Speed sensor
By using a precision-machined housing and base, along with the application of high-temperature resistant ceramic piezoelectric crystals, the stability and accuracy issues of existing sensors in bearing vibration detection under megawatt-level nuclear power plant conditions have been resolved, achieving effective monitoring of high-frequency vibrations and improving sensor stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA TECHENERGY
- Filing Date
- 2025-05-12
- Publication Date
- 2026-04-17
AI Technical Summary
Existing velocity sensors are unable to reliably and accurately acquire bearing vibration data under the special operating conditions of megawatt-class nuclear power plants, and cannot meet the actual needs of bearing vibration monitoring.
A speed sensor was designed, which uses a precision-machined housing that fits tightly with the base, combined with a high-temperature resistant ceramic piezoelectric crystal and epoxy resin filler to ensure high efficiency in vibration transmission and waterproof and dustproof performance of the sensor, thereby improving the stability and reliability of the sensor in harsh environments.
It enables effective detection of bearing vibration in high-frequency vibration environments, possesses excellent frequency characteristics and high sensitivity, enhances the performance and stability of the sensor, and is suitable for bearing vibration monitoring in megawatt-class nuclear power plants.
Smart Images
Figure CN224137315U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of measurement technology, and in particular to a speed sensor. Background Technology
[0002] A megawatt-class nuclear power turbine refers to a turbine equipment used in nuclear power plants with a single unit rated power of 1 million kilowatts or close to 1 million kilowatts. It can efficiently convert nuclear energy into electrical energy and is one of the core key equipment for energy conversion in the nuclear power industry chain.
[0003] As a critical component in megawatt-class nuclear power turbines, the operating status of bearings directly affects the stability and safety of the entire turbine. The detection and diagnosis of bearing vibration is a core monitoring point in the inspection and system diagnosis of megawatt-class nuclear power turbines. Given the specific frequency characteristics of bearing vibration, current monitoring technologies typically employ velocity sensors to detect bearing vibration data.
[0004] However, megawatt-class nuclear power plants operate under extremely unique conditions, including but not limited to: extremely high vibration frequencies and harsh environments. Existing velocity sensors struggle to reliably and accurately acquire bearing vibration data under such conditions, failing to meet the practical requirements for bearing vibration monitoring in megawatt-class nuclear power plants. Therefore, developing a high-performance velocity sensor specifically adapted to the operating conditions of megawatt-class nuclear power plants for bearing vibration monitoring is urgently needed. Utility Model Content
[0005] To address the aforementioned issues, this application provides a velocity sensor with a high upper limit to its frequency response range, enabling it to effectively detect high-frequency vibrations under the operating conditions of megawatt-class nuclear power plants. It also boasts excellent waterproof and dustproof performance, allowing for stable operation in harsh environments, thus meeting the requirements for detecting bearing vibrations under the operating conditions of megawatt-class nuclear power plants.
[0006] The embodiments of this application disclose the following technical solutions:
[0007] This application discloses a speed sensor, including: a connector, a circuit board, a preload nut, a mass block, a piezoelectric ceramic crystal, a housing, and a base;
[0008] The bottom of the housing is connected to the base, and the top of the housing is sealed to the connector;
[0009] A stud is provided at the center of the cavity of the housing, and the piezoelectric ceramic crystal is mounted on the stud; the mass block is pressed on the piezoelectric ceramic crystal; the piezoelectric ceramic crystal and the mass block are both connected to the stud by the preload nut.
[0010] The circuit board is mounted on the upper end of the cavity of the housing; the circuit board is connected to the piezoelectric ceramic crystal via a first wire; the circuit board is connected to the connector via a second wire.
[0011] The empty spaces inside the shell are filled with epoxy resin.
[0012] In one alternative implementation, the piezoelectric ceramic crystal is a PTZ-5 piezoelectric ceramic crystal.
[0013] In one alternative implementation, two piezoelectric ceramic crystals are mounted on the stud; the two piezoelectric ceramic crystals are isolated from each other by an insulating material.
[0014] In one alternative implementation, the top of the housing is welded to the connector.
[0015] In one alternative implementation, the bottom of the housing is a flat surface with a groove located at the center of the flat surface, and the inner edge of the groove is threaded; the base carries a nut that passes through the base;
[0016] The bottom of the housing is connected to the base by means of a nut that passes through the base and a thread on the inner edge of the groove, thereby connecting the bottom of the housing to the base.
[0017] In one optional implementation, a platform is provided inside the cavity of the housing; the circuit board is mounted on the platform; the distance between the platform and the base is greater than the distance between the mass block and the base.
[0018] In one alternative implementation, the connector is of model number MIL-C-5015.
[0019] In one alternative implementation, both the housing and the mounting base are made of a nickel-based alloy.
[0020] In one alternative implementation, the mass block is made of a nickel-based alloy.
[0021] In one alternative implementation, the smoothness of the bottom surface of the housing is better than 0.8 micrometers.
[0022] Compared with the prior art, this application has the following beneficial effects:
[0023] The speed sensor disclosed in this application includes a connector, a circuit board, a preload nut, a mass block, a piezoelectric ceramic crystal, a housing, and a base. The bottom of the housing is connected to the base, and the top of the housing is sealed to the connector. A stud is provided at the center of the cavity of the housing, and a piezoelectric ceramic crystal is mounted on the stud. A mass block is pressed onto the piezoelectric ceramic crystal. The piezoelectric ceramic crystal and the mass block are connected by the preload nut and the stud. A circuit board is mounted at the upper end of the cavity of the housing. The circuit board and the piezoelectric ceramic crystal are connected by a first wire. The circuit board and the connector are connected by a second wire. The empty space inside the housing is filled with epoxy resin.
[0024] In this way, the precision-machined housing and base fit together tightly, ensuring efficient vibration transmission. Combined with a high-temperature resistant ceramic piezoelectric crystal, it achieves excellent frequency characteristics and high sensitivity. The housing and connector are sealed together, and the cavity is filled with epoxy resin, enhancing the sensor's reliability, waterproof and dustproof performance; ultimately improving the sensor's performance and enhancing its stability in harsh environments. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 A cross-sectional view of a speed sensor provided in an embodiment of this application;
[0027] Figure 2 A schematic diagram of the measured sensitivity amplitude and error analysis table of a target velocity sensor at different frequencies provided in the embodiments of this application;
[0028] Figure 3 This is a schematic diagram of the sensitivity amplitude and error analysis table of a target velocity sensor at a fixed frequency, provided in an embodiment of this application. Detailed Implementation
[0029] A megawatt-class nuclear power turbine refers to a turbine equipment used in nuclear power plants with a single unit rated power of 1 million kilowatts or close to 1 million kilowatts. It can efficiently convert nuclear energy into electrical energy and is one of the core key equipment for energy conversion in the nuclear power industry chain.
[0030] As a critical component in megawatt-class nuclear power turbines, the operating status of bearings directly affects the stability and safety of the entire turbine. The detection and diagnosis of bearing vibration is a core monitoring point in the inspection and system diagnosis of megawatt-class nuclear power turbines. Given the specific frequency characteristics of bearing vibration, current monitoring technologies typically employ velocity sensors to detect bearing vibration data.
[0031] However, megawatt-class nuclear power plants have extremely special operating conditions, including but not limited to: extremely high vibration frequency and harsh operating environment; existing velocity sensors are difficult to reliably and accurately acquire bearing vibration data under such operating conditions, and cannot meet the actual needs of bearing vibration monitoring in megawatt-class nuclear power plants.
[0032] Therefore, it is urgent to develop a high-performance velocity sensor specifically adapted to the operating conditions of megawatt-class nuclear power plants and used for bearing vibration monitoring.
[0033] The speed sensor disclosed in this application includes a connector, a circuit board, a preload nut, a mass block, a piezoelectric ceramic crystal, a housing, and a base. The bottom of the housing is connected to the base, and the top of the housing is sealed to the connector. A stud is provided at the center of the cavity of the housing, and a piezoelectric ceramic crystal is mounted on the stud. A mass block is pressed onto the piezoelectric ceramic crystal. The piezoelectric ceramic crystal and the mass block are connected by the preload nut and the stud. A circuit board is mounted at the upper end of the cavity of the housing. The circuit board and the piezoelectric ceramic crystal are connected by a first wire. The circuit board and the connector are connected by a second wire. The empty space inside the housing is filled with epoxy resin.
[0034] In this way, the precision-machined housing and base fit together tightly, ensuring efficient vibration transmission. Combined with a high-temperature resistant ceramic piezoelectric crystal, it achieves excellent frequency characteristics and high sensitivity. The housing and connector are sealed together, and the cavity is filled with epoxy resin, enhancing the sensor's reliability, waterproof and dustproof performance; ultimately improving the sensor's performance and enhancing its stability in harsh environments.
[0035] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0036] Figure 1 This is a cross-sectional view of a speed sensor provided in an embodiment of this application. (In conjunction with...) Figure 1As shown, the speed sensor in this application includes: a connector 1, a circuit board 2, a preload nut 3, a mass block 4, a piezoelectric ceramic crystal 5, a housing 6, and a base 7.
[0037] Combination Figure 1 As shown, the bottom of the housing 6 is connected to the base 7, and the top of the housing 6 is sealed to the connector 1; a stud is provided at the center of the cavity of the housing 6, the stud and the housing 6 are integrally machined, and a piezoelectric ceramic crystal 5 is installed on the stud; a mass block 4 is pressed on the piezoelectric ceramic crystal 5; the piezoelectric ceramic crystal 5 and the mass block 4 are both connected to the stud by a preload nut 3.
[0038] Figure 1 The area enclosed by the circular circle contains two parallel vertical lines in the center of a U-shaped structure, representing the studs. The bottom of the housing 6 has a threaded mounting hole that mates with the base 7 for installation, using a threaded connection for secure fastening.
[0039] Combination Figure 1 As shown, a circuit board 2 is installed at the upper end of the cavity of the housing 6; the circuit board 2 is connected to the piezoelectric ceramic crystal 5 through a first wire; the circuit board 2 is connected to the connector 1 through a second wire; the empty space inside the housing 6 is filled with epoxy resin.
[0040] In one alternative implementation, the piezoelectric ceramic crystal in this application can be a PTZ-5 piezoelectric ceramic crystal. The PTZ-5 piezoelectric ceramic crystal is a crystal made from lead zirconate titanate (PZT) piezoelectric ceramic material, characterized by rapid response, high sensitivity, mature fabrication technology, and ease of processing and shaping. It can effectively sense high-frequency vibrations around 4 kHz.
[0041] In one alternative implementation, this application uses two piezoelectric ceramic crystals, which are sequentially mounted on a stud at the center of the bottom of the housing. The two piezoelectric ceramic crystals are isolated from each other by an insulating material. The stud is cylindrical, and the piezoelectric ceramic crystal is a hollow ring structure. An insulating material is placed on the stud first, followed by another piezoelectric ceramic crystal; then another insulating material is placed, followed by another piezoelectric ceramic crystal; then another insulating material is placed, and finally a mass block is placed. This effectively isolates the electric field, ensuring stable operation of the electrical components; prevents charge or current leakage, ensuring the safety and reliability of the device, while also improving the reliability, waterproofing, and dustproofing performance of the sensor.
[0042] In one alternative implementation, the top of the housing is open, and the top of the housing can be welded to the connector by laser welding to achieve a sealed connection between the top of the housing and the connector.
[0043] It is understandable that laser welding can achieve high-precision and high-strength connections, improve the sealing performance, wear resistance and corrosion resistance of mechanical seal components, and achieve a high-efficiency and high-precision sealed connection between the top of the housing and the connector.
[0044] In one alternative implementation, the bottom of the housing is a flat surface with a groove located at the center of the surface, and the inner edge of the groove is threaded; the base carries a nut that passes through the base (see...). Figure 1 (See base shown in Figure 7); the bottom of the housing is connected to the base via a nut passing through the base and threads on the inner edge of the groove. This design, which uses a threaded groove at the center of the bottom of the housing to engage with the through nut on the base, achieves a stable and easy-to-operate connection; it not only ensures precise alignment and secure fixation between the housing and the base, but also facilitates installation and disassembly, and is beneficial for maintenance. Furthermore, the threaded connection helps to evenly distribute the load, improves the sealing effect, enhances the stability and durability of the overall structure, and also improves production efficiency and cost-effectiveness.
[0045] In one optional implementation, a platform is provided inside the cavity of the housing; the circuit board is mounted on the platform; the distance between the platform and the base is greater than the distance between the mass block and the base.
[0046] In one alternative implementation, the connector is a two-core US military standard connector of type MIL-C-5015, made of SUS316L.
[0047] In one alternative implementation, Figure 1 The housing, base, mass block, and preload nut of the speed sensor are all made of nickel-based alloy.
[0048] In one alternative implementation, the smoothness of the bottom surface of the housing is better than 0.8 micrometers; the purpose of this is to allow the housing and the base to fit together tightly.
[0049] In use, the base of the speed sensor is tightly mounted to the object being measured (such as a bearing housing) using screws. When the object vibrates, the vibration force is transmitted through the base to the housing. The housing acts as a medium for vibration transmission, transferring the vibration to a stud at the bottom of the housing. The piezoelectric ceramic crystal on the stud receives the vibration force and undergoes corresponding mechanical deformation. When subjected to mechanical stress, the piezoelectric ceramic crystal undergoes polarization, that is, equal amounts of opposite charges are generated on two corresponding crystal faces. When the direction of the external force (i.e., vibration) changes, the polarity of the charges also changes, resulting in a charge change on the crystal corresponding to the vibration.
[0050] The charge change on the piezoelectric ceramic crystal is transmitted to a circuit board mounted on the upper end of the housing cavity via a first wire. The charge amplification circuit and integral conversion circuit on the circuit board convert the charge signal generated by the piezoelectric ceramic into a velocity voltage signal. After obtaining the velocity voltage signal, the circuit board transmits the converted velocity voltage signal to a connector via a second wire. The connector transmits the signal to an external signal amplifier or data processing system for further signal processing. The processed signal can be received by a device to monitor or record the vibration data of the object under test in real time.
[0051] Throughout operation, the velocity sensor's base is tightly mounted to the object being measured, ensuring effective vibration transmission. The piezoelectric ceramic crystal inside the sensor, based on its inherent properties, can detect high-frequency vibrations up to approximately 4kHz. The epoxy resin filling inside the housing provides additional stability and protection, preventing damage to internal components due to vibration. Furthermore, the housing and connector are sealed using laser welding, ensuring the velocity sensor's waterproof and dustproof performance and improving its reliability in harsh environments.
[0052] This application presents performance tests on the target velocity sensor. Figure 1 As shown, the piezoelectric ceramic crystal in the target velocity sensor is a PTZ-5 piezoelectric ceramic crystal; two PTZ-5 piezoelectric ceramic crystals are mounted on the stud; the two PTZ-5 piezoelectric ceramic crystals are isolated by insulating material; the top of the housing is connected to the connector by laser welding; the connector model is MIL-C-5015; the housing, base and mass block are all made of nickel-based alloy.
[0053] Figure 2 This is a schematic diagram of the measured sensitivity amplitude and error analysis table of a target velocity sensor at different frequencies, provided in an embodiment of this application. Figure 2 The paper shows the measured sensitivity amplitude (unit: mV / mm / s) of the target velocity sensor and the corresponding error percentage (%) under different frequency (5Hz to 4000Hz) and vibration values (10mm / s to 2mm / s).
[0054] Combination Figure 2 As shown, the vibration value gradually decreases with increasing frequency, while the measured sensitivity amplitude remains relatively stable at most frequencies, showing only a slight decrease at 1000Hz. The error percentage varies at different frequencies and vibration values, but remains at a low level overall, indicating that the sensor has good measurement accuracy and stability over a wide frequency range, meeting the error requirement of ≤5%.
[0055] Figure 3This is a schematic diagram of the sensitivity amplitude and error analysis table of a target velocity sensor at a fixed frequency, provided in an embodiment of this application. Figure 3 The paper demonstrates the relationship between the amplitude (in mV) and error (percentage) of the target velocity sensor under different vibration values (from 2 mm / s to 60 mm / s) at a fixed frequency of 80 Hz.
[0056] Combination Figure 3 As shown, with the increase of vibration value, the amplitude of the target velocity sensor gradually increased from 4.050mV to 4.105mV, while the error increased from 1.25% to 2.63%. This indicates that within the tested vibration value range, the amplitude of the target velocity sensor exhibits a certain linear growth trend, while the error remains at a low level, meeting the error requirement of ≤5%, indicating that the sensor has good linearity and measurement accuracy at this frequency.
[0057] It is understood that the above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A speed sensor, characterized by, include: Connectors, circuit boards, preload nuts, mass blocks, piezoelectric ceramic crystals, housings, and bases; The bottom of the housing is connected to the base, and the top of the housing is sealed to the connector; A stud is provided at the center of the cavity of the housing, and the piezoelectric ceramic crystal is mounted on the stud; the mass block is pressed on the piezoelectric ceramic crystal; the piezoelectric ceramic crystal and the mass block are both connected to the stud by the preload nut. The circuit board is mounted on the upper end of the cavity of the housing; the circuit board is connected to the piezoelectric ceramic crystal via a first wire; the circuit board is connected to the connector via a second wire. The empty spaces inside the shell are filled with epoxy resin.
2. The speed sensor of claim 1, wherein, The piezoelectric ceramic crystal is a PTZ-5 piezoelectric ceramic crystal.
3. The speed sensor of claim 1, wherein, Two piezoelectric ceramic crystals are mounted on the stud; the two piezoelectric ceramic crystals are isolated from each other by an insulating material.
4. The speed sensor of claim 1, wherein, The top of the housing is welded to the connector.
5. The speed sensor according to claim 1, characterized in that, The bottom of the housing is a flat surface with a groove, the groove being located at the center of the flat surface, and the inner edge of the groove being threaded; the base carries a nut that passes through the base; The bottom of the housing is connected to the base by means of a nut that passes through the base and a thread on the inner edge of the groove, thereby connecting the bottom of the housing to the base.
6. The speed sensor of claim 1, wherein, A platform is provided inside the cavity of the housing; the circuit board is mounted on the platform; the distance between the platform and the base is greater than the distance between the mass block and the base.
7. The speed sensor of claim 1, wherein, The connector model is MIL-C-5015.
8. The speed sensor according to any one of claims 1-7, characterized in that, Both the housing and the base are made of nickel-based alloy.
9. The speed sensor according to any one of claims 1-7, characterized in that, The mass block is made of a nickel-based alloy.
10. The speed sensor of claim 1, wherein, The smoothness of the bottom surface of the shell is better than 0.8 micrometers.