A composite sensor for acceleration and pressure monitoring and its operating method

Abstract

This invention relates to a composite sensor for acceleration and pressure monitoring and its operating method, belonging to the field of sensors. It includes an upper housing, a middle housing, and a lower housing. The upper housing has an M6 mounting thread at its upper end and a hexagonal base at its lower end, with a groove space on the inner side of the lower end of the hexagonal base. The middle housing also has a hexagonal base, with M5 connector mounting holes on both sides. A double-ended beam is located in the middle of the inner side of the middle housing; the double-ended beam is a sheet-like structure, with both ends fixedly connected to or integrally formed with the front and rear inner walls of the middle housing. An integrally connected cylindrical screw is located at the center of the double-ended beam, and an acceleration sensor core structure is mounted on the cylindrical screw. The lower housing also has a hexagonal base with a mounting groove at the bottom for mounting a pressure sensor core structure. The upper, middle, and lower housings are welded together. This invention has a simple structure, enables simultaneous and non-interfering monitoring of acceleration and pressure, and can be applied in multiple scenarios.

Description

Technical Field

[0001] This invention relates to a composite sensor for acceleration and pressure monitoring and its operating method, belonging to the field of sensor technology. Background Technology

[0002] Piezoelectric accelerometers and piezoelectric pressure sensors use piezoelectric materials as sensing elements. An accelerometer is a sensor that measures acceleration under external force. It typically consists of a mass, an elastic element, and a sensing element. During acceleration, the sensor measures the inertial force acting on the mass and uses Newton's second law to obtain the acceleration value. A pressure sensor is a device that senses pressure signals and converts them into a usable output electrical signal according to a certain rule. Both types of sensors are used in numerous industries, including water conservancy and hydropower, railway transportation, intelligent buildings, production automation, aerospace, military, petrochemicals, oil wells, power, shipbuilding, machine tools, and pipelines. Traditional sensors often have limited applications, cannot simultaneously measure acceleration and pressure, and lack multi-scenario application capabilities. Traditional accelerometers also have small vibration output magnitudes and poor measurement sensitivity; therefore, the structure of these sensors needs further improvement. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a composite sensor for acceleration and pressure monitoring and its operating method. It has a simple structure, can achieve synchronous monitoring of acceleration and pressure without interference, and can be applied in multiple scenarios.

[0004] The present invention adopts the following technical solution:

[0005] On one hand, the present invention provides a composite sensor for acceleration and pressure monitoring, comprising an upper housing, a middle housing and a lower housing. The upper end of the upper housing has an M6 mounting thread, and the lower end has a hexagonal base. The inner side of the lower end of the hexagonal base has a groove space for vibration of the core structure of the acceleration sensor.

[0006] The inner shell is a hexagonal base with M5 connector mounting holes on both sides for mounting connectors. A double-ended beam is located in the middle of the inner side of the inner shell, which is a sheet structure and is fixedly connected to the front and rear inner walls of the inner shell or integrally formed at both ends. An integrally connected cylindrical screw is located at the center of the double-ended beam, which serves as the screw for the accelerometer sensor structure, and the accelerometer sensor core structure is mounted on the cylindrical screw.

[0007] The lower housing is shaped like a hexagonal base with a mounting groove at the bottom for mounting the pressure sensor core structure; the upper housing, middle housing, and lower housing are welded together.

[0008] Preferably, the accelerometer core structure includes an electrode plate, a mass block, a fastening nut, and two large piezoelectric ceramics. The first large piezoelectric ceramic, the electrode plate, the second large piezoelectric ceramic, and the mass block are sequentially arranged on the cylindrical screw of the double-end beam plate. The top of the cylindrical screw is provided with an M2 mounting thread, and the fastening nut is tightened on the M2 mounting thread. In the accelerometer core structure, during the assembly process, the first large piezoelectric ceramic, the electrode plate, the second large piezoelectric ceramic, and the mass block are concentrically processed, eliminating the need for an insulating sleeve and thus avoiding short circuits.

[0009] Preferably, the electrode sheet is a thin-film circular ring structure with a convex surface on one side for wire welding and fixing. The wire connection connector is used for signal output. The connector is a conventional cylindrical structure with an M5 thread for testing purposes. Both the large piezoelectric ceramic and the mass block are circular ring structures with a through hole in the middle.

[0010] Preferably, the thickness of the double-ended beam is 0.5 mm. The signal output amplification factor based on the double-ended beam structure is related to the thickness of the double-ended beam. The specific amplification factor needs to be recorded during standard sensor calibration, and the acceleration and charge signal output can be calculated based on the actual amplification factor.

[0011] Preferably, the pressure sensor core structure includes an insulating ring, a lower mounting threaded post, a pre-tightening screw, two small piezoelectric ceramics, and two electrode blocks. The insulating ring is placed in the mounting groove of the lower housing, and the first small piezoelectric ceramic is disposed inside the insulating ring and fits against the top surface of the mounting groove. The first electrode block, the second small piezoelectric ceramic, and the second electrode block are sequentially disposed below the first small piezoelectric ceramic inside the insulating ring.

[0012] The top of the lower mounting threaded post is attached to the second electrode block, and the lower mounting threaded post is welded to the lower housing after docking; a pre-tightening screw is provided inside the lower mounting threaded post.

[0013] Preferably, the insulating ring is a circular ring structure, the small piezoelectric ceramic is a circular ring structure with a through hole in the middle; the electrode block is a solid circular plate structure, used for the electrical signal output of the small piezoelectric ceramic and to provide support; a wire is welded to the center of the first electrode block, and the wire is connected to the connector through the through hole of the first small piezoelectric ceramic for signal transmission;

[0014] The lower housing has a φ0.5 wire through hole at its center for wire output; the lower mounting threaded post is a cylindrical structure with a hole in the middle, and a thin plate is provided at the top of the lower mounting threaded post. The thin plate is integrally formed with the lower mounting threaded post and is used as a deformation diaphragm of the pressure sensor; the lower mounting threaded post has an M6 thread on the outside for sensor installation and an M4 internal thread on the inside for tightening the preload screw.

[0015] The pre-tightening screw is of a cylindrical structure, with external threads provided on the outer side of the middle and lower ends for mating with the M4 internal threads inside the lower mounting threaded column. A through-hole with a diameter of φ1.5 is provided in the middle of the pre-tightening screw for the circulation and transmission of fluid media. The upper end surface of the pre-tightening screw is flat and has a surface area similar to that of the small piezoelectric ceramic, which is used for compressive support of the small piezoelectric ceramic after screwing tight.

[0016] Preferably, a "rice" - shaped groove is provided at the bottom of the pre-tightening screw. This groove can not only concentrate the pressure on the screw through-hole, but also serve as a pre-tightening adjustment groove. A "one" or "cross" - shaped screwdriver can be used to screw it tight. By controlling the screwing force, the diaphragm can be deformed, thereby controlling the pre-tightening force of the pressure sensor structure. When the screwing force is small, the test range of the sensor increases; when the screwing force is large, the test range of the sensor decreases, and at the same time, the linear performance is also getting better, so that it can be applied to a variety of different application scenarios.

[0017] Preferably, the thickness of the thin sheet of the lower mounting threaded column is 0.2 mm.

[0018] Preferably, the assembly process is as follows:

[0019] (1) Place the insulating ring into the installation groove at the lower end of the lower housing, and place the first small piezoelectric ceramic inside the insulating ring. The first small piezoelectric ceramic is in contact with the top surface of the installation groove;

[0020] (2) Weld the wire to the center of the first electrode block. The top surface of the first electrode block is in contact with the first small piezoelectric ceramic, and the wire passes through the through-hole of the first small piezoelectric ceramic and the φ0.5 wire through-hole of the lower housing in sequence;

[0021] (3) Place the second small piezoelectric ceramic inside the insulating ring and contact it with the first electrode block; place the second electrode block inside the insulating ring, and its top is in contact with the second small piezoelectric ceramic;

[0022] (4) Connect the upper end of the lower mounting threaded column to the lower end of the lower housing, and weld it after pre-pressing;

[0023] (5) Screw the pre-tightening screw into the M4 internal threads inside the lower mounting threaded column;

[0024] (6) Slip the first large piezoelectric ceramic onto the cylindrical screw of the double-ended beam until it is in contact with the surface of the double-ended beam;

[0025] (7) Slip the electrode plate onto the cylindrical screw until it is in contact with the first large piezoelectric ceramic, and weld a wire on the convex surface on one side of the electrode plate for signal transmission;

[0026] (8) Slip the second large piezoelectric ceramic onto the cylindrical screw until it is in contact with the electrode plate; slip the mass block onto the cylindrical screw until it is in contact with the second large piezoelectric ceramic;

[0027] (9) Tighten the fastening nut onto the cylindrical screw;

[0028] (10) Weld the contact surfaces of the upper shell, middle shell and lower shell together;

[0029] (11) Lead out the two wires from the M5 connector mounting holes at both ends of the middle housing and solder them to the center output point of the connector;

[0030] (12) Connect the connector to the M5 connector mounting hole of the middle housing and weld it to the contact surface.

[0031] The upper shell, middle shell, lower shell, lower mounting threaded column, pre-tightening screw, electrode block, electrode sheet and fastening nut of this invention are all made of 17-4 stainless steel and are all sealed and welded, which gives them high strength.

[0032] On the other hand, the present invention provides a working method for a composite sensor for acceleration and pressure monitoring based on the above-mentioned composite sensor. The composite sensor can be installed on the top or bottom, and can be used in multiple scenarios.

[0033] When the composite sensor does not require pressure monitoring, it is mounted on the top and installed on the pipe through the M6 ​​mounting thread on the upper end of the upper housing. In this case, only the acceleration sensor is working.

[0034] When a composite sensor needs to monitor both pressure and acceleration simultaneously, a bottom-mounted method is used. It is installed on the pipeline via a threaded post on the lower housing. In this case, the accelerometer and pressure sensor operate simultaneously. When the fluid medium in the pipeline passes through the pressure source, it compresses the thin plate at the top of the threaded post by passing through the through-hole in the middle of the pre-tightening screw. This pressure is transmitted through the thin plate to the electrode block and further to the small piezoelectric ceramic. After being compressed, the small piezoelectric ceramic outputs a signal based on the piezoelectric effect, thus enabling pressure monitoring within the pipeline. If vibration occurs on the pipeline surface, the sensor body experiences minute vibrations. These vibrations are amplified by the double-end beams, causing the mass block on the accelerometer core structure to compress the large piezoelectric ceramic due to inertia during its up-and-down movement. Based on the piezoelectric effect, it outputs a charge signal, thereby enabling vibration monitoring of the pipeline surface.

[0035] Where this invention is not detailed, existing technologies may be used.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. The sensor of the present invention has a symmetrical structure, and the outer shell has a hexagonal structure with M6 threads at both the upper and lower ends. The output connectors are located on both sides, which reduces interference and greatly enhances the applicability of use and installation.

[0038] 2. This invention employs a composite structure of an accelerometer and a pressure sensor. The lower end houses the pressure sensor, while the middle end contains the accelerometer. This allows for both vibration monitoring of conventional objects and pressure signal monitoring. When pressure monitoring is not required, the sensor can be mounted from the top; when pressure monitoring is needed, it can be mounted from the bottom, enabling multi-scenario applications and significantly improving performance.

[0039] 3. This invention, based on conventional compression and bending piezoelectric accelerometer structures, designs a double-end beam structure similar to the cantilever beam of a bending accelerometer. An integrated cylindrical screw is located at the center of this double-end beam structure to mount the core structure of the compression accelerometer. The two ends of the double-end beam are integrally integrated with the sensor housing, and the thickness of the double-end beam is approximately 0.5 mm. When the sensor is operating, the sensor structure is subjected to external forces (such as inertial forces caused by changes in acceleration), and the mass block will generate corresponding acceleration due to inertia. This acceleration causes the mass block to bend the double-end beam, further stretching or compressing the large piezoelectric ceramic, thereby generating charge output. The magnitude of the charge is proportional to the magnitude of the acceleration; therefore, the magnitude of the acceleration can be calculated by measuring the amount of charge. This structure not only avoids the disadvantages of large size and inconvenience of bending piezoelectric accelerometers but also possesses the characteristics of low resonant frequency and high sensitivity of conventional bending piezoelectric accelerometers, thus making it suitable for low-frequency measurements.

[0040] Furthermore, the double-ended beam of this invention is based on the principle of mounting an accelerometer on a cantilever beam for testing. This allows it to amplify the sensor output signal during minute vibrations. However, compared to conventional cantilever beam testing structures, this structure has fixed ends, which helps to ensure that the core is constrained to vibrate vertically during vibration, avoiding lateral signal interference as in conventional cantilever beam vibration structures. Therefore, this invention can be used for the measurement of micro-vibrations in large structures such as earthquake foundation vibrations and dams and power plants, as well as the detection of low-frequency vibration signals such as pipeline leaks, greatly improving testing performance.

[0041] 4. The deformation diaphragm (thin sheet) of the pressure sensor structure of the present invention is located between the lower mounting threaded column and the electrode block. The deformation diaphragm and the lower mounting threaded column are of an integral structure, with a thickness of about 0.2 mm and strong strain resistance. In addition, internal threads are provided inside the hole of the lower mounting threaded column, and a pre-tightening screw is fitted. The pre-tightening screw can be screwed tightly into the inside of the lower mounting threaded column hole. A "cross" shaped groove is provided at the bottom of the pre-tightening screw. This groove can not only concentrate the pressure in the through hole of the pre-tightening screw, but also serve as a pre-tightening adjustment groove to control the pre-tightening force of the pressure sensor structure. In addition, a through hole with a diameter of φ1.5 is provided at the bottom of the pre-tightening screw. The deformation diaphragm is exposed inside the through hole and contacts the fluid medium. When pressure is generated, it can directly pressurize the core structure of the pressure sensor, resulting in the deformation of the small piezoelectric ceramic and the output of a charge signal.

[0042] 5. The upper shell, double-end beam plate and middle shell of the present invention are of an integral structure, with high rigid strength and not easily damaged. And vibration spaces are left at the upper ends of the upper shell to avoid output interference. The pressure sensor structure of the present invention has a simple design structure. Due to the double-end beam plate structure on the acceleration sensor and the large distance between the two, they do not interfere with each other during synchronous operation. Brief Description of the Drawings

[0043] Figure 1 Schematic diagram of the overall structure of the composite sensor for acceleration and pressure monitoring according to the present invention;

[0044] Figure 2 Cross-sectional view of the composite sensor for acceleration and pressure monitoring according to the present invention;

[0045] Figure 3 Anatomical three-dimensional view of the composite sensor for acceleration and pressure monitoring according to the present invention;

[0046] Figure 4 Schematic diagram of the three-dimensional structure of the upper shell of the present invention, (a) is angle one, (b) is angle two;

[0047] Figure 5 Schematic diagram of the structure of the middle shell of the present invention, (a) is a three-dimensional view, (b) is a top view, (c) is a left view;

[0048] Figure 6 Schematic diagram of the three-dimensional structure of the lower shell of the present invention, (a) is angle one, (b) is angle two;

[0049] Figure 7 Schematic diagram of the three-dimensional structure of the lower mounting threaded column of the present invention, (a) is angle one, (b) is angle two;

[0050] Figure 8 Schematic diagram of the three-dimensional structure of the pre-tightening screw of the present invention, (a) is angle one, (b) is angle two, (c) is angle three;

[0051] Figure 9 This is a three-dimensional structural diagram of the fastening nut of the present invention, where (a) is angle one and (b) is angle two.

[0052] Figure 10 This is a schematic diagram of the three-dimensional structure of the mass block of the present invention;

[0053] Figure 11 This is a schematic diagram of the three-dimensional structure of the large piezoelectric ceramic of the present invention;

[0054] Figure 12 This is a schematic diagram of the three-dimensional structure of the electrode sheet of the present invention;

[0055] Figure 13 This is a schematic diagram of the three-dimensional structure of the insulating ring of the present invention;

[0056] Figure 14 This is a schematic diagram of the three-dimensional structure of the electrode block of the present invention;

[0057] Figure 15 This is a schematic diagram of the sensor mounting method of the present invention;

[0058] In the figure, 1-upper shell, 2-middle shell, 3-connector, 4-lower shell, 5-insulating ring, 6-lower mounting threaded post, 7-preload screw, 8-electrode block, 9-small piezoelectric ceramic, 10-electrode plate, 11-large piezoelectric ceramic, 12-mass block, 13-fastening nut, 14-double-end beam plate, 15-cylindrical screw, 16-thin sheet. Detailed Implementation

[0059] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments. However, this description is not limited thereto. All aspects not described in detail in the present invention are based on conventional techniques in the field.

[0060] In the description of this invention, it should be noted that the terms "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0061] Example 1

[0062] A composite sensor for acceleration and pressure monitoring, such as Figures 1 to 14 As shown, it includes an upper housing 1, a middle housing 2 and a lower housing 4. The upper end of the upper housing 1 has an M6 mounting thread, and the lower end is a hexagonal base. The inner side of the lower end of the hexagonal base has a groove space for vibration of the accelerometer core structure.

[0063] The middle housing 2 has a hexagonal base and M5 connector mounting holes on both sides for mounting connectors 3. A double-end beam 14 connecting the housing is located in the middle of the inner side of the middle housing. The double-end beam is a sheet structure and its two ends are fixedly connected to the front and rear inner walls of the middle housing or integrally formed. An integrally connected cylindrical screw 15 is located at the center of the double-end beam 14. The cylindrical screw 15 is used as the screw of the acceleration sensor structure, and the acceleration sensor core structure is mounted on the cylindrical screw 15.

[0064] The lower housing 4 is shaped like a hexagonal base with a mounting groove at the bottom for mounting the pressure sensor core structure; the upper housing 1, the middle housing 2 and the lower housing 4 are welded together.

[0065] Example 2

[0066] A composite sensor for acceleration and pressure monitoring, as described in Example 1, differs in that the acceleration sensor core structure includes an electrode plate 10, a mass block 12, a fastening nut 13, and two large piezoelectric ceramics 11. The first large piezoelectric ceramic 11, the electrode plate 10, the second large piezoelectric ceramic 11, and the mass block 12 are sequentially arranged on a cylindrical screw 15 of a double-end beam. The top end of the cylindrical screw 15 is provided with an M2 mounting thread, which is tightened by the fastening nut 13.

[0067] Electrode 10 is a thin-film ring structure with a convex surface on one side for wire welding and fixing. The wire connection connector is used for signal output. The connector is a conventional cylindrical structure with an M5 thread for testing purposes. The large piezoelectric ceramic and the mass block are both ring structures with a through hole in the middle.

[0068] The thickness of the double-ended beam 14 is 0.5 mm. The signal output amplification factor based on the double-ended beam structure is related to the thickness of the double-ended beam. The specific amplification factor needs to be recorded during the calibration with the standard sensor. The acceleration and charge signal output can be calculated based on the actual amplification factor.

[0069] Example 3

[0070] A composite sensor for acceleration and pressure monitoring, as described in Example 2, differs in that the pressure sensor core structure includes an insulating ring 5, a lower mounting threaded post 6, a pre-tightening screw 7, two small piezoelectric ceramics 9, and two electrode blocks 8. The insulating ring 5 is placed in the mounting groove of the lower housing 4, and the first small piezoelectric ceramic 9 is disposed inside the insulating ring 5 and fits against the top surface of the mounting groove. The first electrode block 8, the second small piezoelectric ceramic 9, and the second electrode block 8 are sequentially arranged below the first small piezoelectric ceramic inside the insulating ring 5.

[0071] The top of the lower mounting threaded post 6 is attached to the second electrode block 8, and the lower mounting threaded post 6 is welded to the lower housing 4 after docking; a pre-tightening screw 7 is set inside the lower mounting threaded post.

[0072] The insulating ring 5 is of an annular structure, the small piezoelectric ceramic 9 is of an annular structure with a through hole left in the middle; the electrode block 8 is of a solid disc structure, which is used for the electrical signal output of the small piezoelectric ceramic and provides support; a wire is welded to the center of the first electrode block 8, and the wire is connected to the nozzle 3 through the through hole of the first small piezoelectric ceramic 9 for signal transmission.

[0073] A wire through hole with a diameter of φ0.5 is provided at the center of the lower housing 4 for wire output; the lower mounting threaded post 6 is of a cylindrical structure with a hole in the middle, and a thin sheet 16 is provided at the top of the lower mounting threaded post 6. The thin sheet 16 is integrally formed with the lower mounting threaded post and is used as the deformation diaphragm of the pressure sensor; an M6 thread is provided outside the lower mounting threaded post 6 for sensor installation, and an M4 internal thread is provided inside for screwing the pre-tightening screw 7.

[0074] The pre-tightening screw 7 is of a cylindrical structure, and external threads are provided on the outer sides of the middle and lower ends for mating with the M4 internal thread inside the lower mounting threaded post. A through hole with a diameter of φ1.5 is provided in the middle of the pre-tightening screw 7 for the flow transmission of the fluid medium. The upper surface of the pre-tightening screw is flat and the surface area is similar to that of the small piezoelectric ceramic, which is used for compressive support of the small piezoelectric ceramic after screwing.

[0075] A "rice" - shaped groove is provided at the bottom of the pre-tightening screw 7. This groove can not only concentrate the pressure in the screw through hole, but also serve as a pre-tightening adjustment groove. A "one" or "cross" - shaped screwdriver can be used to tighten it. By controlling the tightening force, the diaphragm can be deformed, so as to control the pre-tightening force of the pressure sensor structure. When the tightening force is small, the test range of the sensor increases; when the tightening force is large, the test range of the sensor decreases, and at the same time, the linear performance is getting better and better, so that it can be applied to a variety of different application scenarios.

[0076] The thickness of the thin sheet 16 of the lower mounting threaded post is 0.2 mm.

[0077] Example 4

[0078] A composite sensor for acceleration and pressure monitoring, as described in Example 3, the difference is that the assembly process is as follows:

[0079] (1) Place the insulating ring 5 into the installation groove at the lower end of the lower housing 4, and place the first small piezoelectric ceramic 9 inside the insulating ring. The first small piezoelectric ceramic 9 is in contact with the top surface of the installation groove.

[0080] (2) Weld the wire to the center of the first electrode block 8. The top surface of the first electrode block 8 is in contact with the first small piezoelectric ceramic 9, and the wire passes through the through hole of the first small piezoelectric ceramic and the φ0.5 wire through hole of the lower housing in sequence.

[0081] (3) Place the second small piezoelectric ceramic 9 inside the insulating ring 5 and attach it to the first electrode block 8; place the second electrode block 8 inside the insulating ring 5 and attach its top to the second small piezoelectric ceramic 9;

[0082] (4) Connect the upper end of the lower mounting threaded post 6 to the lower end of the lower housing 4, pre-press and then weld;

[0083] (5) Screw the preload screw 7 into the M4 internal thread inside the lower mounting threaded post 6;

[0084] (6) Place the first large piezoelectric ceramic 11 onto the cylindrical screw 15 of the double-end beam 14 until it is in contact with the surface of the double-end beam 14.

[0085] (7) Fit the electrode sheet 10 onto the cylindrical screw 15 until it is in contact with the first large piezoelectric ceramic 11, and weld a wire on the convex side of the electrode sheet 10 for signal transmission.

[0086] (8) Place the second large piezoelectric ceramic 11 onto the cylindrical screw 15 until it is in contact with the electrode plate 10; place the mass block 12 onto the cylindrical screw 15 until it is in contact with the second large piezoelectric ceramic 11;

[0087] (9) Tighten the fastening nut 13 onto the cylindrical screw 15;

[0088] (10) After the upper shell 1, the middle shell 2 and the lower shell 4 are joined together, the contact surfaces are welded.

[0089] (11) Lead out the two wires from the M5 connector mounting holes at both ends of the middle shell and solder them to the center output point of connector 3;

[0090] (12) Connect the connector 3 to the M5 connector mounting hole of the middle housing 2 and weld it to the contact surface.

[0091] All metal materials used in this invention are made of 17-4 stainless steel, and the entire structure is sealed and welded, resulting in high strength.

[0092] Example 5

[0093] A method for operating a composite sensor for acceleration and pressure monitoring, wherein the composite sensor can be mounted on top or bottom, enabling applications in multiple scenarios;

[0094] When the composite sensor does not require pressure monitoring, it is mounted on the pipe via the M6 ​​mounting thread on the upper end of the upper housing 1. In this case, only the acceleration sensor is working.

[0095] When a composite sensor needs to monitor both pressure and acceleration, a bottom-mounted installation method is used, such as... Figure 15As shown, the lower mounting threaded post 6 of the lower housing 4 is installed on the pipeline. At this time, the accelerometer and pressure sensor work simultaneously. When the fluid medium in the pipeline passes through the pressure source, the fluid medium passes through the through hole in the middle of the pre-tightening screw 7 and squeezes the thin plate 16 at the top of the lower mounting threaded post 6. This pressure is transmitted through the thin plate 16 to the electrode block 8 and further to the small piezoelectric ceramic. After being squeezed, the small piezoelectric ceramic outputs a signal based on the piezoelectric effect, thereby realizing the monitoring of the pressure inside the pipeline. If the pipeline surface vibrates, the sensor body will vibrate slightly. The vibration is amplified by the double-end beam 14, causing the mass block 12 on the accelerometer core structure to squeeze the large piezoelectric ceramic due to inertia when it moves up and down. Based on the piezoelectric effect, it outputs a charge signal, thereby realizing the monitoring of the vibration of the pipeline surface.

[0096] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite sensor for acceleration and pressure monitoring, characterized in that, It includes an upper housing, a middle housing and a lower housing. The upper end of the upper housing is provided with an M6 mounting thread, and the lower end has a hexagonal base shape. There is a groove space inside the lower end of the hexagonal base for the vibration of the acceleration sensor core structure. The middle housing has a hexagonal base shape, and there are M5 nozzle mounting holes provided on both the left and right sides for mounting nozzles. In the middle position inside the middle housing, there is a double-ended beam piece which is a sheet-like structure, and both ends are fixedly connected or integrally formed with the front and rear inner walls of the middle housing. A cylindrical screw rod integrally connected is provided at the center of the double-ended beam piece, and an acceleration sensor core structure is mounted on the cylindrical screw rod. The lower housing has a hexagonal base shape, and there is an installation groove provided at the bottom for mounting the pressure sensor core structure. The upper housing, the middle housing and the lower housing are connected by welding. The acceleration sensor core structure includes electrode plates, a mass block, fastening nuts and two large piezoelectric ceramics. Among them, the first large piezoelectric ceramic, the electrode plate, the second large piezoelectric ceramic and the mass block are sequentially arranged on the cylindrical screw rod of the double-ended beam piece. There is an M2 mounting thread provided at the top of the cylindrical screw rod, and a fastening nut is screwed tightly on the M2 mounting thread. The thickness of the double-ended beam piece is 0.5 mm. The electrode plate is a thin sheet-like ring structure, and there is a convex surface provided on one side for wire welding and fixing. The wire is connected to the nozzle for signal output. The large piezoelectric ceramics and the mass block are both ring structures, and there are through holes left in the middle. The pressure sensor core structure includes an insulating ring, a lower mounting threaded column, a pre-tightening screw rod, two small piezoelectric ceramics and two electrode blocks. The insulating ring is placed in the installation groove of the lower housing, and the first small piezoelectric ceramic is arranged inside the insulating ring and fits with the top surface of the installation groove. Inside the insulating ring, the first electrode block, the second small piezoelectric ceramic and the second electrode block are sequentially arranged below the first small piezoelectric ceramic. The top of the lower mounting threaded column fits with the second electrode block, and after the lower mounting threaded column is butted with the lower housing, they are connected by welding. A pre-tightening screw rod is arranged inside the lower mounting threaded column. The insulating ring is a ring-type structure, the small piezoelectric ceramic is a ring structure, and there are through holes left in the middle. The electrode block is a solid circular sheet structure, which is used for the electrical signal output of the small piezoelectric ceramic and provides support. A wire is welded at the center of the first electrode block, and the wire is connected to the nozzle through the through hole of the first small piezoelectric ceramic for signal transmission. There is a wire through hole provided at the center of the lower housing for wire output. The lower mounting threaded column is a cylindrical structure, there is a hole in the middle, and there is a thin sheet provided at the top of the lower mounting threaded column. The thin sheet is integrally formed with the lower mounting threaded column and is used as the deformation diaphragm of the pressure sensor. There is an M6 thread provided outside the lower mounting threaded column for sensor installation, and an M4 internal thread is provided inside for screwing the pre-tightening screw rod. The pre-tightening screw rod is a cylindrical structure, and there is an external thread provided on the outer side of the middle and lower ends for matching with the M4 internal thread inside the lower mounting threaded column. There is a through hole provided in the middle of the pre-tightening screw rod for the flow transmission of the fluid medium. There is a "cross" shaped groove provided at the bottom of the pre-tightening screw rod. [[ID= 2. The composite sensor for acceleration and pressure monitoring according to claim 1, characterized in that, The electrode sheet is a thin ring structure with a convex surface on one side for wire welding and fixing, and the wire connection connector is used for signal output; the large piezoelectric ceramic and the mass block are both ring structures with a through hole in the middle.

3. The composite sensor for acceleration and pressure monitoring according to claim 2, characterized in that, The assembly process is as follows: (1) Place the insulating ring into the mounting groove at the lower end of the lower housing, and place the first small piezoelectric ceramic inside the insulating ring. The first small piezoelectric ceramic is attached to the top surface of the mounting groove. (2) Weld the wire to the center of the first electrode block. The top surface of the first electrode block is in contact with the first small piezoelectric ceramic. The wire passes through the through hole of the first small piezoelectric ceramic and the wire through hole of the lower shell in sequence. (3) Place the second small piezoelectric ceramic inside the insulating ring and attach it to the first electrode block; place the second electrode block inside the insulating ring and attach its top to the second small piezoelectric ceramic. (4) Connect the upper end of the lower mounting threaded column to the lower end of the lower housing, pre-press and then weld; (5) Screw the preload screw into the M4 internal thread inside the lower mounting threaded post; (6) Place the first large piezoelectric ceramic piece onto the cylindrical screw of the double-end beam piece until it is in contact with the surface of the double-end beam piece; (7) Fit the electrode sheet onto the cylindrical screw until it is in contact with the first large piezoelectric ceramic, and weld a wire on the convex side of the electrode sheet for signal transmission; (8) Place the second large piezoelectric ceramic piece onto the cylindrical screw until it is in contact with the electrode piece; place the mass block onto the cylindrical screw until it is in contact with the second large piezoelectric ceramic piece; (9) Tighten the fastening nut onto the cylindrical screw; (10) Weld the contact surfaces of the upper shell, middle shell and lower shell together; (11) Lead out the two wires from the M5 connector mounting holes at both ends of the middle shell and solder them to the center output point of the connector; (12) Connect the connector to the M5 connector mounting hole of the middle shell and weld it to the contact surface.

4. A method for operating a composite sensor for acceleration and pressure monitoring based on claim 3, characterized in that, Composite sensors can be mounted on top or bottom, enabling applications in multiple scenarios; When the composite sensor does not require pressure monitoring, it is mounted on the top and installed on the pipe through the M6 ​​mounting thread on the upper end of the upper housing. In this case, only the acceleration sensor is working. When a composite sensor needs to monitor both pressure and acceleration simultaneously, a bottom-mounted method is used. It is installed on the pipeline via a threaded post on the lower housing. In this case, the accelerometer and pressure sensor operate simultaneously. When the fluid medium in the pipeline passes through the pressure source, it compresses the thin plate at the top of the threaded post by passing through the through-hole in the middle of the pre-tightening screw. This pressure is transmitted through the thin plate to the electrode block and further to the small piezoelectric ceramic. After being compressed, the small piezoelectric ceramic outputs a signal based on the piezoelectric effect, thus enabling pressure monitoring within the pipeline. If vibration occurs on the pipeline surface, the sensor body vibrates. This vibration is amplified by the double-end beam, causing the mass block on the accelerometer core structure to compress the large piezoelectric ceramic due to inertia during its up-and-down movement. Based on the piezoelectric effect, it outputs a charge signal, thus enabling vibration monitoring of the pipeline surface.

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