JP3033196U - Water tank heater - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To prevent a fire from occurring due to overheating of a heating conductor of a water tank when it is energized while the heater for a water tank used in water is exposed to the air. . SOLUTION: A heat-generating conductor 7 arranged inside a heat-resistant pipe 1.
And the connecting portion of the electric cord 5 that energizes the heating conductor,
A thermal switch 11 that stops energization to the heat-generating conductor 7 when the temperature inside the heat-resistant pipe 1 reaches a high temperature above a certain level is interposed, and the heat-generating conductor 7 is provided along the inside of the heat-resistant pipe 1.
A heat induction layer 12 having a high thermal conductivity that guides the radiant heat of the heat radiation to the periphery of the thermal switch 11 is formed.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an aquarium heater used for heating water in an aquarium for raising tropical fish and the like.

[0002]

[Prior art]

 For this type of heater, two pairs of electric cords are inserted from one end into a heat-resistant glass tube that has a waterproof structure such as a heat-resistant glass tube, and one of the electric cords is coiled. A heating conductor showing electric resistance, such as a nichrome wire, is connected to the other side, and a temperature sensor such as a thermistor that outputs a temperature detection signal according to the change in water temperature is connected to the other electric cord and It is known that the sensor and the heat-generating conductor are isolated from each other on one end side and the other end side of the heat resistant tube by an insulating filler or a partition wall. Then, based on the temperature detection signal output from the temperature sensor, the temperature controller controls the on / off of electricity to the heating conductor to keep the water temperature constant.

[0003]

[Problems to be solved by the invention]

 By the way, in the conventional heater as described above, if the heater is mistakenly energized while being put out in the air without being immersed in water, the heat-generating conductor overheats in a few minutes from the start of the energization and the heat generation is concerned. The inside of the heat-resistant pipe containing the conductor may be heated to an abnormally high temperature, which may cause a fire, or softening, melting, or excessive oxidation of the heat-generating conductor, which may limit the life of the heater.

In addition, in the Great Hanshin Earthquake, the water tank for raising the appreciation fish was destroyed or collapsed by the earthquake, and the water tank for the appreciation fish was destroyed or collapsed due to the frequent occurrence of fires from electric appliances after repair of the power failure accident due to the earthquake. If water in the room escapes, the heat-generating conductor of the aquarium heater may overheat, causing the surface of the heat-resistant pipe to heat to a high temperature, causing flammable substances that come into contact with the surface to ignite, which may cause a fire. .

A temperature sensor for controlling on / off of electricity to the heat-generating conductor is housed in the heat-resistant pipe of the heater, but there is no insulation between the temperature sensor and the heat-generating conductor. Since the heat-resistant tube made of glass or the like has a low heat conduction speed because it is isolated by the filling material and partition walls, it is not possible to immediately detect overheating of the heat-generating conductor and immediately stop energizing the heat-generating conductor. Have difficulty. In view of this, the present invention has a technical problem of reliably eliminating the risk of fire due to overheating of the aquarium heater.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention relates to a water tank heater in which an electrically insulating heat-resistant tube having a waterproof structure is provided with a heat-generating conductor exhibiting electric resistance. A thermal switch that stops energization of the heat-generating conductor when the temperature inside the heat-resistant pipe reaches a high temperature above a certain level is provided at the connection with the electric cord that energizes the conductor. A heat induction layer having a high thermal conductivity is formed along the inner side of the heat conducting layer to guide the radiant heat of the heat generating conductor to the periphery of the thermal switch.

According to the present invention, when the heat-generating conductor is energized while the aquarium heater is exposed to the air, and the inside of the heat-resistant pipe containing the heat-generating conductor reaches a high temperature above a certain level, the heat-generating conductor and the electric The thermal switch installed at the connection with the cord automatically stops the energization of the heat-generating conductor to prevent the occurrence of fire due to overheating of the heat-generating conductor. Particularly, as in the present invention, when a heat induction layer having a high thermal conductivity that guides the radiant heat of the heat generating conductor to the surroundings of the thermal switch is formed along the inside of the heat resistant tube, abnormal heat due to overheating of the heat generating conductor is generated. The high temperature is quickly transmitted to the thermal switch, and the thermal switch is activated immediately, so that a fire can be more reliably prevented.

[0008]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. 1 is a sectional view showing an example of a water tank heater according to the present invention, FIGS. 2 and 3 are perspective views showing an example of a heat induction layer formed inside a heat-resistant tube of the water tank heater, and FIG. 4 is a view showing the present invention. It is sectional drawing which shows the other example of the heater for water tanks.

The water tank heater shown in FIG. 1 has a waterproof structure in which a waterproof cap 3 made of a rubber-like substance is capped on the opening of a heat-resistant glass tube or a ceramics tube 2 having one end opened to provide an electrically insulated structure. Inside the flexible heat resistant tube 1, an electric cord 5 is inserted through the center of the waterproof cap 3 in a watertight manner, and a heating conductor 7 connected to the electric cord 5 is arranged.

The heat-generating conductor 7 is formed of a coil-shaped nichrome wire or the like, is held by the mica plate 10 having electrical insulation and fire resistance, and is heat-resistant at the connection portion with the electric cord 5. A thermal switch 11 is provided to stop energization of the heating conductor 7 when the temperature inside the tube 1 reaches a high temperature above a certain level. That is, one of the two core wires 13 and 14 of the electric cord 5 is directly connected to one end of the heating conductor 7, and the other one is connected to the other end of the heating conductor 7 via the thermal switch 11. There is. As the thermal switch 11, a bimetal type temperature switch that turns on and off at high temperature, a high temperature thermistor temperature switch that uses a sudden change in resistance of PTC or CTR, and the like are used, and the power supply to the heating conductor 7 is stopped. The operating temperature to be set can be arbitrarily set according to the thermal conductivity of the heat-resistant tube 1, the heat-generating capacity of the heat-generating conductor 7, etc., but in the present example, the surface of the heat-resistant tube 1 is exposed with the water tank heater in the air. The temperature inside the heat-resistant pipe 1 when the temperature reaches, for example, about 150 ° C. (for example, about 300 to 500 ° C.) is set.

Inside the heat resistant tube 1, a heat induction layer 12 having a high thermal conductivity that guides the radiant heat of the heat generating conductor 7 to the periphery of the thermal switch 11 is formed. This heat induction layer 12 is made of a metal tube such as an aluminum tube, a copper tube, a stainless tube, a nickel tube or a brass tube that integrally covers the periphery of the heat-generating conductor 7 and the periphery of the thermal switch 11, or a cylindrical metal foil, which is heat-resistant. A metal plate which is inserted into the pipe 1 or is formed into a C-shape as shown in FIG. 2 is fitted into the heat-resistant pipe 1 or an arc-shaped pair is formed as shown in FIG. The metal plate is adhered along the inner wall of the heat-resistant pipe 1 and the like. An insulating tube 15 is fitted inside the heat induction layer 12.

The above is the configuration of the water tank heater shown in FIG. 1, and its operation will be described below. In a normal use state in which the water tank heater is immersed in water, the temperature inside the heat-resistant pipe 1 containing the heat-generating conductor 7 rises only up to around 200 ° C. Therefore, the thermal switch 11 energizes the heat-generating conductor 7. Hold the state.

When this heater for water tank is mistakenly energized with the heater in the air, the temperature inside the heat-resistant pipe 1 rises rapidly and the surface temperature of the heat-resistant pipe 1 also rises. When this happens, the temperature inside the pipe reaches the operating temperature of the thermal switch 11 and the power supply to the heat-generating conductor 7 is automatically stopped, preventing the occurrence of fire due to overheating of the heat-generating conductor 7 and at the same time degrading the heat-generating conductor 7. Is also prevented.

In particular, since the periphery of the heat generating conductor 7 and the thermal switch 11 is covered with the heat induction layer 12 having a high thermal conductivity formed along the inside of the heat resistant tube 1, the heat generating conductor is provided in the thermal switch 11. The radiant heat of 7 is transferred efficiently and quickly. Therefore, the thermal switch 11 can quickly and reliably detect an abnormal increase in the temperature inside the heat-resistant pipe 1 due to overheating of the heat-generating conductor 7 and instantaneously stop energization of the heat-generating conductor 7.

Next, in the water tank heater shown in FIG. 4, waterproof caps 3 and 4 made of a rubber-like substance are respectively capped on the respective openings of a heat-resistant glass tube or ceramics tube 2 having both ends open to prevent water. Two pairs of electric cords 5 and 6 are inserted through the center of the waterproof cap 3 capped on one end side into the heat-resistant pipe 1 having an electrically insulating structure, and one of the electric cords is inserted. A heating conductor 7 having electrical resistance, such as a coil-shaped nichrome wire, is connected to 5, and the other electric cord 6 is a temperature such as a thermistor that outputs a temperature detection signal according to a change in water temperature. The sensor 8 is connected.

The temperature sensor 8 is molded with an insulating filler 9 such as silicon resin or magnesium oxide and held in the heat-resistant tube 1, and is insulated from the heat conductor 7 by the insulating filler 9. . Further, the heating conductor 7 is held by the mica plate 10, and the thermal switch 11 is interposed at the connection portion with the electric cord 5 which is wired through the inside of the insulating filler 9 as in the case of FIG. Has been done. Then, inside the heat-resistant tube 1, along the portion where the heat-generating conductor 7 is accommodated, the heat-generating conductor 7 and the surroundings of the thermal switch 11 are covered, and the radiant heat of the heat-generating conductor 7 is guided to the periphery of the thermal switch 11. The heat induction layer 12 is formed.

The above is the configuration of the water tank heater shown in FIG. 4, and its operation will be described below. First, when the aquarium heater is used, a temperature controller (not shown) connected to the electric cords 5 and 6 is operated to heat the water in the aquarium heater by the aquarium heater. It is preset to 25 to 27 ° C suitable for the above.

As a result, the heater placed in the water tank is turned on / off by the feedback control of the temperature controller performed based on the temperature detection signal corresponding to the change in the water temperature output by the temperature sensor 8. Then, the water temperature in the water tank is maintained at a predetermined temperature, for example, 25 to 27 ° C. Then, in this state, when the water in the water tank suddenly escapes due to an earthquake or the like and the temperature inside the heat-resistant pipe 1 reaches a high temperature above a certain level, the heat conduction effect of the heat induction layer 12 becomes the same as in the case of FIG. The thermal switch 11 that quickly detects the high temperature due to the heat radiating action instantaneously stops the energization of the heat-generating conductor 7 and reliably prevents the occurrence of fire due to overheating of the heat-generating conductor 7.

[0019]

[Effect of the invention]

 According to the present invention, when a heater for a water tank is erroneously supplied with electricity in the air without being immersed in the water, or the water tank using the heater in water is destroyed due to an earthquake or the like. When the water in the water tank escapes due to being overturned and the heater is left in the air, the thermal switch that detects abnormally high temperature of the heater quickly stops the power supply to the heating conductor. Even if the surface of the heat-resistant pipe is in contact with a flammable substance, the occurrence of a fire due to the ignition of the flammable substance is prevented, and at the same time the life of the heater due to overheating of the heating conductor is also prevented. There is an excellent effect.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an aquarium heater according to the present invention.

FIG. 2 is a perspective view showing an example of a heat induction layer formed inside a heat resistant tube of a water tank heater.

FIG. 3 is a perspective view showing an example of a heat induction layer formed inside a heat resistant tube of a water tank heater.

FIG. 4 is a sectional view showing another example of the aquarium heater according to the present invention.

[Explanation of symbols]

 1 ... Heat-resistant tube 5 ... Electric cord 7 ... Heating conductor 11 ... Thermal switch 12 ... Heat induction layer

Claims (2)

[Utility model registration claims] 1. A water tank heater in which a heat-generating conductor (7) having an electric resistance is disposed inside a heat-resistant pipe (1) having a waterproof structure and having electrical insulation properties, and the heat-generating conductor (7) and its heat generation. A thermal switch (11) that stops energizing the heat-generating conductor (7) when the temperature inside the heat-resistant pipe (1) reaches a high temperature above a certain level at a connection portion with an electric cord (5) that energizes the conductor. ) Is interposed, and along the inside of the heat-resistant pipe (1), the radiant heat of the heat-generating conductor (7) is guided to the periphery of the thermal switch (11) and the heat induction layer (12) having high thermal conductivity ) Is formed, the aquarium heater. 2. The metal pipe, metal foil or metal plate according to claim 1, wherein the heat induction layer (12) integrally covers the periphery of the heat generating conductor (7) and the periphery of the thermal switch (11). Water tank heater.