CN215175966U

CN215175966U - Heating device of electric water heater and electric water heater

Info

Publication number: CN215175966U
Application number: CN202121130305.6U
Authority: CN
Inventors: 金胜昔; 张志华; 汤亮; 杨鹏; 张瑞; 曾森
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-05-25
Filing date: 2021-05-25
Publication date: 2021-12-14
Anticipated expiration: 2031-05-25

Abstract

The application relates to a heating device of an electric water heater and the electric water heater, the device comprises a heating element and a heating control circuit, the heating element is arranged between an inner box body and an outer box body of the electric water heater, and the inner box body is used for storing water; the heating control circuit comprises a gear adjusting circuit and a driving circuit, the gear adjusting circuit is connected with the driving circuit, and the driving circuit is connected with the heating element. The drive circuit can be controlled by the gear adjusting circuit to drive the heating element to work, water and electricity are separated and heated, the electric shock risk is reduced, and the use safety of the electric water heater is effectively improved.

Description

Heating device of electric water heater and electric water heater

Technical Field

The application relates to the technical field of electrical equipment, in particular to an electric water heater heating device and an electric water heater.

Background

With the development of science and technology and the continuous progress of society, more and more electrical equipment appears in the daily work and life of people. Water heaters in the market at present mainly comprise gas water heaters, solar water heaters and electric water heaters, and the electric water heaters are prone to potential safety hazards of electric shock in the heating process and suffer from scaling.

The traditional electric water heater is mainly heated by an electric heating rod, and in the heating process, the electric heating rod converts electric energy into heat energy. The heating mode is high in heating efficiency, but water and electricity are not separated in the heating process, so that in the process of long-term use of the electric water heater, scales are attached to the heating rod due to the fact that scales such as calcium carbonate exist in water, when the scales are attached to the heating rod more and the heating rod is damaged due to poor heat dissipation, alternating current can be directly connected into the water, and when a user installs the electric water heater at home, the electric water heater is poor in grounding, and at the moment, the electric water heater is dangerous to get an electric shock. The traditional electric water heater heating mode has the defect of low use safety.

SUMMERY OF THE UTILITY MODEL

Therefore, it is necessary to provide a heating device of an electric water heater and an electric water heater to solve the problem of low safety of the conventional electric water heater, so as to effectively improve the safety of the electric water heater.

A heating device of an electric water heater comprises a heating element and a heating control circuit, wherein the heating element is arranged between an inner box body and an outer box body of the electric water heater, and the inner box body is used for storing water; the heating control circuit comprises a gear adjusting circuit and a driving circuit, the gear adjusting circuit is connected with the driving circuit, and the driving circuit is connected with the heating element.

In one embodiment, the gear adjusting circuit comprises a knob switch and a switch control component, the driving circuit comprises a driving switch, the knob switch is connected with the switch control component, the switch control component is connected with the driving switch, and the driving switch is connected with the heating element.

In one embodiment, the switch control assembly comprises a switch tube, a pull-up resistor and a current-limiting resistor, wherein a control end of the switch tube is connected with the knob switch and is connected with a power end through the pull-up resistor, an input end of the switch tube is connected with the power end through the current-limiting resistor, and an output end of the switch tube is connected with the driving switch.

In one embodiment, the number of the heating elements is two or more, the number of the switch control assemblies is two or more, the number of the driving switches is the same as that of the switch control assemblies, each switch control assembly is connected with the knob switch and is respectively connected with a control part of one driving switch, one end of a controlled part of each driving switch is connected with a live wire, and the other end of the controlled part of each driving switch is respectively connected with the corresponding heating element.

In one embodiment, the switch control assembly comprises a first switch control assembly, a second switch control assembly and a third switch control assembly, and the driving switch comprises a driving switch S2, a driving switch S3 and a driving switch S4;

the first switch control assembly is connected with the control part of the driving switch S2 and the knob switch, one end of the controlled part of the driving switch S2 is connected with a live wire, and the other end of the controlled part is connected with a corresponding heating element; the second switch control assembly is connected with the control part of the driving switch S3 and the knob switch, one end of the controlled part of the driving switch S3 is connected with a live wire, and the other end of the controlled part is connected with a corresponding heating element; the third switch control assembly is connected with the control part of the driving switch S4 and the knob switch, one end of the controlled part of the driving switch S4 is connected with the live wire, and the other end of the controlled part is connected with the corresponding heating element.

In one embodiment, the heating elements include a heating lamp U, a heating lamp U2, a heating lamp U3, and a heating lamp U4, and the driving circuit further includes an auxiliary switch S6;

one end of a controlled part of the driving switch S2 is connected with a live wire, the other end of the controlled part is connected with the input end of the heating lamp U2, the output end of the heating lamp U2 is connected with the input end of the heating lamp U1, and the output end of the heating lamp U1 is connected with a zero line; one end of a controlled part of the driving switch S3 is connected with a live wire, the other end of the controlled part is connected with the input end of the heating lamp U3, the output end of the heating lamp U3 is connected with the input end of the heating lamp U4, and the output end of the heating lamp U4 is connected with a zero line; one end of the controlled part of the driving switch S4 is connected with a live wire, and the other end is connected with the common end of the heating lamp U2 and the heating lamp U1; the control part of the auxiliary switch S6 is connected with the second switch control assembly, one end of the controlled part of the auxiliary switch S6 is connected with the common end of the driving switch S2 and the heating lamp U2, and the other end of the controlled part of the auxiliary switch S6 is connected with the common end of the driving switch S3 and the heating lamp U3.

In one embodiment, the heating control circuit further comprises a heating control circuit main switch, and the controlled part of each driving switch is connected with the live wire through the heating control circuit main switch.

In one embodiment, the heating control circuit further comprises a fuse, and the heating control circuit main switch is connected with a live wire through the fuse.

An electric water heater comprises a water tank and the electric water heater heating device, wherein the water tank comprises an outer box body and an inner box body, the heating element is arranged between the inner box body and the outer box body of the electric water heater, and the inner box body is used for storing water.

In one embodiment, the electric water heater further comprises a reflective coating disposed on the inner wall of the outer box.

According to the heating device of the electric water heater and the electric water heater, the heating element is arranged between the inner box body and the outer box body of the electric water heater, and the inner box body is used for storing water. The drive circuit can be controlled by the gear adjusting circuit to drive the heating element to work, water and electricity are separated and heated, the electric shock risk is reduced, and the use safety of the electric water heater is effectively improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a block diagram of a heating device of an electric water heater according to an embodiment;

FIG. 2 is a schematic diagram of a heating control circuit in one embodiment;

FIG. 3 is a schematic diagram of a water tank of the electric water heater according to an embodiment;

FIG. 4 is a schematic view of a water tank of an electric water heater in another embodiment;

FIG. 5 is a schematic view of a water tank of an electric water heater according to another embodiment;

FIG. 6 is a flow diagram of the heating control of the electric water heater in one embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. The first resistance and the second resistance are both resistances, but they are not the same resistance.

It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" and "including," or "having," etc., specify the presence of stated features, integers, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, operations, components, parts, or groups thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.

In one embodiment, as shown in fig. 1, there is provided a heating device of an electric water heater, which comprises a heating element 200 and a heating control circuit, wherein the heating element is arranged between an inner box and an outer box of the electric water heater, and the inner box is used for storing water. The heating control circuit comprises a gear adjusting circuit 110 and a driving circuit 120, wherein the gear adjusting circuit 110 is connected with the driving circuit 120, and the driving circuit 120 is connected with the heating element 200.

The number of the heating elements 200 can be one or more, the water tank of the electric water heater is designed into a double-layer structure of an inner tank body and an outer tank body, the inner tank body is used for storing water and preserving heat, and the heating elements 200 are arranged between the inner tank body and the outer tank body. The state of the driving circuit 120 is controlled by the gear adjusting circuit 110, so that the driving circuit 120 controls the heating element 200 to heat the water in the inner box body, and the heating gear can be adjusted according to actual requirements. It is understood that when the number of the heating elements 200 is plural, the plural heating elements 200 may be disposed at different positions, and the driving circuit 120 controls the corresponding number of the heating elements 200 to operate according to the instruction of the step adjustment circuit 110, so as to realize the heating step adjustment. In addition, when the number of the heating elements 200 is one, the driving circuit 120 may also adjust the voltage and current output to the heating elements 200 according to the instruction of the gear adjusting circuit 110, so as to change the heating power of the heating elements 200, and also achieve the heating gear adjustment.

The installation position of the heating element 200 is not exclusive, and specifically, a plurality of heating elements 200 may be disposed on the inner walls of the opposite sides of the outer case, a plurality of heating elements 200 may be disposed on the inner walls of the top of the outer case, or the heating elements 200 may be disposed on the inner walls of both the top and sides of the outer case. The specific type of heating element 200 is also not exclusive and may be a heating lamp, heating plate, or the like. In one embodiment, the heating element 200 is a far infrared heating lamp, which is also called a super bath lamp, and heats water by radiating far infrared rays, and water in the inner tank is heated by vigorous movement of water molecules by the far infrared rays. The heating mode of the bath heater is applied to the heating process of the electric water heater, and the heating element 200 is more convenient to replace.

In the heating device of the electric water heater, the heating element 200 is disposed between the inner box and the outer box of the electric water heater, and the inner box is used for storing water. The drive circuit 120 can be controlled by the gear adjusting circuit 110 to drive the heating element to work, so that water and electricity are separated and heated, the electric shock risk is reduced, and the use safety of the electric water heater is effectively improved.

In one embodiment, as shown in FIG. 2, the range adjustment circuit 110 includes a knob switch S5 and a switch control assembly, and the driving circuit 120 includes a driving switch, the knob switch S5 is connected to the switch control assembly, the switch control assembly is connected to the driving switch, and the driving switch is connected to the heating element 200. The user' S accessible changes knob switch S5 gear to make the switch control assembly switch on, the switch control assembly controls drive switch closure when switching on, inserts outside commercial power and supplies power for heating element 200. The specific structure of the switch control assembly is not exclusive, and in one embodiment, the switch control assembly includes a switch tube, a pull-up resistor and a current-limiting resistor, a control end of the switch tube is connected to the knob switch S5 and is connected to a power supply end through the pull-up resistor, an input end of the switch tube is connected to the power supply end through the current-limiting resistor, and an output end of the switch tube is connected to the driving switch.

Further, in one embodiment, the number of the heating elements 200 is two or more, the number of the switch control assemblies is two or more, the number of the driving switches is the same as that of the switch control assemblies, each switch control assembly is connected to the knob switch S5 and is connected to the control portion of one driving switch, one end of the controlled portion of each driving switch is connected to the live wire, and the other end of the controlled portion of each driving switch is connected to the corresponding heating element 200. Specifically, different ports of the knob switch S5 may be connected to the switch control assemblies, respectively, and the gear of the knob switch S5 is changed to control the corresponding switch control assembly to be turned on, so as to close the corresponding driving switch. After the driving switch is closed, the mains supply is connected to supply power to the connected heating element 200. The user can be according to actual demand control corresponding heating element 200 work, conveniently heats the gear and adjusts.

In one embodiment, with continued reference to fig. 2, the switch control assembly includes a first switch control assembly 112, a second switch control assembly 114, and a third switch control assembly 116, and the drive switches include a drive switch S2, a drive switch S3, and a drive switch S4. The first switch control assembly 112 is connected with the control part of the driving switch S2 and the knob switch S5, one end of the controlled part of the driving switch S2 is connected with the live wire L, and the other end is connected with the corresponding heating element 200; the second switch control assembly 114 is connected with the control part of the driving switch S3 and the knob switch S5, one end of the controlled part of the driving switch S3 is connected with the live wire L, and the other end is connected with the corresponding heating element 200; the third switch control assembly 116 is connected to the control part of the driving switch S4 and the knob switch S5, and one end of the controlled part of the driving switch S4 is connected to the live wire L, and the other end is connected to the corresponding heating element 200. The driving switch S2, the driving switch S3, and the driving switch S4 may specifically adopt relays, coils of the relays are used as a control portion, contact switches of the relays are used as a controlled portion, one end of each coil of each relay is connected to a corresponding switch control assembly, and the other end of each coil is grounded. The on-off states of the three driving switches are controlled by the three switch control assemblies, so that the corresponding heating elements 200 are controlled to work, the electric water heater can be heated in three different states, and different heating requirements are met.

Specifically, also taking as an example that the switch control component includes a switch tube, a pull-up resistor and a current-limiting resistor, as shown in fig. 2, the first switch control component 112 includes a switch tube Q1, a pull-up resistor R1 and a current-limiting resistor R4, a control end of the switch tube Q1 is connected to the knob switch S5 and is connected to the power supply terminal VDD through the pull-up resistor R1, an input end of the switch tube Q1 is connected to the power supply terminal VDD through the current-limiting resistor R4, and an output end of the switch tube Q1 is connected to the control part of the driving switch S2. The second switch control assembly 114 comprises a switch tube Q2, a pull-up resistor R2 and a current-limiting resistor R5, wherein the control end of the switch tube Q2 is connected with the knob switch S5 and is connected with a power supply end VDD through the pull-up resistor R2, the input end of the switch tube Q2 is connected with the power supply end VDD through the current-limiting resistor R5, and the output end of the switch tube Q2 is connected with a control part of the driving switch S3. The third switch control assembly 116 includes a switch tube Q3, a pull-up resistor R3 and a current-limiting resistor R6, wherein the control end of the switch tube Q3 is connected to the knob switch S5 and is connected to the power supply terminal VDD through the pull-up resistor R3, the input end of the switch tube Q3 is connected to the power supply terminal VDD through the current-limiting resistor R6, and the output end of the switch tube Q3 is connected to the control part of the driving switch S4.

The power supply terminal VDD is + 5V. The switching tube Q1, the switching tube Q2, and the switching tube Q3 may be transistors or MOS transistors, in this embodiment, the switching tube Q1, the switching tube Q2, and the switching tube Q3 are all NPN-type transistors, a base of the transistor is used as a control terminal, a collector of the transistor is used as an input terminal, and an emitter of the transistor is used as an output terminal. Specifically, the knob switch S5 may include three switches, one end of each switch is connected to the output terminals of the switch tube Q1, the switch tube Q2 and the switch tube Q3, and the other end of each switch is grounded. The user can control the on-off of the switch tube Q1, the switch tube Q2 and the switch tube Q3 by changing the on-off states of different switches in the knob switch S5, and further change the on-off states of the drive switch S2, the drive switch S3 and the drive switch S4.

Further, in one embodiment, the heating element 200 includes a heat lamp U1, a heat lamp U2, a heat lamp U3, and a heat lamp U4, and the driving circuit further includes an auxiliary switch S6. One end of a controlled part of the driving switch S2 is connected with the live wire L, the other end of the controlled part is connected with the input end of the heating lamp U2, the output end of the heating lamp U2 is connected with the input end of the heating lamp U1, and the output end of the heating lamp U1 is connected with the zero line N; one end of a controlled part of the driving switch S3 is connected with the live wire L, the other end of the controlled part is connected with the input end of the heating lamp U3, the output end of the heating lamp U3 is connected with the input end of the heating lamp U4, and the output end of the heating lamp U4 is connected with the zero line N; one end of a controlled part of the driving switch S4 is connected with the live wire L, and the other end is connected with the common end of the heating lamp U2 and the heating lamp U1; the control part of the auxiliary switch S6 is connected with the second switch control assembly 114, one end of the controlled part of the auxiliary switch S6 is connected with the common end of the driving switch S2 and the heating lamp U2, and the other end of the controlled part of the auxiliary switch S6 is connected with the common end of the driving switch S3 and the heating lamp U3.

The auxiliary switch S6 may also be a relay, a coil of the relay is used as a control unit, and a contact switch is used as a controlled unit. Specifically, one end of the coil of the relay is connected to the output end of the switch Q2 in the second switch control component 114, and the other end of the coil of the relay is grounded. The heating lamp U1, the heating lamp U2, the heating lamp U3 and the heating lamp U4 are all far infrared heating lamps. The heating lamps U1, U2, U3, and U4 may be a single heating lamp or an integrated structure in which two or more heating lamps are connected in series.

In addition, in one embodiment, as shown in fig. 2, the heating control circuit further includes a heating control circuit main switch S1, and the controlled part of each driving switch is connected to the live line L through the heating control circuit main switch S1. The heating control circuit main switch S1 is used as a heating control main switch, and a user can perform power switch control on the electric heater through the heating control circuit main switch S1. Further, in one embodiment, the heating control circuit further comprises a fuse tube X1, and the heating control circuit main switch S1 is connected to the live line L through the fuse tube X1.

In one embodiment, an electric water heater is further provided, which comprises a water tank and the heating device of the electric water heater, wherein the water tank comprises an outer box body and an inner box body, the heating element is arranged between the inner box body and the outer box body of the electric water heater, and the inner box body is used for storing water. As shown in fig. 3, the inner box 3 is disposed inside the outer box 1, and the heating element is specifically a bathroom heater lamp 2. The inner box body 3 is also provided with a water inlet 4 and a water outlet 5. Specifically, the super bath lamps 2 may be disposed at opposite sides of the inner case 3, as shown in fig. 3 and 4. The bathroom heater lamp 2 may be disposed on the upper side of the inner box 3 as shown in fig. 5. It is understood that in other embodiments, the bathroom heater lamps 2 may be disposed on the upper side and opposite sides of the inner box 3.

Furthermore, in one embodiment, the electric water heater further comprises a reflective coating disposed on the inner wall of the outer case 1. The water in the inner box body 3 is heated again by reflecting the far infrared light through the reflecting coating, so that the energy utilization rate is improved.

In the electric water heater, the heating element is arranged between the inner box body 3 and the outer box body 1 of the electric water heater, and the inner box body 3 is used for storing water. The drive circuit can be controlled by the gear adjusting circuit to drive the heating element to work, water and electricity are separated and heated, the electric shock risk is reduced, and the use safety of the electric water heater is effectively improved.

In order to better understand the heating device and the electric water heater, the following detailed explanation is made in conjunction with specific embodiments.

The application provides a new heating method of electric water heater, with the in-process of the heating of electric water heater is applied to the heating method of bathroom heater, make electric water heater heating safer to it is more simple and convenient to change heating element. Specifically, as shown in fig. 2 to 5, the electric water heater includes:

1. the outer box of water tank: the inner wall is coated with a coating layer reflecting far infrared light.

2. Bathroom heater lamp: it also acts as a far infrared lamp, radiating far infrared rays and heating water.

3. A water tank inner box body: storing and maintaining the water, and heating the water molecules by violent movement under the action of far infrared light.

4. Water inlet: and an external cold water inlet position.

5. Water outlet: the hot water outlet position of the water tank.

6. R1-R6: and (4) resistance.

7. X1: and a protective tube.

8. Q1-Q3: the switch tube specifically adopts a triode and has a switch control function in the circuit.

9. S1: a heating control circuit main switch.

10. S2-S4, S6: the driving switch and the auxiliary switch specifically adopt a relay to control the on-off of the far infrared lamp.

11. S5: the knob switch controls the heating mode of the electric water heater.

12. U1-U4: the heating lamp is a far infrared lamp.

The relay S2 is connected with one lamp on each side of the box in the figures 3 and 4 or one half lamp on the upper side of the box in the figure 5, the relay S3 is connected with and controls all the lamps, and the relay S4 is connected with one lamp in the figures 3 and 4 or two lamps on the upper side of the box in the figure 5.

The water tank box includes: the inner wall of the outer box body is coated with a reflective coating and is used for placing a far infrared lamp; inner box, water storage. The far infrared lamp of outer box launches the far infrared, and the water absorption far infrared of inner box, thereby the hot motion aggravation of molecule is heated to the reflective coating of outer water tank retrains far infrared light in the water tank the inside, reduces the thermal radiation energy and scatters and disappears, and inside and outside water tank has realized the water and electricity separation, avoids the potential safety hazard of electric leakage. The knob switch S5 is used to implement the selection of the heating mode of the water tank, the far infrared lamps U1-U4 are used to radiate far infrared light, and the water in the water tank is subjected to the temperature rise by the far infrared light.

As shown in fig. 6, the electric water heater operates according to the following principle:

when the electric water heater works, a far infrared lamp is adopted to heat water based on a bathroom heater heating mode. When the water heater heats water, the far infrared lamp is electrified to radiate far infrared rays, and electric energy is converted into light energy. When the radiation wavelength of the far infrared ray is consistent with the receiving wavelength of the water molecules, the water molecules absorb the energy of the far infrared ray, and the internal movement of the water molecules is intensified, so that the water temperature is increased.

The electric water heater in the application is divided into three working modes in total during heating, wherein the working modes comprise a heat preservation mode, a heating mode and a full-power heating mode. When the knob switch S5 is switched to the heat preservation mode, the relay S4 is closed, the relays S2, S3 and S6 are disconnected, the far infrared lamp U1 starts to work, and the electric water heater works in the low-power mode; when the knob switch S5 is switched to a heating mode, the relay S2 is closed, the relays S4, S3 and S6 are disconnected, and the electric water heater works in a medium-power mode, so that the electric water heater is suitable for heating water without too high temperature and water temperature, has relatively long heating time and is relatively energy-saving; when the knob switch S5 is switched to the full-power heating mode, the relays S3 and S6 are closed, the relays S2 and S4 are disconnected, all the infrared heating lamps are turned on at the moment, and the water temperature of the electric water heater is heated fastest.

When the heating control circuit main switch S1 is disconnected, the electric water heater is turned off. The electric water heater adopts water-electricity separation, and the water tank box has the two-stage structure, can avoid because the incrustation scale accumulation, thereby heating element heat dissipation is not damaged the hidden danger of electric leakage well to heating element adopts infrared lamp heating, and it is more convenient to change the maintenance.

Above-mentioned electric water heater utilizes far infrared heating temperature through changing heating element into far infrared heating lamp to carry out the inside and outside separation of water tank box, realize the water and electricity separation, avoid the potential safety hazard of electric shock, simultaneously because heating element changes into far infrared heating lamp, it is more convenient to make the maintenance change.

In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A heating device of an electric water heater is characterized by comprising a heating element and a heating control circuit, wherein the heating element is arranged between an inner box body and an outer box body of the electric water heater, and the inner box body is used for storing water; the heating control circuit comprises a gear adjusting circuit and a driving circuit, the gear adjusting circuit is connected with the driving circuit, and the driving circuit is connected with the heating element.

2. The heating device of claim 1, wherein the gear adjusting circuit comprises a knob switch and a switch control component, the driving circuit comprises a driving switch, the knob switch is connected with the switch control component, the switch control component is connected with the driving switch, and the driving switch is connected with the heating element.

3. The heating device of claim 2, wherein the switch control assembly comprises a switch tube, a pull-up resistor and a current-limiting resistor, the control end of the switch tube is connected to the knob switch and connected to the power source through the pull-up resistor, the input end of the switch tube is connected to the power source through the current-limiting resistor, and the output end of the switch tube is connected to the driving switch.

4. The heating device of the electric water heater according to claim 2 or 3, wherein the number of the heating elements is two or more, the number of the switch control components is two or more, the number of the driving switches is the same as that of the switch control components, each switch control component is connected with the knob switch and is respectively connected with a control part of the driving switch, one end of a controlled part of each driving switch is connected with a live wire, and the other end of the controlled part of each driving switch is respectively connected with the corresponding heating element.

5. The heating device of claim 4, wherein the switch control assembly comprises a first switch control assembly, a second switch control assembly and a third switch control assembly, the driving switch comprises a driving switch S2, a driving switch S3 and a driving switch S4;

6. The heating device of claim 5, wherein the heating element comprises a heat lamp U1, a heat lamp U2, a heat lamp U3 and a heat lamp U4, the driving circuit further comprises an auxiliary switch S6;

7. The heating device of claim 4, wherein the heating control circuit further comprises a heating control circuit main switch, and the controlled part of each driving switch is connected with a live wire through the heating control circuit main switch.

8. The heating device of claim 7, wherein the heating control circuit further comprises a fuse, and the heating control circuit main switch is connected to a live wire through the fuse.

9. An electric water heater comprising a water tank and the heating device of any one of claims 1-8, wherein the water tank comprises an outer casing and an inner casing, the heating element is disposed between the inner casing and the outer casing of the electric water heater, and the inner casing is used for storing water.

10. The electric water heater of claim 9, further comprising a reflective coating disposed on an inner wall of the outer box.