阅读说明：本技术 燃气热水器及其控制方法 (Gas water heater and control method thereof ) 是由 刘宁 詹雄 王志昂 张果 赖煜华 薛婷婷 于 2021-08-25 设计创作，主要内容包括：本发明涉及燃气热水器技术领域,公开了一种燃气热水器及其控制方法,包括：换热器；盘管,缠绕在换热器上；进水管和出水管,进水管和出水管均与盘管密封连通；旁通排水管,与出水管密封连通；第一电磁阀,设置在进水管上并能控制进水管的通断；第二电磁阀,设置在出水管上并能控制出水管的通断；第三电磁阀,设置在旁通排水管上并能控制旁通排水管的通断；进水温度传感器,设置在进水管上；环境温度传感器,用于检测环境温度；以及控制器,控制器分别与第一电磁阀、第二电磁阀、第三电磁阀、进水温度传感器以及环境温度传感器电连接。该燃气热水器具有有效地防止冬季温度过低冻裂水管,避免漏水、漏电等的不良后果的优点。(The invention relates to the technical field of gas water heaters, and discloses a gas water heater and a control method thereof, wherein the gas water heater comprises the following steps: a heat exchanger; the coil pipe is wound on the heat exchanger; the water inlet pipe and the water outlet pipe are both communicated with the coil pipe in a sealing way; the bypass water outlet pipe is communicated with the water outlet pipe in a sealing way; the first electromagnetic valve is arranged on the water inlet pipe and can control the on-off of the water inlet pipe; the second electromagnetic valve is arranged on the water outlet pipe and can control the on-off of the water outlet pipe; the third electromagnetic valve is arranged on the bypass drain pipe and can control the on-off of the bypass drain pipe; the inlet water temperature sensor is arranged on the water inlet pipe; an ambient temperature sensor for detecting an ambient temperature; and the controller is respectively and electrically connected with the first electromagnetic valve, the second electromagnetic valve, the third electromagnetic valve, the water inlet temperature sensor and the environment temperature sensor. The gas water heater has the advantages of effectively preventing the freezing and cracking of the water pipe due to the over-low temperature in winter and avoiding the adverse consequences of water leakage, electric leakage and the like.)

1. A gas water heater, comprising:

a heat exchanger;

a coil pipe wound around the heat exchanger;

the water inlet pipe and the water outlet pipe are both communicated with the coil pipe in a sealing way;

the bypass water outlet pipe is communicated with the water outlet pipe in a sealing way;

the first electromagnetic valve is arranged on the water inlet pipe and can control the on-off of the water inlet pipe;

the second electromagnetic valve is arranged on the water outlet pipe and can control the on-off of the water outlet pipe;

the third electromagnetic valve is arranged on the bypass drain pipe and can control the on-off of the bypass drain pipe;

the inlet water temperature sensor is arranged on the water inlet pipe;

an ambient temperature sensor for detecting an ambient temperature; and

and the controller is electrically connected with the first electromagnetic valve, the second electromagnetic valve, the third electromagnetic valve, the water inlet temperature sensor and the environment temperature sensor respectively.

2. The gas water heater of claim 1, further comprising a gas water heater housing, the heat exchanger and the ambient temperature sensor both disposed within the gas water heater housing;

the gas water heater also comprises a combustion chamber, and the combustion chamber is arranged below the heat exchanger.

3. The gas water heater of claim 2, wherein a fan is disposed above the heat exchanger for drawing hot gas from the combustion chamber from bottom to top through the heat exchanger.

4. The gas water heater of claim 2, wherein the bypass drain is disposed outside of the gas water heater housing.

5. The gas water heater of claim 2, further comprising a gas tube opening into the combustion chamber.

6. The gas water heater of claim 5, wherein a gas proportional valve is provided at the inlet end of the gas pipe.

7. A control method of a gas water heater based on any one of the above claims 1 to 6, characterized by comprising:

respectively acquiring the current environment temperature and the water inlet temperature;

comparing the current environment temperature with an environment temperature set value, and simultaneously comparing the current water inlet temperature with a water inlet temperature set value;

if the current environment temperature is lower than the set value of the environment temperature and the water inlet temperature is lower than the set value of the water inlet temperature, starting anti-freezing protection;

the first electromagnetic valve and the second electromagnetic valve are controlled to be closed so that the water inlet pipe and the water outlet pipe are cut off, and the third electromagnetic valve is controlled to be opened so that water is discharged from the bypass water discharging pipe.

8. The control method of a gas water heater according to claim 7, further comprising: and after the water is drained from the bypass drain pipe for a first preset time, closing the third electromagnetic valve.

9. The control method of the gas water heater according to claim 7, wherein the gas water heater is powered off, the first solenoid valve and the second solenoid valve are controlled to be closed to intercept the water inlet pipe and the water outlet pipe, and the third solenoid valve is controlled to be opened to promote the water to be discharged from the bypass water discharge pipe.

10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of the control method of a gas water heater according to any one of claims 7 to 9 when executing said program.

11. A non-transitory computer readable storage medium having a computer program stored thereon, wherein the computer program when executed by a processor implements the steps of the control method of a gas water heater according to any one of claims 7 to 9.

Technical Field

The invention relates to the technical field of gas water heaters, in particular to a gas water heater and a control method thereof.

Background

The gas water heater is one of household appliances commonly used in daily life, wherein the gas water heater or other types of water heaters are usually installed outdoors, and when the outdoor temperature is low in winter, the water tank may leak water due to frost cracking. Secondly, because of unstable power supply, the water heater is suddenly powered off, so that the water heater cannot judge the environmental temperature in time and cannot start the anti-freezing function in time, and the water pipe of the water heater is easy to crack and leak water.

Therefore, the water leakage caused by frost cracking of the water tank still exists in winter due to untimely starting of the anti-freezing protection function of the water heater or other reasons. Meanwhile, it is a relatively safe way to let the user drain the water in the water tank by himself, but the user often misses a proper time for draining because of lack of related knowledge or because of delayed treatment, and finally the water tank is frozen and cracked. Therefore, the actual conditions of the user cannot be fully considered in the water heater, and therefore the anti-freezing effect of the water heater cannot be guaranteed.

Disclosure of Invention

Therefore, the invention aims to solve the technical problem of overcoming the defect that the water pipe is frozen and cracked due to the fact that water in the water pipe on the water heater cannot be discharged in time when the outdoor temperature of the water heater in winter is low and the power is cut off suddenly in the prior art, and provides the gas water heater and the control method thereof.

According to a first aspect of the present invention, there is provided a gas water heater comprising: a heat exchanger; the coil pipe is wound on the heat exchanger; the water inlet pipe and the water outlet pipe are both communicated with the coil pipe in a sealing way; the bypass water outlet pipe is communicated with the water outlet pipe in a sealing way; the first electromagnetic valve is arranged on the water inlet pipe and can control the on-off of the water inlet pipe; the second electromagnetic valve is arranged on the water outlet pipe and can control the on-off of the water outlet pipe; the third electromagnetic valve is arranged on the bypass drain pipe and can control the on-off of the bypass drain pipe; the inlet water temperature sensor is arranged on the water inlet pipe; an ambient temperature sensor for detecting an ambient temperature; and the controller is respectively and electrically connected with the first electromagnetic valve, the second electromagnetic valve, the third electromagnetic valve, the water inlet temperature sensor and the environment temperature sensor.

The gas water heater also comprises a gas water heater shell, and the heat exchanger and the ambient temperature sensor are both arranged in the gas water heater shell; the gas water heater also comprises a combustion chamber, and the combustion chamber is arranged below the heat exchanger.

Wherein, a fan which can suck hot gas in the combustion chamber from bottom to top and pass through the heat exchanger is arranged above the heat exchanger.

Wherein the bypass drain pipe is disposed outside the gas water heater housing.

The gas water heater also comprises a gas pipe, and the gas pipe is communicated into the combustion chamber.

Wherein, the gas inlet end of the gas pipe is provided with a gas proportional valve.

According to a second aspect of the present application, there is also provided a control method of a gas water heater, including: respectively acquiring the current environment temperature and the water inlet temperature; comparing the current environment temperature with an environment temperature set value, and simultaneously comparing the current water inlet temperature with a water inlet temperature set value; if the current environment temperature is lower than the set value of the environment temperature and the water inlet temperature is lower than the set value of the water inlet temperature, starting anti-freezing protection; the first electromagnetic valve and the second electromagnetic valve are controlled to be closed so that the water inlet pipe and the water outlet pipe are cut off, and the third electromagnetic valve is controlled to be opened so that water is discharged from the bypass water discharging pipe.

The control method of the gas water heater further comprises the following steps: and after the water is drained from the bypass drain pipe for a first preset time, closing the third electromagnetic valve.

And when the gas water heater is powered off, the first electromagnetic valve and the second electromagnetic valve are controlled to be closed so that the water inlet pipe and the water outlet pipe are cut off, and the third electromagnetic valve is controlled to be opened so that water is discharged from the bypass water discharge pipe.

According to a third aspect of the present application, there is also provided an electronic device, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the control method of the gas water heater when executing the program.

According to a fourth aspect of the present application, there is also provided a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the control method of a gas water heater as described above.

Compared with the prior art, the gas water heater provided by the invention has the following advantages:

when the gas water heater is suddenly powered off or the environment temperature detected by the environment temperature sensor is lower than the set value of the environment temperature, and meanwhile, the water inlet temperature sensor detects that the water inlet temperature is lower than the set value of the water inlet temperature, the anti-freezing protection is started, namely, the first electromagnetic valve and the second electromagnetic valve are controlled to be closed so that the water inlet pipe and the water outlet pipe are cut off, and the third electromagnetic valve is controlled to be opened so as to promote water to be discharged from the bypass drain pipe. Therefore, the water inlet pipe or the water outlet pipe can be effectively prevented from being frozen and cracked due to the over-low temperature in winter, and the adverse effects of water leakage, electric leakage and the like are effectively avoided. Meanwhile, the experience of the user is greatly improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic view of the overall structure of a gas water heater according to an embodiment of the present invention;

FIG. 2 is a schematic view of the connection structure of the water inlet pipe, the coil pipe and the water outlet pipe in FIG. 1;

FIG. 3 is a flow chart illustrating the steps of a method for controlling a gas water heater according to an embodiment of the present invention;

FIG. 4 is a logic control diagram of a control method of a gas water heater of an embodiment of the present invention;

fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Description of reference numerals:

1: a heat exchanger; 2: a coil pipe; 3: a water inlet pipe; 4: a water outlet pipe; 5: a bypass drain pipe; 6: a first solenoid valve; 7: a second solenoid valve; 8: a third electromagnetic valve; 9: an inlet water temperature sensor; 10: an ambient temperature sensor; 11: a controller; 12: a gas water heater housing; 13: a combustion chamber; 14: a fan; 15: a gas pipe; 301: a processor; 302: a memory; 303: a communication interface; 304: a communication bus.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1 to 2, the gas water heater is schematically shown to include a heat exchanger 1, a coil 2, a water inlet pipe 3, a water outlet pipe 4, a bypass drain pipe 5, a first solenoid valve 6, a second solenoid valve 7, a third solenoid valve 8, an inlet water temperature sensor 9, an ambient temperature sensor 10, and a controller 11.

In the embodiment of the present application, the coil 2 is wound around the heat exchanger 1.

The water inlet pipe 3 and the water outlet pipe 4 are both communicated with the coil pipe 2 in a sealing way. Namely, the water inlet pipe 3 is communicated with the water inlet end of the coil pipe 2 in a sealing way, and the water outlet pipe 4 is communicated with the water outlet pipe of the coil pipe 2 in a sealing way.

The bypass drain pipe 5 is in sealed communication with the outlet pipe 4. It should be noted that a through hole (not shown) is formed in the outlet pipe 4, and the water inlet end of the bypass drain pipe 5 is inserted into and is in sealed communication with the through hole.

The first electromagnetic valve 6 is arranged on the water inlet pipe 3 and can control the on-off of the water inlet pipe 3.

The second electromagnetic valve 7 is arranged on the water outlet pipe 4 and can control the on-off of the water outlet pipe 4.

The third electromagnetic valve 8 is arranged on the bypass drain pipe 5 and can control the on-off of the bypass drain pipe 5.

The inlet water temperature sensor 9 is arranged on the inlet pipe 3.

The ambient temperature sensor 10 is used to detect the ambient temperature.

The controller 11 is electrically connected to the first solenoid valve 6, the second solenoid valve 7, the third solenoid valve 8, the incoming water temperature sensor 9 and the ambient temperature sensor 10, respectively. Specifically, when the gas water heater is suddenly powered off or when the ambient temperature detected by the ambient temperature sensor 10 is lower than the ambient temperature set value, and the incoming water temperature detected by the incoming water temperature sensor 9 is lower than the incoming water temperature set value, the anti-freeze protection is activated, that is, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed so as to block the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened so as to facilitate the water to be discharged from the bypass drain pipe 5. Therefore, the water inlet pipe 3 or the water outlet pipe 4 can be effectively prevented from being frozen and cracked due to the fact that the temperature is too low in winter, and therefore adverse effects of water leakage, electric leakage and the like are effectively avoided. Meanwhile, the experience of the user is greatly improved.

As shown in fig. 1, in a preferred embodiment of the present application, the gas water heater further comprises a gas water heater housing 12, the heat exchanger 1 and the ambient temperature sensor 10 both being disposed within the gas water heater housing 12. In this way, by disposing both the heat exchanger 1 and the ambient temperature sensor 10 in the gas water heater case 12, the purpose of reducing the occupied space can be achieved.

The gas water heater also comprises a combustion chamber 13, and the combustion chamber 13 is arranged below the heat exchanger 1. Specifically, by arranging the combustion chamber 13 below the heat exchanger 1, the hot air in the combustion chamber 13 will flow upward and heat the coil 2 in the heat exchanger 1, and by heating the coil 2, the water flowing through the coil 2 can be heated, thus achieving the purpose of supplying hot water to the user.

In a preferred embodiment of the present application, as shown in fig. 1, a fan 14 is further disposed above the heat exchanger 1, and the fan is capable of drawing hot gas in the combustion chamber 13 from bottom to top and passing through the heat exchanger 1. Specifically, the fan 14 is arranged to accelerate the flow of the hot gas released from the combustion chamber 13 toward the heat exchanger 1, thereby effectively improving the heat exchange efficiency of the heat exchanger 1 and accelerating the generation of hot water.

In a preferred embodiment of the present application, as shown in FIG. 1, the bypass drain 5 is disposed outside of the gas water heater housing 12. Therefore, the third electromagnetic valve 8 is convenient to open and close, so that when the power is cut off suddenly or the ambient temperature detected by the ambient temperature sensor 10 is lower than the ambient temperature set value, and meanwhile, when the water inlet temperature detected by the water inlet temperature sensor 9 is lower than the water inlet temperature set value, the anti-freezing protection is started, so that adverse consequences of water leakage, electric leakage and the like can be avoided effectively and timely. Meanwhile, the experience of the user is greatly improved.

In a preferred embodiment of the present application, as shown in fig. 1, the gas water heater further comprises a gas pipe 15, the gas pipe 15 opening into the combustion chamber 13. Specifically, by additionally providing the gas pipe 15, gas can be introduced into the gas pipe 15 to be combusted in the combustion chamber 13.

In a preferred embodiment of the present application, a gas proportional valve (not shown) is provided at the inlet end of the gas pipe 15. Specifically, the setting of gas proportional valve can control the air input of gas better, and control is more nimble.

As shown in fig. 3 and 4, according to a second aspect of the present invention, there is also provided a control method of a gas water heater, including:

in step S1, the current ambient temperature and the intake water temperature are acquired, respectively.

In step S2, the current ambient temperature is compared to the ambient temperature set point, and the current inlet water temperature is compared to the inlet water temperature set point.

In step S3, if the current ambient temperature is lower than the ambient temperature setting value and the incoming water temperature is lower than the incoming water temperature setting value, the anti-freeze protection is started.

In step S4, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to block the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass water discharge pipe 5. Specifically, after the gas water heater works for a period of time, the current ambient temperature and the water inlet temperature are respectively obtained. The current ambient temperature is compared to an ambient temperature set point, while the current inlet water temperature is compared to an inlet water temperature set point. And if the current environment temperature is lower than the environment temperature set value and the water inlet temperature is lower than the water inlet temperature set value, starting the anti-freezing protection. The first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to cut off the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass drain pipe 5. Therefore, the water pipe can be effectively prevented from being frozen and cracked due to the over-low temperature in winter, and adverse effects such as water leakage and electric leakage can be avoided.

In a preferred embodiment of the present application, the control method of the gas water heater further includes: after the water is drained from the bypass drain pipe 5 for a first preset time, the third solenoid valve 8 is closed. Specifically, if the current ambient temperature is lower than the ambient temperature set value and the inflow water temperature is lower than the inflow water temperature set value, the anti-freezing protection is started. That is, the third solenoid valve 8 is opened, the first solenoid valve 6 and the second solenoid valve 7 are closed, and when the water is drained for a first preset time, it indicates that the water in the pipeline is drained, and at this time, the third solenoid valve 8 may be closed.

In a preferred embodiment of the present application, the first preset time is preferably 10 seconds.

In a preferred embodiment of the present application, the gas water heater is powered off, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed so that the water inlet pipe 3 and the water outlet pipe 4 are intercepted, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass water discharge pipe 5. Specifically, after the gas water heater works for a period of time, if the gas water heater is suddenly powered off, the anti-freezing protection is started. The first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to cut off the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass drain pipe 5. Therefore, the water pipe can be effectively prevented from being frozen and cracked due to the over-low temperature in winter, and adverse effects such as water leakage and electric leakage can be avoided.

As shown in fig. 5, according to the third aspect of the present application, there is also provided an electronic device, which includes a memory 302, a processor 301, and a computer program stored on the memory 302 and executable on the processor 301, wherein the processor 301 implements the steps of the control method of the gas water heater according to the above-mentioned embodiment when executing the program.

The electronic device specifically comprises the following contents: a processor 301, a memory 302, a communication interface 303, and a communication bus 304.

The processor 301, the memory 302 and the communication interface 303 complete communication with each other through the communication bus 304.

The processor 301 is configured to call a computer program in the memory 302, and when the processor executes the computer program, the processor implements all the steps of the control method of the gas water heater, for example, when the processor executes the computer program, the processor implements the following processes:

in step S1, the current ambient temperature and the intake water temperature are acquired, respectively.

In step S2, the current ambient temperature is compared to the ambient temperature set point, and the current inlet water temperature is compared to the inlet water temperature set point.

In step S3, if the current ambient temperature is lower than the ambient temperature setting value and the incoming water temperature is lower than the incoming water temperature setting value, the anti-freeze protection is started.

In step S4, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to block the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass water discharge pipe 5.

According to a fourth aspect of the present invention, there is also provided a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements all the steps of the control method of a gas water heater according to the above embodiments, for example, the processor implements the following processes when executing the computer program: in step S1, the current ambient temperature and the intake water temperature are acquired, respectively.

In step S2, the current ambient temperature is compared to the ambient temperature set point, and the current inlet water temperature is compared to the inlet water temperature set point.

In step S3, if the current ambient temperature is lower than the ambient temperature setting value and the incoming water temperature is lower than the incoming water temperature setting value, the anti-freeze protection is started.

In step S4, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to block the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass water discharge pipe 5.

Furthermore, the logic instructions in the memory 302 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

In summary, when the gas water heater is suddenly powered off or when the ambient temperature detected by the ambient temperature sensor 10 is lower than the ambient temperature setting value, and the incoming water temperature detected by the incoming water temperature sensor 9 is lower than the incoming water temperature setting value, the anti-freeze protection is activated, that is, the first solenoid valve 6 and the second solenoid valve 7 are controlled to be closed to block the water inlet pipe 3 and the water outlet pipe 4, and the third solenoid valve 8 is controlled to be opened to facilitate the water to be discharged from the bypass drain pipe 5. Therefore, the water inlet pipe 3 or the water outlet pipe 4 can be effectively prevented from being frozen and cracked due to the fact that the temperature is too low in winter, and therefore adverse effects of water leakage, electric leakage and the like are effectively avoided. Meanwhile, the experience of the user is greatly improved.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.