JP2008224157A - Electric water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric water heater capable of obtaining the required amount of hot water when necessary without needing a large installation space and moreover preventing a hot water temperature from becoming unstable. <P>SOLUTION: A heat transfer body 6 is formed of material with high heat conductivity, and a planar heater 4 formed by covering a plurality of strip thin films made of stainless steel, with resin is mounted on the outer peripheral surface of the heat transfer body 6. An impeller 9 rotationally driven by a motor 12 is arranged in the heat transfer body 6, and a laminar film formed on the inner peripheral surface of the heat transfer body 6 is stripped off by the impeller 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric water heater called an electric water heater or a water heater.

  A conventional electric water heater heats a heater of a hot water storage tank with late-night power, stores hot water boiled to about 85 ° C. in a large amount (often about several hundred liters), and supplies hot water.

  The electric water heater does not require an air supply / exhaust system, and has an advantage that cheap late-night power can be used.

However, the conventional electric water heater has the following problems.
(1) A large space for installing a hot water storage tank is required.
(2) In small-sized households and those who tend to be away, the loss during heat storage is large and uneconomical.
(3) When using hot water that requires reheating, the hot water temperature becomes unstable.

  The present invention has been made in view of such circumstances, and the problem is that a large installation space is not required, a necessary amount of hot water can be obtained when necessary, and the hot water temperature becomes unstable. It is difficult to provide an electric water heater.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a cylindrical heat transfer body made of a material having good thermal conductivity, and a plurality of stainless steel strips mounted on the outer peripheral surface of the heat transfer body. A sheet-like heating element formed by coating a thin film of resin with a resin, an impeller which is rotatably arranged in the heat transfer body and peels off a boundary film formed on an inner peripheral surface of the heat transfer body, and the impeller Drive means for rotationally driving the motor.

  According to a second aspect of the present invention, in the electric water heater according to the first aspect, there is a minute gap between the tip of the impeller and the inner peripheral surface of the heat transfer body.

  According to a third aspect of the present invention, in the electric water heater according to the first aspect, the tip of the impeller is in contact with the inner peripheral surface of the heat transfer body.

  According to a fourth aspect of the present invention, in the electric water heater according to any one of the first to third aspects, the stainless steel is heat-treated at 1300 ° C. by adding indium, zinc and boric acid to nickel. Features.

  According to a fifth aspect of the present invention, in the electric water heater according to any one of the first to fourth aspects, the planar heating element is in close contact with substantially the entire outer peripheral surface of the heat transfer body. .

  A sixth aspect of the present invention is the electric water heater according to any one of the first to fifth aspects, wherein the planar heating element is surrounded by a heat insulating material.

  According to the present invention, it is possible to provide an electric water heater that does not require a large installation space, can obtain a necessary amount of hot water when necessary, and that does not make the hot water temperature unstable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Fig.1 (a) is sectional drawing of the electric water heater which concerns on one Embodiment of this invention, FIG.1 (b) is sectional drawing which follows the AA line of Fig.1 (a).

  This electric water heater includes a jacket 1, closing members 2a and 2b, a heat insulating material 3, a planar heater (planar heating element) 4, a heat transfer body 6, holders 7a and 7b, an impeller 9, an impeller driving device (driving) Means) 20.

  Plate-shaped closing members 2a and 2b are fixed to both ends of the cylindrical jacket 1 in a watertight manner. Holders 7a and 7b are joined to the closing members 2a and 2b.

  A cylindrical heat transfer body 6 is coaxially accommodated in the jacket 1, and one end of the heat transfer body 6 is connected to the central portion of the holder 7 a via a hole 2 a-1 formed in the central portion of the closing member 2 a. Is inserted into the recess 7a-1. The other end of the heat transfer body 6 is inserted into a recess 7b-1 provided in the center of the holder 7b through a hole 2b-1 formed in the center of the closing member 2b.

  The planar heater 4 is in close contact with almost the entire outer peripheral surface of the heat transfer body 6. The planar heater 4 is supplied with electric power from an AC power source (not shown). The planar heater 4 is a heater formed by coating a plurality of strip-shaped thin films with a resin. The material of the thin film is, for example, stainless steel. As an example of stainless steel, there is one in which indium, zinc and boric acid are added to nickel and heat treated at 1300 ° C. Moreover, as resin which coat | covers a some strip | belt-shaped thin film, there exists a polyimide, for example.

  In this embodiment, the number of thin films of stainless steel is 10, the thickness of the thin film is 30 μm, and the width of the thin film is 10 mm. The length of the polyimide film that covers the thin film is 1600 mm and the width is 280 mm.

  In addition, as a material of the heat transfer body 6, for example, a material having good thermal conductivity such as copper or stainless steel is used.

  Inside the jacket 1, a heat insulating material 3 is disposed so as to surround the planar heater 4, and the heat generated by the planar heater 4 is prevented from escaping to the outside.

  The holders 7a and 7b rotatably support both ends of the rotating shaft 9b of the impeller 9. The blade 9a of the impeller 9 is accommodated in the heat transfer body 6, one end of the rotating shaft 9b is in the hole 7a-1 formed in the center of the holder 7a, and the other end of the rotating shaft 9b is in the center of the holder 7b. Are respectively inserted into holes 7b-2 formed in the portion. The number of blades 9a is not limited to two, and may be one or three or more.

  Three fluid passage holes 9c are formed in the blade 9a. The shape of the fluid passage hole 9c is not limited to the illustrated long hole. A blade 9d made of Teflon (registered trademark) is attached to the tip of the blade 9a.

  A pulley 11 is fitted to one end of the rotating shaft 9b.

  A V-belt 13 is laid between the pulley 11 and the pulley 12b fitted to the shaft 12a of the motor 12. The motor 12 is connected to an AC power source (not shown). The impeller driving device 20 includes a motor 12, a pulley 12 b fitted to a shaft 12 a of the motor 12, a V belt 13, and a pulley 11.

  In this embodiment, a pulley type mechanism is used as a mechanism for rotating the impeller 9. However, instead of this, for example, a gear type or a chain type may be used. You may employ | adopt the direct drive system directly connected to the axis | shaft 12a.

  The holder 7b is provided with an inlet 10a for water W, and the holder 7a is provided with an outlet 10b. When water that has flowed into the heat transfer body 6 from the inlet 10a connected to a water supply (not shown) passes through the heat transfer body 6, heat exchange is performed between the water and the planar heater 4 so that the hot water flows. It flows out from the outlet 10b.

  Next, the operation of this electric water heater will be described.

  Water is fed into the heat transfer body 6 from the inlet 10a to supply power (25V, 1.1A) to the planar heater 4 and power to the motor 12.

  When power is supplied to the planar heater 4, the temperature of the planar heater 4 rises to 135 ° C.

  Further, when electric power is supplied to the motor 12, the shaft 12a of the motor 12 rotates. The rotational force is transmitted to the rotating shaft 9b of the impeller 9 through the pulley 12b, the belt 13, and the pulley 11, and the blade 9a rotates (for example, 1500 rpm). Heat exchange is performed between the water and the planar heater 4 through the heat transfer body 6, and the water in the heat transfer body 6 flows out from the outlet 10b as hot water. At this time, since the film formed on the inner peripheral surface of the heat transfer body 6 is peeled off by the two blades 9a of the impeller 9, the efficiency of heat exchange is improved. For example, when water at 20 ° C. was introduced from the inlet 10a at a rate of 15 liters per minute, hot water at 55 ° C. exited from the outlet 10b.

  Next, the temperature characteristics of the planar heater 4 used in this embodiment will be described in comparison with the temperature characteristics of a conventional planar heater.

  FIG. 2 is a diagram comparing temperature characteristics of a conventional planar heater and the planar heater used in this embodiment. In FIG. 2, the vertical axis and the horizontal axis are temperature (unit: ° C.) and time (unit: second), respectively. A solid line a indicates the temperature characteristic of the planar heater 4 used in the present invention, and a broken line b indicates the temperature characteristic of the conventional planar heater.

  A conventional planar heater is obtained by silk-printing a film obtained by kneading carbon powder with a binder (ink or paint-like organic chemical adhesive). The electric power supplied to this conventional planar heater is 120 W (100 V, 1.2 A).

  The power supplied to the planar heater 4 used in this embodiment is 117 W (100 V, 1.17 A).

  It can be seen from FIG. 2 that the planar heater 4 used in this embodiment is heated more quickly than the conventional planar heater, and at a higher temperature than the conventional planar heater. The temperature can be set from room temperature (20 ° C.) to 1480 ° C. by controlling the power supplied to the planar heater 4.

  According to this embodiment, since the water stored in the tank is not boiled and hot water is supplied, a large space for installing an electric water heater is not required, and a necessary amount of hot water is obtained when necessary. be able to. In addition, since the water temperature can be quickly raised, the temperature of the hot water is not likely to become unstable.

  Further, since the blade 9d located at the tip of the blade 9a is in contact with the inner peripheral surface of the heat transfer body 6, the boundary film can be surely peeled off.

  Furthermore, since the planar heater 4 is surrounded by the heat insulating material 3, the heat of the planar heater 4 is prevented from moving toward the jacket 1, and the thermal efficiency is improved.

  In the above-described embodiment, the blade 9d located at the tip of the blade 9a and the inner peripheral surface of the heat transfer body 6 are in contact with each other, but a minute amount is between the blade 9d and the inner peripheral surface of the heat transfer body 6. A gap (for example, about 2 mm) may be formed. Further, a minute gap (for example, about 2 mm) may be formed between the tip of the blade 9a and the inner peripheral surface of the heat transfer body 6 without using the blade 9d. In this way, since the blade 9d is not worn, durability can be improved.

  Further, in the above-described embodiment, the planar heater 4 is in close contact with almost the entire outer peripheral surface of the heat transfer body 6, but the planar heater 4 may be in close contact with only a part of the outer peripheral surface of the heat transfer body 6. .

  Furthermore, in the said embodiment, although the impeller 9 was rotated, you may make it rotate the heat exchanger 6 instead of rotating the impeller 9. FIG.

Fig.1 (a) is sectional drawing of the electric water heater which concerns on one Embodiment of this invention, FIG.1 (b) is sectional drawing which follows the AA line of Fig.1 (a). FIG. 2 is a diagram comparing temperature characteristics of a conventional planar heater and the planar heater used in this embodiment.

Explanation of symbols

  3: heat insulating material, 4: planar heater (planar heating element), 6: heat transfer body, 9: impeller, 11: pulley, 12: motor, 12a: motor shaft, 12b: pulley, 13: V belt , 20: Impeller driving device (driving means).

Claims (6)

A cylindrical heat transfer body made of a material with good thermal conductivity;
A sheet heating element mounted on the outer peripheral surface of the heat transfer body and coated with a plurality of stainless steel strip-shaped thin films with a resin;
An impeller that is rotatably arranged in the heat transfer body and peels off a film formed on an inner peripheral surface of the heat transfer body;
An electric water heater comprising: driving means for rotating the impeller.   The electric water heater according to claim 1, wherein there is a minute gap between the tip of the impeller and the inner peripheral surface of the heat transfer body.   The electric water heater according to claim 1, wherein a tip of the impeller is in contact with an inner peripheral surface of the heat transfer body.   The electric water heater according to any one of claims 1 to 3, wherein the stainless steel is obtained by adding indium, zinc and boric acid to nickel and heat-treating at 1300 ° C.   The electric water heater according to any one of claims 1 to 4, wherein the planar heating element is in close contact with substantially the entire outer peripheral surface of the heat transfer body.   The electric water heater according to any one of claims 1 to 5, wherein the planar heating element is surrounded by a heat insulating material.

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