JP7429518B2 - liquid heating device - Google Patents

Description

The present invention relates to liquid heating devices such as electric water heaters.

The main body has a heating resistor and can be filled with water to boil it, and a base to which the main body is coupled, a female electrical connector is provided at the bottom of the main body, and a male electrical connector is provided at the base. For example, Patent Document 1 describes a kettle in which electric power for energizing a heating resistor is supplied from the base side to the main body side by electrically coupling these electric connectors.

JP2014-226555A

In the water kettle of Patent Document 1, although the female electrical connector on the main body side is provided to be waterproof, it is difficult to connect the female electrical connector with the male electrical connector with moisture remaining in the female electrical connector. Considering the risks involved, it was difficult to thoroughly clean the main body from the outside by pouring a lot of water on it or soaking it in water.

In view of this problem, an object of the present invention is to provide a liquid heating device that can thoroughly clean the entire container.

A liquid heating device according to a first aspect of the present invention includes: a heating coil through which a high-frequency current is passed; a casing in which the heating coil is housed; a container that can be installed in the casing and stores a liquid; a heating element provided at the bottom of the container to heat the liquid in the container. Here, the heating coil has a circular donut plate shape with an opening at the center of the heating coil. The heating body has a disc shape and includes an upper surface and a lower surface parallel to the upper surface, and is heated from the bottom surface of the container so that both the upper surface and the lower surface are in contact with the liquid in the container. When the containers are spaced apart and installed in the housing, heat is generated by electromagnetic induction from the heating coil. A plurality of holes through which air bubbles generated on the lower surface side pass are formed in the heating body only in a central portion of the heating body that overlaps with a central portion of the heating coil when viewed in the vertical direction . The heating coil does not exist directly below the center of each hole in the plurality of holes.

According to the above configuration, since there is no electrical connection between the outside of the container and the casing, the entire container can be thoroughly washed with water. Moreover, since the heat of the heating body is directly transferred to the water, the efficiency of heating the water is improved. Furthermore, since the heat of the heating body is effectively transferred to the water, the heating efficiency of the water by the heating body is further improved. Furthermore, since air bubbles are less likely to remain between the bottom surface portion and the heating element, contact between the heating element and water is less likely to be hindered by air bubbles, and the efficiency of heating water by the heating element is improved.
Further, the plurality of holes are formed only in the central portion of the heating body, and since the heating coil is shaped like a donut plate, eddy current is less likely to be generated in this central portion due to electromagnetic induction from the heating coil. Therefore, a decrease in heat generation efficiency of the heating body due to the formation of a plurality of holes can be suppressed.

A liquid heating device according to a second aspect of the present invention includes a heating coil through which a high-frequency current is passed, a housing in which the heating coil is housed, a container that can be installed in the housing and stores a liquid, and the container. a heating element provided at the bottom of the container to heat the liquid in the container. The heating coil has a circular donut shape with an open center. The heating body has a disc shape and includes an upper surface and a lower surface parallel to the upper surface, and is heated from the bottom surface of the container so that both the upper surface and the lower surface are in contact with the liquid in the container. When the containers are spaced apart and installed in the housing, heat is generated by electromagnetic induction from the heating coil. A plurality of holes through which air bubbles generated on the lower surface side pass are formed in the heating body only at an outer circumferential portion of the heating body that overlaps with an outer circumferential portion of the heating coil when viewed in the vertical direction. The plurality of holes do not exist in the heating body at a position on a circumferential line that is a center between an inner circumferential edge and an outer circumferential edge of the heating coil.

A liquid heating device according to a third aspect of the present invention includes a heating coil through which a high-frequency current is passed, a housing in which the heating coil is housed, a container that can be installed in the housing and stores a liquid, and the container. a heating element provided at the bottom of the container to heat the liquid in the container. The heating coil has a circular donut shape with an open center. The heating body has a disc shape and includes an upper surface and a lower surface parallel to the upper surface, and is heated from the bottom surface of the container so that both the upper surface and the lower surface are in contact with the liquid in the container. When the containers are spaced apart and installed in the housing, heat is generated by electromagnetic induction from the heating coil. In the heating body, a plurality of holes through which air bubbles generated on the lower surface side pass are formed only at the center and outer circumference of the heating body, which overlap with the center and outer circumference of the heating coil, respectively, when viewed in the vertical direction. be done. The heating coil does not exist directly below the center of each hole in the plurality of holes in the central part of the heating body, and the plurality of holes in the outer peripheral part of the heating body are located directly below the center of each of the holes in the heating body. It does not exist at the position on the circumferential line that is the center between the inner circumferential edge and the outer circumferential edge.

In the liquid heating device according to the first, second, and third aspects, a gap is provided continuously along the entire circumference between the heating body and the peripheral surface of the container. The center of the heating body is supported by a support so that the heating body is spaced from the bottom surface portion. The plurality of holes are formed in a central portion of the heating body so as to extend in a circumferential direction around the pillar.

In the liquid heating device according to this aspect, the container may have a double wall structure including an inner wall and an outer wall.

According to the above configuration, when the water in the container is heated, heat is not easily transmitted to the outer surface of the container, and the outer surface of the container is less likely to become hot.

In addition , in the scope of claims, "installed in the casing" means "installed on the casing, etc., as long as electromagnetic induction occurs," such as "installed on the casing, etc." means to be placed in such a way that

As described above, according to the present invention, it is possible to provide a liquid heating device that can thoroughly clean the entire container.

The effects and significance of the present invention will become clearer from the following description of the embodiments. However, the embodiment shown below is merely one example of implementing the present invention, and the present invention is not limited to what is described in the embodiment below.

FIG. 1(a) is a perspective view of an electric water heater according to the first embodiment, and FIG. 1(b) is a plan view of a container according to the first embodiment. FIG. 2 is a sectional view of the electric water heater according to the first embodiment. FIG. 3 is a block diagram showing the configuration of the base according to the first embodiment. FIG. 4(a) is a perspective view of an electric water heater according to the second embodiment, and FIG. 4(b) is a plan view of a container according to the second embodiment. FIG. 5 is a sectional view of an electric water heater according to a second embodiment. FIGS. 6A and 6B are a cross-sectional view of a container with a lid and a plan view of the container, respectively, showing a screw-type fixing structure according to a modified example. FIGS. 7A and 7B are a cross-sectional view of a container with a lid and a plan view of the container, respectively, showing a fitting type fixing structure according to a modification. FIGS. 8(a) and 8(b) are cross-sectional views of a container with a lid according to a modified example. FIGS. 9A and 9B are cross-sectional views of a container with a lid according to a modified example. FIG. 10(a) is a sectional view of the bottom of the container according to the modified example, and FIGS. 10(b) to 10(d) are plan views of the heating body according to the modified example. FIGS. 11(a) and 11(b) are a perspective view and a sectional view, respectively, of a container with a lid according to a modified example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric water heater, which is an embodiment of a liquid heating device of the present invention, will be described below with reference to the drawings.

<First embodiment>
FIG. 1(a) is a perspective view of an electric water heater 1 according to the first embodiment, and FIG. 1(b) is a plan view of a container 100 according to the first embodiment. FIG. 2 is a sectional view of the electric water heater 1 according to the first embodiment. FIG. 3 is a block diagram showing the configuration of the base 300 according to the first embodiment. Note that in FIG. 2, the temperature detector 330 is not shown in cross section for convenience.

The electric water heater 1 includes a container 100 in which water (liquid to be heated) is stored, a lid 200 that closes a water supply port 103 of the container 100, and a base 300 on which the container 100 is placed.

Container 100 is made of, for example, glass, particularly heat-resistant glass, and includes a circular bottom portion 101 and a cylindrical peripheral portion 102 , and is open so that the top surface serves as a water supply port 103 . The peripheral surface portion 102 has a taper and slightly widens upward. An annular handle 104 is formed on the rear side of the peripheral surface portion 102, and a spout 105 for pouring water from the container 100 is formed on the upper end portion of the front side. Note that the container 100 may be formed of a material other than glass, such as ceramic or resin, and it is desirable that the material has heat resistance.

A heating element 110 for heating the water in the container 100 is provided at the bottom of the container 100. The heating body 110 is made of, for example, stainless steel, has a disk shape, and includes an upper surface 111 and a lower surface 112 parallel to (facing away from) the upper surface 111 . The heating body 110 is supported by a cylindrical support 120 formed integrally with the heating body 110 so as to be slightly away from the bottom surface 101 of the container 100. Thereby, when water is stored in the container 100, both the upper surface 111 and the lower surface 112 of the heating body 110 come into contact with the water.

The center of the heating body 110 coincides with the center of the bottom part 101. The diameter of the heating body 110 is smaller than the inner diameter of the container 100, and a gap is provided between the heating body 110 and the peripheral surface portion 102. When water is poured into the container 100, the water flows into the lower side of the heating element 110 through this gap.

The heating element 110 is fixed to the bottom part 101 of the container 100 so that the user can remove it without using a tool such as a screwdriver, that is, the heating element 110 can be attached and detached by the user. In this embodiment, a fixing structure using a magnet 130 is adopted. That is, a magnet 130 having a flat cylindrical shape is attached to the center of the bottom part 101 so that its upper side protrudes from the bottom part 101. The protruding part will fit in. The magnetic force of the magnet 130 fixes the heating body 110 so that it does not come off the bottom part 101 upward. A cylindrical knob 140 is formed at the center of the upper surface of the heating body 110, and the user can lift the heating body 110 by holding this knob 140 with a force greater than the magnetic force of the magnet 130. With this, the heating body 110 can be removed from the container 100. This facilitates cleaning of the lower surface 112 of the heating body 110 and the inner surface of the bottom surface portion 101 of the container 100.

When the fixed structure using the magnet 130 is adopted as described above, the heating body 110 is made of ferrite or martensitic stainless steel that can be attracted to the magnet 130.

Note that the heating body 110 may be formed of a metal material other than stainless steel that has excellent conductivity and corrosion resistance.

The lid 200 is made of, for example, glass, particularly heat-resistant glass, has a disc shape, and has a tapered peripheral surface corresponding to the tapered shape of the peripheral surface 102 of the container 100. The upper surface of the lid 200 is recessed in a curved shape leaving the outer periphery, and a handle 202 is formed in the center of the recess 201. Note that the lid 200 may be formed of a material other than glass, such as a resin, particularly a heat-resistant resin. The lid 200 can be removed upward from the water inlet 103 of the container 100, thereby opening the water inlet 103.

The base 300 includes a housing 310 and a heating coil 320 and a temperature detector 330 housed within the housing 310.

The housing 310 has a substantially rectangular parallelepiped shape that is flat in the vertical direction, and includes a case 311 with an open top surface, and a cover 312 that is a top plate and covers the top surface of the case 311. The housing 310, that is, the case 311 and the cover 312, are made of glass, for example. A circular mark 313 is drawn on the top surface of the casing 310, which is a mounting surface, as a mark indicating the position when the container 100 is placed on the base 300, that is, the casing 310. The diameter of the mark 313 is approximately the same (slightly larger) than the diameter of the bottom portion 101 of the container 100. The container 100 is placed in alignment with the mark 313. Further, instead of the mark 313, a circular recess slightly recessed from the upper surface may be formed as a mark on the upper surface of the housing 310. Note that the housing 310 does not have to have a substantially rectangular parallelepiped shape, and may have a substantially cylindrical shape, for example.

The heating coil 320 is formed into a donut plate shape by a spirally wound coil. The heating coil 320 is arranged in the housing 310 in close proximity to the cover 312 so that its center position is at the center of the cover 312. Heating coil 320 is attached to the back surface of cover 312, for example, via an attachment member (not shown).

The center of the heating coil 320 coincides with the center of the mark 313, that is, the center of the top surface of the housing 310. Therefore, when the container 100 is placed at the center of the top surface of the housing 310 so as to match the mark 313, the center of the heating coil 320 and the center of the heating body 110 coincide. Here, the diameter of the heating body 110 is made larger than the diameter of the heating coil 320. Therefore, even if the container 100 is placed somewhat offset from the center of the top surface of the housing 310, the heating coil 320 fits within the region of the heating body 110, so that stable induction heating efficiency can be obtained.

Furthermore, when the container 100 is placed on the base 300, the heating body 110 and the heating coil 320 are in a parallel state. That is, the distance between the heating body 110 and the heating coil 320 is constant at any position when viewed from the direction in which they are lined up (up and down direction). Thereby, the heating efficiency of the heating body 110 as a whole can be stabilized. For example, if the inner surface of the bottom portion 101 of the container 100 is a concavely curved surface and the heating plate 110 is shaped like a concavely curved plate to match the inner surface, the heating coil 320 also has an arbitrary shape when viewed from above and below. It may be shaped like a donut plate with a concave curved surface so that the distance is constant at the position. That is, no matter what shape the heating plate 110 has, the heating coil 320 is arranged so that the distance is constant at any position when viewed from the direction in which the heating plate 110 and the heating coil 320 are lined up. It is desirable that the shape is

Temperature detector 330 is attached to the center of the back surface of cover 312. The temperature detector 330 includes a thermistor, and indirectly detects the temperature of the water (hot water) stored in the container 100 through the bottom surface 101 and the cover 312 of the container 100. Outputs a detection signal (voltage signal) according to temperature.

As shown in FIG. 3, the base 300 includes a heating coil 320 and a temperature detector 330, as well as an operation switch 340, a control section 350, and an inverter 360.

The operation switch 340 is arranged, for example, on the side surface of the housing 310, and is operated to start the water boiling operation. The control unit 350 includes a microcomputer and the like, and controls energization of the heating coil 320 based on an operation signal from the operation switch 340 and a detection signal from the temperature detector 330. Inverter 360 supplies high frequency current (high frequency alternating current) to heating coil 320 according to a control signal from control unit 350 . For example, the frequency of the alternating current may be selected from within the range of 20kHz to 90kHz.

Next, the operation of the electric water heater 1 based on the above configuration will be explained.

The user places the container 100 containing water on the base 300, that is, the upper surface of the housing 310, and operates the operation switch 340. Upon receiving the operation signal from the operation switch 340, the control unit 350 starts the water boiling operation. That is, the control unit 350 drives the inverter 360, and the high frequency current is supplied from the inverter 360 to the heating coil 320. Electromagnetic induction from the heating coil 320 generates eddy current in the heating element 110 within the container 100, causing the heating element 110 to generate heat. As a result, the water in the container 100 is heated. At this time, since the heating element 110 comes into contact with water, the heat of the heating element 110 is directly transferred to the water, improving the efficiency of heating the water. In particular, since both the upper surface 111 and the lower surface 112 of the heating body 110 are in contact with water, the heat of the heating body 110 is effectively transferred to the water. Therefore, water heating efficiency is further improved.

When the temperature of the water in the container 100 increases, bubbles are generated at the upper surface 111 and lower surface 112 of the heating element 110 due to water vaporization. In the heating body 110, heat generation on the lower surface 112 is greater than heat generation on the upper surface 111, and bubbles are likely to be generated on the lower surface 112 side. The bubbles generated on the upper surface 111 of the heating body 110 rise as they are. On the other hand, bubbles generated on the lower surface 112 of the heating element 110 rise through the gap between the heating element 110 and the peripheral surface 102 of the container 100 and escape from between the heating element 110 and the bottom surface 101 of the container 100. .

When the water in the container 100 boils, that is, the water boils and the temperature of the water in the container 100 reaches the boiling temperature, the temperature detector 330 detects the temperature of the cover 312 that is correlated to the boiling temperature, and the temperature of the cover 312 is A detection signal corresponding to the temperature, that is, the boiling temperature, is output to the control section 350. When this detection signal is input, control section 350 stops energizing heating coil 320 by stopping driving of inverter 360 . Thereby, heating of the water by the heating body 110 is stopped.

In this way, the water boiling operation is completed. The user detaches the container 100 from the base 300 and uses the hot water in the container 100.

<Effects of the first embodiment>
According to this embodiment, the following effects can be achieved.

The electric water heater 1 is configured such that a heating element 110 provided at the bottom of a container 100 generates heat due to electromagnetic induction from a heating coil 320 housed in a housing 310, thereby heating water in the container 100. . Therefore, since there is no electrical connection between the outside of the container 100 and the housing 310, the entire container 100 can be thoroughly washed with water.

Furthermore, since the heating element 110 is configured to come into contact with the water stored in the container 100, the heat of the heating element 110 is directly transferred to the water, improving the efficiency of heating the water.

Furthermore, since the heating body 110 is configured such that both the upper surface 111 and the lower surface 112 are in contact with water, the heat of the heating body 110 is effectively transferred to the water. Therefore, the efficiency of heating water by the heating body 110 is further improved.

<Second embodiment>
FIG. 4(a) is a perspective view of the electric water heater 2 according to the second embodiment, and FIG. 4(b) is a plan view of the container 500 according to the second embodiment. FIG. 5 is a sectional view of the electric water heater 2 according to the second embodiment. Note that in FIG. 5, the temperature detector 730 is not shown in cross section for convenience.

The electric water heater 2 includes a container 500 in which water (liquid to be heated) is stored, a lid 600 that closes a water supply port 503 of the container 500, and a base 700 on which the container 500 is placed.

Container 500 is made of glass, particularly heat-resistant glass, for example, and includes a circular bottom portion 501 and a cylindrical circumferential portion 502, and is open so that the top surface serves as a water supply port 503. The container 500 may be made of a material other than glass, such as ceramic or resin, and it is desirable that the material has heat resistance.

A heating element 510 for heating the water in the container 500 is provided at the bottom of the container 500. The heating body 510 is made of, for example, stainless steel, has a cylindrical shape, and includes an inner circumferential surface 511 and an outer circumferential surface 512 parallel to the inner circumferential surface 511. The outer peripheral surface 512 faces the peripheral surface portion 502 of the container 500. The heating body 510 has a height such that its upper end reaches the center of the container 500.

The heating body 510 can be fixed to the container 500 by a fixing method such as screwing or adhesive. Like the heating element 110 of the first embodiment, the heating element 510 may be configured to be detachable so that the user can remove it without using a tool such as a screwdriver.

The outer diameter of the heating element 510 is smaller than the inner diameter of the container 500, and a gap is formed between the outer peripheral surface 512 of the heating element 510 and the peripheral surface portion 502 of the container 500. Thereby, when water is stored in the container 500, both the inner circumferential surface 511 and the outer circumferential surface 512 of the heating body 510 come into contact with the water.

Note that the heating body 510 may be formed of a metal material other than stainless steel that has excellent conductivity and corrosion resistance.

The lid 600 is made of, for example, glass, particularly heat-resistant glass, and has a disc shape. The top surface of the lid 600 is recessed in a curved shape leaving the outer periphery, and a handle 602 is formed in the center of the recess 601. Note that the lid 600 may be formed of a material other than glass, such as a resin, particularly a heat-resistant resin. Although not shown in FIG. 8, the peripheral surface 502 of the container 500 is provided with an annular bulge that slightly bulges inward to support the lid 600 in order to secure the lid 600 to the upper end of the container 500. .

The base 700 includes a housing 710 and a heating coil 720 and a temperature detector 730 housed within the housing 710.

The housing 710 is made of resin, for example, and has a hollow cylindrical shape with a bottom. The container 500 is accommodated in the recess 711 of the housing 710 and placed on the bottom surface of the recess 711.

The heating coil 720 is composed of a cylindrically wound coil, and is arranged within the housing 710 so as to surround the recess 711 . When the container 500 is placed on the base 700, that is, the housing 710, the heating body 510 and the heating coil 720 face each other with the peripheral surface 502 of the container 500 in between. Note that the length (vertical dimension) of the heating body 510 is larger than the length (vertical dimension) of the heating coil 720.

The temperature detector 730 is installed in the housing space at the bottom of the housing 710 at the center of the surface facing the bottom of the recess 711. The temperature detector 730 is the same as the temperature detector 330 of the first embodiment.

Furthermore, like the base 300 of the first embodiment, the base 700 includes an operation switch 340, a control section 350, and an inverter 360 shown in FIG. The operation switch 340 can be provided on the outer peripheral surface of the housing 710, and the control unit 350 and the inverter 360, like the temperature detector 730, can be arranged in the housing space at the bottom of the housing 710.

The electric water heater 2 of this embodiment can also perform the same water heating operation as the electric water heater 1 of the first embodiment.

During water heating operation, when a high frequency current is supplied to the heating coil 720, the heating body 510 inside the container 500 generates heat due to electromagnetic induction from the heating coil 720. This heats the water in the container 500. At this time, since the heating element 510 comes into contact with water, the heat of the heating element 510 is directly transferred to the water, improving the efficiency of heating the water. In particular, since both the inner circumferential surface 511 and the outer circumferential surface 512 of the heating body 510 come into contact with water, the heat of the heating body 510 is effectively transferred to the water. Therefore, water heating efficiency is further improved.

<Effects of the second embodiment>
According to this embodiment, the same effects as the first embodiment can be achieved.

<Example of change>
Although the embodiments of the present invention have been described above, the present invention is not limited to the first embodiment and the second embodiment, and the application examples of the present invention also include the above embodiments. Various modifications are possible.

For example, in the first embodiment described above, a fixing structure using the magnet 130 was adopted in order to detachably fix the heating body 110 to the bottom part 101 of the container 100. However, the fixing structure of the heating body 110 is not limited to the above. For example, the fixing structure of the heating body 110 as shown in FIGS. 6(a), (b) and FIGS. 7(a), (b) below may be adopted.

FIGS. 6A and 6B are a cross-sectional view of a container 100 with a lid 200 and a plan view of the container 100, respectively, showing a screw-type fixing structure according to a modification.

In this modification, a fixture 150 for fixing the heating body 110 is provided in the container 100. The fixture 150 is made of metal, resin, or the like, and includes a cylindrical knob portion 151 and a threaded portion 152 provided at the center of the lower surface of the knob portion 151. The threaded portion 152 is formed with a male thread.

A strut 120 supporting the heating body 110 is integrally formed with the bottom surface 101 of the container 100, and a screw hole 122 with a female thread is provided on the upper surface of the strut 120. A through hole 113 is formed in the center of the heating body 110 .

The heating body 110 is fixed to the support 120, that is, the container 100, by screwing the screw portion 152 of the fixture 150 passed through the through hole 113 into the screw hole 122 of the support 120. When attaching or detaching the heating element 110 from the container 100, the user can tighten or loosen the screw part 152 by holding the knob 151 of the fixture 150, and can tighten or loosen the screw part 152 of the heating element 110 without using a tool such as a screwdriver. It can be easily attached and detached.

FIGS. 7A and 7B are a cross-sectional view of a container 100 with a lid 200 and a plan view of the container 100, respectively, showing a fitting type fixing structure according to a modified example.

In this modification, a fixture 160 is attached to the center of the heating body 110. The fixture 160 includes a cylindrical knob 161 and a fitting part 162 provided below the knob 161. The heating body 110 is sandwiched and fixed between the knob part 161 and the fitting part 162. A circular fitting recess 163 having a T-shaped cross section is formed in the fitting part 162, and the diameter of the entrance part is smaller than the diameter of the inner part.

A strut 120 supporting the heating body 110 is integrally formed with the bottom surface 101 of the container 100, and the strut 120 has a cylindrical shape with a T-shaped cross section so as to correspond to the fitting recess 163 of the fitting portion 162. ing.

The heating body 110 is fixed to the support 120, that is, to the container 100, by fitting the support 120 into the fitting recess 163 of the fitting part 162 of the fixture 160. The fitting portion 162 is made of an elastic material such as rubber, and when it is attached to or removed from the support column 120, the entrance portion of the fitting recess 163 expands due to its elasticity. Therefore, the user can easily attach and detach the heating body 110 without using a tool such as a screwdriver by holding the knob 161 of the fixture 160 and attaching or detaching the fitting part 162 to the support 120. be able to.

Furthermore, in the first embodiment, the heating element 110 is arranged so as to float above the bottom part 101 of the container 100, and both the upper surface 111 and the lower surface 112 of the heating element 110 come into contact with the water stored in the container 100. was taken. However, the arrangement of the heating body 110 at the bottom of the container 100 is not limited to the above.

For example, as shown in FIGS. 8A and 8B, a configuration may be adopted in which only the upper surface 111 of both surfaces of the heating body 110 comes into contact with the water in the container 100.

In the modification shown in FIG. 8A, the heating body 110 is insert-molded inside the bottom portion 101 of the container 100. A circular opening 106 is formed in the bottom portion 101 to expose the upper surface 111 of the heating body 110 to the inside of the container 100 except for the outer peripheral edge portion thereof. As a result, most of the upper surface of the heating body 110 comes into contact with the water stored in the container 100.

The electric water heater 1 has a configuration in which the heating body 110 generates heat by induction heating by the heating coil 320, and since no heater is attached to the bottom surface 112 of the heating body 110, on the bottom surface 101 of the bottom surface 112 of the heating body 110, There is no opening or the like that exposes the lower surface 112 to the outside, and the bottom surface portion 101 is completely closed. Therefore, there is no need to provide a water seal structure between the heating body 110 and the bottom part 101, and the structure of the container 100 is less likely to become complicated.

In the modified example of FIG. 8(b), in the container 100, the heating body 110 is arranged on the bottom part 101 so that the lower surface 112 thereof is in contact with the bottom part 101. For example, the container 100 is provided with an annular claw portion 107 on the bottom, and the heating body 110 is fixed to the bottom surface portion 101 by being pressed by the claw portion 107 . Almost the entire upper surface 111 of the heating body 110 other than the portion that engages with the claw portion 107 comes into contact with the water stored in the container 100 . In this configuration, it is desirable that the container 100 be formed of resin so that the claw portions 107 can be easily elastically deformed when the heating body 110 is attached to the bottom surface 101 of the container 100.

Furthermore, similar to the modified example of FIGS. 8(a) and 8(b), even if the arrangement of the heating element 110 as shown in FIG. 9(a) is adopted as a configuration in which one side of the heating element 110 contacts water. good.

In the modification shown in FIG. 9A, the bottom of the container 100 is made of a metal material that can be heated by induction, such as stainless steel, and is used as a heating body 110. That is, the heating body 110 is not provided separately from the bottom of the container 100, but is also used as the bottom of the container 100. For example, as shown in FIG. 9A, the heating body 110 includes a bottom surface portion 110a and a peripheral surface portion 110b rising from the bottom surface portion 110a and coupled to the peripheral surface portion 102 of the container 100. The upper surface of the bottom surface portion 110a and the inner peripheral surface of the peripheral surface portion 110b of the heating body 110 come into contact with the water stored in the container 100. Note that the heating body 110 may be configured to include only the bottom portion.

Also in the configurations shown in FIGS. 8(a), (b), and 9(a), the heat of the heating body 110 is directly transferred to the water, which improves the heating efficiency of the water.

Furthermore, instead of adopting a configuration in which at least one surface of the heating element 110 comes into contact with the water in the container 100 as described above, the heating element 110 is formed by insert molding as shown in FIG. 9(b). A configuration may be adopted in which the heating element 110 is completely embedded inside the bottom part 101 of the container 100 so that the heating element 110 is not exposed inside the container 100 and does not come into contact with water.

Furthermore, in the container 500 of the second embodiment, the heating body 510 is configured so that only the inner circumferential surface 511 is exposed inside the container 500, with a configuration similar to that of FIGS. 8(a) and 8(b). The heating body 510 is placed at the bottom of the container 500 in a configuration similar to the configuration shown in FIG. As a configuration in which the heating element 510 is also used as a heating element, and a configuration similar to the configuration shown in FIG.

Furthermore, in the first embodiment, air bubbles generated on the lower surface 112 side of the heating body 110 when the water in the container 100 is heated pass through the gap between the heating body 110 and the peripheral surface 102 of the container 100. As a result, it escaped above the heating element 110. However, as shown in FIGS. 10A to 10D, a configuration may be adopted in which bubbles generated on the lower surface 112 side of the heating element 110 can more easily escape from between the bottom surface portion 101 and the heating element 110.

FIG. 10(a) is a sectional view of the bottom of the container 100 according to the modified example, and FIG. 10(b) is a plan view of the heating body 110 according to the modified example. In addition, in FIG. 10(b), the position of the heating coil 320 is shown by a dashed line for convenience.

In this modification, a plurality of circular holes 114 are formed in the center of the heating body 110 along the circumferential direction. There is no heating coil 320 directly below the center of the plurality of holes 114. In this configuration, as shown in FIG. 10(a), air bubbles generated on the lower surface 112 side of the heating element 110 are spread not only in the gap between the heating element 110 and the circumferential surface 102 of the container 100, but also in the plurality of holes 114. By passing through the heating element 110 , the heating element 110 is released from between the bottom part 101 and the heating element 110 . Therefore, air bubbles are less likely to remain between the bottom part 101 and the heating element 110, so that contact between the heating element 110 and water is less likely to be hindered by air bubbles, and the efficiency of heating water by the heating element 110 is improved. Moreover, the plurality of holes 114 are formed in the center of the heating body 110, and since the heating coil 320 has a donut plate shape, eddy currents are less likely to be generated in this center due to electromagnetic induction from the heating coil 320. . Therefore, a decrease in the heat generation efficiency of the heating body 110 due to the formation of the plurality of holes 114 is suppressed.

FIGS. 10(c) and 10(d) are plan views showing other configurations of the heating body 110 according to modified examples. Note that in FIGS. 10(c) and 10(d), the position of the heating coil 320 is shown by a dashed-dotted line for convenience.

The outer peripheral portion of the heating body 110 tends to be less likely to generate eddy current due to electromagnetic induction from the heating coil 320, and is less likely to generate heat. Therefore, as shown in FIG. 10(c), a plurality of circular holes 115 may be formed in the outer peripheral portion of the heating body 110 along the circumferential direction. Further, as shown in FIG. 10(d), a plurality of circular holes 114 and 115 may be formed in both the central portion and the outer peripheral portion of the heating body 110, respectively. These configurations also make it difficult for air bubbles to remain between the bottom part 101 and the heating element 110, so that the efficiency of heating water by the heating element 110 is improved.

In the above example, the plurality of holes 114 and 115 are formed in one row in the radial direction, but they may be formed in two or more rows in the radial direction. In this case, the diameter of the holes 114, 115 may be made smaller than in the above example.

Furthermore, instead of the container 100 of the first embodiment, a container 100A shown in FIG. 11 may be used.

FIGS. 11A and 11B are a perspective view and a sectional view, respectively, of a container 100A with a lid 200 according to a modified example.

The container 100A has a double wall structure, and the bottom part 101 has an inner wall part 101a (hereinafter referred to as the inner bottom wall part 101a) and an outer wall part 101b (hereinafter referred to as the outer bottom wall part 101b). The peripheral surface portion 102 consists of an inner wall portion 102a (hereinafter referred to as the inner peripheral wall portion 102a) and an outer wall portion 102b (hereinafter referred to as the outer peripheral wall portion 102b). A gap is formed between the inner bottom wall part 101a and the outer bottom wall part 101b and between the inner peripheral wall part 102a and the outer peripheral wall part 102b, and an air layer is interposed therebetween. The other configuration of the container 100A is the same as the container 100 of the first embodiment. In addition, in the container 100A, insulation is provided in the gaps between the inner bottom wall part 101a and the outer bottom wall part 101b and between the inner peripheral wall part 102a and the outer peripheral wall part 102b to enhance the heat insulation effect between these walls. Insulating material may be included to form a layer. Further, as a heat insulating layer, a vacuum layer may be formed by evacuating the gap between the inner bottom wall 101a and the outer bottom wall 101b and between the inner peripheral wall 102a and the outer peripheral wall 102b. An air layer having a pressure lower than the atmospheric pressure may be formed.

If the container 100A is used, when the water in the container 100A is heated, heat is less likely to be transferred to the outer surface of the container 100A, and the outer surface is less likely to become hot.

Note that since heat is not easily transferred to the outer bottom surface of the container 100A, the cover 312 of the housing 310 is not likely to reach a high temperature. Therefore, the cover 312 can be formed of resin, which is generally more sensitive to heat than glass. When the cover 312 is made of resin, it is possible to reduce costs, reduce weight, and diversify shapes.

Further, in the second embodiment, the base 700 is formed into a hollow cylindrical shape with a bottom, and the temperature detector 730, the control unit 350, and the inverter 360 are arranged in the housing space at the bottom. However, the base 700 is composed of a hollow cylindrical part without a bottom and a storage part provided adjacent to the cylindrical part, and the heating coil 720 is arranged in the cylindrical part, and the control part 350 and the inverter are installed in the storage part. 360 may be arranged. In this case, in the electric water heater 2, when the base 700 is placed in a kitchen or the like, the container 500 is not placed on the base 700, but is installed inside the cylindrical part of the base 700. .

Furthermore, in the first embodiment and the second embodiment, the electric water heaters 1 and 2 were equipped with only the function of boiling water, but the electric water heaters 1 and 2 have the function of boiling water as well as the function of boiling water. It may also have a function to keep hot water warm.

Furthermore, in the first embodiment and the second embodiment, the liquid heating device of the present invention was applied to the electric water heaters 1 and 2. However, the present invention can also be applied to liquid heating devices that heat liquid stored in a container other than electric water heaters that heat liquid stored in a container. For example, it can be applied to a coffee maker that can keep the coffee in the container warm after brewing. Further, the liquid heating device to which the present invention is applied may have a heat retention function but not a water boiling function.

In addition, the embodiments of the present invention can be modified in various ways within the scope of the claims.

1 Electric water heater (liquid heating device)
2 Electric water heater (liquid heating device)
100 Container 100A Container 101a Inner wall 101b Outer wall 102a Inner wall 102b Outer wall 110 Heating body 111 Top surface (first surface)
112 Bottom surface (second surface)
310 Housing 320 Heating coil 350 Control unit

Claims (4)

a heating coil through which a high-frequency current is passed;
a housing in which the heating coil is housed;
a container that can be installed in the housing and that stores liquid;
a heating element provided at the bottom of the container to heat the liquid in the container,
The heating coil has a circular donut plate shape with an opening at the center of the heating coil,
The heating body is
It has a disc shape and includes an upper surface and a lower surface parallel to the upper surface,
disposed away from a bottom portion of the container such that both the top surface and the bottom surface are in contact with the liquid in the container;
When the container is installed in the housing, heat is generated by electromagnetic induction from the heating coil,
A plurality of holes are formed in the heating body only in a central portion of the heating body that overlaps with a central portion of the heating coil when viewed in the vertical direction, and a plurality of holes are formed through which air bubbles generated on the lower surface side pass.
The heating coil does not exist directly below the center of each hole in the plurality of holes,
A liquid heating device characterized by: a heating coil through which a high-frequency current is passed;
a housing in which the heating coil is housed;
a container that can be installed in the housing and that stores liquid;
a heating element provided at the bottom of the container to heat the liquid in the container,
The heating coil has a circular donut plate shape with an opening at the center of the heating coil,
The heating body is
It has a disc shape and includes an upper surface and a lower surface parallel to the upper surface,
located away from the bottom of the container such that both the top surface and the bottom surface are in contact with the liquid in the container;
When the container is installed in the housing, heat is generated by electromagnetic induction from the heating coil,
A plurality of holes through which air bubbles generated on the lower surface side pass are formed in the heating body only at the outer circumference of the heating body that overlaps with the outer circumference of the heating coil when viewed in the vertical direction,
The plurality of holes are not present in the heating body at a position on a circumferential line that is a center between the inner peripheral edge and the outer peripheral edge of the heating coil.
A liquid heating device characterized by: a heating coil through which a high-frequency current is passed;
a housing in which the heating coil is housed;
a container that can be installed in the housing and that stores liquid;
a heating element provided at the bottom of the container to heat the liquid in the container,
The heating coil has a circular donut plate shape with an opening at the center of the heating coil,
The heating body is
It has a disc shape and includes an upper surface and a lower surface parallel to the upper surface,
disposed away from a bottom portion of the container such that both the top surface and the bottom surface are in contact with the liquid in the container;
When the container is installed in the housing, heat is generated by electromagnetic induction from the heating coil,
A plurality of holes through which air bubbles generated on the lower surface side pass are formed in the heating body only in the center and outer circumferential parts of the heating body, which overlap with the center and outer circumferential parts of the heating coil when viewed in the vertical direction. is,
The heating coil is not present directly below the center of each hole in the plurality of holes in the central part of the heating body,
The plurality of holes in the outer peripheral portion of the heating body are not located at a position on a circumferential line that is a center between the inner peripheral edge and the outer peripheral edge of the heating coil in the heating body.
A liquid heating device characterized by: The liquid heating device according to claim 1 or 3 ,
A gap is provided between the heating body and the peripheral surface of the container without interruption along the entire circumference,
The center of the heating body is supported by a support so that the heating body is spaced from the bottom part,
The plurality of holes are formed in a central portion of the heating body along a circumferential direction around the pillar,
A liquid heating device characterized by:

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