoustic waves. The second IDT is used to receive the surface acoustic waves generated by the piezoelectric substrate and convert them into electrical signals for transmission to the circuit board. The circuit board is also used to process the electrical signals sent by the second IDT and determine changes in dust concentration based on changes in the electrical signals.

2. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 1, characterized in that: The graphene layer, the first IDT and the second IDT are located on the same side of the piezoelectric substrate.

3. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 2, characterized in that: The graphene layer is a porous graphene layer.

4. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 1, characterized in that: The first interdigital transducer includes a first bus electrode and a plurality of first interdigital electrodes, the first bus electrode extends along the length direction of the piezoelectric substrate, the plurality of first interdigital electrodes are arranged on the first bus electrode at intervals along the length direction of the first bus electrode, and the first interdigital electrodes extend along the width direction of the piezoelectric substrate.

5. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 4, characterized in that: It also includes a first reflection grid, which includes a first bus bar and a plurality of first bar electrodes. The first bus bar extends along the length direction of the piezoelectric substrate and is arranged at intervals with the first bus electrode. The plurality of first bar electrodes are arranged on the first bus bar at intervals along the length direction of the piezoelectric substrate. The first bar electrodes extend along the width direction of the piezoelectric substrate. The first bar electrodes and the first interdigitated electrodes are arranged alternately in sequence.

6. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 5, characterized in that: The second interdigital transducer includes a second bus electrode and a plurality of second interdigital electrodes, the second bus electrode extends along the length direction of the piezoelectric substrate, the plurality of second interdigital electrodes are arranged on the second bus electrode at intervals along the length direction of the second bus electrode, and the second interdigital electrodes extend along the width direction of the piezoelectric substrate.

7. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 5, characterized in that: It also includes a second reflective grid, which includes second bus bars and a plurality of second bar electrodes. The second bus bars extend along the length direction of the piezoelectric substrate and are arranged at intervals with the second bus electrodes. The plurality of second bar electrodes are arranged on the second bus bars at intervals along the length direction of the piezoelectric substrate. The second bar electrodes extend along the width direction of the piezoelectric substrate. The second bar electrodes and the second interdigitated electrodes are arranged alternately in sequence.

8. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 1, characterized in that: It also includes a base plate and a protective cover, which is detachably covered on the base plate. A protective cavity is defined between the protective cover and the base plate. The protective cover has a plurality of dust holes arranged at intervals. The piezoelectric substrate and the circuit board are arranged in the protective cavity.

9. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 8, characterized in that: The protective cover is provided with a wire-passing hole, and the wire-passing hole is used for the power line to enter the protective cavity.

10. The underground coal mine dust concentration sensor based on surface acoustic wave according to claim 8, characterized in that: It also includes a first support frame and a second support frame, the first support frame and the second support frame are arranged on the bottom plate at intervals and located in the protective cavity, the piezoelectric substrate is arranged on the first support frame, and the circuit board is arranged on the second support frame.

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