JPH0646420Y2 - Electric water heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric water heater that heats and retains a contained liquid.

2. Description of the Related Art A conventional electric water heater of this type is disclosed in, for example, JP-A-61-50514.
As shown in the publication, the structure is as shown in FIG. 5 and FIG. That is, it has a bottomed cylindrical shape and is approximately D
A heat generating element 33 is attached to the back side of the bottom surface of a container 32 having a heat transfer surface 31 protruding in a shape, and a good heat conductive member 34 made of a non-magnetic material.
A thermal fuse 36 covered with an insulating material 35 is integrally wound around one end of the above, and the other end of the good thermal conductive member 34 is attached to the temperature detecting surface 31a of the projecting portion of the container 32 which is cut into a substantially D shape. Abut, and the thermal fuse 36 is connected to the heating element 33.
The pressing spring 37 was attached to the heat shield plate 38 together with the good heat conductive member 34 with the screw 39 in a state of facing the lower part of the.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-mentioned conventional configuration, a good heat conductive member 34 made of a non-magnetic material integrally wound with a thermal fuse 36 covered with an insulating material 35, and the thermal fuse 36 with a heating element 33. Since the pressing spring 37 attached to the heat shield plate 38 together with the good heat conductive member 34 in the state facing the lower part of the plate is required, the number of parts is increased, and as a result, the assembling workability is poor.

Further, since the thermal fuse 36 is attached so as to face below the heating element 33, it is good in terms of radiant heat from the heating element 33, but in terms of heat conduction from the bottom surface of the container 32, the influence of other parts. Or a heating element due to variations in mounting dimensions
When the size from 33 is different, the thermal fuse 36 does not operate accurately, and as a result, there is a problem that the heating element 33 is damaged or parts or the like are damaged.

Further, since the thermal fuse 36 is covered with the thermal shield 38, the thermal shield 38 may raise the temperature of the thermal fuse 36 more than necessary during normal use and may melt the thermal fuse 36. In order to prevent this, it is necessary to raise the set temperature of the thermal fuse 36 so that it will not be cut off during normal use. In this case,
If the set temperature of 36 is too high, it will take time until the thermal fuse 36 is blown, which causes a problem of damaging other parts.

The present invention solves such a problem, and in the unlikely event that the temperature controller does not operate normally due to a failure or a mounting error, the temperature fuse is promptly followed by the temperature rise of the heating element. It is an object of the present invention to provide an electric water heater that can be melt-cut and does not malfunction during normal use due to radiant heat from a heating element.

Means for Solving the Problems In order to solve the above problems, the present invention provides a bottom surface of a container having a bottomed cylindrical bottom surface having a heat transfer surface protruding in a substantially D shape, and a bottom surface of the container. Attach a temperature controller in the center,
A heat shield plate is provided below the bottom surface of the container, one end of a pressing spring is attached to the heat shield plate, and a thermal fuse covered with an insulating material is integrally wound around the other end of the pressing spring. The heat shield plate is provided with an opposed portion that abuts the end on a substantially D-shaped temperature detecting surface and that faces the mounting plane of the pressing spring with a gap.

Action According to the above configuration, even if the temperature controller does not operate normally due to a failure or a mounting error,
Since the thermal fuse receives heat conduction from the heating element directly from the temperature sensing surface, for example, if the hot water in the container is exhausted and it is in an air-burned state, the thermal fuse must be sure before the danger such as ignition occurs. As a result, the temperature of each part can be prevented from rising rapidly, and the heat conduction from the heat shield plate is reduced, so that the set temperature of the thermal fuse can be lowered.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 to 4, reference numeral 1 denotes a heat transfer surface having an outer peripheral side green 1a formed by protruding a central portion upward in a substantially D shape. The heat transfer surface 1 is a D-cut outer peripheral side edge. A bottomed cylindrical container 2 is formed by having a temperature detection surface 1b on the lower surface of 1a, and fixing the outer edge portion to the lower end of a metal cylindrical body in a watertight manner by means such as welding. Reference numeral 3 is an exterior body that encloses the container 2 via a space.

Further, on the lower surface of the heat transfer surface, a heating element 4 constituted by sandwiching the upper and lower sides of the heating wire with insulating plates is mounted. Further, the heating element 4 also has a through hole in the central portion,
And a heat diffusion plate 5 and a back plate 6 made of a material having good thermal conductivity
Is fixed to the heat transfer surface 1 by spot welding or the like with a pressing margin provided, so that the heating element 4 is built into the heating element portion.

Further, the rear plate 6 has a heat shield plate 7 that substantially covers the bottom surface of the container 2.
A substantially Z-shaped container fitting 8 for fixing the container is fixed. A temperature controller 9 is attached to the center of the heat shield plate 7 by a mounting spring 10.

Reference numeral 11 denotes a pressing spring having a spring property and formed of a heat-resistant material such as stainless steel. A curling portion 11a having a substantially curled shape is formed at the other end of the pressing spring 11, and the curling portion 11a and A screw mounting hole 11b is provided at one end of the pressing spring 11 located on the opposite side. A screw 12 is attached to the screw mounting hole 11b and a hole provided in the convex portion 7a of the heat shield plate 7, whereby the pressing spring 11 and the heat shield plate 7 are integrated. Further, the other end curl portion 11a of the pressing spring 11 comes into contact with the temperature detection surface 1b cut into the substantially D shape. A thermal fuse 13 covered with an insulating material 13 'is integrally attached to the other end curl portion 11a to form a thermal fuse unit. In addition, a pressure spring is attached to the heat shield plate 7.
A facing portion A facing the mounting plane 11 is provided at a distance.

The heat shield plate 7 is fixed to the bottom surface of the container 2 by a mounting member 14 via the container member 8 so that the heat receiving portion of the temperature controller 9 is in close contact.

Next, the operation of the above configuration will be described. When the liquid is stored in the container 2 and the energization is started, the heating element 4 is heated and is transferred to the liquid in the container 2 via the heat transfer surface 1. At the same time, the heat transferred to the back plate 6 by the heat diffusion plate 5 is transferred to the outer peripheral side portion and is used for heating the liquid. Then, when the liquid reaches the boiling temperature, the temperature controller 9 coupled to the central projection of the heat transfer surface 1 is activated to turn off the power supply to the heating element 4. The liquid temperature in the container 2 is lowered by turning off the power,
When the temperature of the liquid reaches a certain temperature, the temperature controller 9 is activated again to turn on the power supply to the heating element 4,
After that, the on / off cycle is repeated to guarantee the heat retention state.

Further, when the temperature controller 9 remains in the ON state due to a failure or an improper mounting, the thermal fuse 13 is caused by heat conduction from the temperature detecting surface 1b on the bottom surface of the container 2 or radiant heat from the back plate 6.
The safety is guaranteed by fusing and cutting off the power of the entire electric water heater.

As described above, in one embodiment of the present invention, the heating element 4 is attached to the bottom side of the bottom surface of the container 2 having the heat transfer surface 1 protruding in a substantially D-shape and having a bottom center of the container 2. A temperature controller 9 is attached to the bottom of the container 2, and a heat shield plate 7 is provided below the bottom surface of the container 2. A pressure spring 11 having a spring property is attached to the heat shield plate 7, and an insulating material is attached to the other end of the pressure spring 11. A thermal fuse 13 covered with 13 'is integrally wound, and the other end curl portion 11a is brought into contact with the temperature detecting surface 1b of the container 2 which is cut into a substantially D shape, and one end of the pressing spring 11 is fixed. It is attached to the heat shield plate 7. Since the protrusion 7a is formed on the heat shield plate 7 at this attachment portion, the pressing spring 11 keeps the temperature from the heat shield plate 7 in a normal use state. As a result, the temperature fuse 13 becomes hard to receive, and as a result, the set temperature of the thermal fuse 13 can be lowered.

Effects of the Invention According to the present invention, as is clear from the description of the above embodiment,
A heating element is attached to the back side of the bottom surface of a container having a heat transfer surface protruding in a substantially D shape with a bottomed cylinder, a temperature controller is attached to the center of the bottom surface of the container, and a heat shield plate is provided below the bottom surface of the container. Is provided, one end of a pressing spring is attached to the heat shield plate, and a temperature fuse covered with an insulating material is integrally wound around the other end of the pressing spring, and the other end is formed as a substantially D-shaped temperature detecting surface. Since the heat shield plate has a facing portion that is abutted and further faces the mounting plane of the pressing spring with a gap, the heat shield plate that covers the back surface of the heat generating pair during normal boiling or in a heat retaining state. Less affected by heat,
As a result, even when the temperature fuse is set at a low temperature, it is possible to prevent the temperature fuse from being blown during boiling or keeping the temperature. In addition, even if the temperature controller does not operate normally due to failure or improper installation, the temperature fuse receives heat conduction from the heating element directly from the temperature detection surface, so that the temperature fuse does not catch fire. It will work reliably before the danger occurs,
As a result, the temperature rise of the heating element and other components can be suppressed, so that damage to them can be prevented.

Further, since the number of parts is also small, it is possible to reduce the variation of parts and improve the assembling workability.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a mounting portion of an essential part of an electric water heater showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of the electric water heater, and FIG. 3 is the electric water heater. FIG. 4 is a vertical sectional view of the electric water heater, FIG. 5 is an enlarged sectional view of a conventional electric water heater, and FIG. 6 is a plan view of the conventional electric water heater. is there. 1 ... Heat transfer surface, 1b ... Temperature detection surface, 2 ... Container, 4 ...
Heater, 7 ... Heat shield, 7a ... Convex part, 9 ... Temperature controller, 11 ... Holding spring, 11a ... Other end curl of holding spring, 13 ... Thermal fuse.

Claims (1)

[Scope of utility model registration request] 1. A heating element is attached to the back side of the bottom surface of a container having a cylindrical bottomed and heat transfer surface protruding in a substantially D shape, and a temperature controller is attached to the center of the bottom surface of the container, A heat shield plate is provided below, one end of a pressing spring is attached to the heat shield plate, and a thermal fuse covered with an insulating material is integrally wound around the other end of the press spring, and the other end is substantially D-shaped. An electric water heater having a facing portion which is in contact with the temperature detecting surface of the above, and which further faces the mounting plane of the pressing spring with a gap therebetween in the heat shield plate.