JP4038945B2 - Electric water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric water heater for heating a liquid in a container.
[0002]
[Prior art]
Conventionally, the heat generating structure of this type of electric water heater generally has a structure as shown in FIGS. That is, reference numeral 1 denotes a container for storing a liquid. A container bottom plate 1a that forms the bottom of the container 1 has a recess 1b as viewed from the outside. A flat ring-shaped heating element 2 that heats the liquid in the container 1 when energized is stored in the recess 1b. An insulating plate 3 is made of mica or the like and insulates the heating element 2. Reference numeral 4 denotes a heat conducting plate disposed between the container bottom plate 1a and the heating element 2, which prevents the heat of the heating element 2 from being directly transmitted to the container bottom plate 1a and partially raising the temperature. Reference numeral 5 denotes a back plate having good heat conductivity disposed on the lower side of the heating element 2. Further, 6 is a fixing plate for fixing the heating element 2 and the like sandwiched between the container bottom plate 1a and the container bottom plate 1a. Here, the container bottom plate 1a is made of stainless steel of about 0.5 mm, and the heat conducting plate 4 is made of iron plate of about 0.3 mm, and its heat capacity is not large compared to the heat generation amount of the heating element 2.
[0003]
Reference numeral 7 denotes a detector such as a thermostat which is attached to the recess 1b and detects the temperature. A bimetal contact plate 7a is incorporated in the detector 7. Then, the heat of the heating element 2 is conducted from the outside of the detector 7 to the inside, whereby the contact plate 7a is warmed. When the temperature reaches a predetermined temperature, the contact is opened, the energization to the heating element 2 is cut off, and the heat generation stops.
[0004]
Next, the heat conduction of the heating structure of the electric water heater in the conventional example will be described. When liquid is put in the container 1, the heat generated when the heating element 2 is energized is transferred to the liquid through the insulating plate 3, the heat conducting plate 4, and the container bottom plate 1a, and the temperature of the liquid rises. To go. Then, as the temperature of the liquid rises, the detector 7 is also warmed, and when the liquid reaches a predetermined temperature, the contact of the detector 7 is opened and the power supply to the heating element 2 is stopped. At this time, the temperature of the container bottom plate 1a does not become high because the heat of the heating element 2 is transmitted to the liquid.
[0005]
[Problems to be solved by the invention]
However, in the above conventional configuration, when the heating element 2 is energized with no liquid in the container 1, the generated heat is transferred to the container bottom plate 1 a via the insulating plate 3 and the heat conduction plate 4. Since there is no liquid that conducts heat first and the heat capacity of the heat conducting plate 4 and the container bottom plate 1a is small, the temperature rises rapidly. At this time, the temperature of the outer shell of the detector 7 also rises, but since the temperature rise of the internal contact plate 7a is indirect, it is slower than the rise of the container bottom plate 1a. Therefore, when the contact plate 7a is warmed and the contact of the detector 7 is opened, the temperature of the container bottom plate 1a is excessively high, and the container bottom plate 1a is changed to brown or deformed. Further, when the inside of the container 1 is coated with fluorine, there is a problem that the fluorine is burnt by heat and becomes black or peels off.
[0006]
The present invention solves such a conventional problem, and even when the heating element is energized in the absence of water, the heat absorption plate absorbs the heat generated until the detector operates, thereby the temperature of the container bottom plate. The purpose is to protect the container from excessively rising.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a heat absorption plate that absorbs heat from a heat generating element and transfers heat to the heat conductive plate between the heat conductive plate and the heat generating element, and generates heat until the detector operates. Is absorbed by the heat-absorbing plate, thereby preventing an excessive temperature rise of the container bottom plate. In addition, an extension that extends to the detector side is provided on the endothermic plate, and this extension is fixed by placing it near the detector on the bottom plate of the container. This speeds up the operation of the detector and reduces the amount of heat generated by the heating element. The temperature rise of the container bottom plate can be reduced. Furthermore, the heat absorption plate is divided into a detector side heat absorption plate and an outer peripheral side heat absorption plate on the detector side from the center of the heating element, and the detector side heat absorption plate is formed of a material having better thermal conductivity than the outer peripheral side heat absorption plate. Thus, the temperature rise of the container bottom plate just above the heating element can be suppressed and the heat conduction to the detector can be improved, so that the operation of the detector can be accelerated and the protection of the container can be further enhanced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention includes a container for storing a liquid, a container bottom plate that forms a bottom surface of the container, a heating element that supplies heat to the container bottom plate, and a gap between the container bottom plate and the heating element. A heat conduction plate that is sandwiched between the heat conduction plate and transfers heat to the container bottom plate ; and a fixing plate that fixes the heat generating element to the outside of the container bottom plate, and generates heat from the heat generation element between the heat conduction plate and the heat generation element. The electric water heater is provided with a metal heat absorbing plate that absorbs and transfers heat to the heat conducting plate. And while the heat | fever generate | occur | produced until the detector operate | moves is absorbed by the heat absorption board, a detector operate | moves and electricity supply to a heat generating body stops and it can prevent the excessive temperature rise of a container bottom plate.
[0009]
In addition , an extension that extends to the detector side is provided on the endothermic plate, and this extension is fixed by placing it near the detector on the bottom plate of the container. This speeds up the operation of the detector and reduces the amount of heat generated by the heating element. The temperature rise of the container bottom plate can be reduced. Furthermore , the heat absorption plate is divided into a detector side heat absorption plate and an outer peripheral side heat absorption plate on the detector side from the heating element center, and the detector side heat absorption plate is formed of a material having better thermal conductivity than the outer peripheral side heat absorption plate. Thus, the temperature rise of the container bottom plate just above the heating element can be suppressed and the heat conduction to the detector can be improved, so that the operation of the detector can be accelerated and the protection of the container can be further enhanced.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
Example 1
In FIG. 1 and FIG. 2, 11 is a container for storing a liquid, and a heat conductive container bottom plate 11a that forms the bottom of the container 11 has a recess 11b as viewed from the outside. And the flat ring-shaped heat generating body 12 which heats the liquid in the container 11 by energizing is stored in the recessed part 11b. An insulating plate 13 is formed of mica or the like and insulates the heating element 12. Reference numeral 14 denotes a heat conduction plate disposed between the container bottom plate 11a and the heating element 12, and prevents the heat of the heating element 12 from being directly transmitted to the container bottom plate 11a to partially increase the temperature. Reference numeral 15 denotes a back plate having a good thermal conductivity disposed on the lower side of the heating element 12. Reference numeral 16 denotes a fixing plate for fixing the heating element 12 and the like sandwiched between the container bottom plate 11a to the container bottom plate 11a, and the inner periphery and outer periphery thereof are fixed to the container bottom plate 11a by welding. Reference numeral 17 denotes a detector such as a thermostat attached to the recess 11b. A bimetal contact plate 17a is incorporated in the detector 17. Then, the heat of the heating element 12 is conducted from the outside of the detector 17 to the inside, whereby the contact plate 17a is warmed. When the temperature reaches a predetermined temperature, the contact is opened, the power supply to the heating element 12 is cut off, and the heat generation stops. Reference numeral 18 denotes a metal heat absorbing plate sandwiched between the heating element 12 and the heat conducting plate 14, which once absorbs the heat generated by the heating element 12 and transmits it to the heat conducting plate 14. The detector 17 is not limited to a thermostat, and may be any device that can detect the temperature of the container bottom plate 11a. Furthermore, the heating element 12 is not limited to a flat shape, and may be anything that generates heat.
[0012]
Next, the heat conduction of the heating structure of the electric water heater will be described. Of the heat generated by energizing the heating element 12, the upward heat heats the container bottom plate 11 a via the insulating plate 13, the heat absorbing plate 18, and the heat conducting plate 14. Further, the downward heat heats the insulating plate 13, the back plate 15, and the fixed plate 16 and is transmitted to the container bottom plate 11 a via the fixed plate 16. When a liquid is contained in the container 11, heat is further transferred from the container bottom plate 11a to the liquid to raise the temperature of the liquid. However, when there is no liquid in the container 11, there is no liquid to be transmitted to the heat generated by the heating element 12, so the temperature of the insulating plate 13, the heat absorbing plate 18, the heat conducting plate 14 and the container bottom plate 11 a is increased. The temperature rises until the detector 17 reaches a predetermined temperature. At this time, since the heat absorbing plate 18 is sandwiched between the heating element 12 and the heat conducting plate 14, a part of the heat generated in the heating element 12 is used to heat the heat absorbing plate 18, and the temperature of the container bottom plate 11a. The rise is suppressed.
[0013]
As a result, the temperature of the container bottom plate 11a does not become excessively high, causing discoloration or deformation. Further, when the inside of the container 11 is coated with fluorine, the fluorine can be prevented from being burned, and even if the liquid is not supplied, it can be used again without replacing the container. Further, when liquid is contained in the container 11, it takes a little time to heat the heat absorbing plate 18 in the initial stage of energization. However, since the heat absorbing plate 18 is made of metal, the heat generated in the heating element 12 is used. Is transferred from the heat absorbing plate 18 to the heat conducting plate 14 and can be used as usual.
[0014]
( Reference Example 1 )
In FIG. 3, the heat absorbing plate 18 is formed of an iron plate having a thickness of 0.3 mm to 0.6 mm. By making the heat absorption plate 18 from 0.3 mm to 0.6 mm in thickness, both the heat absorption effect and the heat conductivity to the heat conduction plate 14 can be achieved. That is, when the endothermic plate 18 is thinner than 0.3 mm, the endothermic amount is small, and the temperature rise of the container bottom plate 11a when energized without liquid is not sufficiently suppressed. On the contrary, when the heat absorbing plate 18 is thicker than 0.6 mm, not only the heat conduction to the heat conducting plate 14 is deteriorated and the heat efficiency is deteriorated, but also the temperature of the heating element 12 is increased and the life of the heating element 12 is shortened. End up.
[0015]
Moreover, the endothermic plate 18 is formed of an iron plate, so that the endothermic effect and the thermal conductivity can be made appropriate and the durability of the endothermic plate 18 can be enhanced.
[0016]
That is, if the heat absorbing plate 18 is formed of a material such as aluminum, the heat conduction to the heat conducting plate 14 is too fast and the temperature rise of the container bottom plate 11a cannot be sufficiently suppressed, or the heating element 12 It may be deformed because it is directly affected by the heat from.
[0017]
From the above, in the present invention, the thickness of the endothermic plate 18 is 0.3 mm to 0.6 mm, and the material is an iron plate. However, when the heat conduction is different due to the difference in the structure of the container 11 or the like, the same effect can be obtained by slightly changing the thickness.
[0018]
(Example 2 )
In FIG. 4, a portion surrounding the detector 17 of the heat absorbing plate 18 is extended to the detector 17 side to provide an extension 18 a. The extended portion 18a has a bent planar shape portion. When the fixing plate 16 is fixed to the container bottom plate 11a by welding, the planar shape portion abuts and is fixed to the container bottom plate 11a.
[0019]
The heat generated when the heating element 12 is energized is directly transmitted from the heat absorbing plate 18 to the periphery of the detector 17 without passing through the heat conducting plate 14. As a result, the detector 17 side of the container bottom plate 11a is heated quickly, the operation of the detector 17 is accelerated, the amount of heat generated by the heating element 12 itself can be reduced, and an excessive temperature rise of the container bottom plate 11a can be prevented.
[0020]
(Example 3 )
In FIG. 4, the endothermic plate 18 is divided on the side close to the detector 17, avoiding the top of the heating element center 12 a that becomes the hottest. The outer peripheral side heat absorption plate 18b is an iron plate, and the detector side heat absorption plate 18c is formed of a material such as brass having good thermal conductivity.
[0021]
As a result, heat is concentrated on the heating element center 12a where the heat is concentrated and becomes the hottest by the outer peripheral side heat absorbing plate 18b, and the detector 17 side quickly transfers the heat to the vicinity of the detector 17 by the detector side heat absorbing plate 18c. It will be. Therefore, excessive temperature rise of the container bottom plate 11a can be prevented by both the heat absorption effect of the outer peripheral side heat absorption plate 18b and the heat conduction effect of the detector side heat absorption plate 18c.
[0022]
( Reference Example 2 )
In FIG. 5, the heat absorbing plate 18 and the heat conducting plate 14 are formed as a single piece to form a heat absorbing conducting plate 19, which is an iron plate having a thickness of 0.6 mm to 0.9 mm. By making the heat absorption conductive plate 19 an iron plate having a thickness of 0.6 mm to 0.9 mm, both the heat absorption effect and the thermal conductivity to the container bottom plate 11a can be achieved. That is, when the heat absorption conductive plate 19 is thinner than 0.6 mm, the amount of heat absorption is small, and the temperature rise of the container bottom plate 11a when energized without liquid is not sufficiently suppressed.
[0023]
On the contrary, when the heat absorption conductive plate 19 is thicker than 0.9 mm, not only the heat conduction to the container bottom plate 11a is deteriorated and the heat efficiency is deteriorated, but also the temperature of the heating element 12 is increased and the life of the heating element 12 is shortened. End up.
[0024]
However, when the heat conduction is different due to the difference in the structure of the container 11 or the like, the same effect can be obtained by slightly changing the thickness. Further, by forming the endothermic conductive plate 19 from an iron plate, the endothermic effect and the thermal conductivity can be made appropriate and the durability of the endothermic conductive plate 19 can be enhanced.
[0025]
Furthermore, by using the heat absorbing conductive plate 19, the number of components can be reduced and the cost can be reduced, and the heat absorbing plate 18 and the heat conductive plate 14 are not forgotten when the container 11 is assembled. As described above, it is possible to prevent an excessive increase in temperature of the container bottom plate 11a with the single endothermic conductive plate 19.
[0026]
【The invention's effect】
According to the first aspect of the present invention, the heat absorption plate that absorbs the heat of the heating element and transfers the heat to the heat conduction plate is provided between the heat conduction plate and the heat generation element, and is generated until the detector operates. While the heat is absorbed by the endothermic plate, the detector operates to stop energization of the heating element and prevent an excessive temperature rise of the container bottom plate.
[0027]
In addition , an extension that extends to the detector side is provided on the endothermic plate, and this extension is placed near the detector on the bottom plate of the container and fixed, thereby speeding up the operation of the detector and reducing the amount of heat generated by the heating element. The temperature rise of the bottom plate can be reduced.
[0028]
Furthermore , the heat absorption plate is divided into a detector side heat absorption plate and an outer peripheral side heat absorption plate on the detector side from the center of the heating element, and the detector side heat absorption plate is formed of a material having better thermal conductivity than the outer peripheral side heat absorption plate. As a result, the temperature rise of the container bottom plate directly above the heating element can be suppressed, and the heat conduction to the detector can be improved to speed up the operation of the detector and further improve the protection of the container.
[Brief description of the drawings]
1 is a perspective view of a heating structure of an electric water heater showing a first embodiment of the present invention [2] the same, cross-sectional view of the heating structure of an electric water heater [3] first of the present invention FIG. 4 is a sectional view of a heating structure of an electric water heater showing a reference example. FIG. 4 is a sectional view of a heating structure of an electric water heater showing a second embodiment of the invention. FIG. 5 is a third embodiment of the invention. FIG. 6 is a sectional view of a heating structure of an electric water heater showing a second reference example of the present invention. FIG. 7 is a sectional view of a heating structure of an electric water heater showing a conventional example. Perspective view of the body [Fig. 8] Cross-sectional view of the heat generating structure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Container 11a Container bottom plate 12 Heat generating body 14 Thermal conduction plate 16 Fixed plate 17 Detector 18 Endothermic plate 18a Extension 18b Detector side endothermic plate 18c Outer end side endothermic plate 18 Endothermic conduction plate

Claims (1)

A container for storing liquid; a container bottom plate that forms a bottom surface of the container; a heating element that supplies heat to the container bottom plate; and heat that is sandwiched between the container bottom plate and the heating element to transfer heat to the container bottom plate. and conducting plates, a solid Teiita for securing the heating element to the outside of the container bottom plate, disposed between the heating element and the heat conducting plate to absorb the heat generation of the heating element and heat to the heat conducting plate A metal endothermic plate for transmission , a detector for detecting the temperature in contact with the container bottom plate, and an extension extending from the endothermic plate to the detector side, the extension portion of the container bottom plate Abutting and fixing in the vicinity of the detector, the heat absorbing plate is divided on the detector side from the center of the heating element to form the detector side heat absorbing plate and the outer peripheral side heat absorbing plate, and the detector side heat absorbing plate An electric water heater made of a material with better thermal conductivity than the side heat sink .

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