JP2012043577A - Temperature variable heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature variable heater that includes a small connector, is not bulky and excellent in usability even when applied to a surface heater which uses a surface heat generation body as a heat generation source, and is free of a failure factor due to an insulation defect, a component defect, etc., even if the surface heater gets wet with urine of a small animal.SOLUTION: The temperature variable heater comprises a heat generation part 2, a power supply cord wire 4 for supplying electric power to the heat generation part 2, and a controller 5 interposed halfway in the power supply cord wire 4. The controller 5 is provided with a knob 51 for temperature control so that the knob can be operated from outside, and a temperature control circuit which variably sets the temperature of the heat generation part 2 by controlling electric energy supplied to the heat generation part 2 through phase control is built in. The temperature control circuit includes a variable resistor for temperature control and a phase shift circuit composed of a capacitor, and the variable resistor is configured to vary in resistance value by the knob 51 for temperature control.

Description

  The present invention relates to a heater used for various applications such as heating a breeding container for breeding small animals such as reptiles, or heating water in an aquarium for ornamental fish, and in particular, the present invention relates to The present invention relates to a variable temperature heater that can freely change a set temperature according to the kind of animal to be bred.

Conventionally, as this type of temperature variable heater, there is one using a planar heating element as a heat source. As shown in FIG. 6, a power cord is connected to a sheet-like surface heater 100 via a connector 101 made of synthetic resin. 102 is electrically connected. A plug 103 to be plugged into a commercial power outlet is attached to the end of the power cord 102.
The surface heater 100 has a heat generating portion 100A having a sheet heating element 104 for heating having a characteristic (generally referred to as “PTC characteristic”) in which an electric resistance value increases as the temperature rises, and heat generation of the heat generating part 100A. A temperature detecting portion 100B having a second planar heating element (not shown) for determining the temperature is provided on the insulating sheet in a divided area (see, for example, Patent Document 1).

Japanese Patent No. 4036859

  As shown in FIG. 7, the connector 101 includes a printed wiring board 106 attached to the position of the temperature detecting portion 100B of the surface heater 100 and a temperature sensor provided so as to be in contact with the surface of the second planar heating element. 107 and an insulating case 108 that covers the printed wiring board 106 and the temperature sensor 107. The printed wiring board 106 is mounted with a temperature control circuit that controls the heating temperature of the planar heating element 104 to be a set temperature set by the variable resistor 109 based on the temperature detected by the temperature sensor 107. .

  When using the temperature variable heater described above, a breeding container is placed on the surface heater 100, the plug 103 is inserted into an outlet, and the surface heater 100 is energized to cause the planar heating element 104 to generate heat. The heating temperature of the planar heating element 104 is maintained at a set temperature set by the variable resistor 109, and the breeding container is warmed to an appropriate temperature according to the animal to be raised.

  In the above temperature variable heater, the surface heater 100 is provided with the temperature detection portion 100B, and the temperature sensor 107, the variable resistor 109, and the printed wiring board 106 are loaded into the case 108 of the connector 101 attached to the temperature detection portion 100B. Therefore, not only does the connector 101 become large and the surface heater 100 becomes bulky and the usability deteriorates, but also when the surface heater 100 gets wet due to urination of small animals, it causes an insulation failure and defective parts, leading to a failure factor. In addition, a temperature sensor 107 such as a thermistor is required, the configuration of the temperature control circuit is complicated, and only a specific heater having a PTC characteristic can be used as a heat source, so that the cost can be reduced. There was a problem that it was not easy.

  The present invention has been made paying attention to the above problems, and even when applied to a surface heater using a planar heating element as a heat source, a small connector is sufficient, and it is not bulky and is easy to use. Even if the surface heater gets wet, there is no risk of failure due to insulation failure or parts failure, a temperature sensor such as a thermistor is unnecessary, the temperature control circuit configuration is simple, and heat is generated. An object of the present invention is to provide an inexpensive temperature variable heater that can use various sources.

  The temperature variable heater according to the present invention includes a heat generating part, a power cord line for supplying power to the heat generating part, and a controller interposed between the power cord lines. The controller is provided with a temperature adjustment knob that can be externally operated, and a temperature control circuit that variably sets the temperature of the heat generating portion by controlling the amount of power supplied to the heat generating portion by phase control. The temperature control circuit includes a phase shift circuit including a variable resistor for temperature adjustment and a capacitor, and the variable resistor is configured such that a resistance value is changed by the knob for temperature adjustment.

In the temperature variable heater having the above-described configuration, when the resistance value of the variable resistor is changed by operating the temperature adjustment knob from the outside, the amount of power supplied to the heat generating portion is controlled according to the resistance value by the temperature control circuit. The temperature of the heat generating part is set to a value corresponding to the amount of power supplied. As described above, since the temperature control is based on the electric power control without using the temperature sensor, the temperature sensor is unnecessary and the configuration of the temperature control circuit is simplified. In addition to those having a PTC characteristic as a heat source, various types such as those using carbon, nichrome wire, etc. can be used.
Also, the printed wiring board on which the variable resistor and temperature control circuit are mounted is built into the controller that is interposed between the power cord lines, so the connector for connecting the power cord lines to the heat generating part is small. The heating part is not bulky. Further, since the printed wiring board is not incorporated in the connector, there is no possibility of causing a failure even if the connector is wet with urination of a small animal.

  In a preferred embodiment of the present invention, the heat generating part is constituted by a surface heater in which a sheet heating element is provided on an insulating sheet, but is not limited thereto.

  According to this invention, even if it implements to a surface heater using a sheet heating element as a heat source, a small connector is sufficient, and it is easy to use without being bulky. Moreover, even if the surface heater gets wet due to urination of small animals, there is no possibility of causing a failure of insulation or defective parts and causing a failure. Furthermore, a temperature sensor such as a thermistor is not required, the configuration of the temperature control circuit is simple, and various types of heat generation sources can be used, so that the cost can be reduced.

It is a top view which shows the external appearance of the temperature variable heater which is one Example of this invention. It is an electric circuit diagram which shows the structure of the temperature control circuit in the Example of FIG. It is a timing chart of the temperature control circuit of FIG. It is a top view which shows the external appearance of the other Example of this invention. It is explanatory drawing which shows the heater for ornamental fish which is another Example of this invention. It is a top view of a prior art example. It is sectional drawing of the connector of the prior art example of FIG.

  FIG. 1 shows the appearance of an animal breeding temperature variable heater 1 according to an embodiment of the present invention. However, the illustrated temperature variable heater 1 is not limited to animal breeding but may be used for other purposes (for example, blood Can also be used for incubation, cell culture, plant growth, etc.).

In the temperature variable heater 1 of this embodiment, a power cord 4 is electrically connected to a heat generating portion 2 composed of a sheet-shaped surface heater by a synthetic resin connector 3, and a synthetic resin is formed in the middle of the power cord 4. The controller 5 is interposed. The power cord 4 is composed of an intermediate cord 41 connecting the heat generating portion 2 and the controller 5 and a connecting cord 42 having a plug 43 inserted into a commercial power outlet at the tip.
As shown in FIG. 4, the intermediate cord 41 is divided into first and second portions 41a and 41b and is attached and detached by a plug 44 and a socket 45 so that the controller 5 and the heat generating portion 2 can be separated. You may comprise.

The heat generating part 2 is formed over almost the entire area of the insulating sheet 20 having a rectangular shape as a whole. The insulating sheet 20 is composed of an insulating film made of a synthetic resin having heat resistance that is stacked up and down, and a rectangular planar heating element 22 for heating is provided between the insulating films. The planar heating element 22 is formed by printing on the surface of one insulating film using an ink mainly composed of conductive carbon particles. The surface of the insulating film is further provided with a first electrode portion 23 composed of two linear electrodes 24 a and 24 b along both sides of the planar heating element 22 and the linear electrode at a position where the planar heating element 22 is equally divided. A second electrode portion 25 composed of one linear electrode 26 arranged in parallel with 24a and 24b is formed by printing using conductive ink.
The upper surface of the sheet heating element 22 and the first and second electrode portions 23 and 25 are covered with the other insulating film, and the two insulating films are integrated.

  The connector 3 connects the first and second electrode portions 23 and 25 of the heat generating portion 2 and the power cord 4 and is caulked to one end edge of the insulating sheet 20. Inside the connector 3, a temperature fuse f arranged in the temperature control circuit 6 shown in FIG. 2 is incorporated, but no other components or boards are incorporated.

The controller 5 is provided with a temperature adjusting knob 51 and a lamp 52 indicating an energized state on the surface of a case 50 made of synthetic resin. The illustrated example 51 is a slide-type knob, but is not limited thereto, and may be a rotary-type knob. A scale plate (not shown) indicating the temperature is attached to the slide position of the knob 51 on the surface of the case 50. The scale of the scale plate is a relationship between the slide position of the knob 51 and the heat generation temperature of the heat generating portion 2. Can be easily determined by obtaining in advance.
Inside the case 50 of the controller 5, a printed wiring board (not shown) on which a circuit pattern of the temperature control circuit 6 shown in FIG.

In FIG. 2, 61 and 62 are input terminals to which an AC voltage V of 100 volts is input, f is a temperature fuse, BR is a varistor for noise removal, and D is a light emitting diode constituting the lamp 52.
The temperature control circuit 6 in the illustrated example is composed of a phase control circuit using a trigger diode TD and a triac TR, and controls the amount of power supplied to the heat generating unit 2 by phase control to vary the temperature of the heat generating unit 2. Set.

  The illustrated phase control circuit includes a phase shift circuit composed of a variable resistor VR for temperature adjustment, a dummy resistor R1, and a capacitor C1, and the variable resistor VR has a resistance value by sliding operation of the knob 51 for temperature adjustment. Is configured to change. In the figure, a series circuit of a resistor R2 and a capacitor C2 connected to both ends of the triac TR is a surge absorption circuit, and prevents destruction of the triac TR due to a surge voltage.

  In the phase shift circuit, when the voltage V1 across the capacitor C1 reaches the breakover voltage of the trigger diode TD, the trigger diode TD is switched on, the capacitor C1 is discharged, and the gate signal ig is given to the gate of the triac TR. And the triac TR is triggered. In the circuit of FIG. 2, in order to prevent an electric shock at the heat generating portion 2, a rectification and smoothing circuit 63 may be provided on the output side to convert an AC output into a DC output.

  FIG. 3 is a timing chart of the temperature control circuit 6. FIG. 3 (1) shows the waveform of the power supply voltage V applied to the input terminals 61 and 62, and FIG. 3 (2) shows the waveform of the triac TR. Each of the gate signals ig is shown. 3 (3) shows the waveform of the voltage Vt across the triac TR, and FIG. 3 (4) shows the waveform of the voltage Vh across the heating part 2.

  Now, when the knob 51 is slid to decrease the resistance value of the variable resistor VR, the charging speed of the capacitor C1 of the phase shift circuit increases, and the phase of the gate signal ig shifts in the direction indicated by the arrow in FIG. To do. At the same time, as shown in FIG. 3 (3), the conduction angle α of the triac TR is increased to α ′ (> α), the voltage Vh across the heat generating part 2 is increased, and the amount of power supplied to the heat generating part 2 To increase the heat generation temperature (see FIG. 3 (4)).

  The above embodiment is an example of the temperature variable heater 1 using a planar heating element as a heat source. However, as shown in FIG. 5, the temperature variable heater 1 using a nichrome wire as a heat source is also used. It is possible to implement. The heater 1 in the figure is for heating the water in the aquarium 9 for aquarium fish. The power cord 4 is electrically connected to the heat generating portion 2 and is made of a synthetic resin in the middle of the power cord 4. A controller 5 is interposed. On the surface of the case 50 of the controller 5, a temperature adjusting knob 51 and a lamp 52 indicating an energized state are provided.

  In the temperature variable heater 1 of each embodiment described above, when the temperature adjustment knob 51 is operated from the outside to change the resistance value of the variable resistor VR, the amount of power supplied to the heat generating unit 2 by the phase control circuit is changed to the resistance value. The temperature is controlled according to the value, and the temperature of the heat generating unit 2 is set to a value according to the amount of power supplied. As described above, since the temperature control is based on the electric power control without using the temperature sensor, the temperature sensor is unnecessary and the configuration of the temperature control circuit 6 is simplified. In addition to those having a PTC characteristic as a heat source, various types such as those using carbon, nichrome wire, etc. can be used.

  Further, since the printed wiring board on which the variable resistor VR and the temperature control circuit 6 are mounted is incorporated in the controller 5 interposed in the middle of the power cord 4, the power cord 4 is connected to the heating unit 2. For this purpose, the connector 3 is small, and the heat generating portion 2 is not bulky. Further, since a printed wiring board or the like is not incorporated in the connector 3, there is no possibility of causing a failure even if the connector 3 gets wet with urination of a small animal.

DESCRIPTION OF SYMBOLS 1 Temperature variable heater 2 Heat generating part 3 Connector 4 Power supply cord line 5 Controller 6 Temperature control circuit 51 Knob for temperature adjustment VR Variable resistor C1 Capacitor

Claims (2)

  It consists of a heat generating part, a power cord for supplying power to the heat generating part, and a controller interposed in the middle of the power cord, and the controller is provided with a temperature adjustment knob for external operation And a temperature control circuit that variably sets the temperature of the heat generating part by controlling the amount of power supplied to the heat generating part by phase control, the temperature control circuit comprising a variable resistor and a capacitor for temperature adjustment The variable resistor includes a phase shift circuit, and the variable resistor is configured such that a resistance value is changed by the temperature adjusting knob.   2. The temperature variable heater according to claim 1, wherein the heat generating portion is configured by a sheet-like surface heater in which a sheet-like heating element is provided on an insulating sheet.

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