JP2001102159A - Metal heater for heating water, hot water supplier using it, and hygienic cleaner with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and thin metal heater for heating water that may be used in water or highly moisturized environment with high heat exchange efficiency, and hot water supplier using it. SOLUTION: A metal heater 71 comprises a metal plate 1, glass insulating layer 2 deposited on a surface of the metal plate, a resistance heating body 3 arranged on the glass insulating layer 2, electrode layers 4a and 4b respectively formed at both ends of the heating body, insulating layer formed on the surface of the resistance heating body except the electrode layers, insulating protective layer 5 formed on the insulating layer with the same material as that, and conductive terminals 6a and 6b connected to the electrode layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a heater for heating hot water for heating water to a predetermined temperature, a hot water apparatus using the same,
And a sanitary washing device provided with the same.

[0002]

2. Description of the Related Art Conventionally, as a heater for heating hot water, for example, a heater disclosed in JP-A-8-262908 shown in FIG. 31 is known. This metal pipe heater 50 is
An insulating layer 52 made of an organic resin such as polyimide, phenol, silicon, or borosiloxane is provided on the outer periphery of the metal pipe 51.
The heating resistor 53 is formed through the
Protective layer 5 made of synthetic resin or glass on the surface of
4 are formed, and electrode rings 55 a and 55 b are attached to both ends of the heating resistor 53.

[0003] A power supply voltage is connected between the two electrode rings 55a and 55b to energize the heating resistor 53 so that the heating resistor 53 is heated. Can be.

[0004] As a heater for heating hot water using the thick film printing technique, a ceramic heater shown in FIG. 32 is also conceivable. This ceramic heater 60 is used for the ceramic sheet 6.
1a, a heating resistor 62 is formed on the surface,
After the ceramic sheet 61b is laminated on the surface of the heating resistor 2 and integrally fired, current-carrying terminals 63a and 63
b.

The power supply voltage is connected between the power supply terminals 63a and 63b and the power supply is energized, so that the heating resistor 62 is heated, and the water in contact with the surface of the ceramic heater 60 can be heated to be hot water.

[0006]

However, FIG.
When the heating resistor 53 is heated in a state where there is no water in the metal pipe 51, the organic resin used for the insulating layer 52 is melted and the insulation is deteriorated.

Further, when the insulating layer 52 is melted, the heating resistor 53 formed on the surface of the insulating layer 52 is distorted or disconnected, and the resistance value is partially changed to cause local heating or an unheatable state. Leads to.

A ceramic heater 60 shown in FIG.
Is weak against thermal shock, so that the ceramic heater 60
When the temperature difference between the internal temperature of the heater and the water to be heated (hereinafter referred to as “cold water”) increases, the heater breaks and the heating resistor 62
May be exposed and leak to water.

In order to prevent this, the ceramic heater 6
It is conceivable to heat the water via a metal instead of directly heating the water on the 0 surface, but the heat transfer rate is reduced due to indirect heating. In this case, it is conceivable to improve the heat transfer coefficient by reducing the thickness of the ceramic heater 60, but on the other hand, the mechanical strength against thermal stress is reduced.

Further, in order to improve the reliability and safety, if the temperature detecting pattern and the crack detecting pattern are arranged in a layer different from the heating resistor 62 inside the ceramic heater 60, the ceramic heater 60 becomes thick. The heat transfer coefficient decreases.

When the wiring density of the heating resistor 62 and the like is increased, when the ceramic sheets 61 are stacked and fired, the adhesion between the ceramic sheets 61 is reduced and voids are generated inside, so that the heat resistance is reduced. There is also the disadvantage that it decreases.

Therefore, the ceramic heater 60 shown in FIG.
Due to the nature and structural problems of ceramic,
There is a limit in reducing the thickness, and it has been difficult to obtain a small and thin hot water device using this.

On the other hand, as shown in FIG. 33, it is conceivable to use a cylindrical ceramic heater 80 to solve the above-mentioned problem and make the water heater compact. The ceramic heater 80 has a water inlet 81 at one end and a tap 8 at multiple ends.
A channel is formed as 2, and hot water is obtained by flowing water only inside the ceramic heater 80. In this case, when much of the heat from the heating resistor 84 embedded in the ceramic base material 83 is released to the outside (surface side) of the ceramic heater 80, the heat exchange efficiency is reduced and the peripheral devices are adversely affected. Is a problem.

When the heating resistor 84 is disposed in a meandering state on the ceramic base 83 in consideration of the heat generation efficiency and the like, current concentrates on the inner peripheral side of the bent portion 84a of the heating resistor 84. The flow causes local heating, and when cold water comes into contact therewith, the ceramic heater 80 is cracked, the heating resistor 84 is disconnected, and the ceramic heater 80 is heated.
There is a risk of water leaking from the broken part.

In addition, abnormal heating due to malfunctions of peripheral devices such as an energization control circuit of the ceramic heater 80 and an opening / closing valve, or cold water in contact with a portion of the ceramic heater 80 that has been locally heated due to adhesion of bubbles or foreign matter, etc. In such a case, a similar phenomenon may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a small or thin metal that can be used in water or in a high-humidity atmosphere and has excellent resistance to cold and thermal shocks and heat exchange efficiency. It is an object of the present invention to provide a heater, a hot water device using the same, and a sanitary washing device including the same.

[0017]

According to a first aspect of the present invention, there is provided an insulating layer formed on a surface of a metal substrate with a material having a thermal expansion coefficient substantially equal to that of the metal substrate. When,
The metal heater includes a heating resistor formed on a surface of the insulating layer, an insulating protection layer formed on a surface of the heating resistor, and a current-carrying terminal connected to the heating resistor.

Therefore, even if the inside of the metal heater is heated to a high temperature due to boil-off or adhesion of foreign matter such as scale when energizing the metal heater, a glass material or the like having the same thermal expansion coefficient as that of the metal base material is used for the insulating layer. Therefore, it is possible to prevent the insulating layer from being deteriorated by melting or cracking. Further, it is possible to prevent abnormal heating such as local heating due to distortion of the heat generating resistor due to melting of the insulating layer and heating impossible state due to disconnection. Furthermore, since the thermal shock resistance is excellent, it is possible to simultaneously improve the heat transfer coefficient and reduce the thickness. Further, the improvement of the heat transfer coefficient makes it possible to increase the watt density, so that the size can be further reduced.

According to a second aspect of the present invention, an electrode layer is formed on the heating resistor, and a current-carrying terminal is connected to the electrode layer. Therefore, the connection strength is improved when the energizing terminals are brazed, etc., the specific resistance of the electrode layer is made lower than that of the heat generating resistor, and the heat generation at the terminal connecting portion can be suppressed.

According to a third aspect of the present invention, the insulating layer and the insulating protective layer are formed of the same material. Therefore, the adhesion at high temperatures is improved, and the durability is improved.

According to a fourth aspect of the present invention, a metal material having the same thermal expansion coefficient as that of the insulating protective layer is laminated on the surface of the insulating protective layer. Thereby, waterproofness is improved, and even when used in water such as a hot water tank, insulation between water and the heating resistor is ensured, and safety is achieved without electric leakage. Furthermore,
If the insulating layer and the insulating protective layer exposed from the end of the metal material are respectively coated with a heat-resistant resin, the waterproofness and safety are further improved.

The invention according to claim 5 is characterized in that the thickness of the metal substrate is in the range of 0.1 to 5 mm. It is preferable that the metal base material used for the metal heater is thinner to reduce the heat capacity, and to improve the thermal responsiveness and the heat transfer coefficient. By improving the heat transfer coefficient, it is possible to increase the watt density, and it is possible to further reduce the size. On the other hand, when manufacturing a metal heater, a metal base material is fixed, and in order to form a uniform insulating layer, a heating resistor, and an insulating protective layer in a predetermined position by screen printing or the like, no distortion occurs in the metal equipment. About the thickness is required. In addition, in order to provide sufficient mechanical strength when used as a metal heater, the thickness of the metal base may need to be further increased.

Therefore, when the metal heater of the present invention is formed for hot water heating in which an unexpected mechanical force does not act on the metal heater and priority is given to control responsiveness, the thickness of the metal heater is set to 0.1 mm.
In the case where the thickness is 1 mm or more and the strength of the metal heater is prioritized, the thickness of the metal substrate is preferably 5 mm or less in order to secure a predetermined watt density and thermal responsiveness.

The invention according to claim 6 is characterized in that the thickness of the insulating layer and the insulating protective layer is in the range of 20 to 500 μm. It is preferable that the insulating layer / insulating protective layer formed on the surface or the like of the metal heater be made thinner to reduce the heat capacity of the metal heater and to improve the thermal responsiveness and the heat transfer coefficient. On the other hand, when forming the insulating layer and the insulating protective layer, a certain thickness is required in order to provide a withstand voltage according to the power supply voltage. In addition, since the insulating layer and the insulating protective layer are formed of a glass material, it is necessary to eliminate the porous state of the glass. Therefore, the metal heater of the present invention has an insulating layer and an insulating layer when the power consumption and the watt density of the metal heater are relatively low (for example, when the power consumption is 50 W or less and the watt density is 1 W / cm ² or less). When the thickness of the protective layer is 20 μm or more, and the power consumption and the watt density of the metal heater are relatively high, the thickness of the insulating layer and the insulating protective layer is 300 μm or less in order to secure a predetermined thermal response. Is preferred. In addition, since the water resistance is improved by increasing the thickness of the insulating protective layer, even when used in water or in a high humidity atmosphere, insulation between water and the heating resistor is ensured, and safety is achieved without leakage.

According to a seventh aspect of the present invention, the heat generating resistor is arranged so that the temperature of the heat generating portion near the heat generating resistor becomes substantially uniform. Therefore, since the temperature difference between the highest temperature portion and the lowest temperature portion of the heat generating portion can be reduced, distortion and warpage of the metal base material due to thermal stress can be prevented.

The invention according to claim 8 is characterized in that a plurality of heating resistors having different resistance values are formed on the same plane. Therefore, power consumption can be easily controlled only by switching the connection to the energizing terminal so as to energize the heating resistor having a large resistance value during warming or standby and to energize the heating resistor having a small resistance value during heating.

According to a ninth aspect of the present invention, a plurality of heating resistors having different resistance values are provided on both surfaces of the insulating layer or both surfaces of the metal substrate, respectively. Therefore, since the heating resistors can be arranged in a well-balanced manner,
The temperature distribution of the heat generating portion can be made uniform.

According to a tenth aspect of the present invention, the temperature detecting means for detecting the temperature of the heat generating portion is formed near the heat generating resistor. Therefore, it is possible to detect the temperature of the heating resistor by using a change in the resistance value due to the temperature characteristic of the temperature detecting means, and it is possible to detect abnormal heating due to empty heating of the metal heater or adhesion of foreign matter on the metal heater surface. In addition, it is possible to conduct electricity efficiently according to the water temperature while detecting the temperature of the heating resistor.

[0029] The invention according to claim 11 is characterized in that an exposure detecting means for detecting the exposure of the heating resistor is formed near the heating resistor. Therefore, even if a crack occurs on the surface of the insulating layer or the insulating protective layer by utilizing the change in the resistance value of the exposure detecting means, the crack or disconnection state of the exposure detecting means is detected before the crack progresses to the heating resistor. Thus, by stopping or cutting off the current supply to the heating resistor, it is possible to prevent electric leakage and electric shock from the heating resistor beforehand.

According to a twelfth aspect of the present invention, a submergence detecting means for detecting a submerged state of the metal base and the insulating protective layer is formed on a surface of the insulating layer. Therefore, it is possible to detect whether the metal heater is submerged by utilizing the resistance component of water generated between the electrodes of the submergence detecting means, and to prevent the metal heater from being idle.

According to a thirteenth aspect of the present invention, a stress relaxation layer is provided on the back surface of the metal base. As the metal base material becomes thinner, bending stress is generated on the surface side of the metal base material on which the insulating layer, the heating resistor, and the insulating protective layer are respectively formed, resulting in distortion. Therefore, distortion can be prevented by forming, on the back surface of the metal base material, a stress relaxation layer having a thickness approximately equal to half of the film thickness formed on the front surface side with a glass material or the like.

According to a fourteenth aspect of the present invention, a flange formed of a heat-resistant resin is disposed in a non-heat generating portion between the current-carrying terminal and the heat generating portion. Therefore, when the metal heater is attached to the hot water tank or the like, the metal heater can be easily installed at a predetermined position, and the water seal can be reliably performed by using a sealing material such as an O-ring. In addition, when the flange is formed integrally with the metal heater using a heat-resistant resin, it is possible to prevent a short circuit between the heating resistors and the like formed on the surface of the metal base material and to manufacture the heater at low cost. .

According to a fifteenth aspect of the present invention, a through hole is provided in the non-heating portion of the metal base. Therefore,
When the metal heater is mounted on a hot water tank or the like, it can be easily installed at a predetermined position in a space-saving manner, and a water seal can be reliably performed by using a sealing material such as an O-ring.

According to a sixteenth aspect of the present invention, the heat generating portion covered with the insulating protective layer and its vicinity are covered with a heat insulating material. Therefore, when water is passed through the metal substrate surface and heated, heat radiation from the surface of the insulating protective layer can be suppressed, and a decrease in heat exchange efficiency can be suppressed. Further, it is possible to prevent the peripheral members from being exposed to a high-temperature environment. Further, it is safe because the human body can be prevented from contacting the heat generating portion of the metal heater during maintenance or the like.

According to a seventeenth aspect of the present invention, there is provided an insulating layer laminated on substantially the entire surface of a metal substrate, a rectangular heating resistor provided on the surface of the insulating layer, and an opposing face of the heating resistor. A plurality of electrodes connected to the end portion, a plurality of terminals respectively connected to the electrodes, a protective layer laminated on the surface of the heating resistor,
It is characterized by having. Since the heating resistor is formed in a rectangular shape (square, rectangle, etc.) having no bent portion, current is not locally sparse and dense, and disconnection due to local abnormal heating can be prevented. Also, for example, when a heating resistor having a low sheet resistance value is disposed in a meandering shape, a portion where the heating resistor is disposed when the thickness of the base material is reduced,
Since a temperature difference is generated between the other portions and the other portions, heat cannot be generated uniformly. However, by forming the heating resistor on substantially the entire surface, even if the thickness of the base material is reduced, heat generation does not occur. When miniaturizing the heater, the W
Density can be reduced, and by reducing the temperature rise per unit area of the heating resistor, distortion due to thermal stress of the substrate can also be suppressed. Further, by disposing a plurality of heating resistors in parallel connection and changing their shapes (width, length, etc.) and sheet resistance values variously. At any position,
It is easy to obtain an arbitrary heating value.

The invention according to claim 18 is characterized in that the sheet resistance of the electrode is lower than the sheet resistance of the heating resistor. If the electrode and the heating resistor have the same sheet resistance, the heater must be larger than the heating resistor in order to prevent the electrode from generating heat. Is extremely smaller than the sheet resistance value of the heating resistor, the electrodes can be made thinner and the heater itself can be made more compact. In addition, it is possible to uniformly supply a current to the entire heating resistor, and the heater can be uniformly heated.

According to a nineteenth aspect of the present invention, a plurality of the heating resistors are provided and connected in series, and connected in series by a conductor having a sheet resistance lower than the sheet resistance of the heating resistor. It is characterized by having. By making the sheet resistance value of the conductor extremely lower than the sheet resistance value of the heating resistor, current does not intensively flow in the bent portion, and local heating can be prevented. By using a material having a low sheet resistance, a high-power heater in which a plurality of thin-line heating elements are provided can be formed.

According to a twentieth aspect of the present invention, in the hot water apparatus according to the present invention, the metal heater is disposed near a tank, and the tank is heated by a water inlet for supplying water into the tank. And a water outlet for discharging the heated water to the outside. Therefore, since the metal heater serving as the heating means is small or thin and has excellent heat transfer coefficient, the entire tank and the hot water device can be reduced in size or thickness.

Further, if a metal heater having a temperature detecting means is used, it is possible to detect the water temperature inside the tank when the heating resistor is not energized by using a thermistor or the like arranged inside the tank or downstream of the water discharge port. By comparing the water temperature detected by the water temperature detecting means with the water temperature detected by the temperature detecting means, it is possible to detect a malfunction of the water temperature detecting means, thereby improving safety. In addition, safety can be improved because it is possible to quickly detect the empty heating of the metal heater and prevent the inside of the tank from becoming hot and damaged. Furthermore, when foreign matter or the like adheres to the surface of the metal heater and the heat transfer coefficient decreases, abnormal heating of the heating resistor can be detected, so that the reliability of the metal heater is improved. Then, it is possible to efficiently energize according to the water temperature while detecting the temperature of the heating resistor. When a metal heater provided with an exposure detection means is used, when a crack is generated from the surface of the insulating layer or the insulating protective layer and the insulation between the heating resistor and water in the tank may be reduced or reduced, the heating resistor may be used. And the leakage of electric current from the heating resistor to water inside the tank can be prevented, thereby improving safety. In addition, when a metal heater having a submergence detecting means is used, when there is no water in the tank and the metal heater heating portion is exposed to the atmosphere, the power supply to the heating resistor is cut off to empty the metal heater. Can be prevented, so that safety is improved.

In recent years, sanitary washing devices have become more compact, and there is a demand for a small-sized hot water device having excellent thermal responsiveness. An instantaneous heating type hot water device using a ceramic heater is mainly used as a hot water heating means. However, ceramic heaters are vulnerable to heat shock. If the temperature difference between the internal temperature of the ceramic heater and the water in contact with the surface exceeds 150 ° C., the ceramic heater is likely to crack. Therefore, it is impossible to increase the watt density and reduce the size. There is a limit. Therefore, by using the small-sized hot water device having a metal heater having excellent heat responsiveness and strong heat shock according to the present invention, it is possible to further reduce the size of the sanitary washing device. In addition, by using the metal heater in which the temperature detecting means, the exposure detecting means, and the submergence detecting means are formed, a malfunction of the instantaneously heated hot water device can be quickly detected, thereby improving safety.

According to a twenty-first aspect of the present invention, there is provided a turbulent flow promoting means provided for promoting turbulent flow of water inside the tank and / or a flow rate improving means for increasing the flow rate of water. Features. Therefore, the water temperature in the tank can be made uniform, and the heat transfer coefficient can be improved even if the flow rate of the water is small. As the turbulence promoting means and the flow velocity improving means, it is possible to appropriately adopt a configuration such as forming an uneven portion on the inner wall of the tank according to the flowing water path or disposing a resin or metal plate inside the tank.

[0042] The invention according to claim 22 is characterized in that:
An opening for contacting the metal base of the metal heater with water supplied to the tank is provided. Therefore, the metal heater can be efficiently arranged near the tank. Further, since the metal heater is small or thin and has an excellent heat transfer coefficient, sufficient hot water can be supplied even if the tank is reduced in size or thickness.

According to a twenty-third aspect of the present invention, there is provided a hot water device using the metal heater,
The metal substrate has a cylindrical shape, one end is connected to a water supply flow path, and the other end is connected to a discharge flow path, and the water flowing from the water supply flow path is heated by the heating resistor and discharged from the discharge flow path. The electrodes are arranged so that a current flowing through the heating resistor flows in a direction perpendicular to a direction in which water enters.

When hot water is generated by flowing water into the cylindrical heater, the surface temperature distribution of the heating resistor is biased with time near the water inlet side and near the water outlet side. In particular, such a problem is solved by, for example, arranging a flow rate improving means such as a rod or a spiral body inside a cylindrical metal base material in order to improve the heat transfer coefficient and reduce the surface temperature and the boiling noise. In such a case, the W density becomes large, so that it appears remarkably. Therefore, by arranging the plurality of electrodes so that the current flowing through the heating resistor flows in a direction perpendicular to the water entry direction, the amount of current flowing through the heating resistor on the water inlet side and the tap hole side is determined. Can be adjusted, so that the surface temperature distribution of the heater can be made uniform.

By adopting the above-mentioned hot water device for a sanitary washing device, the entire device can be reduced in size, can be installed in a narrow toilet which has conventionally been difficult to install, and can be easily installed and maintained. A cleaning device can be obtained.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a metal heater according to the present invention and a water heater using the same will be described. Since the configuration of the sanitary washing device is conventionally known, illustration and detailed description are omitted.

(First Embodiment of Hot Water Device) FIG. 1 shows an embodiment of a hot water device for a sanitary washing device using a flat metal heater according to the present invention.
Is a so-called hot water storage type, and includes a tank 22 for storing water for a predetermined time, and a metal heater 71 for heating water supplied to the tank 22 to generate hot water. A hot air path 35 is also provided. The tank 22 includes a tank 22
A water inlet 23 for supplying water to the water, a water outlet 24 for discharging hot water to the outside, and an opening 29 through which a metal base 1 side of the metal heater 71, which will be described later, comes into contact with water are formed.
An O-ring 25 is provided around the opening 29 to ensure watertightness.

The metal heater 71 is disposed so that the metal substrate 1 side is exposed to the tank 22 side and the opposite side to the metal substrate 1 is exposed to the warm air path 35 side, and both the water and the air are simultaneously exposed. Heating is performed so that hot water for local cleaning and hot air used for local drying or room heating can be simultaneously formed. The metal heater 71 has a through hole 19 to be described later.
The through-hole 19 is used to form an opening 29.
A metal heater 71 is fixed from outside or inside of the tank 22 with screws 26 to form a hot water device.

The air flowing from the external air intake 36 provided in the hot air path 35 is heated by the metal heater 71,
The air is blown to the outside by the blowing fan 34 and can be used as a drying and heating device. Reference numeral 6 denotes an energizing terminal of a metal heater 71 described later. Then, a power supply voltage is connected to the energizing terminal 6 of the flat metal heater 71 and energized, so that the water inlet 2
The water that has flowed into the tank 22 from 3 is instantaneously heated and becomes warm water, and flows out from the water discharge port 24. In addition, water inlet 2
By forming the water discharge port 3 and the water discharge port 24 with a conductive metal such as stainless steel and grounding the water, it is possible to prevent the water in the tank 22 from being charged and leaking out of the tank 22 when a leak occurs from the metal heater 71.

(Second Embodiment of Hot Water Device) A second embodiment of the hot water device shown in FIG.
A plurality of projecting walls 27 as turbulence promoting means are provided integrally with
It is characterized in that the heat exchange efficiency is improved by actively disturbing the flow of the water supplied from the water inlet 23 and increasing the area and time during which the metal heater 71 contacts the water. .

Further, in this embodiment, the entire metal heater 71 is disposed so as to be housed in the tank 22, and almost the entire surface of the metal heater 71 is brought into contact with water to improve the heat exchange efficiency. I have. In this embodiment, the tank 22 is divided and formed. First, the metal heater 71 is fixed to the tank 22 with screws 26 in a state where a part of the tank 22 is opened, and then the tank 22 is integrated to form the hot water device 40. . In such a configuration, since the head of the screw 26 also projects into the tank 22, the head of the screw 26 also functions as the turbulence promoting means. In this embodiment, the hot air path 35 is separately provided as necessary.

Since the water inlet 23 is provided below the metal heater 71, turbulence is generated below the metal heater 71, and the heat exchange efficiency can be improved. By tilting the tip of the metal heater 71 upward by 1 to 30 degrees in the drawing, it is possible to prevent the adhesion and stagnation of air bubbles on the surface of the metal heater 71. The internal temperature rise of 71 and local heating can be prevented.

(Third Embodiment of Water Heating Apparatus) FIG. 3 shows a third embodiment of the water heating apparatus according to the present invention. This embodiment is of a so-called instantaneous heating type, and the tank 22 is configured as a flow path through which supplied water simply passes. As in the second embodiment, the inside of the tank 22 is provided with a plurality of walls 28 as flow rate improving means, and the metal heater 71 is provided with a heat insulating material 21 on the side opposite to the contact surface with water.
The feature is that it is covered with.

The heat insulating material 21 can suppress the heat radiation from the metal heater 71 to the atmosphere and improve the heat exchange efficiency. The thickness of the heat insulating material 21 is appropriately adjusted according to the heat radiation amount of the metal heater 71 and the like. Other configurations are the same as those of the above-described embodiments.

(Fourth Embodiment of Water Heating Apparatus) FIG. 4 shows a fourth embodiment of the water heating apparatus. 1 to 3 are cross-sections in the left-right direction, while FIG. 4 is cross-sections in the front-rear direction. In this embodiment, a plurality of projecting walls 28 are provided on the inner wall of the tank 22 as flow rate improving means, and the flow rate of water in the tank 22 is narrowed to increase the flow rate, so that the flow rate of water (supply) is small. The feature is that the heat transfer coefficient is improved.

(First Embodiment of Metal Heater) FIGS. 5 to 7
Next, a first embodiment of the metal heater 71 according to the present invention will be described. The metal heater 71 has a flat metal substrate 1 made of stainless steel, and has an insulating layer 2 having a thickness of about 75 μm formed on the surface thereof using a glass material having substantially the same thermal expansion coefficient as stainless steel. The material of the metal substrate 1 is BA in consideration of corrosion resistance.
SUS304 or SUS44 that has been subjected to a treatment or electrolytic polishing treatment
4. Use a stainless steel material containing a small amount of aluminum.
The thickness of the metal substrate 1 is 0.3 mm or more in consideration of productivity and workability, and 2 m in consideration of heat transfer coefficient and weight reduction.
m is preferable, for example, about 0.5 mm to 1 mm. The heating resistor 3 is formed on the surface of the insulating layer 2 using silver-palladium containing glass, and the electrode layers 4a and 4b are formed on both ends using silver. Electrode layers 4a, 4
The insulating protective layer 5 having a thickness of about 75 .mu.m is formed on the surface of the heating resistor 3 except for the surface b using the same glass material as the insulating layer 2, and the current-carrying terminals 6a and 6b are brazed to the electrode layers 4a and 4b. Connected at And, the two energizing terminals 6
By connecting the power supply voltage between a and 6b, the heating resistor 3 generates heat and acts as a heater for heating hot water. The surface of the metal substrate 1 is formed with good roughness for adhesion to the material of the insulating layer 2.

The insulating layer 2 and the insulating protective layer 5 have a thickness of 1
Using a screen of about 00 μm and baking at a time by repeating printing and drying so that the desired thickness is obtained after baking,
Alternatively, they can be formed by firing each printing.

The heating resistor 3 uses a mixture of glass and a conductive material such as metal to improve the adhesion strength between the insulating layer 2 and the insulating protective layer 5. Further, if the resistance temperature change rate of the heating resistor 3 is set to about 1000 ppm / ° C. and the change in the resistance value due to the temperature change is reduced, the change in the power consumption is small and the controllability is improved. Further, by appropriately changing the glass content, the resistance value, that is, the watt density of the metal heater 71 can be changed without changing the wiring shape of the heating resistor 3.

The wiring width of the heating resistor 3 is 0.3 to 1.5 m.
By setting m, the film thickness can be made uniform at the time of screen printing, and wiring unevenness or bleeding can be prevented, and uneven heating of the metal heater 71 can be prevented. Also, if the wiring width is 0.3 mm or more, an insulation distance corresponding to the power supply voltage can be secured, and even if the wirings are blurred during screen printing, the wirings can be prevented from contacting each other and changing the resistance value. Further, by disposing the heating resistor 3 inside the insulating layer 2 and the insulating protective layer 5 by 0.3 mm or more, variations in the external dimensions of the metal base 1 and screen printing are absorbed, and the heating resistor 3 is insulated. Layer 2 and insulating protective layer 5
Can be reliably coated.

The electrode layers 4 (4a, 4b) are
In addition, it is preferable to use a metal conductive material having good adhesion to the current-carrying terminals 6. Since the connection between the electrode layer 4 and the current-carrying terminal 6 is brazed, there is no problem that the connection between the electrode layer 4 and the current-carrying terminal 6 is disconnected even when the connection portion is heated to a high temperature due to idle heating or the like. In this embodiment, a pin with a header is used for the current-carrying terminal 6, but it is also possible to solder the curved surface of the lead wire to the electrode layer 4.

By forming a plurality of metallized layers on the surface of the metal substrate 1 and brazing a plurality of metal plates to form a heat sink, the heat transfer area can be increased and the heat transfer coefficient can be improved. Suitable for instant heating type hot water equipment.

In the present embodiment, the heating resistor 3 is formed in a serial pattern. However, the heating resistor 3 may be formed in a parallel pattern or a combination of a serial pattern and a parallel pattern according to the heat generation area and the watt density. The metal substrate 1 may be made of a material other than stainless steel, and copper or aluminum can be used as the metal substrate by changing the coefficient of thermal expansion of the glass material used for the insulating layer 2. Since stainless steel has excellent corrosion resistance, it is suitable when sanitary hot water heating is required. On the other hand, copper has a good heat transfer coefficient and can increase the watt density, so that it is suitable when a metal heater needs to be downsized.

Further, the shape of the metal substrate can be appropriately selected from a rod shape, a cylindrical shape, a curved surface shape and the like according to the installation environment of the metal heater 71 and the like. Further, as a material for forming the heating resistor 3, in addition to silver-palladium containing glass,
Silver, silver palladium, platinum, copper,
Tungsten, molybdenum, or the like can be appropriately selected. Tungsten and molybdenum have a large resistance change rate due to the ambient temperature, and the resistance increases as the temperature rises to suppress the current. Therefore, power consumption can be reduced when the ambient environment is high temperature. In addition, the connection position of the energizing terminals 6 can be arranged on both ends of the metal base 1 one by one or on both front and back surfaces according to the installation environment of the metal heater 71.

FIG. 7 is an exploded perspective view of the metal heater 71. The metal heater 71 is formed by laminating an insulating layer 2, a heating resistor 3, an electrode layer 4, and an insulating protective layer 5 in this order on the surface of a flat metal substrate 1, and two heating resistors 3 a on the same plane.
3b is disposed also as the electrode layer 4c. By also using one of the electrodes, the electrode arrangement interval can be widened and the number of conducting terminals 6 can be reduced. With this configuration, a plurality of heating resistors 3 can be formed by one printing, which is advantageous in terms of manufacturing cost and the like.

When the walls 27 and 28 as turbulence promoting means and flow rate improving means are formed of a resin material and brought into contact with the surface of the metal heater 71 as in the embodiment of FIG. In order to prevent the wall portions 27 and 28 from melting due to the heat conduction from 3 and to reduce the heat exchange efficiency of the metal heater 71, it is necessary to pay attention to the positional relationship. That is, it is preferable that the portion where the metal heater 71 abuts on the wall portions 27 and 28 is not located near the heating resistor 3 and the contact area is reduced as much as possible.

FIGS. 8 and 9 show a modification of the metal heater 71. FIG. This modification is characterized in that a flat stainless steel 1b having a thickness of 1 mm is arranged on the surface of the insulating protective layer 5, and the insulating layer 2 and the insulating protective layer 5 exposed at the ends are covered with a heat resistant resin 8. Since the glass material having the same thermal expansion coefficient as that of stainless steel is used for the connection between the insulating protective layer 5 and the flat stainless steel 1b, it is excellent in waterproofness and heat resistance. Insulation protection layer 5
The heat-resistant resin 8 can also be used to connect the flat stainless steel 1b.

(Second Embodiment of Metal Heater) FIG. 10 is an exploded perspective view showing a second embodiment of the metal heater 71. In this embodiment, a plurality of heating resistors 3
This is characterized in that a and 3b are laminated via insulating layers 2a and 2b, respectively. With such a configuration, the heat generating resistors having different heat values can be arranged in a well-balanced manner, and the temperature distribution of the heat generating portion can be made uniform.

Similarly, as shown in FIG.
Heating elements 3a, 3b, insulating layers 2a, 2b
Etc. may be provided. This configuration is suitable when one surface of the metal heater 71 is exposed to the ventilation path 35 shown in FIG. When it is desired to change the resistance value of one of the heating resistors 3, the sheet resistance value (Ω / □) or the glass content of the heating resistor 3 can be changed without changing the wiring shape. Further, when water is passed and heated in parallel on both sides of the metal base material 1, the heat transfer coefficients on both sides become the same by heating with the heating resistors 3 arranged on both sides, thereby suppressing a difference in water temperature. can do.

FIG. 12 shows an example of the wiring pattern of the heating resistor 3. By making the line width of the central portion where the heat is concentrated in the heat generating portion 9 around the heat generating resistor 3 wider than the both side portions, it becomes easy to make the temperature distribution uniform.

(Third Embodiment of Metal Heater) FIG. 13 shows a third embodiment of the metal heater 71. In this embodiment, a temperature detecting resistor 10 as a temperature detecting means is disposed above the heating resistor 3 via an insulating layer 2b. Detection terminals 31a and 31b are connected to both ends of the temperature detection resistor 10 via electrode layers 11a and 11b, respectively.
31b and the energization control circuit. Similarly, FIG. 14 shows a configuration in which an exposure detection resistor 12 as exposure detection means is laminated on the same layer as the heating resistor 3, and FIG. 15 shows submergence detection bodies 14a and 14b as submergence detection means. The structure in which the insulating layer 2b is interposed on the upper layer of the body 3 is shown.

Although the configuration shown in each figure is almost the same, the submersion detection resistors 14a and 14b shown in FIG.
If submersion is detected by applying a low voltage between the detection terminals 33a and 33b, a metal substance is deposited on the surfaces of the detection electrodes 16a and 16b.
It is necessary to prevent a metal substance from depositing on the surfaces of the detection electrodes 16a and 16b by applying a reverse voltage between the electrodes 3b. By brazing a metal plate such as silver or stainless steel to the detection electrodes 16a and 16b, deterioration of the electrode layer can be prevented. When detecting the water resistance between the two detection electrodes 16a and 16b, the optimal distance is about 1 to 10 mm. If the distance is too large, the resistance value of the water becomes too large and the detection accuracy is reduced. In addition, by adjusting the length of the submergence detection resistors 14a and 14b according to the tank shape and the fixed state of the metal heater, or by arranging a large number of submergence detection resistors 14a and 14b, the submersion detection accuracy can be improved.

Each of the above detection resistors may be provided on the same layer as the heating resistor 3 or may be provided on the upper and lower layers via the insulating layer 2 or the like. 3
When a crack or the like generated on the surface of the insulating protection layer 5 progresses and the resistance value of the temperature detecting means 10 increases or breaks, the power supply to the metal heater is surely cut off by the power supply control circuit. There is an effect that can be. On the other hand, by arranging the temperature detecting means 10 on the upper and lower layers of the heating resistor 3 respectively, it is possible to detect a temperature difference inside the metal heater. Further, a metal heater 71 and a flange 18 described later are used.
The temperature detecting means 10 is arranged at a portion where the metal heater 71 is in contact with the metal heater 71, and is connected to the metal heater 71 energization control circuit. To prevent the flange 18 from reaching a high temperature. And the temperature detecting means 1
By arranging a plurality of zeros, it is possible to improve the temperature detection accuracy per unit area and prevent local heating.

The exposure detecting resistor 12 is connected to the heating resistor 3.
By placing it in the upper layer and setting its resistance to 0Ω,
When a crack generated on the surface of the insulating protective layer 5 advances and reaches the exposure detection resistor 12, it is previously determined that the heating resistor 3 may be exposed due to a minute change in the resistance value even without disconnection. Can be detected.

Further, as shown in FIG. 14, by arranging the exposure detecting resistor 12 in the same layer as the heating resistor 3 and on the outer periphery of the heating resistor 3, the insulating layer 2 and the insulating protection layer 5 are formed.
Cracks and the like generated at the ends of the
When the resistance value of No. 2 increases or breaks, the power supply to the metal heater 71 can be cut off by the power supply control circuit.

The reliability and safety of the metal heater 71 are further improved by combining two or more of the detection resistors and arranging them in the same layer as the heating resistor 3 or in the upper layer and / or the lower layer. In addition, when a plurality of wiring patterns are arranged on the metal base material 1 and the respective electrode layers are formed, the manufacturing process can be simplified by collectively printing and firing after forming the uppermost wiring pattern.

Next, an energization control circuit for the metal heater 71 will be described with reference to FIG. For convenience of explanation, an example in which the temperature detection resistor 10 of FIG. 13 is provided will be described below. The energization control circuit of the metal heater 71 includes a comparison circuit and a cutoff circuit. The detection terminal 31a is connected to GND, and the detection terminal 31b is connected to the input terminal of the comparator IC1 and the resistor R3. When the resistance value of the temperature detecting resistor 10 and the divided voltage value of the resistor R3 exceed the voltage value determined in advance by the resistors R1 and R2, a signal is output from the comparator IC1 and the transistor Tr1 is activated, thereby turning on the power supply voltage. The relay RLY1 connected in series between the heating resistor 3 and the heating resistor 3 is opened to cut off the power supply to the heating resistor 3. The safety may be improved by combining with a semiconductor circuit such as a CPU or an SSR.

By forming the temperature detecting means 10 in a serial pattern, the initial resistance value can be increased, so that the accuracy of detecting the temperature can be improved and the arrangement space can be reduced.

When the sheet resistance (Ω / □) and the rate of change in resistance of the material forming the temperature detecting means 10 are large, the initial resistance can be increased, and a minute temperature change can be easily detected. it can.

(Fourth Embodiment of Metal Heater) FIG. 17 shows a fourth embodiment of the metal heater 71. In this embodiment, a stress relaxation layer 17 made of a glass material having substantially the same thermal expansion coefficient as that of the metal base 1 is formed on the metal base 1 on the side opposite to the surface on which the heating resistors 3 and the like are arranged. There is a feature. The stress relaxation layer 17 improves the resistance to thermal shock and can effectively prevent cracks such as cracks. The material, thickness,
The shape and the like are appropriately changed and adjusted according to the coefficient of thermal expansion and the shape of the metal substrate 1.

FIGS. 18 and 19 show an example in which the flange 18 is formed integrally with the metal heater 71. This flange 1
Reference numeral 8 denotes a non-heat-generating portion (other than the heat-generating portion 9) of the metal heater 71, which is integrally formed by using a heat-resistant resin, and a plurality of through holes 19 for fixing at a predetermined position with screws. Flange 1
In order to prevent the temperature of the heating unit 8 from rising due to heat conduction from the heating unit 9 and adversely affecting other members such as heat melting, the distance from the heating unit 9 is appropriately adjusted according to the amount of heat conduction from the heating unit 9. decide.

FIGS. 20 and 21 show that the heat generating resistor 3 and the insulating layer 2 are disposed at a relatively central portion of the metal base 1 so that the outer peripheral side is widely used as a non-heat generating portion. A through hole 20 for fixing the heater 71 at a predetermined position with a screw (not shown)
An example in which a to 20d are provided is shown. The position where the metal heater 71 is attached to a sanitary washing device (through holes 20a to 20a)
(Near 0d) is a non-heat generating portion, and the heat generating portion 9 is covered with the heat insulating material 21, so that heat conduction to the sanitary washing device main body and other members can be reliably prevented. Through holes 20a to 20d
Since the metal substrate 1 is exposed around the heating resistor 3
And the fixing screw do not overlap, and it is possible to reliably prevent cracks and the like from occurring in the insulating layer and the insulating protective layer (not shown) when the screw is tightened.

(Fifth Embodiment of Metal Heater) FIG. 22 shows a fifth embodiment of a flat metal heater 71 according to the present invention.
The metal heater 71 is characterized in that a rectangular heating resistor 3 is disposed on a flat metal base 1 via an insulating layer 2. Both sides of the metal substrate 1 (only the front side is shown)
Over a substantially entire surface, an insulating layer 2 mainly composed of crystallized glass that sinters at about 850 ° C. has a constant thickness (for example, 100 μm).
Degree). By using such crystallized glass, the heat resistance is improved, and the glass does not flow during printing or baking of the heating resistor 3 or the electrode layer 4. Variations in the withstand voltage between the resistor 3 and the resistance value of the heating resistor 3 can be suppressed. Further, if the insulating layer 2 is formed to have a thickness of about 100 μm, the dielectric strength between the metal substrate 1 made of stainless steel or the like and the heating resistor 3 can be secured to 2 kV or more. The insulating layer 2 is preferably formed by a method such as screen printing or electrophoretic electrodeposition in consideration of the warpage and corrosion resistance of the metal base material 1.

The rectangular heating resistor 3 has a sheet resistance of 20Ω by mixing glass frit with silver.
But with a TCR of 2000-3000 ppm
When the TCR is to be reduced in consideration of the inrush current, palladium is mixed to make the TCR 100 to
It can be reduced to 1500 ppm. In addition, since the W density of the heating resistor 3 can be increased by including palladium, the heater 81 can be reduced in size. Furthermore, by mixing the heating resistor 3 with glass frit of the same material as the insulating layer 2, the adhesion to the insulating layer 2 is improved.

Here, in order to arrange the heating resistor 3 compactly on the surface of the insulating layer 2 with a sheet resistance value of about 100 to 500 mΩ, it is necessary to meander the heating resistor 3 formed in a thin line shape. There are problems such as manufacturing costs and local heating, but these problems can be solved by increasing the sheet resistance. For example, the resistance value is determined by the width of the resistor in contact with the electrode and the length of the resistor between the electrodes. When a sheet resistance of 20Ω is used, the shape of the heating element is determined as follows. . Heating element power 1000
Assuming that W and the voltage are 100 V, the resistance value of the heating element is 10Ω from the formula of power (W) = voltage (V) × voltage (V) / resistance (Ω). When a material having a sheet resistance value of 20Ω / □ is used, the number of tracks required to obtain a resistance value of 10Ω is expressed by the following equation: track number = resistance (Ω) ÷ sheet resistance (Ω / □). □. Considering the rise in surface temperature and the generation of boiling noise, if the power density is 0.4 W / mm ² ,
The track area of the heating element of 1000 W is 2500 mm ² from the equation: track area = power (W) ÷ power density (W / mm ² ). The width and length of the heating element are determined as follows from the number of tracks and the track area. The film thickness at this time is around 10 μm. Width = √ (track area ÷ number of tracks), length = width × number of tracks Width: 70.7 mm, length: 35.4 mm When 200 mΩ is used for sheet resistance under the same conditions, width: 7.1 mm, length Length: 353.6 mm Also, by doubling the sheet resistance value and doubling the film thickness, even if a current flows locally due to variation in the film thickness even if the resistance value is the same, the heating resistor is disconnected. Can be prevented. When the heating resistor is formed on the surface of the insulating layer by screen printing or the like, there is a possibility that the resistance value may vary by about ± 10%. As a method of improving the resistance value accuracy of the heating resistor, the shape of the heating resistor is determined so as to have a resistance value of about 90% with respect to a target resistance value as a specification. When the target resistance value has not reached the target resistance value after the formation of the heating resistor, the side end of the heating resistor is cut with a laser in parallel with the current flowing through the heating resistor, and the resistance value is increased and adjusted. It can absorb variations in values.

At the opposite ends (upper and lower ends in the drawing) of the heat generating resistor 3, a pair of thin line-shaped electrode layers 4a and 4b made of silver having a sheet resistance of 20 mΩ or less are provided. A pair of current-carrying terminals 6a and 6b are provided at wide ends that are not in contact with the resistor 3, respectively.

Further, the further surface (outermost surface) of the heating resistor 3
Is laminated with an insulating protective layer 5 mainly composed of glass. In the drawing, the insulating protective layer 5 is shown to be hidden under the heating resistor 3 and the insulating layer 2 for convenience of explanation, but actually, the insulating protective layer 5 covers substantially the entire surface of the heating resistor 3 and the like. Is coated. If crystallized glass is used as the material of the insulating protective layer 5, when firing at about 850 ° C,
Intrusion of glass into the heating resistor 3 can be suppressed, and variation in the resistance value of the heating resistor 3 can be suppressed. Further, by laminating the crystallized glass or laminating the amorphous glass on the surface of the crystallized glass, the pores in the crystallized glass can be filled, and creeping discharge can be prevented.

The pair of current-carrying terminals 6a and 6b are plated with silver belonging to the group Ib of the periodic table, which does not form a nonconductive film on the surface of the nickel wire even in a high-temperature atmosphere at 300 to 800 ° C. By using a material having a small specific resistance such as silver, heat generation of the terminal can be prevented. Further, the electrode layers 4a and 4b and the current-carrying terminals 6a and 6b are
The bonding strength and heat resistance can be improved by bonding by baking at 00 to 800 ° C. in the atmosphere, and further, the bonding strength with the glass material forming the metal substrate 1 and the insulating layer 2 is affected. Do not give. In addition, as a material of the energizing terminal 6,
Gold, an alloy of an Ib group element and a platinum group element, or the like can also be used.

The flat metal heater 71 having the above-described structure
In the case where the scale is generated in the exposed portion of the stainless steel metal substrate 1 due to repeated high-temperature baking at the time of molding, the heating resistor 3 is not provided in order to ensure corrosion resistance. Pickling the surface in contact with water with nitric acid, etc.
What is necessary is just to coat with a fluorine material.

(Sixth Embodiment of Metal Heater) FIG. 23 shows a sixth embodiment of the metal heater. The sheet-shaped metal heater 71 according to this embodiment has the same sheet resistance value and the same shape (width).
Are characterized in that a plurality of heating resistors 3a, 3b, 3c are connected in parallel to the pair of electrode layers 4a, 4b. With such a configuration, it is easy to obtain an arbitrary amount of heat at an arbitrary position by changing the shape (width, length, etc.) of the heating resistor 3 in various ways.

(Seventh Embodiment of Metal Heater) FIG. 24 shows a seventh embodiment of the metal heater. The flat metal heater 71 according to this embodiment has a plurality of strip-shaped
The heating resistor 3a, 3b, 3c, 3d
And a plurality of (three in the figure) conductors 90a, 90b, 90c formed of a material having a sheet resistance smaller than that of the plurality of heat generating resistors 3 and adjacent to the heat generating resistor 3. By arranging such that the ends are connected to each other, the entire resistor (3a to 3d, 90a to 90
c) is connected in series. As an example, the plurality of heating resistors 3a to 3d are formed of a sheet resistance value material of 200 mΩ, and the plurality of conductors 90a to 90c are
It is formed of a sheet resistance value material of 0 mΩ or less. Further, the pair of electrode layers 4 a and 4 b are also formed of the same material as the conductor 90. As described above, by forming the bent portion of the series resistor, which is likely to cause local heating, with the conductors 90a to 90c having a low sheet resistance value, heat generation near the bent portion can be reduced, and the heating resistors 3a to 3d can be uniformly formed. To generate heat.

FIGS. 25 to 30 show examples of a water heater using a cylindrical metal heater. Since the configuration of the water heating device itself is the same as that of the embodiment shown in FIGS.
Detailed description is omitted. In the metal heater 72, since the surface of the heat generating portion also has a curved surface, air bubbles do not adhere to or stagnate on the surface, so that a decrease in heat transfer coefficient, an increase in the internal temperature of the metal heater 72, and local heating can be prevented.

In the embodiment shown in FIG. 25, a through hole of a metal heater 72 using a cylindrical metal
3, and a plurality of protrusions 42 (or notches) are provided so that the water supplied into the through hole becomes a swirling flow or a turbulent flow. The plurality of protrusions 42 function as turbulence promoting means and flow velocity improving means. With this configuration, the heat transfer area can be increased, and the flow rate can be increased to further improve the heat transfer coefficient. Therefore, the structure is particularly suitable for the heating means of the instantaneous heating type hot water device.

Although the embodiment shown in FIG. 26 has substantially the same configuration, a rod-shaped member 43 having a spiral or comb-shaped projection 43a radially inserted into a through hole of a metal heater 72 is inserted and inscribed. It is characterized by The rod-shaped member 43 is
It may be either integral with or separate from 2 and may be inserted and fixed in the metal heater 72 in advance. This rod-shaped member 43
Also, the same operation and effect as those of the protrusion 42 can be obtained.

The embodiment shown in FIG. 27 is an example in which a plurality of through holes of the metal heater 72, that is, a flow path of water supplied to the tank 22 are formed. The plurality of flow paths have an action and an effect as a flow rate improving means. Instead of the plurality of flow paths, a plurality of protrusions may be provided inward from the inner wall of the through hole to narrow the flow path.

The embodiment shown in FIGS. 28A and 28B is an example in which the vicinity of the heat generating portion 9 of the metal heater 72 is covered with the heat insulating material 21. The same operation and effect as those of the embodiment described with reference to FIGS. Play.

The embodiment shown in FIG. 29 is characterized in that tubes 30, 30 for entering and discharging water are connected to both ends of a metal heater 72, respectively, so that a tank is unnecessary and a compact hot water device can be provided. In addition to this, the process of screwing the metal heater 72 to the tank or the like can be omitted, so that the manufacturing cost can be reduced.

In the embodiment shown in FIG. 30, one end (right side in the figure) of a cylindrical metal heater 72 in which a rectangular heating resistor 3 is arranged on substantially the entire surface of the metal base 1 is used as a water inlet 23 to supply water (not shown). The other end (left side in the figure) is connected to a discharge path (not shown) as a tap hole 24. A ground terminal 1 is provided on an exposed portion of the metal base 1 not covered with the insulating layer 2 or the like.
3 are connected. The water flowing in from the water inlet 23 is
The water is gradually heated in the course of passing through the internal flow path of the cylindrical metal heater 72, and is discharged as hot water from the tap hole 24.

Here, the heating resistor 3 is disposed such that the current flowing in the heating resistor 3 (the direction of α in the figure) is perpendicular to the flow path of water (from right to left in the figure). Have been. With such a configuration, it is possible to prevent a temperature difference between the water inlet side and the tap hole side of the cylindrical metal heater 72 as much as possible.

Further, by disposing a plurality of rectangular heating resistors 3 in parallel according to the heat transfer coefficient at each portion,
The surface temperature distribution of the cylindrical metal heater 72 can be made uniform.

Since the ground terminal 13 is connected to the exposed portion of the metal base 1, even if the insulating layer 2 is broken, the water flowing into the metal base 1 does not leak to the peripheral devices, Charging and electric shock to the human body can be prevented.

[0101]

According to the construction described above, the present invention provides a method for forming a metal base on an insulating layer even when the inside of a metal heater is heated to a high temperature due to an empty boil or adhesion of a foreign substance such as a scale when the metal heater is energized. Since a glass material or the like having the same thermal expansion coefficient is used, it is possible to prevent the insulating layer from being deteriorated by melting or cracking. In addition, it is possible to prevent heating abnormalities such as local heating due to distortion of the heating resistor due to melting of the insulating layer, and a heating impossible state due to disconnection, and furthermore, since it has excellent cold shock resistance, the heat transfer coefficient is improved. In addition, various effects can be achieved, such as realization of thinning at the same time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a water heater according to the present invention.

FIG. 2 is a sectional view of the second embodiment.

FIG. 3 is a sectional view of the third embodiment.

FIG. 4 is a sectional view of the fourth embodiment.

FIG. 5 is a perspective view of a first embodiment of a metal heater according to the present invention.

FIG. 6 is a sectional view of the same.

FIG. 7 is an exploded perspective view of the same.

FIG. 8 is a perspective view of the modification.

FIG. 9 is a sectional view of the same.

FIG. 10 is an exploded perspective view of the second embodiment.

FIG. 11 is a sectional view of the same.

FIG. 12 is an exploded perspective view of the modification.

FIG. 13 is an exploded perspective view of the third embodiment.

FIG. 14 is an exploded perspective view of the modification.

FIG. 15 is an exploded perspective view of the modification.

FIG. 16 is a circuit diagram of a metal heater energization control circuit.

FIG. 17 is a sectional view of the fourth embodiment.

FIG. 18 is a perspective view of the same.

FIG. 19 is a plan view of the same.

FIG. 20 is a plan view of the same.

FIG. 21 is a sectional view of the same.

FIG. 22 is a plan view of the fifth embodiment.

FIG. 23 is a plan view of the sixth embodiment.

FIG. 24 is a plan view of the seventh embodiment.

FIG. 25 is a sectional view of a water heater using a cylindrical metal heater.

FIG. 26 is a sectional view of the modification.

FIG. 27 is a cross-sectional view of the modification.

28A and 28B show the same modified example, in which a is a side sectional view and b is a center sectional view of a.

FIG. 29 is a sectional view of the modification.

30 shows the same modified example, wherein a is a side sectional view and b is a BB 'line sectional view of a. FIG.

FIG. 31 is an explanatory view of a conventional water heater using a metal pipe heater.

FIG. 32 is an explanatory diagram of the same ceramic heater.

FIG. 33 is an explanatory view of a water heater using the cylindrical ceramic heater.

[Explanation of symbols]

1: metal base material 2: insulating layer 3: heating resistor 4: electrode layer (for heating resistor) 5: insulating protective layer, 22: tank, 40: hot water device, 7
1, 72: metal heater

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Sekaku 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Inside Totoki Co., Ltd. (72) Inventor Yasuhiro Yanagawa Kokurakita-ku, Kitakyushu-shi, Fukuoka 2-1-1 Nakajima Totoki Kiki Co., Ltd. (72) Inventor Eiji Kitamoto 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Totoki Kiki Co., Ltd. (72) Inventor Yasuaki Yamaguchi Kitakyushu, Fukuoka Prefecture 2-1-1, Nakajima, Kokurakita-ku, Tochi-shi

Claims (24)

[Claims] An insulating layer formed on the surface of the metal substrate with a material having a thermal expansion coefficient substantially equal to that of the metal substrate; a heating resistor formed on the surface of the insulating layer; A metal heater comprising: an insulating protective layer formed on a surface of a body; and a current-carrying terminal connected to the heating resistor. 2. The metal heater according to claim 1, wherein an electrode layer is formed on the heating resistor, and the current-carrying terminal is connected to the electrode layer. 3. The metal heater according to claim 1, wherein the insulating layer and the insulating protective layer are formed of the same material. 4. The metal heater according to claim 1, wherein a metal material having the same thermal expansion coefficient as that of the insulating protective layer is laminated on the surface of the insulating protective layer. 5. The metal heater according to claim 1, wherein the thickness of the metal substrate is in a range of 0.1 to 5 mm. 6. The thickness of the insulating layer and the insulating protective layer is 20 to 5
6. The range of 1 to 5 μm.
The metal heater according to any one of the above. 7. The metal heater according to claim 1, wherein a heating resistor is arranged so that a temperature of a heating portion near the heating resistor becomes substantially uniform. 8. The metal heater according to claim 1, wherein a plurality of heating resistors having different resistance values are formed on the same plane. 9. The metal heater according to claim 1, wherein a plurality of heating resistors having different resistance values are provided on both surfaces of the insulating layer or both surfaces of the metal base, respectively. 10. The metal heater according to claim 1, wherein a temperature detecting means for detecting a temperature of the heat generating portion is formed near the heat generating resistor. 11. The metal heater according to claim 1, wherein an exposure detecting means for detecting the exposure of the heating resistor is formed near the heating resistor. 12. The metal heater according to claim 1, wherein submergence detecting means for detecting a submerged state of the metal base and the insulating protective layer is formed on a surface of the insulating layer. 13. The metal heater according to claim 1, wherein a stress relaxation layer is provided on a back surface of the metal base. 14. The metal heater according to claim 1, wherein a flange made of a heat-resistant resin is disposed in a non-heat generating portion between the current-carrying terminal and the heat generating portion. 15. The metal heater according to claim 1, wherein a through hole is provided in a non-heat-generating portion of the metal base. 16. The metal heater according to claim 1, wherein the heat generating portion covered with the insulating protective layer and the vicinity thereof are covered with a heat insulating material. 17. An insulating layer laminated on substantially the entire surface of a metal substrate, a rectangular heating resistor provided on the surface of the insulating layer, and connected to opposite ends of the heating resistor. A plurality of electrodes, a plurality of terminals respectively connected to the electrodes, and a protective layer laminated on the surface of the heating resistor. 18. The hot water heating metal heater according to claim 17, wherein a sheet resistance value of the electrode is lower than a sheet resistance value of the heating resistor. 19. A heating device comprising a plurality of heating resistors, wherein the heating resistors are connected in series and connected in series by a conductor having a sheet resistance lower than the sheet resistance of the heating resistor. The hot water heating metal heater according to claim 17. 20. The metal heater according to claim 1, wherein the metal heater is disposed near the tank, an inlet for supplying water into the tank, and a hot water heated by the metal heater. And a water outlet for discharging water. 21. A turbulent flow promoting means for promoting turbulent flow of water and / or a flow velocity improving means for increasing a flow velocity of water in the tank. Hot water equipment. 22. The hot water apparatus according to claim 20, wherein the tank is provided with an opening for contacting the metal base of the metal heater with water supplied to the tank. 23. A hot water apparatus using the metal heater according to claim 1, wherein the metal base has a cylindrical shape, one end of which is a water supply flow path, and the other end of which is a discharge flow path. Connected, the water flowing in from the water supply flow path is heated by the heating resistor and discharged from the discharge flow path, and the current flowing through the heating resistor flows in a direction perpendicular to the water inflow direction. A hot water device comprising an electrode. 24. A sanitary washing device comprising the hot water device according to claim 20.