A magnetic temperature sensor

Abstract

This utility model relates to the field of temperature sensor technology and provides a magnetic temperature sensor, including a cable, a heat-conducting pipe with a built-in temperature-sensing element, and a base with a permanent magnet. The cable is connected to the temperature-sensing element. The base has a recess with a through hole at the bottom, through which the heat-conducting pipe slidably passes. One end of the heat-conducting pipe is flared to form a temperature-sensing end, and the other end has a limiting member. A pressure spring is fitted over the heat-conducting pipe between the recess and the temperature-sensing end. The heat-conducting pipe is filled with thermally conductive sealant for encapsulating the temperature-sensing element and flexible thermally conductive adhesive for contacting the object being measured. This utility model can improve response speed and measurement data accuracy.

Description

Technical Field

[0001] This utility model relates to the field of temperature sensor technology, and more specifically, to a magnetic temperature sensor. Background Technology

[0002] Magnetic surface temperature sensors are crucial in industrial temperature monitoring, and one of their core performance indicators is response speed—the ability to quickly and accurately reflect the true temperature changes of the measured object's surface. However, current magnetic temperature sensors generally suffer from a technical bottleneck of slow thermal response speed, which severely affects their application in scenarios requiring rapid temperature measurement and real-time control.

[0003] The slow response can be attributed to two main reasons: First, the "remote" packaging structure of the temperature-sensing element results in a large inherent thermal inertia. For example, the magnetic temperature sensor disclosed in publication number "CN219641096U" has its temperature-sensing element encapsulated inside a plastic casing. Heat must pass through multiple layers of media, such as a copper cap and thermally conductive adhesive, before reaching the temperature-sensing element. Each layer of media introduces thermal resistance and delays heat transfer. Similarly, other existing magnetic temperature sensors often embed temperature-sensing elements, such as platinum resistance thermometers, deep into the bottom of a metal heat pipe or fix them through a complex assembly structure. This makes the temperature-sensing element physically far from the measured surface, resulting in a huge inherent thermal inertia.

[0004] Secondly, an unstable "air gap" exists between the temperature sensing element and the surface being measured, which cannot be eliminated. Most existing magnetic temperature sensors rely on the static attraction force provided by magnetism to ensure contact, and their sensing ends are rigid or semi-rigid structures. This structure cannot adapt to the microscopic unevenness, curvature, or vibrations commonly found on the surfaces of industrial equipment, resulting in the sensor actually only making point or line contact with the surface being measured. This uncertain air gap causes slow heat transfer, leading to a slow response, and the heat carried away by airflow also causes measurement errors.

[0005] While some existing technologies attempt to improve thermal conductivity by using superior thermally conductive adhesives, thermally conductive pads, or metal materials with higher thermal conductivity, their improvement effect is limited in the face of the aforementioned multi-layer thermally conductive structures and air gaps. Utility Model Content

[0006] The purpose of this invention is to provide a magnetic temperature sensor to overcome the aforementioned deficiencies in the prior art.

[0007] This utility model is achieved through the following technical solution: A magnetic temperature sensor includes a cable, a heat-conducting pipe with a built-in temperature-sensing element, and a base with a permanent magnet. The cable is connected to the temperature-sensing element. The base has a recess with a through hole at the bottom. The heat-conducting pipe is slidably inserted into the through hole. One end of the heat-conducting pipe is flared to form a temperature-sensing end, and the other end has a limiting member. A pressure spring is fitted over the heat-conducting pipe between the recess and the temperature-sensing end. The heat-conducting pipe is filled with thermally conductive sealant for encapsulating the temperature-sensing element and flexible thermally conductive adhesive for contacting the object being measured.

[0008] Optionally, the sink groove extends through both opposite sides of the base, the base is made of magnetically conductive material and has mounting grooves on both sides of the sink groove, and the permanent magnet is disposed in the mounting groove.

[0009] Optionally, the base is connected to a connecting joint via a thread, the connecting joint is connected to a bend via a thread, and the cable passes through the inside of the bend and is connected to a connector.

[0010] Optionally, an operating handle is welded onto the bend.

[0011] Optionally, a liner is provided inside the end of the bend away from the connector, and the liner and the bend press and fix the cable.

[0012] Optionally, a protective spring is fitted onto the portion of the cable extending out of the bend, with one end of the protective spring fixed to the bend.

[0013] Optionally, the cable is a four-core cable, in which two cores are welded to one pin and the other two cores are welded to another pin, and the two leads of the temperature sensing element are welded to the two pins one-to-one.

[0014] Optionally, an insulating tube and a pressing tube are sequentially arranged inside the heat-conducting tube along the direction away from the temperature measuring end. The thickness of the pressing tube is greater than that of the insulating tube and one end extends out of the heat-conducting tube. An insulating I-shaped plate and a ceramic tube are arranged inside the insulating tube. The pins are arranged on both sides of the insulating I-shaped plate, and the lead of the temperature sensing element passes through the ceramic tube.

[0015] Optionally, the thermally conductive sealant is epoxy resin, the flexible thermally conductive adhesive is silicone thermally conductive adhesive, and the thermally conductive tube is a copper tube.

[0016] Optionally, the temperature sensing element is 0.03-0.1 mm below the end face of the temperature measuring end of the heat pipe, the thermally conductive sealant does not exceed the outer side of the temperature sensing element, and the flexible thermally conductive adhesive is flush with or extends beyond the end face of the temperature measuring end of the heat pipe by ≤0.2 mm.

[0017] The technical solution of this utility model has at least the following advantages and beneficial effects: In this utility model, on the one hand, the heat-conducting pipe adopts a structure with one end flared, the temperature-sensing element is set inside the heat-conducting pipe and close to the flared end, and then it is sealed with thermally conductive sealant and contacts the object being measured through flexible thermally conductive adhesive, which can reduce the heat conduction distance, make the response time faster, and make the measurement data more accurate; on the other hand, under the action of the pressure spring, the temperature-sensing end of the heat-conducting pipe can be pressed tightly onto the object being measured. At the same time, the flexible thermally conductive adhesive has soft properties after curing (i.e., it can deform), which eliminates the small gaps between it and the object being measured, avoids the heat transfer efficiency being affected by the existence of small gaps, and also avoids the measurement error caused by heat loss due to air flowing through the small gaps, further improving the response speed and the accuracy of the measurement data. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a magnetic temperature sensor provided by this utility model; Figure 2 A cross-sectional view of a magnetic temperature sensor provided by this utility model; Figure 3 for Figure 2 Enlarged view of point A in the image; Figure 4 This is a schematic diagram showing the connection relationship between the heat pipe and the limiting component; Figure 5 This is a schematic diagram of the installation of the insulating I-shaped plate and the ceramic tube; Figure 6 This is an enlarged structural schematic diagram of the insulating I-shaped plate; Figure 7 This is a schematic diagram showing the pin relationship between the lead and the wire core of the temperature sensing element; Figure 8 for Figure 2 Enlarged view of point B in the image; Reference numerals: 1-Cable, 2-Temperature sensing element, 201-Pin, 3-Heat conduction tube, 301-Slot, 4-Base, 5-Permanent magnet, 6-Limiting element, 7-Compression spring, 8-Connecting joint, 9-Bend, 10-Connector, 11-Liner, 12-Operating handle, 13-Protective spring, 14-Pin, 15-Insulating tube, 16-Pressure tube, 17-Insulating I-shaped plate, 18-Ceramic tube. Detailed Implementation

[0019] refer to Figures 1-3A magnetic temperature sensor includes a cable 1, a heat-conducting pipe 3 with a built-in temperature-sensing element 2, and a base 4 with a permanent magnet 5. The cable 1 is connected to the temperature-sensing element 2. The base 4 has a recess with a through hole at the bottom. The heat-conducting pipe 3 is slidably inserted into the through hole. Specifically, the outer wall of the heat-conducting pipe 3 fits with the through hole, allowing the heat-conducting pipe 3 to slide axially within the through hole. The heat-conducting pipe 3 is filled with thermally conductive sealant (not shown) for encapsulating the temperature-sensing element 2 and flexible thermally conductive adhesive (not shown) for contacting the object being measured. One end of the heat-conducting pipe 3 is flared (in practical applications, it can be flared using a flaring mold and a press to form a trumpet shape) to form a temperature-sensing end. The other end has a limiting member 6. A pressure spring 7 is fitted over the heat-conducting pipe 3 between the recess and the temperature-sensing end. It is easy to understand that the pressure spring 7 will cause the heat-conducting pipe 3 to slide out of the through hole. The limiting member 6 prevents the heat-conducting pipe 3 from slipping off.

[0020] It is worth noting that the heat pipe 3 of this utility model adopts a structure with one end flared. The temperature sensing element 2 is placed inside the heat pipe 3 and close to the flared end. It is then sealed with thermally conductive sealant and contacts the object being measured through the flexible thermally conductive adhesive. This reduces the heat conduction distance, resulting in a faster response time and more accurate measurement data. In practical applications, the magnetic force generated by the permanent magnet 5 attracts the base 4 to the surface of the object being measured. Under the action of the pressure spring 7, the temperature sensing end of the heat pipe 3 can be pressed firmly onto the object being measured. At the same time, the flexible thermally conductive adhesive, after curing, has soft properties (i.e., it can deform), eliminating the tiny gaps between the heat pipe and the object being measured. This avoids the presence of tiny gaps affecting the heat transfer efficiency, further improving the response speed and the accuracy of the measurement data.

[0021] The sink groove runs through both opposite sides of the base 4, giving the base 4 a U-shaped structure. The base 4 is made of magnetically conductive material, and mounting grooves are provided on both sides of the sink groove. The permanent magnet 5 is placed in the mounting groove. With this configuration, the U-shaped structure and magnetic properties of the base 4 concentrate magnetic field lines at the end of the base 4 that contacts the object being measured. When the base 4 is in contact with the object being measured, it forms a closed magnetic field, enhancing the magnetic force and ensuring that the sensor is firmly attached to the object being measured, preventing insufficient magnetic force from causing the sensor to fall off and affecting the test.

[0022] The specific materials of the base 4 and the permanent magnet 5 are not limited. For example, the base 4 can be made of carbon steel, and the permanent magnet 5 can be made of N45H neodymium iron boron permanent magnet. In practical applications, the permanent magnet 5 can be fixed in the mounting groove with epoxy resin. Multiple permanent magnets 5 can also be stacked in each groove to enhance the magnetic force. Of course, different grades of permanent magnets 5 can also be used to achieve different magnetic force requirements.

[0023] The temperature sensing element 2 is positioned 0.03-0.1 mm below the end face of the heat pipe 3's measuring end. Specifically, the distance from the outer side of the temperature sensing element 2 (the side closest to the measuring end of the heat pipe 3) to the end face of the heat pipe 3 is 0.03-0.1 mm. The specific value is not limited; for example, 0.03 mm, 0.65 mm, or 0.1 mm are all acceptable (and other values ​​are also possible). This design prevents the temperature sensing element 2 from directly contacting the object being tested during testing, thus avoiding damage or shortened lifespan due to impact or vibration. Furthermore, the thermally conductive sealant does not extend beyond the outer side of the temperature sensing element 2. Even after the sealant is applied, the side of the temperature sensing element closest to the measuring end of the heat pipe 3 remains exposed, allowing the temperature sensing element 2 to directly contact the flexible thermally conductive sealant, significantly reducing the heat transfer distance between the object being tested and the temperature sensing element 2. In this embodiment, the distance of the flexible thermally conductive adhesive extending beyond the end face of the temperature measuring end of the heat pipe 3 is less than or equal to 0.2 mm. The specific value is not limited; for example, it can extend by 0.01 mm, 0.1 mm, or 0.2 mm (or other values). In other embodiments, the flexible thermally conductive adhesive may be flush with the end face of the temperature measuring end of the heat pipe 3.

[0024] As an alternative, in this embodiment, epoxy resin is chosen as the thermally conductive sealant, silicone thermally conductive adhesive is chosen as the flexible thermally conductive adhesive (it is soft after curing and can deform under pressure), and copper tube is chosen as the heat pipe 3 to ensure excellent thermal conductivity and reduce the time required for heat transfer. In other embodiments, other materials can of course be chosen for the thermally conductive sealant, flexible thermally conductive adhesive, and heat pipe 3.

[0025] In this embodiment, the temperature sensing element 2 is a platinum resistance thermometer. In other embodiments, other types can be used, such as thermocouples, thermistors, etc.

[0026] refer to Figures 4-7 In this embodiment, cable 1 is a four-core cable 1. Two cores of the four-core cable 1 are soldered to one pin 14, and the other two cores are soldered to another pin 14. The two pins 201 of the temperature sensing element 2 are soldered to the two pins 14 one-to-one, and the solder joints are tinned to prevent them from falling off. Specifically, each core is wrapped with a sheath, and the outer sheath completely covers the sheath of each core. In actual applications, the sheath colors corresponding to the four cores are red, red, white, and white, respectively. The two red cables 1 are soldered to one pin 14, and the two white cables are soldered to the other pin 14. It is worth noting that using a four-wire connection for the platinum resistance thermometer can eliminate line resistance, and the four wires can meet the requirements of both three-wire and two-wire measurements, providing multiple measurement methods.

[0027] An insulating tube 15 and a clamping tube 16 are sequentially arranged inside the heat-conducting tube 3 along the direction away from the temperature measuring end. The thickness of the clamping tube 16 is greater than that of the insulating tube 15, and one end extends out of the heat-conducting tube 3. The materials of the insulating tube 15 and the clamping tube 16 are preferably Teflon to ensure insulation. An insulating I-shaped plate 17 and a ceramic tube 18 are arranged inside the insulating tube 15. The leads 14 welded to the wire core are located on both sides of the middle rib of the insulating I-shaped plate 17 (and are located between the two webs). The ceramic tube 18 has four through holes, through which the lead 201 of the temperature sensing element 2 passes.

[0028] In this embodiment, the cable 1 and the heat-conducting pipe 3 are fixed by compression. Specifically, after the first insulating tube 15, the compression tube 16, the insulating I-shaped plate 17, and the ceramic tube 18 are installed with the heat-conducting pipe 3, the heat-conducting pipe 3 is inserted into the grooving machine, and the groove 301 is pressed on the outer wall of the heat-conducting pipe 3 at the location of the compression tube 16 to press the compression tube 16, so that the cable 1 is pressed and prevented from shifting. After adjusting the position of the temperature sensing element 2, the adhesive is applied (i.e., filled with thermally conductive sealant). Before applying the adhesive, in order to prevent the thermally conductive sealant from flowing out from the other end of the heat-conducting pipe 3 (i.e. the end opposite to the flared end), an appropriate amount of silicone is applied to seal the other end. After the thermally conductive sealant has cured, flexible thermally conductive adhesive is applied.

[0029] Based on the groove 301 pressed into the outer wall of the heat pipe 3, the aforementioned limiting member 6 can be replaced by an E-type retaining spring, which is disposed within the groove 301. In other embodiments, the limiting member 6 can of course be other structures, such as a plate fixed to the outer wall of the heat pipe by welding.

[0030] refer to Figure 1 , Figure 2 and Figure 8 The base 4 is threadedly connected to a connecting joint 8, which in turn is threadedly connected to a bent pipe 9. An appropriate amount of epoxy resin is applied to the threaded connection for fixation and bonding. Alternatively, in this embodiment, the base 4 has an internal thread, and one end of the bent pipe 9 has an external thread. Therefore, one end of the connecting joint 8 has an external thread connecting to the base 4, and the other end has an internal thread connecting to the bent pipe 9. In other embodiments, the internal and external threads can be arranged in other ways to achieve the connection.

[0031] Cable 1 passes through the inside of the bend 9 and is connected to connector 10. Further, a liner 11 is provided inside the end of the bend 9 away from the connector 8. The liner 11 and the bend 9 press and fix cable 1. Preferably, the liner 11 is made of brass. In practical applications, an appropriate amount of epoxy resin is applied to the inner and outer surfaces of the liner 11 to increase the firmness between the three components. Then, a crimping machine is used to press the bend 9 and the liner 11, deforming them and pressing the cable 1 to prevent it from slipping. An appropriate amount of sheath is stripped from the outer end of cable 1, and an appropriate amount of outer sheath is stripped from the core. A terminal corresponding to the color of the core sheath is crimped, and then the cable is connected to connector 10 for easy insertion and removal. As an option, in this embodiment, connector 10 is a four-pin aviation socket; in other embodiments, other connectors 10 capable of quick insertion and removal can also be selected.

[0032] An operating handle 12 is welded onto the bend 9, making it convenient for operators to hold and operate the sensor. This avoids the need to directly pull the cable 1 or operate the sensor by touching the probe, as is common with traditional sensors (this method can easily damage the sensor and is inconvenient). In this embodiment, the operating handle 12 and the bend 9 form a T-shape and are perpendicular to the connecting joint 8. In other embodiments, the operating handle 12 can be welded to other locations, as long as it is convenient for operators to hold and operate.

[0033] A protective spring 13 is fitted over the portion of cable 1 extending out of the bend 9. One end of the protective spring 13 is fixed to the bend 9, and the protective spring 13 prevents damage to cable 1 from bending at the point where it extends out of the bend 9. Specifically, the protective spring 13 is a variable diameter spring, with one end having a larger diameter and fitting onto the bend 9, and the other end having a smaller diameter and fitting onto cable 1. The method of fixing the protective spring 13 to the bend 9 is not limited (e.g., welding).

[0034] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A magnetically attracted temperature sensor, comprising a cable, a heat-conducting pipe with a built-in temperature-sensing element, and a base with a permanent magnet, wherein the cable is connected to the temperature-sensing element, characterized in that: The base has a recessed groove with a through hole at the bottom, through which the heat pipe can be slidably inserted. One end of the heat pipe is flared to form a temperature measuring end, and the other end is equipped with a limiting component. A pressure spring is pressed between the sink and the temperature measuring end on the outer sleeve of the heat pipe. The heat pipe is filled with thermally conductive sealant for encapsulating the temperature sensing element and flexible thermally conductive adhesive for contacting the object being measured.

2. The magnetic temperature sensor according to claim 1, characterized in that, The sink groove extends through both opposite sides of the base. The base is made of magnetically conductive material and has mounting grooves on both sides of the sink groove. The permanent magnet is placed in the mounting groove.

3. The magnetic temperature sensor according to claim 1, characterized in that, The base is connected to a connector via a threaded connection, and the connector is connected to a bend via a threaded connection. The cable passes through the inside of the bend and is connected to a connector.

4. The magnetic temperature sensor according to claim 3, characterized in that, An operating handle is welded onto the bend.

5. The magnetic temperature sensor according to claim 3, characterized in that, The end of the bend away from the connector is provided with a liner, and the liner and the bend press and fix the cable.

6. The magnetic temperature sensor according to claim 3, characterized in that, The portion of the cable extending out of the bend is fitted with a protective spring, one end of which is fixed to the bend.

7. The magnetic temperature sensor according to any one of claims 1-6, characterized in that, The cable is a four-core cable, with two cores welded to one pin and the other two cores welded to another pin. The two leads of the temperature sensing element are welded to the two pins in a one-to-one correspondence.

8. The magnetic temperature sensor according to claim 7, characterized in that, An insulating tube and a compression tube are arranged sequentially inside the heat-conducting tube along the direction away from the temperature measuring end. The thickness of the compression tube is greater than that of the insulating tube and one end extends out of the heat-conducting tube. An insulating I-shaped plate and a ceramic tube are arranged inside the insulating tube. The pins are located on both sides of the insulating I-shaped plate, and the lead of the temperature sensing element passes through the ceramic tube.

9. The magnetic temperature sensor according to any one of claims 1-6, characterized in that, The thermally conductive sealant is epoxy resin, the flexible thermally conductive adhesive is silicone thermally conductive adhesive, and the thermally conductive tube is a copper tube.

10. The magnetic temperature sensor according to any one of claims 1-6, characterized in that, The temperature sensing element is 0.03-0.1mm below the end face of the temperature measuring end of the heat pipe, the thermally conductive sealant does not exceed the outer side of the temperature sensing element, and the flexible thermally conductive adhesive is flush with or extends beyond the end face of the temperature measuring end of the heat pipe by ≤0.2mm.

Images