High temperature resistant piezoelectric acceleration sensor

Abstract

The application relates to the technical field of acceleration sensors, in particular to a high-temperature-resistant piezoelectric acceleration sensor, which comprises a piezoelectric measuring body, the piezoelectric measuring body can output a piezoelectric signal according to the vibration of a measured device; a mounting seat, the lower side of the mounting seat is used for connecting the measured device, and the upper side of the mounting seat is provided with the piezoelectric measuring body; a sealing shell, the lower end of the sealing shell is sealingly and fixedly connected with the upper end of the mounting seat, and the sealing shell is used for sealing the piezoelectric measuring body; a sealing joint, the sealing joint is arranged on the sealing shell, and a positive connection pole and a negative connection pole are sealingly and telescopically arranged in the sealing joint; wherein the positive connection pole and the negative connection pole are used for connecting the piezoelectric measuring body and an external cable. The application can ensure the sealing property of the whole sealing shell, and can stably operate in a high-temperature environment, so the application can be widely applied to vibration testing in a high-temperature environment in the nuclear power field.

Description

Technical Field

[0001] This invention relates to the field of acceleration sensor technology, and more specifically to a high-temperature resistant piezoelectric acceleration sensor. Background Technology

[0002] A piezoelectric accelerometer is a device that uses the piezoelectric effect to convert electromechanical energy. It has the advantages of high sensitivity, wide frequency response, and strong environmental adaptability. It is widely used in military and civilian fields such as nuclear power, aerospace, road and bridge construction and building design, and holds a special position in the nuclear power industry.

[0003] Nuclear power equipment is constantly subjected to vibration loads caused by fluid vibration, water hammer, and gas-liquid two-phase flow, which can induce fatigue vibration problems, leading to the deterioration of material and structural performance. This, in turn, affects the stability and reliability of the equipment during operation, and in severe cases, can cause leaks or even forced reactor shutdown. Particularly when a nuclear-grade pipeline ruptures, the high-energy fluid ejected from the rupture point can cause the pipeline itself to vibrate, damaging surrounding equipment and causing even more severe secondary damage. Therefore, during the operation of nuclear power systems, it is necessary to use sensors to conduct online vibration monitoring of critical nuclear power equipment to identify structural defects and potential threats.

[0004] In practical applications, piezoelectric accelerometers are typically used to measure acceleration amplitude for online monitoring and vibration evaluation of key nuclear power equipment. However, nuclear power systems operate at temperatures exceeding 300°C, requiring accelerometers to operate stably in such high-temperature environments for extended periods. Currently, domestically produced piezoelectric accelerometers have low temperature tolerance; while they can operate stably at room temperature, their accuracy is limited and their impedance is low at high temperatures, making them unsuitable for long-term stable operation and failing to meet the testing requirements of nuclear power equipment. Summary of the Invention

[0005] To address the technical problem of low temperature tolerance in existing piezoelectric accelerometers, this invention provides a high-temperature resistant piezoelectric accelerometer that can operate stably in high-temperature environments and can be widely used for vibration testing in high-temperature environments in the nuclear power field.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides a high-temperature resistant piezoelectric accelerometer, comprising: a piezoelectric measuring body capable of outputting a piezoelectric signal based on the vibration of a device under test; a mounting base for connecting the device under test to its lower side, and mounting the piezoelectric measuring body to its upper side; a sealing shell, the lower end of which is sealed and fixedly connected to the upper end of the mounting base, the sealing shell for sealing the piezoelectric measuring body; and a sealing connector disposed on the sealing shell, wherein a positive connection electrode and a negative connection electrode are sealed and inserted within the sealing connector; wherein the positive connection electrode and the negative connection electrode are used to connect the piezoelectric measuring body and an external cable.

[0008] The high-temperature resistant piezoelectric accelerometer provided by this invention has a piezoelectric measuring body mounted on a mounting base, and a sealing shell that is sealed and fixedly connected to the upper end of the mounting base. The piezoelectric measuring body is sealed by the sealing shell, and the electrical signal of the piezoelectric measuring body is led out through the positive and negative terminals of the sealing joint. The sealing joint is sealed through the upper wall of the sealing shell, which can ensure the overall sealing performance of the sealing shell and prevent the external medium from directly exchanging heat with the piezoelectric measuring body. This allows it to operate stably in high-temperature environments and can be widely used for vibration testing in high-temperature environments in the nuclear power field.

[0009] In an optional embodiment, the piezoelectric measuring body is fixedly connected to the mounting base by a preload bolt, so as to provide a preload force to the piezoelectric measuring body through the preload bolt.

[0010] In an optional embodiment, the piezoelectric measuring body has a through hole in the middle, and the mounting base has a screw hole at the upper end. The preload bolt passes through the through hole and is screwed into the screw hole to ensure the reliability of the piezoelectric measuring body installation.

[0011] In an optional embodiment, a mass block is provided between the head of the pre-tightening bolt and the piezoelectric measuring body to effectively increase the output charge of the sensor.

[0012] In an alternative embodiment, the piezoelectric measuring body comprises multiple piezoelectric ceramic sheets stacked together to facilitate adjustment of the sensitivity of the piezoelectric measuring body.

[0013] In an alternative embodiment, the opposite sides of two adjacent piezoelectric ceramic sheets have the same polarity.

[0014] In an optional embodiment, the piezoelectric ceramic sheet is made of bismuth layered or perovskite-based high-temperature piezoelectric ceramic to ensure that the piezoelectric measuring body has sufficient high-temperature resistance.

[0015] In an optional embodiment, the top of the sealing shell is provided with a connection hole for inserting the sealing joint.

[0016] In an optional embodiment, the negative electrode connection is fitted with a first sealing element, and the first sealing element is fitted with a sealing cap, which is used to seal the gap between the first sealing element and the sealing shell; the negative electrode connection is provided with a plug hole, the positive electrode connection is inserted into the plug hole, and the positive electrode connection is fitted with a second sealing element, which is used to seal the gap between the positive electrode connection and the negative electrode connection, so as to export the measurement data of the piezoelectric measuring body while ensuring the sealing performance of the sealing shell.

[0017] In an optional embodiment, the first seal and the second seal are made of glass or metallized insulating ceramic.

[0018] The present invention has the following advantages and beneficial effects:

[0019] The high-temperature resistant piezoelectric accelerometer provided by this invention has a piezoelectric measuring body mounted on a mounting base, and a sealing shell that is sealed and fixedly connected to the upper end of the mounting base. The piezoelectric measuring body is sealed by the sealing shell, and the electrical signal of the piezoelectric measuring body is led out through the positive and negative terminals of the sealing joint. The sealing joint is sealed through the upper wall of the sealing shell, which can ensure the overall sealing performance of the sealing shell and prevent the external medium from directly exchanging heat with the piezoelectric measuring body. This allows it to operate stably in high-temperature environments and can be widely used for vibration testing in high-temperature environments in the nuclear power field. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] In the attached diagram:

[0022] Figure 1 This is a schematic diagram of the structure of the high-temperature resistant piezoelectric accelerometer sensor according to an embodiment of the present invention;

[0023] Figure 2 for Figure 1 Enlarged schematic diagram of part A;

[0024] Figure 3 for Figure 1 Enlarged schematic diagram of part B.

[0025] In the attached diagram:

[0026] 10-Piezoelectric measuring body, 11-Through hole, 12-Mass block, 13-Piezoelectric ceramic plate, 14-Positive electrode plate, 15-Negative electrode plate, 20-Mounting base, 21-Screw hole, 30-Sealing shell, 31-Connecting hole, 40-Sealing joint, 41-Negative electrode connection, 42-Positive electrode connection, 43-First seal, 44-Second seal, 45-Insertion hole, 46-Sealing cover, 50-Pre-tightening bolt. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, embodiments and features in the embodiments of this invention can be combined with each other.

[0029] In the description of the embodiments of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of the present invention and to simplify the description, and are not intended to 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 limitations on the present invention.

[0030] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] It should be noted that nuclear power systems operate at temperatures exceeding 300°C, requiring the accelerometers used to operate stably in such high-temperature environments for extended periods. Currently, the high-temperature resistant piezoelectric accelerometers used in nuclear power systems are heavily reliant on imports, resulting in long delivery cycles and high prices.

[0032] To address the above problems, this invention provides a high-temperature resistant piezoelectric accelerometer that can operate for extended periods in a 400°C environment and has advantages such as high sensitivity, wide frequency response, and strong anti-interference capabilities, as detailed in the embodiments.

[0033] Example

[0034] Combination Figure 1 This embodiment provides a high-temperature resistant piezoelectric accelerometer, comprising: a piezoelectric measuring body 10, which outputs a piezoelectric signal based on the vibration of the device under test; a mounting base 20, the lower side of which is used to connect to the device under test, and the upper side of which the piezoelectric measuring body 10 is mounted; a sealing shell 30, the lower end of which is sealed and fixedly connected to the upper end of the mounting base 20, and the sealing shell 30 is used to seal the piezoelectric measuring body 10; and a sealing connector 40, which is disposed on the sealing shell 30, and a negative electrode 41 and a positive electrode 42 are sealed and inserted into the sealing connector 40; wherein the negative electrode 41 and the positive electrode 42 are used to connect the piezoelectric measuring body 10 and an external cable.

[0035] Combination Figure 2 Specifically, the piezoelectric measuring body 10 is fixedly connected to the mounting base 20 by a pre-tightening bolt 50, and the pre-tightening bolt 50 provides a pre-tightening force to the piezoelectric measuring body 10.

[0036] Correspondingly, the piezoelectric measuring body 10 has a through hole 11 in the middle, and the mounting base 20 has a screw hole 21 at the upper end. The pre-tightening bolt 50 passes through the through hole 11 and is screwed into the screw hole 21 to ensure the reliability of the installation of the piezoelectric measuring body 10.

[0037] Based on this, a mass block 12 is provided between the head of the pre-tightening bolt 50 and the piezoelectric measuring body 10 to effectively increase the output charge of the sensor. In this embodiment, the mass block 12 is made of a high-density alloy, which not only significantly improves the charge sensitivity of the sensor but also effectively reduces the size of the sensor.

[0038] In this embodiment, the piezoelectric measuring body 10 includes multiple stacked piezoelectric ceramic sheets 13 to facilitate adjustment according to the required sensitivity. Typically, the number of piezoelectric ceramic sheets 13 is 4 to 6.

[0039] Specifically, the opposite sides of two adjacent piezoelectric ceramic sheets 13 have the same polarity.

[0040] The piezoelectric ceramic sheet 13 is made of bismuth layered or perovskite materials, or other materials capable of withstanding high temperatures. In this embodiment, bismuth layered high-temperature piezoelectric ceramic is preferred, allowing the piezoelectric ceramic sheet 13 to operate at temperatures exceeding 400°C.

[0041] Furthermore, each piezoelectric ceramic sheet 13 has a positive electrode 14 mounted on its positive end and a negative electrode 15 mounted on its negative end to extract the charge generated by the piezoelectric ceramic sheet 13. In other words, the piezoelectric ceramic sheet 13, the positive electrode 14, and the negative electrode 15 are assembled to form a piezoelectric measuring body 10, and the number of piezoelectric ceramic sheets 13 in the piezoelectric measuring body 10 can be adjusted according to the required sensitivity.

[0042] It is understood that insulating sheets are placed at both the upper and lower ends of the piezoelectric measuring body 10 to achieve electrical insulation between the piezoelectric measuring body 10 and other components (mass block 12 and mounting base 20). That is, the mounting base 20, piezoelectric measuring body 10, mass block 12 and insulating sheets are locked together by pre-tightening bolts 50, which provide pre-tightening force for the entire structure.

[0043] On this basis, continue to combine Figure 1 Specifically, in this embodiment, the top of the sealing shell 30 is provided with a connection hole 31 for inserting the sealing connector 40. In this embodiment, a nickel-chromium-iron high-temperature alloy is used instead of traditional stainless steel to ensure that the sealing shell 30 has sufficient high-temperature resistance.

[0044] Combination Figure 3 The negative electrode connection 41 is covered with a first sealing element 43, and the first sealing element 43 is covered with a sealing cover 46. The sealing cover 46 is used to seal the gap between the first sealing element 43 and the sealing shell 30. The negative electrode connection 41 is provided with a plug hole 45, and the positive electrode connection 42 is inserted into the plug hole 45. The positive electrode connection 42 is covered with a second sealing element 44. The second sealing element 44 is used to seal the gap between the positive electrode connection 42 and the negative electrode connection 41, so as to ensure the sealing performance of the sealing shell 30 while exporting the measurement data of the piezoelectric measuring body 10.

[0045] It is known that traditional rubber sealing rings can only withstand temperatures up to about 200°C, making them unsuitable for this embodiment. Therefore, in this embodiment, the first sealing element 43 and the second sealing element 44 are made of glass or metallized insulating ceramic to ensure that the sealing joint 40 has sufficient high-temperature resistance. Simultaneously, in this embodiment, the sealing cap 46 is made of nickel-chromium-iron alloy to ensure it also has sufficient high-temperature resistance.

[0046] When the first sealing element 43 and the second sealing element 44 are made of glass, during manufacturing and assembly, the glass powder is first fired into a glass blank, and then the sealing cap 46, the first sealing element 43, the negative electrode connection 41, the second sealing element 44, and the positive electrode connection 42 are sequentially fitted together. Then, all the parts are placed in a high-temperature environment for sintering, so that the parts are stably connected into a whole. Finally, a series of surface treatments are performed to obtain the sealing joint 40.

[0047] When the first seal 43 and the second seal 44 are made of insulating ceramic, during manufacturing and assembly, the first seal 43 and the second seal 44 are first metallized, and then the sealing cap 46, the first seal 43, the negative electrode connection 41, the second seal 44, and the positive electrode connection 42 are sequentially fitted together. Then, all the parts are placed in a high-temperature environment for sintering, so that the parts are firmly connected into a whole, and the sealing joint 40 is obtained.

[0048] Furthermore, the mounting base 20 and the preload bolt 50 are made of the same material, nickel-chromium-iron alloy, which ensures the structural and performance stability of the sensor under high-temperature environments. Typically, the mounting base 20 has a circular structure; the mounting base 20 and the device under test can be connected in multiple ways, including through a standard threaded interface at the bottom center, or by adhesive bonding.

[0049] The assembly steps for the high-temperature resistant piezoelectric accelerometer sensor provided in this embodiment are as follows:

[0050] S10. Stack the negative electrode sheet 15, piezoelectric ceramic sheet 13, and positive electrode sheet 14 in sequence. Use special tooling to center the stacking to keep all parts coaxial.

[0051] S20. When stacking, ensure that the angle of the long ends of all positive electrode sheets 14 is consistent and the angle of the long ends of all negative electrode sheets 15 is consistent. There is a certain angle deviation between the long ends of positive electrode sheets 14 and negative electrode sheets 15. After stacking, the relative angle between the long ends of positive electrode sheets 14 and negative electrode sheets 15 is 90°.

[0052] S30. After stacking (the topmost electrode sheet), bend the long ends of the electrode sheets at the same angle to ensure that the bent electrode sheets are tightly attached to the side of the piezoelectric ceramic sheet 13. Then, weld the electrode sheets at the same angle together to form the positive and negative electrodes respectively. All the parts together form the piezoelectric measuring body 10. A certain length of wire is welded to the positive and negative electrodes.

[0053] S40. Place the insulating sheet, piezoelectric measuring body 10, insulating sheet, and mass block 12 on the upper part of the mounting base 20 in sequence and use special tooling to center them so that all parts are coaxial; after centering, place the pre-tightening bolt 50 on the top and apply a certain torque to tighten it.

[0054] S50. Place the sealing shell 30 on the upper end of the mounting base 20 and weld the connection.

[0055] S60. The positive electrode 42, the second seal 44, the negative electrode 41, the first seal 43 and the sealing cap 46 are sequentially fitted together, and then all parts are placed in a high-temperature environment for sintering, so that the parts are firmly connected into a whole to form a sealing joint 40.

[0056] S70. Solder the negative electrode connection 41 to the wire at the end of the negative electrode plate 15 and the positive electrode connection 42 to the wire at the end of the positive electrode plate 14 respectively.

[0057] S80. Place the sealing joint 40 on the upper end of the sealing shell 30 and weld it to form a complete high-temperature resistant piezoelectric accelerometer.

[0058] For welding between various metal components, laser welding or fine brazing is used in this embodiment to ensure the high-temperature sealing of the sealing shell.

[0059] After high-temperature life test verification, the high-temperature resistant piezoelectric accelerometer provided in this embodiment can work stably for a long time in an operating environment of 400℃.

[0060] In summary, the high-temperature resistant piezoelectric accelerometer provided in this embodiment has a piezoelectric measuring body mounted on a mounting base, and a sealing shell that is sealed and fixedly connected to the upper end of the mounting base. This seals the piezoelectric measuring body, while the electrical signal of the piezoelectric measuring body is led out through the positive and negative terminals of the sealing joint. The sealing joint is sealed through the upper connection hole of the sealing shell, ensuring the overall sealing performance of the sealing shell and preventing direct heat exchange between the external medium and the piezoelectric measuring body. This allows for stable operation in high-temperature environments, and the sealing shell can shield external electromagnetic interference (mainly because the piezoelectric measuring body is insulated from other parts by an insulating sheet).

[0061] Therefore, the high-temperature resistant piezoelectric accelerometer provided in this embodiment can operate stably in high-temperature environments and has advantages such as high sensitivity, wide frequency response, and strong anti-interference. It can meet the vibration measurement and online monitoring requirements of key nuclear power equipment and can be widely used in vibration testing in high-temperature environments in the nuclear power field and other fields.

[0062] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0063] That is, within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. For example, the number and polarity of the piezoelectric ceramic sheets can be modified, as can the material and dimensions of each component. If these modifications and variations fall within the scope of the claims of the present invention and their equivalents, then these modifications and variations are all within the protection scope of the present invention.

Claims

1. A high-temperature resistant piezoelectric accelerometer, characterized in that, include: The piezoelectric measuring body (10) is capable of outputting a piezoelectric signal based on the vibration of the device under test. Mounting base (20), the lower side of which is used to connect the device under test, and the upper side of which is mounted the piezoelectric measuring body (10). A sealing shell (30) is provided, the lower end of which is sealed and fixedly connected to the upper end of the mounting base (20). The sealing shell (30) is used to seal the piezoelectric measuring body (10). A sealing connector (40) is provided on the sealing shell (30), and a positive electrode connection (42) and a negative electrode connection (41) are sealed and inserted inside the sealing connector (40). The positive electrode (42) and the negative electrode (41) are used to connect the piezoelectric measuring body (10) and the external cable. The top of the sealing shell (30) is provided with a connection hole (31) for inserting the sealing joint (40); The negative electrode connecting electrode (41) is covered with a first sealing element (43), and the first sealing element (43) is covered with a sealing cover (46). The sealing cover (46) is used to seal the gap between the first sealing element (43) and the sealing shell (30). The negative electrode connection (41) is provided with a plug hole (45), the positive electrode connection (42) is inserted into the plug hole (45), and the positive electrode connection (42) is covered with a second sealing member (44), which is used to seal the gap between the positive electrode connection (42) and the negative electrode connection (41); The first seal (43) and the second seal (44) are made of glass or metallized insulating ceramic.

2. The high-temperature resistant piezoelectric accelerometer sensor according to claim 1, characterized in that, The piezoelectric measuring body (10) is fixedly connected to the mounting base (20) by a pre-tightening bolt (50).

3. The high-temperature resistant piezoelectric accelerometer sensor according to claim 2, characterized in that, The piezoelectric measuring body (10) has a through hole (11) in the middle, and the mounting base (20) has a screw hole (21) at the upper end. The pre-tightening bolt (50) passes through the through hole (11) and is screwed into the screw hole (21).

4. The high-temperature resistant piezoelectric accelerometer sensor according to claim 2, characterized in that, A mass block (12) is provided between the head of the pre-tightening bolt (50) and the piezoelectric measuring body (10).

5. The high-temperature resistant piezoelectric accelerometer sensor according to claim 2, characterized in that, The piezoelectric measuring body (10) comprises multiple piezoelectric ceramic sheets (13) stacked together.

6. The high-temperature resistant piezoelectric accelerometer sensor according to claim 5, characterized in that, The opposite sides of two adjacent piezoelectric ceramic sheets (13) have the same polarity.

7. The high-temperature resistant piezoelectric accelerometer sensor according to claim 5, characterized in that, The piezoelectric ceramic sheet (13) is made of bismuth layered or perovskite-type high-temperature piezoelectric ceramic.

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