JP2002005522A - Rapid rise electric water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start supply of hot water several seconds after a faucet is turned on or from a first time, regarding an electric instantaneous water heater. SOLUTION: A heating part is structured with a heating container making contact with water being manufactured, for example, in a short tube state by using copper or its alloy, the side opposite to a portion making contact with water forms a gathering of the surfaces of a cylinder or a regular hexagonal cylinder, an aluminum nitride sheet is laminated thereon as an insulating sheet, and further, the thin resistance sheet of an iron-chrome alloy, etc., is laminated as a heater wire, and the substances are fully adhered together by a heat insulation support tool, and the structure is charged with a heavy current from a source control circuit for heating. Furthermore, in addition to ordinary switch functioned through turning on water by turning on a faucet, a switch which is turned on by pushing it by hand is provided. By previously turning on the switch, a heating part is charged with a heavy-current is a short time of approximate 3-5 seconds for heating. When the faucet is turned on, cold water is set to a minimum level or zero, and hot water is caused to flow out immediately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric instant water heater, which can be fixed in a washroom or a kitchen, or can be carried for nursing care or the like.

[0002]

2. Description of the Related Art Conventionally, an electric water heater winds a heater wire made of a nichrome alloy or the like around an insulating plate such as mica, and heats a pipe through which cold water flows by using a heater covered with the mica as a heater.
Although mica is an excellent insulator, it is also an excellent thermal insulator, so hot water of a sufficient temperature comes out of the water heater only when it is close to the high temperature where the heater wire melts.
It was as late as 3 minutes.

As disclosed in Japanese Patent Application Laid-Open No. 4-278142, there has been a heat exchanger for improving the heat exchange rate by using aluminum nitride, silicon carbide, beryllium oxide or the like as an insulating plate. Since the wire uses a wire, and the insulated and heat-conductive conductor is in contact only with a continuous line of points, it takes time as in the embodiment of FIG. However, when the heat exchange rate was improved, the rise of the initial heating was slow, and the input power was 5.2 KW using a partition plate made of silicon carbide or the like having a diameter of 30 cm. Was 13 times as large because it could be as small as 52 square centimeters with the same power.

Most of the commonly used instantaneous water heaters are gas-type because the electric type is slow. Since the gas type burns, its intake and exhaust are necessary, and since the device also becomes hot,
Many homes and offices are located outside the building. Because of that, the piping from the water heater to the faucet became long, so I had to twist the faucet and wait 0.5 to 1 minute for hot water to come out, and during that time I had to pour out a lot of cold water . After use, the hot water in the long pipe just cooled down uselessly.

[0005]

SUMMARY OF THE INVENTION It was desired that hot water be released as soon as the faucet was twisted. As a result, it was desired to eliminate useless cold water and subsequent warm water until the conventional warm water comes out.
Also, it was desired that the device had a small and simple structure.

[0006]

Means for Solving the Problems An instantaneous water heater is made of electricity, and a heating vessel of a heating section to be inserted into a part or the inside of a fluid vessel is made of, for example, a short tube made of copper or an alloy thereof, and is made of cold water. The opposite side of the contacting surface is a set of surfaces such as a cylinder or a regular hexagonal cylinder, an aluminum nitride thin plate is stacked as an insulating plate on it, and a heater wire made of iron chromium alloy etc. as thin as possible is further stacked, They were sufficiently adhered to each other with a heat insulating support, and a large current was supplied from a power supply control circuit to heat them.

Further, in addition to a normal switch which functions by twisting a faucet to supply water to the power supply control circuit, a switch which is turned on by an operation such as pushing by hand is provided, and 3 to 5 which are set by turning on the switch in advance are provided. The heating section was heated by applying a large current to the heating section for a short time of about 2 seconds, and when the faucet was twisted, the amount of cold water was reduced to a minimum or zero so that hot water was immediately discharged.

[0008]

FIG. 1 shows a pipe-shaped fluid container 1 according to an embodiment of the present invention.
In the perspective view of FIG. 2, the heating unit 2 forms a part thereof, but a heat insulating support, such as a heat insulating material and a waterproof cover, which is a part of the heating unit is removed for easy understanding in the figure. The fluid container 1 has an inner diameter of 12
A copper pipe having a thickness of 1 mm and a thickness of 1 mm is used, and both ends thereof are formed into flares, and a flare nut 3 is fitted so that the pipes can be connected to the front and rear pipes. The heating container 4 was formed in the middle thereof into a regular hexagonal column having a side of 7 mm, and a 0.6 mm thin aluminum nitride plate 5 and a heater wire 6 were further laminated on the plane.

When the heater wire 6 is strengthened by appropriately tempering a metal plate such as an iron chromium alloy and tempering such as tempering, the thickness is reduced to about 0.1 mm. As shown in the above, even if a zigzag shape having a width of 2 mm is formed on each surface of a regular hexagonal prism having a width of 7 mm, the shape can be maintained independently. The method of bringing it into close contact is a heat insulating support, that is, covering with a ceramic heat insulating material, wrapping a tape such as silicon rubber, and pressing,
The material may be held down by a spring-like housing, and a material capable of absorbing thermal deformation may be partially used.

Next, when a current is sent from the lead portion 7 whose outlet is drawn out, the heater wire 6 generates heat, but is immediately absorbed by the closely adhered aluminum nitride plate 5 having a thermal conductivity nearly ten times higher. Heat is also absorbed by the copper heating vessel 4 which is more than twice as high. Heat is transmitted to the inner wall 0.5 seconds after the current starts to flow, so that the warm water that has received the heat starts to be emitted in a few seconds.

With the structure shown in FIG. 1, the heating can be performed at a density of 100 W per square centimeter of the aluminum nitride plate.
If the electric energy is W, the area of the hexagonal prism of the short pipe 4 is 20 square centimeters,
That is, if one side of the hexagon is 7 mm in width, the length may be only 5 cm. Although the power can be applied even at twice the density of the heat shock resistance of the aluminum nitride plate, if a part of the heater wire 6 is slightly floated from the aluminum nitride plate 5, it may be burned out. Consideration was also given to safety in manufacturing.

Thereafter, since the thermal conductivity of water is poor, the temperature of the copper wall surface rises, the temperature difference increases, the amount of thermal conductivity increases, and the calorie is settled down. However, the heat transfer from the copper wall to the water is not only due to the heat flow from the wall and the water flow including convection, but also because the water turns into steam, and the amount of heat transfer is very large. Not far from the steam temperature.

Accordingly, the heating area may be reduced positively, and a large number of fine screw-shaped depressions may be provided on the inner wall so that nucleate boiling is performed instead of film boiling as in a boiler. The temperature difference can be reduced and the temperature of the heating section can be reduced by devising the length of the heating section and the structure of the inner wall such as fins so that only a large surface area and a flow velocity can be obtained.

When heating is performed in the same manner as in a boiler heat transfer tube, minerals in water are deposited on the inner wall of the tube and the scale adheres to the tube, which may reduce the heat transfer effect.
It is necessary to remove with a chemical such as citric acid. Therefore, as shown in FIG. 1, it may be in a form that can be inspected if it is detached. However, as shown in the side view of FIG. 2, the fluid container 8 is a cylinder, and the connecting portions 9 to the front and rear pipes are branched off in front of both ends. Thus, a shape that facilitates maintenance and inspection by opening the flange 10 at the end of the short pipe 8 or by throwing a chemical through the inspection port 11 without removing the pipe may be used.

In this case, the heating section can be provided outside,
As shown by a dotted line in the center of FIG. 2, the heating vessel 12 may be a short tube inserted from below. This heating container 12
Is closed at one end, an aluminum nitride plate and a heater wire are closely adhered to the inner wall surface, and a heat insulating material such as glass cloth or magnesium oxide powder is filled. To be attached to the fluid container 8

When an aluminum nitride plate is brought into close contact with the inner and outer walls of the heating vessel, an adhesive obtained by mixing aluminum nitride fine powder with silicon, or an adhesive or a grease that enhances the same heat transfer effect is applied to the gap. Since the heater of the present invention heats at a relatively low temperature, it can be used and is very effective. Using these, the aluminum nitride plate 16 may be fitted to the curved surface while the wall surface 15 of the heating vessel remains cylindrical as shown in the sectional view of FIG. The point is that the wall should be flat or a loose quadratic surface

According to the present invention, the heater wire is formed in a zigzag shape so as to absorb linear expansion due to heat. Therefore, the heater wire is preferably folded at a shorter distance. In addition, not only iron chrome but also high resistance metal such as nichrome and kanthal can be used. When the resistance is constant, that is, when the cross-sectional area is constant, if the thickness is reduced to half, the contact area becomes 2
In order to make it as thin as possible, it is tempered by quenching and tempering to give it waist and tenacity, and the shape is devised as follows.

Since the water heater has a large amount of heat, a large current flows through the heater wire. However, if the heater wire does not adhere to the aluminum nitride, it quickly becomes hot and burns out. At the ridges and corners 17 of the container and the lead portion 7 of the heater wire, the heater wire must be widened 18 to 2 to 5 times to suppress the heat generation itself. However, if the narrow width is suddenly widened, stress concentrates on the narrow portion immediately before, and it is easy to break depending on the width. Therefore, it is preferable to gradually widen or narrow the width as shown in FIG. With these measures and quenching, the heater wire 6 can maintain its shape autonomously even if it is as thin as about 0.1 mm, that is, even by handling during processing or thermal expansion during use.

Even if the heating vessel is not a short tube, even if the vessel is provided with an inlet and an outlet and a water flow path, for example, a disc-shaped vessel, the present invention can function as long as the aluminum nitride thin plate or the heater wire comes into close contact with the outside. However, since the present invention heats in a very short time, if the whole does not expand uniformly, distortion or fatigue occurs at each rapid heating, and if it accumulates, shift or breakage occurs, and the life is shortened. Due to the shortening, the entire container needs to be made of copper or alloys thereof having high thermal conductivity, and heating from all around is desirable.

The electric water heater should be waterproof so that there is no danger of electric leakage due to water leakage. However, since the heater wire of this water heater is thin and is close to the inner wall in contact with running water by aluminum nitride, it has a low temperature and glass cloth. It can be wound with silicone rubber, and the gap can be waterproofed with caulking material, or it can be wound with urethane rubber with ceramic insulation added. Can be selected.

Materials that conduct heat very well while electrically insulating the heater wire and the heating vessel include aluminum nitride, silicon carbide, beryllium oxide, boron nitride, etc., but silicon carbide is too hard. It cannot be processed into a thin plate, beryllium oxide has a high toxicity, and boron nitride has a drawback such as poor heat conduction in the thickness direction of the layer. Therefore, only aluminum nitride or a mixture thereof is practical, has high thermal conductivity as well as high thermal shock, and allows a large current to flow, so that the rapid heating of the present invention functions.

As shown in FIG. 1, if a temperature sensor 19 is provided at a position slightly downstream or upstream of the heating section as shown in FIG. 1, the minimum safety management for hot water can be performed. However, in some cases, the control section may be faulty or the supplied water may be too large, resulting in overheating due to a small amount of flowing water.Therefore, a safety device such as a mechanical hot-water mixer is installed between the faucet and high-temperature water or steam is never discharged. It is good not to have it.

The electric water heater of the present invention can reduce useless cold water by further devising a power supply control circuit. The power control circuit has a switch that senses the reduced water pressure by twisting the faucet and discharging water, but separately from it, for example, if you manually press the switch provided on the top of the wash basin, If an extra circuit is provided for heating the heating section by flowing an electric current only for a few seconds, then when the faucet is twisted immediately thereafter, the amount of cold water is reduced by that amount, and hot water comes out.

In this case, the time to be set is short enough to wait until the faucet is twisted, so that it may be slightly longer. In addition to pressing the switch by hand, the sensor operates by standing in front of the sink. Alternatively, it may be based on a predetermined operation set in advance. Further, the expression of turning on the switch means that the same relay as the faucet is turned on in the circuit in the sense that the circuit is operated or a signal for that is transmitted.

The timing of twisting the faucet is preferably immediately after the short time expires, but it may be overlapped, or may be delayed for a while, so that care is not taken so much. For this reason, in the case where the switch is repeatedly pressed and the switch is overheated, the temperature may be detected by the provided temperature sensor and the temperature may be prevented from being further heated. Of course, this control circuit is not limited to the electric water heater of the present invention, but can be applied to any electric water heater that performs quick heating.

[0026]

The water heater according to the present invention is very energy-saving, so that the hot water comes out as soon as the faucet is twisted, so that there is little waste of cold water, and there is little hot water stored in the piping when it has been used.

Not only resources such as energy and water,
There is little wasted time waiting.

The structure in which the switch is pressed before the power supply control circuit further reduces waste of energy and time.

It is convenient for transportation, and since the heating part is at a low temperature, heat insulation and waterproofing can be easily performed, and the device becomes extremely small.

The low temperature of the heating section facilitates maintenance, makes the life of the heater wires and other components long, and makes it easy to maintain high heating performance for a long time.

[0031] Despite its high performance, it is very economical and requires a minimum of expensive aluminum nitride plates and low manufacturing costs.

[Brief description of the drawings]

FIG. 1 is a perspective view of a fluid container and a heating unit showing an example of the present invention.

FIG. 2 is a side view of an example of another fluid container and a heating container.

FIG. 3 is a cross-sectional view of an aluminum nitride plate in close contact with a pipe-shaped heating vessel.

[Explanation of symbols]

1 fluid container 2 heating unit 3 connection nut 4 heating container
5 Aluminum nitride plate 6 Heater wire 7 Lead 8 Fluid container 9 Connection
10 Flange 11 Inspection port 12 Heating vessel 13 Lead wire 14 Mounting flange 15 Heating vessel 16 Aluminum nitride plate 17 Ridge or corner 1
8 wide section 19 temperature sensor

Claims (6)

[Claims] 1. A heating unit provided at least in part or inside of a fluid container which comprises at least a fluid container, a heating unit, and a power supply control circuit and is connected to front and rear pipes to allow water to flow inside. In an electric water heater that heats by flowing an electric current from a circuit, a heating part of the heating vessel, which also constitutes a part or the inside of the fluid container, is made of copper or an alloy thereof with a flat surface or a surface opposite to a surface in contact with water. Formed as a set of easy-to-adhere surfaces such as loose quadratic surfaces, and overlaid aluminum nitride thin plates on those surfaces,
Furthermore, quenching a metal plate such as an iron-chromium alloy strengthens the stiffness, superimposes heater wires formed as thin as possible to maintain their shape independently, and closely adheres them to each other with heat insulating supports. An electric water heater characterized in that it has a structure that allows a large current to flow through the heater wire, thereby rapidly heating water. 2. A heating vessel of a heating section is formed as a short pipe of a part of a pipe-shaped fluid vessel, and the outside thereof is formed into a set of surfaces that are easily adhered to each other, such as a cylinder or a regular hexagonal cylinder. 2. The electric water heater according to claim 1, wherein a heater wire of a thin plate of aluminum nitride or a thin metal plate of iron chrome alloy or the like is superposed on the surface, and the heater wires are closely adhered by a heat insulating support. 3. The heating vessel of the heating section is a short pipe inserted into the fluid container, and the inside thereof is formed into a set of easily adhered surfaces such as a cylinder and a regular hexagonal cylinder, and is formed on the surface. 2. The electric water heater according to claim 1, wherein a heater wire of a thin plate of aluminum nitride and a thin metal plate of an iron-chromium alloy or the like is overlapped, and they are closely adhered to each other with a heat insulating support. 4. A shape in which a heater wire of a heating unit is made of a thin plate made of iron-chromium alloy or the like to be strengthened by tempering, and furthermore, a heat-generating portion has a constant narrow width, and is desirably folded back at a shorter distance. In addition, the parts that do not adhere to the aluminum nitride thin plate at the leads, ridges and corners are greatly widened, and the width change is desirably gradual, and the thickness is reduced as far as their shapes can be maintained independently. The electric water heater according to claim 1, wherein the electric water heater has a structure. 5. A power supply control circuit is provided with a switch which can be turned on by a predetermined operation such as pushing by hand, in addition to a normal switch which functions by turning a faucet and discharging water, and set by turning on the switch in advance. It is characterized by a structure in which a large current is passed through the heating section for a short time of about 3 to 5 seconds to heat it, and when the faucet is twisted, the cold water is minimized or eliminated, and the hot water comes out immediately. Electric water heater that can be heated. 6. A power supply control circuit is provided with a switch which can be turned on by a predetermined operation such as pushing by hand, in addition to a normal switch which functions by twisting a faucet and discharging water, and set by turning on the switch in advance. A structure in which a large current is supplied to the heating section for a short period of time, about 3 to 5 seconds, and heating is performed. When the faucet is twisted, the temperature of the cold water is minimized or reduced to zero so that hot water is immediately discharged. 1 electric water heater.