WO2014094550A1

WO2014094550A1 - Intelligent bolt having temperature measurement function

Info

Publication number: WO2014094550A1
Application number: PCT/CN2013/088735
Authority: WO
Inventors: 杨志强; 汪俊
Original assignee: 珠海一多监测科技有限公司
Priority date: 2012-12-21
Filing date: 2013-12-06
Publication date: 2014-06-26
Also published as: CN103233966A; HK1184843A1; CN103233966B

Abstract

An intelligent bolt having a temperature measurement function, comprising a bolt (1) having a screw rod (102) and a screw cap (101), and a temperature measurement device (2) integrally assembled with the bolt (1); the temperature measurement device (2) comprises a PCB (202), a heat sink (203), and a thermoelectric generator (201) supplying power for the PCB (202); the thermoelectric generator (201) has a cold end and a hot end; the heat sink (203) is disposed on the cold end side, and conducts heat directly with the cold end; the screw cap (101) of the bolt (1) is located on the hot end side, and conducts heat directly with the hot end; the PCB (202) is provided with a temperature measurement sensor (206) and a transmission aerial (205) for transmitting a temperature signal; and the temperature sensing end of the temperature measurement sensor (206) contacts the screw cap (101) of the bolt (1). The intelligent bolt having a temperature measurement function not only has the function of fastening and connecting to an electrical contact, but also has the function of measuring the temperature of the electrical contact. The thermoelectric generator (201) can automatically collect the heat of the electrical contact to supply power for the intelligent bolt.

Description

Intelligent bolt with temperature measuring function

The invention relates to a smart bolt with a temperature measuring function.

Background technique

Power equipment is a general term for power generators, transformers, power lines, transformers, contactors, circuit breakers, etc., including power generation equipment and power supply equipment. In the power system, especially with the rapid development of modern power systems toward high voltage, large units, and large capacity, the requirements for safety and reliability of power equipment are also increasing. Various contacts and connection points of electrical equipment, such as switch contacts, cable joints, busbar joints, generator and transformer lead-in joints, motor junction box joints, etc., after the current is supplied, the temperature of the equipment changes. The heat is proportional to the square of the incoming current. When the high-voltage equipment is overloaded or the contact is poor, it often causes the temperature of the relevant part of the high-voltage equipment to rise. Overheating may cause the insulation to age or even burn the insulation material, causing short-circuit faults and major economic losses. Therefore, it is very important to monitor the temperature of the contact on-line. When it exceeds a certain set value, it will issue local and remote alarm signals, prompting the production and maintenance personnel to find the precursor of the fault in time, which is very important for the safe and stable operation of the high-voltage power equipment and the power system. The meaning.

The connection method of electrical contacts is mainly bolted. The "Code for Construction and Acceptance of Bus Installations for Electrical Installations GBJ149-90" stipulates: The fasteners for installation of busbars should be in accordance with national standards except for anchor bolts. Galvanized products, fasteners for outdoor use, hot-dip galvanized products. The bolts are generally made of steel, and the temperature rise is often abnormal at the bolt joints. The main reasons for the analysis are as follows:

1. Different metals have different expansion effects. The metal expansion coefficient of steel bolts is much smaller than that of copper and aluminum busbars, especially for bolt-type equipment joints, which vary with load current and temperature during operation. The degree of expansion and contraction of aluminum or copper and iron will be different to produce creep, that is, the slow plastic deformation of the metal under the action of stress, and the creep process is also closely related to the temperature at the joint. Practice has shown that when the operating temperature at the joint exceeds 80 ° C, the joint metal will expand due to overheating, causing the contact surface to be staggered, forming a small gap and oxidizing. When the load current decreases and the temperature returns to the original contact position, the contact between the contact surface oxide film may affect the contact effect, that is, it may not be the direct contact between the metals during the original installation. Therefore, the increased contact resistance of each cycle of temperature change will increase the heat of the next cycle, which in turn will further deteriorate the working condition of the joint, thus forming a vicious circle.

2. The fastening bolts at the joints are not properly pressurized. Some installation or maintenance personnel think that the connection bolts are tightened as much as possible on the conductor connection, but it is not. In particular, the aluminum bus bar has a small modulus of elasticity. When the pressure of the nut reaches a certain critical pressure value, if the strength of the material is poor, and then continue to increase the improper pressure, the deformation of the contact surface will be caused, and the contact area will be reduced. The contact resistance increases, thereby affecting the conductor contact effect and increasing the amount of operating heat at the joint.

In summary, it is necessary to monitor the temperature of the bolt connection point. Therefore, it is urgent to propose a new temperature monitoring device for the bolt connection point, and it must meet the simple structure and the volume needs to be small enough, and the outside world does not need to provide additional energy. Its work and other conditions.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a smart bolt with a temperature measuring function that is simple and compact in structure and can automatically collect energy.

The technical solution adopted by the present invention is: The intelligent bolt with temperature measuring function of the invention comprises a bolt with a screw and a nut and a temperature measuring device integrated with the bolt, the temperature measuring device comprises a PCB circuit board a heat sink and a thermoelectric generator for supplying power to the PCB circuit board, the heat The electric generator has a cold end and a hot end, the heat sink is disposed on one side of the cold end and directly thermally conductive with the cold end, and the nut of the bolt is located at one side of the hot end and directly thermally conductive with the hot end; The circuit board is provided with a temperature measuring sensor and a transmitting antenna for transmitting a temperature signal, and the temperature sensing end of the temperature measuring sensor is in contact with the nut of the bolt.

Further, the temperature measuring device further includes a casing, the casing is assembled with the lower end of the heat sink to form an inner cavity, the PCB circuit board and the thermoelectric generator are located in the inner cavity, and the nut of the bolt is located The inner cavity and the screw pass out to the outside of the outer casing.

Further, the outer casing has a cavity matching the shape of the nut of the bolt, and the cavity is provided with a through hole through which the screw accommodating the bolt passes.

Further, a groove is provided on the outer circumference of the outer casing, and the inner transmitting antenna passes through the outer casing and is disposed around the outer circumference in the groove.

Further, a recess matching the shape of the thermoelectric generator and a placement hole for inserting the temperature measuring sensor are formed on the end surface of the nut of the bolt.

Further, the heat sink includes an intermediate body and a cylindrical heat sink arranged along the axial direction of the body, the PCB circuit board is annular, and the lower end of the main body of the heat sink passes through the cavity in the middle of the PCB circuit board and The cold end of the thermoelectric generator is in contact.

Further, the PCB circuit board further includes an energy storage device for storing electrical energy and an energy management circuit.

Further, the energy management circuit includes a boosting circuit, a voltage stabilizing circuit, and a starting circuit. Further, a heat conductive material is disposed between the cold end of the thermoelectric generator and the heat sink, between the hot end of the thermoelectric generator and the nut of the bolt.

Further, a ground screw hole is further formed on an end surface of the nut of the bolt for receiving and PCB Connection bolts for the board ground connection. The present invention has the following advantages: Since the present invention includes a bolt and a temperature measuring device integrated with the bolt, the temperature measuring device includes a PCB circuit board, a heat sink, and a thermoelectric generator for supplying power to the PCB circuit board. The temperature measuring device and the bolt assembly are integrated and the shape is also matched with the bolt. The invention itself becomes a "bolt" from the appearance, which not only has the function of the bolt itself, but also is used for fastening the electrical contact, but also It has the function of measuring the temperature of the electrical contact and transmitting it through data processing. In addition, since the present invention includes a thermoelectric generator internally having a cold end and a hot end, the heat sink is disposed on one side of the cold end and is directly thermally conductive with the cold end, and the hot end, the nut of the bolt is located One side of the hot end is directly thermally conductive at the hot end, and can convert the temperature difference between the electrical contact and the heat sink end into electric energy for other circuits to work normally, without external energy supply, so the present invention is remotely at the electrical contact temperature Monitoring systems as a key temperature acquisition component are of great importance.

DRAWINGS

Figure 1 is a schematic view of the external structure of the present invention;

Figure 2 is a cross-sectional view taken along line A-A of Figure 1;

Figure 3 is an exploded view of the components in the length direction of the present invention;

4 is a block diagram of circuit hardware on a PCB circuit board of the present invention;

Figure 5 is a block diagram showing the implementation of the energy management circuit of the present invention.

detailed description

As shown in FIG. 1 and FIG. 2, the intelligent bolt according to the present invention comprises a bolt 1 having a screw 102 and a nut 101 and a temperature measuring device 2 integrated with the bolt 1. The bolt 1 has a minimum design size. M8 or greater than M8, in this case the performance can still meet the design requirements, M8 and above The inch bolt 1 is capable of meeting the field application of most electrical connection points. The temperature measuring device 2 includes a PCB circuit board 202, a heat sink 203, and a thermoelectric generator 201 for supplying power to the PCB circuit board 202. The thermoelectric generator 201 has a cold end and a hot end, and the heat sink 203 is disposed at One side of the cold end is directly thermally conductive with the cold end, and the nut 101 of the bolt 1 is located on one side of the hot end and is directly thermally conductive with the hot end. Both ends of the thermoelectric generator 201 can be respectively coupled to the heat sink 203 and the nut 101 Direct contact, but in order to optimize the heat conduction channel, a heat conductive material 207 may be respectively disposed between the cold end of the thermoelectric generator 201 and the heat sink 203, between the hot end of the thermoelectric generator 201 and the nut 101 of the bolt 1. 208; Since the bolt 1 is used for fastening the electrical contact, the normal working electrical contact generates heat and has a certain temperature. When the temperature is transmitted to the thermoelectric generator 201 through the bolt 1, the cold end and the hot end have a certain temperature. When the temperature difference is different, the thermoelectric generator 201 operates to convert the heat into electrical energy, and the invention supplies power to the invention after subsequent circuit processing. The PCB circuit board 202 is provided with a temperature measuring sensor 206 and a transmitting antenna 205 for transmitting a temperature signal. The temperature sensing end of the temperature measuring sensor 206 is in contact with the nut 101 of the bolt 1 for measuring bolts in real time. The temperature of 1 (i.e., the temperature of the electrical contacts) is sent to the temperature data monitoring system via the transmitting antenna 205 after processing by subsequent circuitry. The heat sink 203 includes an intermediate body 2031 and a cylindrical fin 2032 arranged along the axial direction of the main body 2031. The temperature measuring device 2 further includes a casing 204, and the outer casing 204 and the lowermost end of the radiator 203 A layer of cylindrical fins 2032 are assembled to form an inner cavity into which the lower end of the body 2031 extends, while the PCB circuit board 202 and the thermoelectric generator 201 are located in the inner cavity. The heat sink 203 and the outer casing 204 can be designed in a cylindrical shape or a shape matching the nut 101 of the bolt 1, for example, a polygonal body or the like; for example, the heat sink 203 and the outer casing 204 are designed in a cylindrical shape, in this embodiment. The size of the heat sink 203 is 40 mm, and the total height of the outer casing 204 and the heat sink 203 after assembly is 30 mm (ie, the bottom of the outer casing 204) To the height of the top of the radiator 203). The internal thermoelectric generator 201 has the following parameters: thermal resistance 9. 2K / W, Seebeck voltage 27. 77mv / K, internal resistance 5. 5 ohms; its minimum starting working temperature difference working temperature difference 7. 5K (K is open This parameter is currently advantageous in the same size design, and the minimum temperature difference for the continuous operation of the temperature sensor 206 is designed to be 10. 5K, continuous operation means that the temperature sensor 206 is measured once per second and wirelessly The transmission requirement; at the same time, the temperature difference of the thermoelectric generator 201 is 10uW at 10K, which can meet the power supply requirements of the various components of the PCB circuit board 202. . The PCB circuit board 202 is annular, and the lower end of the main body 2031 of the heat sink 203 extends into the cavity through the hole in the middle of the PCB circuit board 202 and is in contact with the cold end of the thermoelectric generator 201 (between Thermally conductive material 207). In order to ensure a better temperature difference effect, the material of the bolt 1 is also selected in this embodiment. By modeling the model, input the thermal resistance parameters of each part of the intelligent bolt, and obtain the temperature difference parameters of different bolt materials by simulation. The simulation results show that the copper bolts can be improved by 38% compared with the stainless steel bolts, and the existing bolts can be used instead of the existing ones. More stainless steel bolts are used in technical applications.

As shown in the exploded view of FIG. 3, the outer casing 204 has a cavity 2041 (for example, an M8 bolt) matching the shape of the nut 101 of the bolt 1, and the cavity 2041 is provided with the bolt. A through hole 2042 through which the screw 102 of the screw 102 passes, a recess 104 matching the shape of the thermoelectric generator 201 and a placement hole 103 for inserting the temperature measuring sensor 206 are formed on the end surface of the nut 101 of the bolt 1. . In the assembly process, the bolt 1 is first assembled in the cavity 2041 through the through hole 2042, and then the thermoelectric generator 201 is placed in the dimple 104, and the annular PCB circuit board 202 is fastened to the outer casing by screws. At 204, the heat sink 203 is finally assembled with the outer casing 204 by screws. At the same time, the PCB circuit board 202 and the transmitting antenna 205 are also arranged in a ring shape, and the PCB circuit board 202 is composed of two circuit boards 2021 and 2022, wherein the energy management circuit related to the thermoelectric generator 201 is formed. Focusing on the circuit board 2021, functions such as temperature acquisition processing, control, and wireless transmission are concentrated on another circuit board 2022; further, a ring groove 2043 is provided on the outer circumference of the outer casing 204, and the inner transmitting antenna 205 passes through the outer casing 204. The wall is disposed in the groove 2043 along the outer circumference. In this embodiment, the transmitting antenna 205 is used in the 433M frequency band, and the ring shape is designed mainly for the overall appearance effect; and the advantages are obvious, the cost is reduced, and the structure is simple. In addition, a grounding screw hole 105 is further formed on the end surface of the nut 101 of the bolt 1 for receiving a connecting bolt connected to the PCB circuit board 202. The connecting bolt passes through the ground screw hole 105 to make the ground of the PCB circuit board 202. Grounding, when the electrical contact is at the high voltage potential, the ground of the PCB circuit board 202 can be at the same potential to avoid damaging components such as the temperature measuring sensor on the PCB circuit board 202.

As shown in FIG. 4, in the circuit hardware of the present invention, the PCB circuit board 202 includes a temperature sensor, an analog-to-digital converter, a processor, and a wireless transceiver, and the working process is: the processor controls the temperature sensor to periodically collect the temperature measurement data. And converting the analog signal into a digital signal through an analog-to-digital converter and providing it to the processor for processing. The processor sends the processed data through the wireless transceiver, and the receiver in the temperature monitoring system receives and uploads the PC display. The energy of the entire apparatus of the present invention is provided by the thermoelectric generator collecting the thermal energy of the electrical contacts.

The PCB circuit board 202 further includes an energy storage device for storing electrical energy and an energy management circuit. The energy storage device mainly refers to a capacitor or a rechargeable battery; since the output energy of the thermoelectric generator is not stable, with or without more or less And the conventional process thermoelectric generator outputs a lower voltage (20 mV/K), so we need to concentrate its energy for subsequent circuits. As shown in FIG. 5, the energy management circuit is mainly composed of a boosting circuit, a starting circuit and a voltage stabilizing circuit, and the boosting circuit is responsible for raising and storing the lower voltage of the thermoelectric generator output in the capacitor or the rechargeable battery; The startup circuit controls the output of the energy. When the voltage of the energy storage device rises to a high voltage threshold, the startup circuit control is turned on. The stage circuit, the energy flow to the latter stage is used by the subsequent circuit. When the voltage of the energy storage device drops to the low voltage threshold, the startup circuit controls the circuit to be turned off, and the energy storage device continues to store energy, and the operation is repeated.

Claims

A smart bolt with a temperature measuring function, comprising: a bolt having a screw and a nut and a temperature measuring device assembled integrally with the bolt, the temperature measuring device comprising a PCB circuit board and a heat sink; a thermoelectric generator for supplying power to the PCB circuit board, the thermoelectric generator having a cold end and a hot end, the heat sink being disposed on one side of the cold end and directly thermally conductive with the cold end, the nut of the bolt being located at the hot end One side is directly thermally conductive with the hot end; the PCB circuit board is provided with a temperature measuring sensor and a transmitting antenna for transmitting a temperature signal, and the temperature sensing end of the temperature measuring sensor is in contact with the nut of the bolt.

2. The smart bolt with temperature measuring function according to claim 1, wherein: the temperature measuring device further comprises a casing, and the casing is assembled with a lower end of the heat sink to form an inner cavity, the PCB A circuit board and a thermoelectric generator are located in the inner cavity, a nut of the bolt is located in the inner cavity and a screw is threaded out to the exterior of the outer casing.

3. The smart bolt with temperature measuring function according to claim 2, wherein: the outer casing has a cavity matching the shape of the nut of the bolt, and the cavity is internally provided to accommodate the The through hole through which the screw of the bolt passes.

4. The intelligent bolt with temperature measuring function according to claim 2, wherein: a groove is provided on an outer circumference of the outer casing, and an inner transmitting antenna passes through the outer casing and is disposed around the outer circumference in the groove. .

5 . The intelligent bolt with temperature measuring function according to claim 1 , wherein: a concave hole matching the shape of the thermoelectric generator is arranged on an end surface of the nut of the bolt and used for placing The road plate is annular, and the lower end of the main body of the heat sink passes through the cavity in the middle of the PCB circuit board and is in contact with the cold end of the thermoelectric generator.

7. The intelligent bolt with temperature measuring function according to any one of claims 1 to 6, wherein: the PCB circuit board further comprises an energy storage device for storing electrical energy and an energy management circuit.

8. The intelligent bolt with temperature measuring function according to claim 7, wherein: the energy management circuit comprises a boosting circuit, a voltage stabilizing circuit and a starting circuit.

9. The intelligent bolt with temperature measuring function according to any one of claims 1 to 6, characterized in that: between the cold end of the thermoelectric generator and the heat sink, the hot end of the thermoelectric generator and the bolt Thermally conductive materials are provided between the nuts.

The intelligent bolt with temperature measuring function according to any one of claims 1 to 6, characterized in that: a grounding screw hole is further formed on an end surface of the nut of the bolt for accommodating the PCB circuit board Connection bolt for ground connection.