JP2559023Y2 - Underwater heater - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a PTC (Positive Temperaturatur) for maintaining a constant water temperature in an aquarium for aquarium fish.
The present invention relates to an underwater heater having a built-in constant-temperature heater having a characteristic of e.coefficient, for example, a barium titanate-based ceramic semiconductor.

[0002]

2. Description of the Related Art Generally, for example, when breeding tropical fish, saltwater fish, and the like in a water tank, the temperature of the water tank is kept constant (26 ° C.
２８28 ° C.). As shown in FIG. 9, a conventional heater 21 used for this purpose houses an alumina electric insulating plate 23 around which a heating element 22 such as a nichrome wire is wound in a hollow tube 24 made of alumina. It is formed by fitting rubber caps 25 at both ends of the hollow tube 24 to seal the inside and electrically insulate the heating element 22 from the outside. The lead wire 26 electrically connected to the heating element 22 is drawn out through a hole (not shown) opened in the cap 25.

[0003] The lead wire 26 of the heater 21 described above is
0, a thermostat 29 connected to the power supply
Is electrically connected to At the time of use, the heater 21 is placed on a gravel 28 spread on the bottom of a water tank 27, for example.
When turned off, the heat generation temperature is controlled to keep the water temperature constant.

[0004]

However, in the above-mentioned conventional heater 21, the heat generation temperature is controlled by turning on / off the power supply by the thermostat 29. Therefore, if the thermostat 29 fails, the heat generation temperature becomes high. Is no longer controlled, making it impossible to keep the water temperature constant.

When the heater 21 is buried in the gravel 28, the heat generated by the heater 21 is not transmitted to the water, so that the water temperature does not rise and the power is always turned on.
There is a possibility that the heater 21 may be locally damaged due to overheating. Further, when local overheating is caused in a state where the heater 21 is in contact with the glass in the water tank 27, there is a problem that the glass generated by the heater 21 may be broken.

[0006] The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to prevent local overheating and the like.
Another object of the present invention is to provide a highly safe underwater heater capable of maintaining a constant water temperature.

[0007]

The underwater heater according to the present invention comprises:
In order to solve the above problems, a heat sink, a heater closely attached to the heat sink, and a tubular container having an opening for accommodating the heat sink and the heater, the heater, A heating element made of a positive temperature coefficient thermistor is provided inside. The heating element has electrodes on the upper and lower surfaces, and a pair of metal terminals electrically connected to each electrode, respectively, and electrically connected to these metal terminals, respectively. And a pair of power supply lines, the periphery of which is covered with an electrically insulating and waterproof covering member.

[0008]

According to the above construction, since the periphery of the heater is covered with the electrically insulating and waterproof covering member, the heater is electrically insulated from the outside and has a waterproof function. Therefore, the heater can be safely installed in the water. Further, since the heating element including the positive temperature coefficient thermistor has a self-temperature control function, it is not necessary to separately provide a so-called thermostat such as a control circuit for keeping the heating temperature constant or a circuit for preventing overheating. Further, since the heater is in close contact with the heat sink, the heat generated by the heater can be efficiently transmitted to the heat sink. Further, since the heater is accommodated in a cylindrical container having an opening, water flows and convects through the opening. Therefore, for example, when it is buried in gravel or when it comes into contact with glass, it is possible to suppress the occurrence of local heating.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the underwater heater according to the present embodiment is provided with a single radiator plate 2 in a case 1 as a cylindrical container having an opening in a state of dividing a circle. The heater 3 is in close contact with the heat sink 2.

The case 1 is formed in a cylindrical shape, and has both ends as opening surfaces 1a. Therefore, the radiator plate 2 to which the heater 3 is closely attached
Can be inserted, and water can pass through the cylinder of the case 1 when the underwater heater is installed in the water tank. Further, holes 1b are formed in the outer peripheral surface of the case 1 as a large number of openings to facilitate convection of water. Further, the case 1 is made of plastic to play a role of protecting the heater 3 and the like, but may be made of metal. When the case 1 is made of metal, the case 1 itself can also function as a heat sink. The case 1 does not necessarily need to be formed in a cylindrical shape for the above purpose. For example, if the case 1 is formed in a cylindrical shape as shown in FIGS. It is also possible to form as.

The radiator plate 2 is made of a metal plate having excellent thermal conductivity, for example, an aluminum plate.
Is formed in a rectangular shape having a diameter width and a cylinder length.
As shown in FIGS. 3 (a) and 3 (b), through holes 2a are formed in the heat sink 2 at three locations in the longitudinal direction in consideration of convection of water.

Further, mounting holes 2b for mounting the heaters 3 are formed in the heat radiating plate 2 at, for example, two places in the longitudinal direction of the heat radiating plate 2 so that the two heaters 3 can be mounted. Has become.

As shown in FIG. 4, the heater 3 is attached to the heat radiating plate 2 by means of, for example, flathead screws 6 and nuts 7. Note that the number of the heat radiating plates 2 is not limited to one as in the present embodiment, but, for example, as shown in FIG. And the heat transfer efficiency can be increased.

On the other hand, as shown in FIGS. 6 and 7, the heater 3 has a heating element 4, metal terminals 8.8, lead wires 9.9 serving as power supply lines, and electrically insulating and waterproof covering members. Of the insulating case 10.

The heating element 4 has a positive temperature coefficient (Positive Tempe
(rature Coefficient), for example, a ceramic semiconductor made mainly of barium titanate or the like,
Although it has a low resistance from room temperature to the Curie temperature Tc (rapid temperature change), it is a positive temperature coefficient thermistor as a thermosensitive element having a characteristic that the resistance value sharply increases when the Curie temperature Tc is exceeded. Due to this characteristic, the heating element 4 has a self-temperature control function. In addition, the Curie temperature Tc of the heating element 4 can be arbitrarily set within a range of about 30 to 300 ° C. depending on the material composition. Therefore, for example, the water temperature of a tank for breeding tropical fish, saltwater fish, and the like using the heater 3 is set to 26 to 28 ° C.
In order to keep the Curie temperature Tc at 3
What is necessary is just to set to 6-38 degreeC.

The heating element 4 has a flat cylindrical shape,
As shown in FIG. 7, electrodes 4a are formed on the upper and lower surfaces by applying, for example, a silver paint.

The metal terminals 8.8 are in close contact with the respective electrodes 4a, 4a, and have a circular plate shape having a diameter substantially equal to the outer diameter of the heating element 4, and have a central portion substantially corresponding to the inner diameter of the heating element 4. Has equal holes. In addition, each metal terminal 8.8 has a power supply portion 8a for connecting a lead wire 9.9.
Are formed respectively. These power supply units 8a
Are parallel to each other and extend in the introduction direction of the corresponding lead wire 9.

The electrical connection between the metal terminals 8.8 and the heating element 4 is performed by attaching the electrode 4a of the heating element 4 and the metal terminal 8 with, for example, an epoxy / silver mixed conductive adhesive. Have been done. In addition, the power supply units 8a and 8a and the lead wires 9.9
Are electrically connected to each other by, for example, soldering corresponding lead wires 9, 9 to the opposing surfaces of the power supply portions 8a, 8a.

The insulating case 10 includes an insulating case lower part 10a as a covering base and an insulating case upper part 10b. This insulating case 10 covers and seals the heating element 4 and the metal terminals 8.8, and has a fixing hole 3a formed at the center thereof when the heater 3 is screwed to the radiator plate 2. ing. In addition, a female screw groove may be formed in the fixing hole 3a as necessary. Further, the insulating case 10 is provided with a terminal portion of the lead wire 9.9 on the metal terminal 8 side so that a mechanical load is not applied to a soldered portion between the lead wire 9 and the power supply portion 8a of the metal terminal 8 to cause disconnection. Is also covered.

The above-mentioned insulating case 10 contains a heating element 4 and the like in an insulating case lower part 10a formed in advance by injection molding or the like, and is set in an injection molding die. Is formed integrally with the insulating case lower part 10a and the insulating case upper part 10b. Thus, the heating element 4 and the like are sealed and fixed inside the insulating case 10.

The insulating case 10 has a small heat shrinkage rate, is excellent in thermal conductivity and mechanical strength, has heat resistance enough to withstand the heat generation temperature of the heating element 4, and has waterproof and air-permeable properties such as water vapor and the like. It is necessary to have airtightness that does not pass through the inside and to have good adhesion to the coating material of the lead wires 9. For example, the lead wire 9 is formed of a polymer alloy made of nylon, polypropylene, and glass.

The lead wires 9 connected to the metal terminals 8 are connected to a power cord (not shown), and are connected to an external power source through the power cord.

A method of manufacturing the underwater heater having the above configuration will be described.

First, in order to attach the heater 3 to the heat sink 2, as shown in FIG.
From the mounting hole 2a. Then, the surface 2 of the heat sink 2
The fixing hole 3a of the heater 3 is fitted into the threaded portion 6b of the flat head screw 6 protruding from c. After that, the flathead screw 6 is tightened with the nut 7 so that the heater 3 and the heat sink 2 are brought into close contact with each other. When the flathead screw 6 is tightened with the nut 7, a washer or a washer may be arranged between the heater 3 and the nut 7 as necessary.

Subsequently, as shown in FIGS. 8A and 8B,
The heat radiating plate 2 to which the two heaters 3 are attached is inserted from the opening surface 1a of the case 1, and the contact portion of the case 1 is attached with an adhesive 11 or soldering (when the case 1 is made of metal). Thereby, the underwater heater is completed.

As described above, in the underwater heater according to the present embodiment, since the heater 3 is covered with the insulating case 10 as the electrically insulating and waterproof covering member made of resin, the heater 3 is electrically connected to the outside. It is insulated and has a waterproof function. For this reason, the heater 3 can be safely installed in water.

A heating element 4 made of a positive temperature coefficient thermistor
Has a self-temperature control function, so that the temperature quickly rises after energization, and when the temperature reaches a predetermined temperature, the temperature is maintained. As a result, the water temperature of the water tank rises, and it becomes possible to maintain a constant temperature. This eliminates the need to separately provide a so-called thermostat such as a control circuit for keeping the heat generation temperature constant or a circuit for preventing overheating.

Further, since the heater 3 is in close contact with the radiator plate 2, the heat generated by the heater 3 can be efficiently dissipated.
And the heat transfer area to water can be enlarged, and the heat transfer efficiency can be further improved.

Since the heater 3 is accommodated in a cylindrical container having the opening surfaces 1a, 1a and the holes 1b, the water flows and convects with the opening surfaces 1a, 1a and the holes 1b. Therefore, for example, when it is buried in gravel or when it comes into contact with glass, it is possible to suppress the occurrence of local heating. Further, since the heater 3 does not directly contact the glass, it is possible to prevent the glass from breaking.

The attachment of the heater 3 to the heat radiating plate 2 is not limited to screwing, but may be performed by using an adhesive, for example. Therefore, in this case, the heating element 4, that is, the fixing hole 3a of the heater 3 becomes unnecessary. Further, the positions and the number of the fixing holes 3a formed in the heating element 4 and the heater 3 are not limited to the above-described embodiment, but can be changed according to the size of the heater. In addition, the arrangement and the number of the heaters 3 on the heat radiating plate 2 are not limited.

Further, in the present embodiment, the opening in the case 1 is constituted by the opening surfaces 1a at both ends and the holes 1b formed in the circumferential surface, but it is not necessarily limited to this. That is, for example, the opening surfaces 1a at both ends
Only by itself, the circulation of water can be secured, so that the effect of the present invention is not hindered.

[0033]

[Effect of the invention] The underwater heater of the invention is, as described above,
A radiator plate, a heater closely attached to the radiator plate, and a cylindrical container having an opening for accommodating the radiator plate and the heater, wherein the heater has a heating element made of a PTC thermistor inside. And a pair of metal terminals electrically connected to each of the electrodes, and a pair of power supply lines electrically connected to these metal terminals, respectively. Then, the periphery is covered with an electrically insulating and waterproof covering member.

Thus, since the heater is electrically insulated from the outside and has a waterproof function, the heater can be safely installed in water. In addition, since the heating element composed of a positive temperature coefficient thermistor has a self-temperature control function,
The water temperature can be kept constant without separately providing a so-called thermostat.

Further, since the heater is in close contact with the radiator plate, the heat generated by the heater can be efficiently transmitted to the radiator plate. Further, since the heater is accommodated in a cylindrical container having an opening, water flows and convects through the opening.
Therefore, for example, when it is buried in gravel or when it comes into contact with glass, it is possible to suppress the occurrence of local heating.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an underwater heater structure according to an embodiment of the present invention.

FIGS. 2A and 2B show a rectangular tubular case of the underwater heater, wherein FIG. 2A is a side view and FIG. 2B is a front view.

FIGS. 3A and 3B show a state in which the heater is attached to a radiator plate in the underwater heater, wherein FIG. 3A is a plan view and FIG.
Is a front view.

FIG. 4 is a longitudinal sectional view showing a state in which the heater is attached to a radiator plate in the underwater heater.

FIG. 5 is a front view showing a state in which two heat sinks are provided above and below a heater.

FIG. 6 is a plan view showing a part of the underwater heater in a partially broken manner.

FIG. 7 is a sectional view of the heater.

FIG. 8 shows the structure of the underwater heater.
(A) is a side view, (b) is a sectional view.

FIG. 9 is an explanatory view showing the structure of a conventional heater.

FIG. 10 is an explanatory diagram showing a use state of the conventional heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case (cylindrical container) 1a Opening surface (opening) 1b Hole (opening) 2 Heat sink 2a Through hole 3 Heater 4 Heating element 4a Electrode 7 Nut 8 Metal terminal 9 Lead wire (power supply line) 10 Insulating case (electric insulation) 10a Insulating case lower part 10b Insulating case upper part

Claims (1)

(57) [Scope of request for utility model registration] 1. A radiator plate, a heater closely attached to the radiator plate, and a cylindrical container having an opening for accommodating the radiator plate and the heater, wherein the heater is provided from a PTC thermistor. And a pair of metal terminals electrically connected to the respective electrodes, and a pair of metal terminals electrically connected to the respective metal terminals. An underwater heater comprising: a power supply line; and a periphery covered with an electrically insulating and waterproof covering member.