CN219368013U - Dry heating prevention heating system and electric water heater - Google Patents

Abstract

The utility model relates to an anti-dry heating system and an electric water heater, and belongs to the technical field of electric appliances. Comprising the following steps: the device comprises a floater, a liner, a floater limiting mechanism, a proximity switch and a heating device; the proximity switch is arranged at the top of the inner container, the float limiting mechanism is arranged in the inner container, and the float limiting mechanism is positioned below the proximity switch; the floater is provided with a magnet, and the floater limiting mechanism is connected with the floater in a sliding manner along the vertical direction; the lifting of the floater controls the lifting of the magnet so as to control the on-off of the proximity switch; the proximity switch is connected with the heating device, and the heating device is used for heating the inner container. The application can judge whether the water in the product is full of water and then heated. The risk of dry burning of the product is avoided, the risk of serious accidents of the product is reduced, and the safety performance is greatly improved.

Description

Dry heating prevention heating system and electric water heater

Technical Field

The application belongs to the technical field of electric appliances, and particularly relates to an anti-dry heating system and an electric water heater.

Background

With the continuous improvement of the production technology level and the continuous increase of the demand of users, the demand of users for electric water heaters is also increasing. The instant electric water heater is widely used in kitchens or toilets because it can rapidly prepare hot water.

The electric water heater in the prior art mainly comprises an inner container, a water inlet pipe, a water outlet pipe and a heating device, wherein the heating device heats the inner container through an electromagnetic coil. The current solution is generally flowing water, and heating is started regardless of whether the water inside the heater is full.

The quick-heating electric water heater has a small product volume, and the instantaneous heating of water is needed, so that the surface load of the heater tube is higher. The inner container of the electric water heater cannot bear dry burning, once the electric water heater is dry-burned, the product is damaged, and the product is leaked when the electric water heater is heavy, so that the safety of a user is threatened.

Disclosure of Invention

The application provides an anti-dry heating system and an electric water heater, which are used for solving the problems that in the prior art, the electric water heater is dry-heated to damage products or cause product leakage due to the fact that water is not full, an inclined test is carried out, or water inlet and outlet pipes are reversely assembled.

In a first aspect, an anti-dry heat heating system includes: the device comprises a floater, a liner, a floater limiting mechanism, a proximity switch and a heating device; the proximity switch is arranged at the top of the inner container, the float limiting mechanism is arranged in the inner container, and the float limiting mechanism is positioned below the proximity switch; the floater is provided with a magnet, and the floater limiting mechanism is connected with the floater in a sliding manner along the vertical direction; the lifting of the floater controls the lifting of the magnet and controls the on-off of the proximity switch; the proximity switch is connected with the heating device, and the heating device is used for heating the inner container.

In the above optional technical solution, the float limiting mechanism is a cylinder, and the float is located inside the cylinder; the cylinder is fixedly connected with the inner wall of the liner, an opening is formed in the bottom of the cylinder, the top of the floater extends outwards to form a clamping part, and the clamping part is clamped with the side wall of the cylinder; the distance between the top of the floater and the top of the liner is smaller than the height of the floater.

In the above alternative solution, the diameter length of the opening is equal to the diameter length of the float.

In the above-mentioned optional technical scheme, float stop gear is including setting up the vertical spout of inner bag lateral wall, float lateral wall fixedly connected with slider, slider and vertical spout are in vertical direction sliding connection, the both ends of vertical spout are provided with the stop part that is used for stopping the slider landing.

In the above-mentioned optional technical scheme, the inner bag top is provided with the mount pad, proximity switch is located the mount pad.

In the above-mentioned optional technical scheme, still include the inlet tube, the inlet tube with the inner bag is connected, the inlet tube is provided with the flow switch who is used for controlling heating device break-make.

In the above optional technical scheme, the water outlet pipe is connected with the liner, and the water outlet pipe is provided with a temperature sensor for measuring the temperature of the water outlet.

In the above-mentioned optional technical scheme, the top of inner bag still is provided with the temperature controller, the temperature controller is connected with heating device, the temperature-sensing district of temperature controller with the laminating of inner bag top.

In the above alternative solution, the magnet is disposed on top of the float.

In a second aspect, the present embodiment further provides an electric water heater, which includes the dry combustion preventing system of the first aspect.

It can be appreciated by those skilled in the art that the embodiments of the present application provide an anti-dry heating system and an electric water heater, including a float, a liner, a float limiting mechanism, a proximity switch, and a heating device; the proximity switch is arranged at the top of the inner container, the float limiting mechanism is arranged in the inner container, and the float limiting mechanism is positioned below the proximity switch; the floater is provided with a magnet, and the floater limiting mechanism is connected with the floater in a sliding manner along the vertical direction; the lifting of the floater controls the lifting of the magnet and controls the on-off of the proximity switch; the proximity switch is connected with the heating device, and the heating device is used for heating the inner container. When the inner container of the electric water heater is filled with water, the floater is close to the proximity switch along with the rising of the water level, after the water in the inner container is filled, the floater is positioned at the top of the inner container, at the moment, the magnet in the floater is positioned in the conduction range of the proximity switch, and the proximity switch is turned on, so that the heating device is turned on to heat the water. Because the float rises along with the rise of the water level in the liner, when the water in the liner is full, the float is positioned at the top of the liner, and the heating device is turned on at the moment, otherwise, the heating device cannot be turned on to heat, so that the condition that the electric water heater is dry-burned due to the fact that the water is not filled is effectively avoided, products are protected, and the safety of users is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic structural diagram of an anti-dry heating system provided in the present application;

fig. 2 is a schematic diagram of an overall structure of an electric water heater provided in the present application;

FIG. 3 is a schematic diagram illustrating the installation of a flow switch and a temperature sensor of an electric water heater according to the present disclosure;

FIG. 4 is an exploded view of an anti-dry heat heating system provided herein;

FIG. 5 is a top cross-sectional view of a float limiting mechanism of an anti-dry heat heating system provided herein;

fig. 6 is a side cross-sectional view of a float limiting mechanism of an anti-dry heat heating system provided herein.

Reference numerals illustrate: 100-inner container; 200-water inlet pipe; 300-a water outlet pipe; 400-float limiting mechanism; 410-vertical sliding grooves; 420-a slider; 430-a barrier; 500-temperature controller; 600-float; 610-magnet; 700-proximity switch; 800-a temperature sensor; 900-flow switch.

Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application, and it is apparent that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein.

In the embodiments of the present application, words such as "exemplary" or "such as" are used to mean examples, illustrations, or descriptions. Any embodiment or design described herein as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

In the description of the embodiments of the present application, it should be understood that the terms "inner," "outer," "upper," "bottom," "front," "rear," and the like indicate orientations or positional relationships, if any, based on those shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

As described in the background art, the electric water heater in the prior art mainly comprises an inner container, a water inlet pipe, a water outlet pipe and a heating device, and the heating device heats the inner container through an electromagnetic coil. The current solution is generally flowing water, and heating is started regardless of whether the water inside the heater is full. The quick-heating electric water heater has a small product volume, and the instantaneous heating of water is needed, so that the surface load of the heater tube is higher. The inner container of the electric water heater cannot bear dry burning, once the electric water heater is dry-burned, the product is damaged, and the product is leaked when the electric water heater is heavy, so that the safety of a user is threatened.

The application provides an anti-dry heating system and an electric water heater, which are used for solving the problems that in the prior art, the electric water heater is dry-heated to damage products or cause product leakage due to the fact that water is not full, an inclined test is carried out, or water inlet and outlet pipes are reversely assembled.

As shown in fig. 1, fig. 1 is a schematic structural diagram of an anti-dry heating system provided in the present application, including: float 600, liner 100, float limiting mechanism 400, proximity switch 700, and heating device; the proximity switch 700 is arranged at the top of the liner 100, the float limiting mechanism 400 is arranged in the liner 100, and the float limiting mechanism 400 is positioned below the proximity switch 700; a magnet 610 is disposed on the float 600, and the float limiting mechanism 400 is slidably connected with the float 600 along a vertical direction; the lifting control magnet 610 of the float 600 lifts to control the on-off of the proximity switch 700; the proximity switch 700 is connected to the heating device, and the heating device is used for heating the liner 100.

Illustratively, the float 600 may be made of a high temperature resistant 304 stainless steel material, and a plastic foam is embedded in the outer shell, so that the float is effectively prevented from being corroded, and the service life is prolonged.

For example, the float 600 may also be a PP float resistant to high temperatures, and resistant to corrosion by acids, bases, salt solutions, and various organic solvents at temperatures below 80 ℃. Since the temperature in the inner container 100 does not exceed 80 c, the safety standard of installation is met.

Illustratively, the liner 100 is a plastic liner or a stainless steel liner, and it should be noted that the stainless steel liner is made of a non-magnetic stainless steel material, and may be martensitic stainless steel or austenitic stainless steel.

Illustratively, the magnets 610 herein are permanent magnets that are cylindrical magnets or square magnets to facilitate installation into the float 600.

In the liner 100 using the metal liner body, corrosion is likely to occur in the liner 100 due to the influence of water quality, and for this purpose, a magnesium rod may be disposed and inserted into the liner 100.

Since magnesium is the lowest potential metal in the electrochemical sequence, it is physiologically non-toxic. Therefore, the magnesium rod protective liner is very ideal to be used for manufacturing the magnesium rod protective liner. The size of the magnesium rod is directly related to the time of protecting the liner and the protecting effect, and the larger the magnesium rod is, the better the protecting effect is and the longer the protecting time is.

Illustratively, the top of the liner 100 is detachably connected with the liner body of the liner 100, so as to facilitate maintenance of the liner 100 and installation of the floating ball 600.

Illustratively, the proximity switch 700 employs a reed switch.

The reed switch structure is that two magnetic reeds are sealed in a glass tube, and the magnetic reeds are usually composed of two metals of iron and nickel; inert gas (such as nitrogen) is arranged in the glass tube, and the two magnetic reeds are overlapped, but a small gap is arranged between the two magnetic reeds, which is only a few micrometers. The contacts on the two magnetic reeds are plated with hard metals, usually rhodium and ruthenium, which greatly improves the switching times and the product life.

The magnetic reed acts as a magnetic flux conductor. When not operated, the two reeds are not contacted; when the magnetic field generated by the permanent magnet or the electromagnetic coil is applied, the magnetic field causes the two leaf springs to generate different polarities near the end points, and when the magnetic force exceeds the elasticity of the spring, the two leaf springs can attract and conduct a circuit; when the magnetic field is reduced or eliminated, the dry reed is released due to its elasticity, and the contact surfaces are separated to open the circuit.

Compared with a common mechanical switch, the reed switch has the advantages of simple structure, small volume, high speed and long service life; compared with electronic switch, it has the characteristics of strong load impact resistance and high working reliability.

The basic principle in this embodiment is that when the magnet 610 in the float 600 approaches the reed pipe under the action of the buoyancy of the float 600, the magnetic reeds in the reed pipe are magnetized under the action of the magnet 610, and the parts of the magnetic reeds at the two ends, which are close to each other, are contacted by attraction of the different-name magnetic poles, so that the reed pipe is conducted, and the heating device is turned on. When the water level in the liner 100 drops, the magnet 610 in the float 600 also drops, and when the magnet 610 is far away from the reed pipe, the magnetism of the magnetic reed disappears, and the two magnetic reeds are separated due to elasticity, so that the reed pipe is disconnected, and the heating device stops working.

The heating device comprises an electric heating tube and a control panel, wherein the control panel is mainly used for receiving signals and controlling the electric heating tube to be opened and closed, and the electric heating tube stretches into the liner 100 to heat water.

In this embodiment, in order to improve the heating efficiency of water, the electrothermal tube may be configured in a spiral shape or a serpentine shape, and this is achieved by increasing the contact area between the electrothermal tube and water.

In this embodiment, after the water in the liner 100 is filled, the float 600 is located at the top of the liner 100, and at this time, the magnet 610 in the float 600 is located in the conducting range of the proximity switch 700, and the proximity switch 700 is turned on, so that the heating device is turned on to heat the water. Because the float 600 rises along with the rise of the water level in the liner 100, when the water in the liner 100 is full, the float 600 is positioned at the top of the liner 100, and the heating device is turned on at the moment, otherwise, the heating device cannot be turned on to heat, so that the condition that the electric water heater is dry-burned due to the fact that the water is not filled fully is effectively avoided, products are protected, and the safety of users is improved.

In the above-mentioned alternative solution, as shown in fig. 4, fig. 4 is an exploded view of an anti-dry heating system provided in the present application; the float limiting mechanism 400 is a cylinder, and the float 600 is positioned in the cylinder; the cylinder is fixedly connected with the inner wall of the liner 100, an opening is formed in the bottom of the cylinder, the top of the floater extends outwards to form a clamping part, and the clamping part is clamped with the side wall of the cylinder; the distance between the top of the float 600 and the top of the liner 100 is smaller than the height of the float 600.

Illustratively, the float 600 is spherical or cylindrical in shape, and the float 600 can slide up and down in the cylinder without being able to move left and right. The float 600 is guaranteed to be positioned at the sensing position of the proximity switch 700 after being lifted to the top of the liner 100, and the problem of sensing failure caused by the movement of the float 600 above the water surface is avoided. The size of the cylinder is adapted to the size of the float 600 and can be designed according to the actual installation requirements.

It should be noted that since the float 600 needs to slide up and down inside the cylinder, care should be taken in design to ensure that the float 600 does not slide out of the cylinder while sliding within the cylinder.

In view of the above, this embodiment proposes an implementation manner, in which a clamping portion is disposed at the top of the float, and the clamping portion is located at a position on the side wall of the float 600 near the top, where the float 600 clamps the float 600 during the sliding process, so that the float 600 does not slide into the cylinder entirely or slide out of the cylinder from the lower end of the cylinder.

Illustratively, the clip and float 600 are integrally formed.

In order to prevent the float 600 from sliding out of the sensing range of the proximity switch from the lifting space between the top of the inner container 100 and the cylinder during the lifting of the float 600, the height of the lifting space between the top of the cylinder and the top of the inner container 100 should be smaller than the height of the float 600.

This design employed in this embodiment ensures that the float 600 does not slip out of the barrel, i.e., that the magnet 610 can always be within the sensing area of the proximity switch during lifting. In the design of this mode, only the position of the cylinder is required to be welded, and then the cylinder is directly put into the floater 600 and covered with the top cover of the liner 100, so that the installation is simple and convenient.

In the above alternative, the diameter length of the opening is equal to the diameter length of the float 600. The water level in the cylinder is guaranteed to be parallel or close to the water level of the liner 100 in the water level rising process, and the heating device is started to heat at the first time when the liner 100 is filled with water.

In another embodiment, the top of the cylinder may be connected to the top of the liner 100, and the inside of the cylinder may be used as a lifting space for the float 600, so that the top and bottom of the cylinder may be covered without providing a locking portion on the float 600.

This approach requires that the cartridge be provided with a notch for ingress and egress of water, in which the size of the notch is smaller than the diameter of the float 600, ensuring that the float 600 is inside the cartridge and does not flow out of the notch. .

In the above-mentioned embodiments, it should be noted that, when the float 600 is mounted, it is necessary to ensure that the float 600 is located at the top of the cylinder within the sensing range of the proximity switch and at the bottom outside the sensing range of the proximity switch.

In the above-mentioned alternative technical solution, the present utility model further proposes another design scheme of the float limiting mechanism 400, as shown in fig. 5 and 6, and fig. 5 is a top cross-sectional view of a float limiting mechanism of an anti-dry heating system provided in the present application; fig. 6 is a side cross-sectional view of a float limiting mechanism of an anti-dry heat heating system provided herein. Specifically, the float limiting mechanism 400 includes a vertical chute 410 disposed on a side wall of the liner 100, a slider 420 is fixedly connected to the side wall of the float 600, the slider 420 is slidably connected to the vertical chute 410 in a vertical direction, and blocking portions 430 for blocking the slider 420 from sliding are disposed at two ends of the vertical chute 410.

In the above technical solution, the vertical chute 410 is connected with the liner 100 by welding, the cross section of the vertical chute 410 is concave, the notch of the slide block 420 is located in the vertical chute 410, the notch of the vertical chute extends toward the middle, and the formed extension part is used for clamping the slide block 420, so that the slide block 420 is ensured to slide in the chute of the vertical chute 410, and in this embodiment, the slide block 420 is ensured to slide up and down only.

In the above technical solution, since the sliding block 420 may slide out from two ends of the vertical sliding slot 410, and in order to facilitate the taking out and placing of the sliding block 420, two ends of the vertical sliding slot 410 are provided with the blocking portions 430, the blocking portions 430 and the vertical sliding slot 410 are in openable connection or snap connection.

In the above technical solution, the blocking portion 430 is connected with the vertical chute 410 in an openable manner, one end of the blocking portion 430 is hinged with the vertical chute 410, the other end is in threaded connection with the vertical chute 410, and the vertical chute 410 is opened by one end in threaded connection, so as to realize the taking out and placing of the slider 420.

In the above technical solution, the blocking portion 430 is connected to the vertical chute 410 in a snap-fit manner, two ends of the blocking portion 430 are respectively connected to the vertical chute 410 through a snap-fit manner, and the snap-fit connection manner is conventional in the art, which is not described in detail in this embodiment.

In this embodiment, since the two ends of the vertical chute 410 are both provided with the blocking portions 430, for convenience in installation, the blocking portions 430 at the lower end may be fixedly connected, and the upper ends may be connected by a buckle or may be connected in an openable manner, and these three connection manners may be freely combined under the condition of ensuring that the slider 420 is taken out and placed.

In the above technical solution, the movement of the float 600 is limited by the slider 420 in the vertical chute 410, and when the water level in the liner 100 rises, the float 600 moves up and down along the vertical chute 410 under the action of the buoyancy, thereby realizing the on and off of the proximity switch 700.

By adopting the float limiting mechanism 400, the float 600 is ensured to be consistent with the water level in the liner 100, so that the proximity switch is opened at the first time of filling the water level, and the response time of the proximity switch is improved.

In the above alternative solution, a mounting seat is provided at the top of the liner 100, and the proximity switch 700 is located in the mounting seat.

The mount pad is a box body, and bottom and the top fixed connection of inner bag 100, proximity switch 700 is located the mount pad inside, and the mount pad is used for protecting proximity switch.

In the above-mentioned alternative solution, as shown in fig. 3, fig. 3 is a schematic installation diagram of a flow switch and a temperature sensor of an electric water heater provided in the present application, and further includes a water inlet pipe 200, where the water inlet pipe 200 is connected to the liner 100, and the water inlet pipe 200 is provided with a flow switch 900 for controlling on-off of a heating device.

The water inlet pipe 200 is used for conveying cold water to the liner 100 and is connected with the bottom of the side wall of the liner 100. The flow switch 900 is a water flow sensor, and is mainly used for monitoring whether water flows through the water inlet pipe and controlling the heating device to be turned on or off.

In the above optional solution, the water outlet pipe 300 is further included, the water outlet pipe 300 is connected to the liner 100, and the water outlet pipe 300 is provided with a temperature sensor 800 for measuring a water outlet temperature.

The water outlet pipe 300 is used for outputting hot water and is connected with the bottom of the liner 100. The temperature sensor 800 is a thermosensitive temperature sensor, and after sensing that the water reaches the set temperature, the heating device is controlled to reduce the power, and the water outlet temperature is kept at the set temperature.

In the above-mentioned optional technical solution, the top of the liner 100 is further provided with a temperature controller 500, the temperature controller 500 is connected with a heating device, and a temperature sensing area of the temperature controller 500 is attached to the top of the liner 100.

When the flow switch, the float switch and the temperature sensor fail, the temperature controller 500 is disconnected after sensing that the temperature at the top of the liner reaches the preset temperature, and the heating device stops heating.

In the alternative, the magnet 610 is disposed on the top of the float 600. The induction strength of the magnet 610 and the proximity switch 700 is improved.

The embodiment also provides an electric water heater, as shown in fig. 2, fig. 2 is a schematic diagram of an overall structure of the electric water heater provided by the application, where the electric water heater includes the dry heating preventing system described above.

Illustratively, an insulation layer is disposed at a gap between the casing of the electric water heater and the liner 100 to prevent heat loss of the liner 100.

The heat insulation materials commonly used for the heat insulation layer are as follows: asbestos, sponge, foam, polyurethane foam, etc., and in order to obtain a good heat-insulating effect, in the conventional technology, a heat-insulating layer is usually formed by adopting a foaming mode.

The casing is also provided with a control device for receiving detection signals sent by related sensors (such as a water temperature sensor and a flow sensor) and controlling the electric heating component to be powered on and powered off.

The housing is also provided with a display device for displaying the temperature, the working state and the like of the electric water heater. The control device and the display device belong to a relatively mature prior art, and the embodiment is not described in detail.

For example, the electric water heater housing is generally made of plastic materials to meet design requirements of attractive and diversified shapes.

The working principle of the electric water heater is that a floater 600 is additionally arranged in a heating body of the quick-heating type water heater, a proximity switch 700 is arranged at the top of a liner 100, when no water exists, the floater 600 sinks, the proximity switch 700 is disconnected, a product has no connection signal, and a heating device is closed; when the inside is filled with water, the floater 600 is lifted, after reaching a designated height, the proximity switch 700 is closed by a signal, a product is connected by a signal, and the heating device can heat; the water inlet pipe 300 is provided with a flow switch 900, when water flows, signals are obtained, and the product can be heated; the water outlet pipe 300 is provided with a temperature sensor 800, when the water outlet reaches the set temperature, the heating device reduces the power and keeps the water outlet temperature at the set temperature, the top of the liner 100 is also provided with a temperature controller 500 (when the flow switch, the float switch and the temperature sensor fail), and when the surface temperature of the top of the liner 100 reaches the preset temperature, the temperature controller 500 is disconnected, so that the product safety is ensured.

The electric water heater in the application can judge whether the water in the product is full of water and then is heated. The risk of dry burning of the product is avoided, the risk of serious accidents of the product is reduced, and the safety performance is greatly improved.

While the technical solutions of the present application have been described with reference to the optional embodiments shown in the drawings, it will be readily understood by those skilled in the art that the scope of the present application is not limited to these specific embodiments, and the above examples are only for illustrating the technical solutions of the present application, not limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A dry heat prevention heating system, comprising: the device comprises a floater, a liner, a floater limiting mechanism, a proximity switch and a heating device;

the proximity switch is arranged at the top of the inner container, the float limiting mechanism is arranged in the inner container, and the float limiting mechanism is positioned below the proximity switch;

the floater is provided with a magnet, and the floater limiting mechanism is connected with the floater in a sliding manner along the vertical direction;

the lifting of the floater controls the lifting of the magnet so as to control the on-off of the proximity switch;

the proximity switch is connected with the heating device, and the heating device is used for heating the inner container.

2. The anti-dry heating system of claim 1, wherein the float limiting mechanism comprises a barrel, the float being located inside the barrel;

the cylinder is fixedly connected with the inner wall of the liner, an opening is formed in the bottom of the cylinder, the top of the floater extends outwards to form a clamping part, and the clamping part is clamped with the side wall of the cylinder; the distance between the top of the floater and the top of the inner container is smaller than the height of the floater.

3. The dry heat protection system of claim 2, wherein the opening has a diameter equal to the diameter of the float.

4. The dry heating prevention system according to claim 1, wherein the float limiting mechanism comprises a vertical chute arranged on the side wall of the inner container, the side wall of the float is fixedly connected with a sliding block, the sliding block is in sliding connection with the vertical chute in the vertical direction, and blocking parts for blocking the sliding block from sliding off are arranged at two ends of the vertical chute.

5. The dry heating prevention system of claim 1, wherein the top of the liner is provided with a mounting seat, and the proximity switch is positioned in the mounting seat.

6. The dry heating prevention system of claim 1, further comprising a water inlet pipe connected to the inner container, the water inlet pipe being provided with a flow switch for controlling on-off of the heating device.

7. The dry heating prevention system of claim 6, further comprising a water outlet pipe connected to the inner container, the water outlet pipe being provided with a temperature sensor for measuring a temperature of the water outlet.

8. The dry heating prevention system of claim 7, wherein a temperature controller is further arranged at the top of the inner container, the temperature controller is connected with the heating device, and a temperature sensing area of the temperature controller is attached to the top of the inner container.

9. The anti-dry heating system as set forth in any one of claims 1 to 8, wherein the magnet is disposed on top of the float.

10. An electric water heater comprising the anti-dry heating system of any one of claims 1-9.