NL2038073A - Magnetic Liquid Metal Thermal Switch Capable of Realising Bidirectional Circuit Feedback, and Circuit Protection Method - Google Patents

Abstract

The present invention provides a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, and a circuit protection method. The magnetic liquid metal thermal switch includes a magnet, a heat transfer pipe, magnetic liquid metal, and an external circuit, Wherein the magnet is arranged at the upper end of the heat transfer pipe, the magnetic liquid metal is arranged in the heat transfer pipe, the upper end and the lower end of the heat transfer pipe are respectively provided with an upper connecting joint and a lower connecting joint, and the external circuit is connected to the magnetic liquid metal by the upper connecting joint or the lower connecting joint. The present invention can make ultra-fast response in the case of overheating.

Description

Magnetic Liquid Metal Thermal Switch Capable of Realising Bidirectional Circuit

Feedback, and Circuit Protection Method

TECHNICAL FIELD

The present invention relates to the field of magnetic liquid metal thermal switches, in particular to a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, and a circuit protection method.

BACKGROUND

Overheating is a major problem for electronic equipment during daily life and industrial production activities, especially in high-power applications such as industrial automation and robotics. Overheating will not only shorten the service life of the electronic equipment, but also quickly lead to the aging and damage of components, and even lead to fire and explosion, posing a serious threat to life and property safety. Thermal switches can mitigate thermal damage in electronic products, detect abnormal temperature and cut off the system before any damage occurs. Unlike thermal fuses, thermal switches can be reset after cooling.

A common thermal switch in the market is mercury thermal switch. However, metallic mercury itself is highly toxic, and will do harm to the ecological environment and the personal safety of users, which does not conform to the environmental protection concept of sustainable development. In addition, the mercury switch needs to be heated and deformed by external devices to cut off the circuit. Another common thermal switch is a mechanical contactor based on metal contacts to control the opening and closing of the circuit. However, these switches have some limitations such as mechanical wear, high energy consumption and limited life. In recent years, magnetic liquid metal thermal switches, as an innovative switching technology, have gradually emerged.

Magnetic liquid metal is a special material that has a low viscosity and is in a liquid state at room temperature. Liquid metal has good electrical conductivity, thermal conductivity and fluidity, but is not magnetic itself, and can be made magnetic by doping particles with magnetocaloric effect into the liquid metal. Magnetocaloric effect refers to the phenomenon that the magnetic entropy inside the material changes by changing the magnitude of the external magnetic field, thus causing the material to absorb heat or release heat. At room temperature or at low temperatures, the material is in a ferromagnetic state, the magnetic moments within the magnetic material will be regularly arranged along the direction of the external magnetic field. When the magnetocaloric material is heated, the temperature of the material rises rapidly and above its Curie temperature, at which time the magnetic moments within the magnetocaloric material change from the original regular arrangement to the disordered arrangement, and accordingly, the magnetocaloric material changes from ferromagnetic to paramagnetic, then when the magnetocaloric material is cooled, the temperature of the magnetocaloric material starts to drop until it is below its Curie temperature, at which point the magnetic moments within the magnetocaloric material again will be restored from the disordered arrangement to the ordered arrangement, and the magnetocaloric material undergoes a magnetic entropy change again and shows ferromagnetism again. With this property, the magnetic liquid metal can undergo a phase change when heated, thereby inducing a change in its magnetism, thereby realising switching of a circuit with the phase change characteristics of the magnetic liquid metal.

When the temperature reaches a threshold, the magnetocaloric material in the magnetic liquid metal undergoes a phase change, thereby changing the magnetism of the material.

This phase change process can be controlled by an external magnetic field, allowing the thermal switch to switch quickly and reliably.

Compared with the conventional thermal switch, the magnetic liquid metal thermal switch has the following advantages: (1) the magnetic liquid metal thermal switch has the advantages of being more environmentally friendly, short in response time, high in accuracy, small in volume, low in cost and strong in reusability, and no mechanical noise, and no external structure damage; (2) the liquid metal in the magnetic liquid metal thermal switch has ultra-high flexibility, electrical conductivity and thermal conductivity, so that the flow channel can be reduced to micro-nano level, which greatly reduces the volume of the thermal switch, which makes the thermal switch flexible in application conditions, wide in application fields and very broad in application prospect; (3) the liquid metal material used in the thermal switch is eutectic gallium indium alloy or gallium indium tin alloy, which has a non-toxic and non-harmful advantage compared to the main mercury switch in the market, and has a very great potential in the development of the biological field, (4) the conventional magnetic reed-type and bimetal-type thermal switch will sound when cutting the circuit, which will generate noise pollution during multi-cycle temperature cycling, and the magnetic liquid metal thermal switch does not have any mechanical noise; (5) the conventional thermal switch can only unidirectionally control the closing and opening of the circuit, while the magnetic liquid metal thermal switch can be designed in a bidirectional circuit feedback mode: opening one circuit while closing the other circuit, having more flexible and efficient application in more complex circuits than the conventional thermal switch on the market; (6) it takes a few minutes for the traditional thermal switch to recover the path, while the magnetic liquid metal droplet can quickly restore the magnetism within 30 s after heating to break the circuit, with short path recovery time, high switching feedback frequency and high recycling efficiency.

Therefore, it is necessary to study a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, and a circuit protection method to deal with the shortcomings of the prior art, so as to solve or alleviate one or more of the above problems.

SUMMARY

In view of this, the present invention provides a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, and a circuit protection method, which can make ultra-fast response in the case of overheating.

In one aspect, the present invention provides a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, including a magnet, a heat transfer pipe, magnetic liquid metal, and an external circuit, wherein the magnet is arranged at an upper end of the heat transfer pipe, and the magnetic liquid metal is arranged in the heat transfer pipe; the upper end and the lower end of the heat transfer pipe are respectively provided with an upper connecting joint and a lower connecting joint, and the external circuit is connected to the magnetic liquid metal by the upper connecting joint or the lower connecting joint.

According to the above aspect and any possible implementation, there is further provided an implementation in which the upper end of the heat transfer pipe is further provided with an upper sealing plug, and the lower end of the heat transfer pipe is further provided with a lower sealing plug; the magnetic liquid metal is hermetically arranged between the upper sealing plug and the lower sealing plug.

According to the above aspect and any possible implementation, there is further provided an implementation in which the upper connecting joint includes an upper connecting positive electrode, an upper positive wire, an upper connecting negative electrode and an upper negative wire, wherein the upper connecting positive electrode and the upper connecting negative electrode are both arranged in the heat transfer pipe; the upper connecting positive electrode is connected to a positive electrode of the external circuit by the upper positive wire, and the upper connecting negative electrode is connected to a negative electrode of the external circuit by the upper negative wire; the upper positive wire and the upper negative wire both hermetically penetrate through the upper sealing plug.

According to the above aspect and any possible implementation, there is further provided an implementation in which the lower connecting joint includes a lower connecting positive electrode, a lower positive wire, a lower connecting negative electrode and a lower negative wire, wherein the lower connecting positive electrode and the lower connecting negative electrode are both arranged in the heat transfer pipe; the lower connecting positive electrode is connected to the positive electrode of the external circuit by the lower positive wire, and the lower connecting negative electrode is connected to the negative electrode of the external circuit by the lower negative wire; the lower positive wire and the lower negative wire both hermetically penetrate through the lower sealing plug.

According to the above aspect and any possible implementation, there is further provided an implementation in which the heat transfer pipe is a thin-walled hollow cylindrical pipe,

and two sides of the heat transfer pipe are each provided with a heat source.

According to the above aspect and any possible implementation, there is further provided an implementation in which a heat conducting solution is provided in the heat transfer pipe; 5 the heat conducting solution and the magnetic liquid metal completely fill the whole heat transfer pipe together, and the heat conducting solution does not chemically react with the magnetic liquid metal.

According to the above aspect and any possible implementation, there is further provided an implementation in which the magnetic liquid metal is in the state of magnetic liquid metal droplet which is a mixture of liquid metal and magnetic nanoparticles; wherein the liquid metal has a melting point lower than room temperature, and the magnetic nanoparticles have a magnetocaloric effect, so that the magnetic nanoparticles are ferromagnetic at room temperature and paramagnetic at high temperature, and have a Curie temperature lower than an overheating temperature of a heating element of an electrical appliance.

According to the above aspect and any possible implementation, there is further provided an implementation in which the gravity of the magnetic liquid metal droplet is smaller than a magnet attraction force, and the magnetic liquid metal droplet can be simultaneously connected to the upper connecting positive electrode and the upper connecting negative electrode or to the lower connecting positive electrode and the lower connecting negative electrode.

According to the above aspect and any possible implementation, there is further provided an implementation in which, the external circuit includes an upper external circuit and a lower external circuit, wherein the upper external circuit and the lower external circuit are each composed of an external wire, an external power source and an electrical appliance; one end of the external wire is connected to the external power source, and the other end of the external wire 1s connected to the electrical appliance by the upper positive wire, the upper connecting positive electrode, the magnetic liquid metal droplet, the upper connecting negative electrode and the upper negative wire, or by the lower positive wire, the lower connecting positive electrode, the magnetic liquid metal droplet, the lower connecting negative electrode and the lower negative wire in sequence.

According to the above aspect and any possible implementation, there is further provided a circuit protection method for a bidirectional circuit, which achieves bidirectional circuit feedback protection by the magnetic liquid metal thermal switch.

Compared with the prior art, the present invention can obtain the following technical effects: according to the present invention, the magnetic liquid metal droplet is encapsulated in the glass pipe, at room temperature, the droplet is ferromagnetic and is thus attracted to the upper side of the pipe by the magnet, so that the upper external circuit is closed and the lower external circuit is opened; when the external temperature rises and exceeds the Curie temperature of the magnetic liquid metal, the droplet changes from ferromagnetic to paramagnetic to break away from the attraction of the magnet and fall to the lower side of the pipe, so that the upper external circuit is opened while the lower external circuit is closed, thus, the effect of bidirectional circuit feedback is achieved in a very short time; when the external temperature decreases and is lower than the Curie temperature of the magnetic liquid metal, the droplet is again restored to be ferromagnetic to be attracted to the upper side of the pipe by the magnet, the lower external circuit is opened while the upper external circuit is closed, and this working process repeats in a cyclic manner.

Of course, it is not necessary for any product embodying the present invention to achieve all of the technical effects described above at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained from these drawings for those skilled in the art without inventive step.

FIG. 1 is a schematic diagram of the working principle of the overall structure of a magnetic liquid metal thermal switch according to an embodiment of the present invention, wherein (a) describes a cooled state, and (b) describes a heated state;

FIG. 2 is an overall structural diagram of a magnetic liquid metal thermal switch according to an embodiment of the present invention, wherein (a) is a front view, and (b) is a half-sectional front view;

FIG. 3 is a front view of a glass pipe according to an embodiment of the present invention;

FIG. 4 is a structural diagram of an upper plug according to an embodiment of the present invention, wherein (a) is a front view, and (b) is a half-sectional front view;

FIG. 5 is a structural diagram of a lower plug according to an embodiment of the present invention, wherein (a) is a front view, and (b) is a half-sectional front view;

FIG. 6 is a front view of a magnet according to an embodiment of the present invention.

In which, in the figures:

I-magnet; 2-upper plug embedded wire; 3-terminal; 4-terminal; S-upper plug embedded wire; 6-upper circuit power supply; 7-upper circuit electrical appliance; 8-upper plug; 9-contact; 10-contact; 11-magnetic liquid metal droplet; 12-glass pipe; 13-heat conducting solution; 14-contact, 15-contact; 16-lower plug; 17-lower plug embedded wire; 18-terminal; 19-terminal; 20-lower plug embedded wire; 21-lower circuit power supply; 22-lower circuit electrical appliance.

DETAILED DESCRIPTION

For better understanding of the technical solutions of the present invention, the detailed description is made below to the embodiments of the present invention in conjunction with the accompanying drawings.

It should be clear that the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making inventive labor, belong to the scope of protection of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in embodiments of the invention and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The present invention provides a magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, including: a magnet, a heat transfer pipe, magnetic liquid metal, and an external circuit, wherein the magnet is arranged at the upper end of the heat transfer pipe, the magnetic liquid metal is arranged in the heat transfer pipe, the upper end and the lower end of the heat transfer pipe are respectively provided with an upper connecting joint and a lower connecting joint, and the external circuit is connected to the magnetic liquid metal by the upper connecting joint or the lower connecting joint.

The upper end of the heat transfer pipe is further provided with an upper sealing plug, the lower end of the heat transfer pipe is further provided with a lower sealing plug, and the magnetic liquid metal is hermetically arranged between the upper sealing plug and the lower sealing plug.

The upper connecting joint includes an upper connecting positive electrode, an upper positive wire, an upper connecting negative electrode and an upper negative wire, wherein the upper connecting positive electrode and the upper connecting negative electrode are both arranged in the heat transfer pipe, the upper connecting positive electrode is connected to a positive electrode of the external circuit by the upper positive wire, the upper connecting negative electrode is connected to a negative electrode of the external circuit by the upper negative wire, and the upper positive wire and the upper negative wire both hermetically penetrate through the upper sealing plug.

The lower connecting joint includes a lower connecting positive electrode, a lower positive wire, a lower connecting negative electrode and a lower negative wire, wherein the lower connecting positive electrode and the lower connecting negative electrode are both arranged in the heat transfer pipe, the lower connecting positive electrode is connected to the positive electrode of the external circuit by the lower positive wire, the lower connecting negative electrode is connected to the negative electrode of the external circuit by the lower negative wire, and the lower positive wire and the lower negative wire both hermetically penetrate through the lower sealing plug.

The heat transfer pipe is a thin-walled hollow cylindrical pipe, and two sides of the heat transfer pipe are each provided with a heat source.

A heat conducting solution is provided in the heat transfer pipe, the heat conducting solution and the magnetic liquid metal completely fill the whole heat transfer pipe together, and the heat conducting solution does not chemically react with the magnetic liquid metal.

According to the above aspect and any possible implementation, there is further provided an implementation in which the magnetic liquid metal is in the state of magnetic liquid metal droplet which is a mixture of liquid metal and magnetic nanoparticles; wherein the liquid metal has a melting point lower than room temperature, and the magnetic nanoparticles have a magnetocaloric effect, so that the magnetic nanoparticle are ferromagnetic at room temperature and paramagnetic at high temperature, and have a Curie temperature lower than an overheating temperature of a heating element of an electrical appliance.

The gravity of the magnetic liquid metal droplet is smaller than a magnet attraction force, and the magnetic liquid metal droplet can be simultaneously connected to the upper connecting positive electrode and the upper connecting negative electrode or to the lower connecting positive electrode and the lower connecting negative electrode.

The external circuit includes an upper external circuit and a lower external circuit, wherein the upper external circuit and the lower external circuit are each composed of an external wire, an external power source and an electrical appliance, one end of the external wire 1s connected to the external power source, and the other end of the external wire is connected to the electrical appliance by the upper positive wire, the upper connecting positive electrode, the magnetic liquid metal droplet, the upper connecting negative electrode and the upper negative wire, or by the lower positive wire, the lower connecting positive electrode, the magnetic liquid metal droplet, the lower connecting negative electrode and the lower negative wire in sequence.

The present invention also provides a circuit protection method for a bidirectional circuit, which achieves bidirectional circuit feedback protection by the magnetic liquid metal thermal switch.

Embodiment 1:

As shown in FIG. 1 (a) and (b), the magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback of this embodiment is divided into a total of three parts: 1) magnet, 2) heat transfer pipe and 3) external circuit. As shown in (a) and (b) in

FIG. 2, the magnetic liquid metal thermal switch system is placed vertically, a glass pipe 12 is a thin-walled hollow cylindrical pipe, and as shown in FIG. 3, the wall thickness of the glass pipe 12 should be as thin as possible to improve the performance of heat transfer from an external heat source to the inside of the glass pipe 12; the upper and lower openings of the glass pipe 12 are sealed by an upper plug 8 and a lower plug 16, respectively. As shown in (a) and (b) in FIG. 4, wires 2 and 5 are embedded into the upper plug 8. One ends of the wires 2 and 5 are exposed to the inside of the glass pipe 12 as contacts 9 and 10, and magnetic liquid metal droplet 11 comes into contact with the contacts 9 and 10 to form a complete closed circuit. The other ends of the wires are exposed to the outside of the glass pipe 12 as terminals 3 and 4, and the terminals 3 and 4 are connected to the upper external circuit formed by the upper circuit power supply 6 and the upper circuit electrical appliance 7. Similarly, as shown in (a) and (b) in FIG. 5, wires 17 and 20 are embedded into the lower plug 16. One ends of the wires 17 and 20 are exposed to the inside of the glass pipe 12 as contacts 14 and 15, and the magnetic liquid metal droplet 11 comes into contact with the contacts 14 and 15 to form a complete closed circuit. The other ends of the wires are exposed to the outside of the glass pipe 12 as terminals 18 and 19, and the terminals 18 and 19 are connected to the lower external circuit formed by the lower circuit power supply 21 and the lower circuit electrical appliance 22. A heat conducting solution 13 and the magnetic liquid metal droplet 11 are encapsulated in the glass pipe 12. The heat conducting solution 13 has high heat transfer performance and insulation performance to improve the performance of heat transfer from the glass pipe 12 to the magnetic liquid metal droplet 11.

The good insulation performance can ensure that two contacts at the end without the magnetic liquid metal droplet 11 will not close a circuit, and the heat conducting solution 13 will not chemically react with the magnetic liquid metal droplet 11 to ensure the stability of the magnetic liquid metal droplet 11. At room temperature, the magnetic liquid metal droplet 11 is stably attracted to the lower surface of the upper plug 8 by the magnet 1, and makes sufficient contact with the two contacts 9 and 10 of the upper plug embedded wires 2 and 5 to ensure that a complete circuit loop is formed. The magnetic liquid metal droplet 11 is a mixture of liquid metal and magnetic nanoparticles. The melting point of the liquid metal should be lower than room temperature, to ensure that the magnetic liquid metal droplet 11 is in a liquid state at room temperature; the magnetic nanoparticles should have a pronounced magnetocaloric effect, i.e, ferromagnetic at room temperature and paramagnetic at high temperature, and the Curie temperature of the magnetic nanoparticles should be slightly lower than the overheating temperature of the equipment to ensure that the magnetic nanoparticles can undergo magnetic transition when the equipment is overheated. The doping ratio of the magnetic nanoparticles in the liquid metal should be strictly controlled. Too low doping ratio will cause the magnetic liquid metal droplet 11 to have low magnetism and be unable to be attracted to the lower surface of the upper plug 8 by the magnet 1. Too high doping ratio will lead to an increase in the kinematic viscosity of the magnetic liquid metal droplet 11, and the magnetic liquid metal droplet 11 tends to be solid, which affects the fluidity of the magnetic liquid metal droplet and makes the magnetic liquid metal droplet unable to fully make contact with the contacts 9 and 10 of the upper plug 8 and the contacts 14 and 15 of the lower plug 16. In addition, the volume of the magnetic liquid metal droplet 11 should also be strictly controlled. Too small droplet volume will cause the droplet to be unable to fully make contact with the contacts 9 and 10 of the upper plug 8 and the contacts 14 and 15 of the lower plug 16. Too large droplet volume will lead to an increase in the overall gravity of the magnetic liquid metal droplet 11. When the gravity of the magnetic liquid metal droplet is greater than the force of attraction of the magnet 1 to the magnetic liquid metal droplet, the magnetic liquid metal 5S droplet 11 will break away from the attraction of the magnet and fall and thus cannot be stably attracted to the lower surface of the upper plug 8 by the magnet 1.

The function of the magnet 1 is to provide a stable magnetic field, as shown in FIG. 6, the geometry of the magnet 1 is cuboid-shaped, and the strength of the magnetic field should ensure that ferromagnetic liquid metal droplet 11 can be attracted at room temperature, so that the liquid metal droplet 11 can stably make contact with the lower surface of the upper plug 8. The magnet 1 is fixed to the upper surface of the upper plug 8 by high-temperature glue to ensure that the position of the magnet 1 is fixed.

The external circuit mainly includes two parts: the upper external circuit and the lower external circuit. The upper external circuit is composed of the wires, the upper circuit power supply 6 and the upper circuit electrical appliance 7, wherein the wires are respectively connected to the terminals 3 and 4 of the upper plug 8, the lower external circuit is formed by the wires, the lower circuit power supply 21 and the lower circuit electrical appliance 22, wherein the wires are connected to the terminals 18 and 19 of the lower plug 16, respectively. When the magnetic liquid metal droplet 11 makes contact with the contacts 9 and 10, the upper external circuit forms a complete loop, and the upper circuit electrical appliance 7 is in a working state; when the magnetic liquid metal droplet 11 makes contact with the contacts 18 and 19, the lower external circuit forms a complete loop, and the lower circuit electrical appliance 22 is in a working state.

As shown in (a) in FIG. 1, the magnetic liquid metal thermal switch system is placed vertically, at room temperature, the magnetic liquid metal droplet 11 is in a ferromagnetic state, so that the magnetic liquid metal droplet is attracted to the lower surface of the upper plug 8 by the magnet 1, and makes contact with the contacts 9 and 10 of the upper plug 8, at this time, the upper circuit can form a complete closed loop, and the upper circuit electrical appliance 7 is in a working state, while the contacts 14 and 15 of the lower plug 16 are not connected to the magnetic liquid metal droplet 11, thus the lower external circuit is in an open state, and the lower circuit electrical appliance 22 is in a rest state; when the equipment overheats, as shown in (b) in FIG. 1, as the external temperature of the glass pipe 12 increases, the temperature of the magnetic liquid metal droplet 11 inside the glass pipe will also rise, when the temperature of the magnetic liquid metal droplet reaches the

Curie temperature of the magnetic liquid metal droplet 11, the droplet changes from the ferromagnetic state to a paramagnetic state, thereby breaking away from the attraction of the magnet 1 and falling to the upper surface of the lower plug 16, at this time, the magnetic liquid metal droplet 11 makes contact with the contacts 14 and 15 of the lower plug 8, so that the lower circuit can form a complete closed loop, and the lower circuit electrical appliance 22 is in a working state, at the same time, the contacts 9 and 10 of the upper plug 8 are not connected to the magnetic liquid metal droplet 11, so that the upper external circuit is in an open state, during which the magnetic liquid metal droplet changes from making contact with the contacts 9 and 10 to making contact with the contacts 14 and 15, and the lower external circuit is closed while the upper external circuit is opened, thus achieving the effect of bidirectional circuit feedback in an extremely short time.

When the overheating of the equipment is over, the equipment returns to the normal working temperature, and the external temperature of the glass pipe 12 gradually decreases to room temperature. As the temperatures of the magnetic liquid metal droplet 11, the glass pipe 12 and the heat conducting solution 13 gradually decrease, when the temperature is lower than the Curie temperature of the magnetic liquid metal droplet 11, the droplet returns from the paramagnetic state to the ferromagnetic state, thus being attracted by the magnet | again, so that the magnetic liquid metal droplet is disconnected from the contacts 14 and 15 of the lower plug 16, and makes contact with the contacts 9 and 10 of the upper plug 8. That is, the upper external circuit is closed while the lower external circuit is opened, and this working process repeats in a cyclic manner.

The magnetic liquid metal thermal switch capable of realising bidirectional circuit feedback, and the circuit protection method provided by embodiments of the present invention are described in detail above. The description of the above embodiments is only used to help understand the method of the present invention and its core idea, at the same time, according to the idea of the present invention, there will be changes in the specific implementation and application scope for those skilled in the art. To sum up, the contents of this description should not be understood as limitations to the present invention.

Certain words are used throughout the description and claims to refer to particular components. Those skilled in the art will appreciate that hardware manufacturers may refer to the same component by different terms. The description and claims do not refer to differences in name as a way of distinguishing between components, but rather to differences in function of components. As mentioned in the whole description and claims, "containing" and "including" are open terms, so they should be interpreted as "containing/including but not limited to". "roughly" means that within the acceptable error range, those skilled in the art can solve the technical problems within a certain error range and basically achieve the technical effects. The follow description in the description is a preferred embodiment for implementing the present invention, but the description is for the purpose of illustrating the general principles of the present invention, and is not intended to limit the scope of the present invention. The scope of the present invention shall be defined by the appended claims.

It should also be noted that the terms "including", "containing" or any other variation thereof are intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such commodity or system. Without more restrictions, the element defined by the sentence "including one ......" does not exclude that there are other identical elements in the commodities or systems that include the element.

It should be understood that the term "and/or" used herein is only a description of the relationship between related objects, which means that there can be three kinds of relationships, for example, A and/or B, which can mean that A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" herein generally indicates that a contextual object is an "OR" relationship.

The foregoing description illustrates and describes several preferred embodiments of the present invention, however, it is to be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified by the above teachings or the technology or knowledge in related fields within the scope of the present invention described herein. Changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention are intended to be within the scope of the appended claims.

Claims (10)

Conclusions: 1. A magnetic liquid metal thermal switch for bidirectional switching feedback, comprising: a magnet, a heat transfer tube, magnetic liquid metal, and an external circuit, wherein the magnet is disposed at an upper end of the heat transfer tube, and wherein the magnetic liquid metal is disposed in the heat transfer tube, wherein the upper end and a lower end of the heat transfer tube are respectively provided with an upper connection piece and a lower connection piece, and wherein the external circuit is connected to the magnetic liquid metal by means of the upper connection piece or the lower connection piece. 2. The magnetic liquid metal thermal switch according to claim 1, wherein the upper end of the heat transfer tube is further provided with an upper sealing plug, and the lower end of the heat transfer tube is further provided with a lower sealing plug; wherein the magnetic liquid metal is hermetically disposed between the upper sealing plug and the lower sealing plug. 3. The magnetic liquid metal thermal switch according to claim 2, wherein the upper connecting piece is provided with a upper connecting positive electrode, an upper positive wire, an upper connecting negative electrode and an upper negative wire, wherein the upper connecting positive electrode and the upper connecting negative electrode are both disposed in the heat transfer tube; wherein the upper connecting positive electrode is connected to a positive electrode of the external circuit using the upper positive wire, and the upper connecting negative electrode is connected to a negative electrode of the external circuit using the upper negative wire; wherein the upper positive wire and the upper negative wire both hermetically pass through the upper sealing plug. 4. The magnetic liquid metal thermal switch according to claim 3, wherein the lower connecting piece comprises a lower connecting positive electrode, a bottom positive wire, a bottom connecting negative electrode and a bottom negative wire, wherein the bottom connecting positive electrode and the bottom connecting negative electrode are both provided in the heat transfer tube; wherein the bottom connecting positive electrode is connected to the positive electrode of the external circuit by means of the bottom positive wire, and the bottom connecting negative electrode is connected to the negative electrode of the external circuit by means of the bottom negative wire; wherein the bottom positive wire and the bottom negative wire both hermetically pass through the bottom sealing plug. 5. The magnetic liquid metal thermal switch according to claim 1, wherein the heat transfer tube is a thin-walled hollow cylindrical tube, and wherein two sides of the heat transfer tube are each provided with a heat source. 6. The magnetic liquid metal thermal switch according to claim 1, wherein a heat conducting solution is provided in the heat transfer tube; wherein the heat conducting solution and the magnetic liquid metal together completely fill the entire heat transfer tube, and wherein the heat conducting solution does not chemically react with the magnetic liquid metal. 7. The magnetic liquid metal thermal switch according to claim 4, wherein the magnetic liquid metal is in the form of a magnetic liquid metal droplet which is a mixture of liquid metal and magnetic nanoparticles; wherein the liquid metal has a melting point lower than room temperature, and the magnetic nanoparticles have a magnetocaloric action, whereby the magnetic nanoparticles are ferromagnetic at room temperature and paramagnetic at high temperatures, and have a Curie temperature lower than a superheating temperature of a heating element of an electrical appliance. 8. The magnetic liquid metal thermal switch according to claim 7, wherein the gravitational force of the magnetic liquid metal droplet is lower than a magnetic attraction force, and wherein the magnetic liquid metal droplet is adapted to be simultaneously connected to the top-connected positive electrode and the top-connected negative electrode or to the bottom-connected positive electrode and the bottom-connected negative electrode. 9. The magnetic liquid metal thermal switch according to claim 8, wherein the external circuit comprises an upper external circuit and a lower external circuit, wherein the upper external circuit and the lower external circuit are each provided with an external wire, an external power supply and an electric appliance, wherein a first end of the external wire is connected to the external power supply, and the other end of the external wire is connected to the electric appliance by means of the upper positive wire, the upper connecting positive electrode, the magnetic liquid metal droplet, the upper connecting negative electrode and the upper negative wire, or by means of the lower positive wire, the lower connecting positive electrode, the magnetic liquid metal droplet, the lower connecting negative electrode and the lower negative wire in succession. 10. A method for protecting a bidirectional circuit, wherein protecting bidirectional circuit feedback is achieved using the magnetic liquid metal thermal switch according to any one of claims 1 to 9.