JPS6245611Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electric water heater that has the function of heating water in a container to boil water.

Conventional structure and problems Generally, tap water contains chlorine called chlorine, inorganic ions, trihalomethane, which is said to be carcinogenic, and carbon dioxide gas.
It is known that there is a risk of health problems and that when used in coffee, tea, etc., if they are not removed, the taste will be significantly degraded. This limescale, trihalomethane, carbon dioxide gas, etc. are removed when the water is boiled, so it is desirable to use a water heater that has the function of boiling.

A conventional electric water heater will be described below with reference to the drawings.

FIG. 1 shows a conventional electric water heater. Reference numeral 51 denotes a cylindrical container with a bottom, which has a band-shaped heating element 52 wrapped around the lower part of the side surface with a heat generating element held therein by a holding member 52a having good thermal conductivity such as aluminum, and has a recess 51a in the center of the bottom surface. Said container 5
An automatic temperature regulator 53 is thermally attached to the back surface of the recess 51a at the center of the bottom surface of the heating element 1, and this automatic temperature regulator 53 is connected in series with the heating element 52.

The operation of the electric water heater configured as above will be explained below.

First, when water is placed in the container 51 and electricity is started, the water in the container 51 is heated by heat from the heating element 52 and boils after a predetermined period of time. Due to the stirring action of the water at this time, the temperature of the water in the recess 51a on the bottom of the container rises rapidly, operating the automatic temperature regulator 53 and cutting off the power supply to the heating element 52.

However, in the above-described configuration, when the amount of water falls below the upper end surface of the heating element 52, the temperature of the heating element 52 during boiling becomes extremely high, and the holding member 52a formed of aluminum or the like softens due to the heat. This may cause the heating element 52 to shift or expose the live parts.

In addition, the recess 51a on the bottom of the container 51 had to be deep and relatively small in diameter to prevent hot water from flowing in due to convection until boiling.
The processing difficulty was high and the cost was increasing.

Furthermore, water contains components such as calcium, and if used for a long period of time, it will stick to the surface of the container 51, but since the recess 51a has a small diameter and is formed deep, it is difficult to clean. Fixed calcium and the like cannot be removed, thus preventing heat conduction to the automatic temperature regulator 53 and delaying its operation. This not only reduces the durability of the heating element 52 and each component, but also poses a safety problem.

Purpose of the invention In view of the above-mentioned drawbacks, the present invention aims to provide an inexpensive and highly reliable electric water heater with improved safety of the heating element, ease of cleaning the inside of the container, and excellent boiling detection accuracy.

Structure of the Invention In order to achieve this object, the electric water heater of the invention includes a container for storing liquid, and a heating element attached to the back side of a heat conductive member that seals the bottom of the container and has a protrusion at approximately the center. , an automatic temperature regulator thermally pressed and held on the back surface of the concave groove formed by the heat conductive member and the side surface of the container, and an overtemperature rise prevention device thermally pressed and held on the substantially central back surface of the heat conductive member. With this structure, it is possible to easily form a concave groove in the heating element and the bottom side of the container that can detect sudden changes in water temperature during boiling on the bottom of the container that the automatic temperature controller contacts, and Cleanability and detection accuracy are improved, and the device can be made inexpensive and highly reliable.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

2 to 4 show an electric water heater according to a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a cylindrical exterior body, on which a spout 2 is placed at the opening at its upper end, and a base 3 is integrally mounted at its lower end. Reference numeral 4 denotes a handle rotatably attached to both outer sides of the spout body 2. Reference numeral 5 denotes a lid body which covers the spout body 2 so as to be openable and closable, and has a steam release passage, and is configured to be attached to and detached from the spout body 2 by pressing a lock knob b provided on the front surface thereof. be. Reference numeral 7 denotes a heat conductive member with good thermal conductivity, which has a central protruding portion 7a and an outer peripheral flange portion 7b, and its upper end flange portion is fixed to the spout body 2 by liquid-tight welding to the base metal or the like. It is fixed to the lower end of a cylindrical container 8. 9 is a heat generating element sandwiched between insulating plates such as mica, which is housed inside the central protrusion 7a of the heat conductive member 7, and has a through hole in the center;
It has a built-in main heat generating section 9a and an auxiliary heat generating section 9b. 10
is a heat diffusion member made of a metal with good thermal conductivity such as aluminum whose top surface contacts the lower part of the heat generating element 9, and the outer surface of the side wall surface 10a is in contact with the inner wall surface of the central protrusion 7a of the heat conduction member 7. Contact, through hole 1 in the center
0b, and has a notch 10c on the side. Reference numeral 11 denotes a back member having a protrusion 11a that contacts the inner surface of the heat diffusion member 10, has a through hole in the center, and has a center plane 11c and an outer peripheral plane 11d welded to the heat conduction member 7, respectively. The heat generating element 9 and the heat diffusion member 10 are held in a strongly compressed state, and the heat generating element 12
forming the whole. 13 is the heat conductive member 7
This is a concave groove formed by the central protruding part 7a, the outer peripheral flange part 7b, and the lower side surface of the container 8.
is thermally pressed and held by the first pressing spring 15. Notch 10c of the heat diffusion member 10
is provided near this main automatic temperature controller 14. Reference numeral 17 denotes an overtemperature rise prevention device that is thermally pressed and held by a mounting spring 19 via a mounting member 18 on the central back surface of the heat conductive member 7 forming the heat generating element 12. 20 is a heat shield plate installed below the heating element 12, and 21 is an auxiliary automatic temperature regulator that is thermally pressed and held on the back surface of the outer peripheral flange portion 7b of the heat conductive member 7 by a second pressing spring 22. , a heat diffusion member 10 is extended nearby.

As shown in FIG. 5, the electric circuit configuration connects the main heat generating part 9a and the main automatic temperature controller 14 in series,
The auxiliary heat generating section 9b and the auxiliary automatic temperature controller 21 are connected in series, connected in parallel, and connected to a power source via the electric circuit of the overtemperature rise prevention device 17.

Next, the operation of the above configuration will be explained. When the container 8 is filled with water and energized, the heat generating element 9 is heated, and the heat on the top surface is transferred to the water through the heat conduction member 7, and at the same time, the heat on the back surface is transferred from the top surface of the heat diffusion member 10 to the side wall surface 10a. The heat is transmitted to the wall surface of the protrusion 7a of the heat conduction member 7 that is in contact with the heat conduction member 7, thereby heating the water. The heat transferred to the back member 11 is transferred to the central plane 11c and the outer peripheral plane 11d, which are welded to the heat conductive member 7, and is used to heat the water, starting to boil water. Since the heating element 12 is attached to the bottom of the container 8, the water in the container 8 is heated at the bottom and rises, and the cold water at the top descends and is heated by so-called convection, but the water near the water surface is heated. The temperature at the bottom becomes slightly higher than the temperature at the bottom, and the water begins to boil. 6th
The figure shows changes in the temperature rise of water. The water temperature at the approximate center of the water contained in the container 8 is assumed to be 40a, and the water temperature above the main automatic temperature controller 14 in the concave groove 13 on the bottom of the container 8 is defined as 40a. 40b. As explained above, the water temperature near the water surface and the water temperature near the bottom have a temperature difference from the water temperature 40a at the center, but the temperature rises with almost the same change. The water temperature in the concave groove 13 on the bottom of the container 8 has a low rate of drop of water heated by convection. 40a, the supply of heat is small and the temperature rise is flat compared to 40a. However, as the boiling process progresses and boiling begins, stirring of the water due to boiling also begins, the flow of water near the wall of the container 8 becomes more intense, and the water temperature 40b in the recessed groove 13 on the bottom of the container 8 also rises rapidly. Almost at the same time, the temperature of the outer peripheral flange portion 7b of the heat conductive member 7 also rises, and the temperature of the temperature sensing portion 14a of the main automatic temperature regulator 14 provided on the back surface thereof also rises rapidly. In other words, the water temperature at approximately the center is 40a.
The temperature D of the temperature sensor 14a when the water starts boiling (point c) is, for example, 80°C, and the maximum boiling time of water is from point C to point E, where the temperature of the temperature sensor 14a is unstable, for example, 2 minutes. Then, the temperature F of the temperature sensing portion 14a at point E is, for example, 92°C. That is, if the operating temperature of the main automatic temperature controller 14 is set within the range of approximately 80°C to 92°C, which is the temperature of the temperature sensor 14a, the water contained in the container 8 will be boiled for 2 minutes or less. Afterwards, the main automatic temperature controller 14 operates to cut off the power supply to the main heat generating section 9a. The auxiliary automatic temperature controller 21 has a heat diffusion member 10 nearby.
Because the water is extended, there is a lot of heat conduction, and the water temperature in the recessed groove 13 rises almost the same as the water temperature 40a in the center.If the operating temperature is set to 100°C or less, the water will start operating before boiling. , the power supply to the auxiliary heating section 9b is cut off.

Next, when the water temperature drops to a predetermined temperature, the auxiliary automatic temperature controller 21 operates to close the circuit, and only the auxiliary heating section 9b is energized, heating the water using much less power than when boiling water. This heating progresses and the water temperature rises, opening the circuit and cutting off the power to the auxiliary heat generating section 9b. By repeating this process, the water temperature is kept at a constant temperature. Note that the operating temperature range of the auxiliary automatic temperature controller 21 is narrower than that of the main automatic temperature controller 14, and the OFF point is set at almost the same operating temperature, so normally the water temperature is lower than that of the auxiliary automatic temperature controller 14. The temperature will not drop below the ON point 21, and the main automatic temperature controller 14 will not be turned ON again and the boiling operation will not be repeated. However, when the heated water is discharged to a certain level or more and the water is supplied again, the water temperature drops below the ON operating temperature of the main automatic temperature controller 14, and the above operation is repeated again and after boiling for a certain period of time, It is kept warm.

Further, in the above explanation, the amount of water is almost full, but even if the amount of water is small, the boiling time will be shorter, and although the boiling time will be slightly longer, the basic operation will remain the same.

Also, if you accidentally turn on electricity without putting water into the container 8, the heat generating element 9 will be heated, and the heat on the top surface will be directly transmitted to the container 8.
The heat on the back surface is transferred to the heat conduction member 7 via the heat diffusion member 10 and the back surface member 11, and the temperature sensing part 17a of the temperature overrise prevention device 17 attached to the center back surface of the heat conduction member 7 is suddenly heated. Raise it up, operate it, and cut off the power supply.

As described above, according to this embodiment, the heating element is formed of a heating element that seals the bottom of the container and is held between the back surface of the heat conductive member having a protrusion at approximately the center, the heat diffusion member, and the back surface member. , by thermally pressing and holding an automatic temperature regulator on the back surface of the recessed groove formed by the heat conductive member and the side surface of the container, and providing a notch on the side wall surface of the heat diffusion member near the automatic temperature regulator, By reducing the conduction of heat from the heating element to the bottom surface of the recessed groove, which is the sensing surface of the automatic temperature controller, boiling can be detected more reliably.Furthermore, by changing the size of this notch, boiling time can be reduced. settings can be changed.

In addition, in this embodiment, the auxiliary automatic temperature controller 21
was brought into contact with the flat surface of the outer periphery flange portion 7b of the heat conduction member 7, and the heat diffusion member 10 was extended and placed near the auxiliary automatic temperature regulator 21. The temperature of the hot water in this portion may be made almost the same as that in the substantially central portion of the container 8, and the member extending to the vicinity of the auxiliary automatic temperature controller 21 may be the back member 11 or the heat shield plate 20.

Furthermore, as shown in FIG. 7, if the second recess 23 is shallowly formed on the surface in contact with the main automatic temperature controller 14, the convection can be further delayed, and it goes without saying that boiling can be detected more reliably.

Effects of the Invention As is clear from the above description of the embodiments, the present invention provides a heating element at the bottom of the container, seals the bottom of the container with the heat conducting member of the heating element, and forms a recess with the side surface of the container and the heat conducting member. By forming a groove, installing an automatic temperature controller on the back side of this recessed groove, and installing an overtemperature rise prevention device on the back side in the approximate center of the heat conductive member, the contact area between the heating element and water is the same even when the amount of water is small. Therefore, the temperature of the heating element does not rise above the temperature that would cause problems, making it safe.

In addition, since the recessed groove at the bottom of the container is formed by the side surface of the container and a heat conductive member that seals the bottom of the container, it is possible to easily form a deep shape that prevents convection, reducing processing costs. Since the concave groove is formed in a circular shape at the bottom of the container, it is easy to clean, and the concave groove, which is the detection part, can always be maintained in its initial state. Therefore, boiling detection accuracy can be improved, carbon dioxide, chloride, trihalomethane, etc. in water can be reliably removed, and the durability of the heating element and various parts can also be improved.

In addition, even during dry energization, since the overtemperature rise prevention device is provided on the back surface of the heat conductive member of the heating element, the power supply can be quickly cut off, resulting in high safety.

Furthermore, since all electrical components are concentrated at the bottom of the container, not only is it possible to reduce assembly man-hours, but also when forming a vacuum layer on the outer surface of the container or wrapping heat insulating material, it is possible to It can be extended to the lower part of the container, improving heat retention performance, and its practical value is extremely great.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of a conventional electric water heater, Fig. 2 is a partially cutaway side view of an electric water heater showing an embodiment of the present invention, and Fig. 3 is a sectional view of the same essential parts. ,
Fig. 4 is a perspective view of the heat diffusion member, Fig. 5 is the electric circuit diagram, Fig. 6 is a characteristic diagram showing the water temperature and temperature change of the temperature sensing section, and Fig. 7 is another embodiment of the present invention. FIG. 7... Heat conduction member, 8... Container, 9... Heat generating element, 10... Heat diffusion member, 11... Back member, 1
2... Heating element, 13... Recess, 14... Main automatic temperature controller, 17... Temperature overrise prevention device.

Claims (1)

[Scope of claims for utility model registration] (1) A container for storing a liquid, a container with a bottom sealed,
a heating element mounted on the back surface of a heat conductive member having a protrusion at approximately the center; an automatic temperature regulator thermally held under pressure on the back surface of a groove formed by the heat conductive member and the side surface of the container; An electric water heater characterized in that it has a temperature overheat prevention mounting that is thermally pressed and held on the central back surface of the heat conductive member, and the temperature regulator and the temperature overheat prevention mounting are connected in series. (2) The electric water heater according to claim 1 of the utility model registration, characterized in that a second recess is provided in the groove of the heat conductive member, and an automatic temperature regulator is provided in the second recess. (3) The heating element consists of a heating element held between the back surface of the heat conduction member, the heat diffusion member, and the back member, and the heat diffusion member has a notch formed in the side wall surface of the heat diffusion member near the automatic temperature controller. Claims 1 or 2 of claims for utility model registration characterized by
Electric water heater as described in section.