JP2001195135A - Electric heater device and method for manufacturing heater body for the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric heater device capable of obtaining a required heating value and executing accurate temperature control even when the electric resistance of a heater body is not comparatively accurate or the electric resistance is changed due to deterioration or the like of the heater body and to provide also the heater body having high product yield in manufacturing. SOLUTION: The electric heater device is provided with a heater body 1 having a heating member 7 to be heated when voltage is impressed and a control device 2 for supplying heating power to the member 7 in the heater body 1. The control device 2 supplies power required per unit time to the member 7 by impressing a fixed DC voltage to the member 7 and intermittently impressing the DC voltage in accordance with temperature detected by a temperature sensor arranged on a suitable position of the heater body 1 so that the temperature of the heater body 1 is maintained at a prescribed temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric heater device suitable for road heating for melting snow and a method for manufacturing a heater body for the device.

[0002]

2. Description of the Related Art Some conventional electric heater devices generate a required heat by applying a constant AC voltage to a heater as a heat generator. A certain amount of heat is obtained accordingly.

[0003] There are various types of heaters, and as a heater of an electric heating device conventionally used for road heating for snow melting, floor heating, and the like, conductive particles are mixed in a resin binder. There is an ink obtained by impregnating or applying a conductive ink such as a carbon ink to a base body made of a mesh-like cloth or a resin film.

In a conventional electric heater, the amount of heat generated is determined by the electric resistance of the heater. Therefore, it is necessary to accurately set the electric resistance of the heater. Strict amount and application amount are required.

However, it is not easy to maintain the amount of the conductive ink impregnated or applied to the base body at an appropriate value.
% Is discarded without reaching the required electric resistance value, resulting in a low product yield and an increase in the cost of the electric heater device.

Further, in the conventional electric heater device, since an AC voltage is supplied to the heater body, a minute vibration is generated in the heater body in accordance with a change in the polarity of the voltage, and the conductive ink is separated from the base by the vibration. As a result, the electric resistance value of the heater body increases, and a required heat generation amount may not be obtained.

[0007] By the way, the heater body of the electric heater device used for road heating is used by being buried in asphalt of a road. Specifically, the heater body is laid on previously cast asphalt. Asphalt having a thickness of about 3 cm is further cast on the heater body.

At this time, the heat (16
(Approximately 0 ° C.), the conductive ink of the heater body peels off from the base and the electric resistance value of the heater body increases, so that the required calorific value is often not obtained. In this case, asphalt is dug up. The heater body must be laid again.

[0009]

The object of the present invention is to reduce the required amount of heat even if the electric resistance of the heater is not very accurate or the electric resistance changes due to deterioration of the heater. An object of the present invention is to provide an electric heater device that can be obtained and that can perform accurate temperature control, and to provide a heater body having a good product yield during manufacturing.

[0010]

According to a first aspect of the present invention, there is provided an electric heater device having a heating member having a heating member which generates heat when a voltage is applied thereto, and a heating member of the heating member. A control device for supplying power for heat generation to the heating member, wherein the control device applies a constant DC voltage to the heat generating member, and furthermore, according to a temperature detected by a temperature sensor provided at an appropriate position of the heater body. By applying the DC voltage intermittently, a required amount of electric power is supplied per unit time to the heat generating member, so that the temperature of the heater body is maintained at a predetermined temperature.

According to a second aspect of the present invention, there is provided an electric heating device having a heating element having a heat generating member which generates heat when a voltage is applied thereto, and a control device for supplying electric power for heat generation to the heat generating member of the heater element. The control device includes a gate circuit that outputs a pulse-like gate voltage synchronized with a zero-cross point of the AC voltage with reference to a waveform of the AC voltage from outside, and a gate circuit that is normally OFF but is supplied from the gate circuit. A switch circuit that is turned on while the gate voltage is being input; and a rectifier circuit that performs double-wave rectification on the output from the switch circuit. The gate circuit is detected by a temperature sensor provided at an appropriate position on the heater body. A gate voltage is output for a required time according to the temperature to be turned on to turn on the switch circuit, and an output from the switch circuit is intermittently applied with a DC voltage to the heating member via the rectifier circuit. By supplying power requirements per unit to the heating member time by pressing, is as constructed as the temperature of the heater body is maintained at a predetermined temperature.

According to a third aspect of the present invention, there is provided an electric heating device having a heating element having a heat generating member which generates heat when a voltage is applied thereto, and a control device for supplying electric power for heat generation to the heat generating member of the heater element. The heater body includes electrodes parallel to each other on the heating member, and includes a temperature sensor in an appropriate position, and the control device synchronizes with a zero cross point of the AC voltage by referring to a waveform of the AC voltage from the outside. A gate circuit that outputs a pulsed gate voltage, a switch circuit that is normally off but is turned on while the gate voltage from the gate circuit is being input, and a double-wave rectification of the output from the switch circuit. A gate circuit that outputs a gate voltage for a required time according to a temperature detected by the temperature sensor, turns on the switch circuit, and switches the switch circuit. A required amount of power per unit time is supplied to the heat generating member by intermittently applying a DC voltage to the heat generating member through the rectifier circuit from the output from the circuit, and the temperature of the heater body is maintained at a predetermined temperature. It has been configured to be.

According to a fourth aspect of the present invention, in a method of manufacturing a heater body for an electric heater device, electrodes made of conductive wires are made parallel to each other in a longitudinal direction on a long mesh cloth made of an insulating material. The base material knitted in a plurality of rows is immersed in an immersion tank containing conductive ink containing conductive particles to impregnate the base material with conductive ink, and after removing excess conductive ink, it is dried. After the heating member is cut to a required length, a required wiring is provided at one end of the electrode and a temperature sensor is disposed at an appropriate position of the heating member, and the entire heating member is covered with a cover made of an insulating material. It is characterized by coating.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an electric heater device according to the present invention. The device of the present invention includes a heater 1 and a control device 2. The heater 1 and the control device 2 are connected by power supply lines 3 a and 3 b and a temperature detection line 4. AC line 5 is connected.

The heater body 1 comprises a sheet-like heat generating member 7 in which the electrodes 6a, 6b, 6c are arranged parallel to each other in the longitudinal direction, and, for example, a thermistor provided at an appropriate position on the heat generating member. An electrode terminal plate 9a, 9b, 9c is attached to one end of each of the electrodes 6a, 6b, 6c of the heating member 7, and the power supply line 3a is connected to the electrode terminal plates 9a, 9c. The end of
An end of the power supply line 3b is connected to the electrode terminal plate 9b, and an end of the temperature detection line 4 is connected to the temperature sensor 8.

The heat generating member 7 is formed by impregnating a conductive ink into a mesh-like cloth made of an insulating material as a base. The conductive ink contains, for example, carbon black as conductive particles by an appropriate resin binder or an adhesive. Use what is mixed in the agent. The electrodes 6a, 6b, and 6c are formed of conductive wires that are previously woven into a mesh-like cloth serving as a base of the heat generating member.

The heater body 1 is covered with an insulating cover 10 made of, for example, a polyester film to prevent water from entering the inside of the heater body and leakage. A method for manufacturing a heater suitable for road heating for snow melting will be described later.

The control device 2 of the electric heater device according to the present invention applies a DC voltage between the electrodes of the heating member 7 in the heater body 1. This DC voltage has a constant maximum voltage value. ON / O at required time intervals
The temperature of the heater (detection temperature) detected by the temperature sensor 8 is repeatedly set to a preset temperature (set temperature).
When the temperature is higher than the set temperature, the power supply time is shortened, that is, the amount of power supply per unit time is reduced to reduce the heat generation, and when the detected temperature is lower than the set temperature, the power supply time is lengthened, that is, the power supply amount per unit time is reduced. The configuration is such that the amount of heat generated is increased by a large amount to keep the temperature of the heater body constant.

More specifically, as shown in the relationship between the supply voltage to the heater 1 and the detected temperature shown in FIG. 2, the energization time when the detected temperature is equal to the set temperature is t ₀ , and the detected temperature is the set temperature. Assuming that the energizing time when the temperature is equal to or less than t _L and the energizing time when the detected temperature is equal to or higher than the set temperature is t _H , t _H <t
_The energization time is controlled so that ₀ <t _L so that the detected temperature is substantially equal to the set temperature.

Hereinafter, a specific configuration of the control device 2 will be described. Control device 2 and the gate circuit 11 connected to the primary side AC line 5a, the input terminal T ₁ is connected to the output side and the primary side AC line 5a of the gate circuit 11, but usually is OFF, the gate circuit Upon receiving the gate voltage and the switch circuit 12 to be oN for example made of triac from 11, rectifier for full-wave rectification made of the connected example bridge circuit to the output terminal T ₂ and the secondary side AC line 5b of the switch circuit 12 The rectifier circuit 1
The output side of 3 is a power supply line 3a, 3b to the heater body 1.
It is connected to the.

The gate circuit 11 is connected to the switch circuit 1
2 to output a gate voltage in the form of a pulse as an energization command to the second side. The operational amplifier 14 is connected to the primary AC line 5a and the output side of the operational amplifier. A trigger 15 for outputting a voltage;
A temperature setting circuit 16 including, for example, a variable resistance circuit is provided in the middle of the temperature detection line 4 reaching the input side of the temperature detection line 4.

The output timing of the gate voltage output from the gate circuit 11 to the switch circuit 12 is synchronized with the zero cross point P in the voltage waveform of the primary AC line 5a.

The operation of each part of the control device 2 configured as described above will be described based on the voltage waveforms of each part in the control device shown in FIG. FIG. 3A shows a voltage waveform between the primary AC line 5a and the secondary AC line 5b.
This is an AC waveform from a commercial power supply of V or 200V.

The gate circuit 11 outputs a pulsed gate voltage to the gate G of the switch circuit 12,
2B shows a waveform of a gate voltage applied between the gate G of _No. 2 and the input terminal T ₁ .

In the present invention, the gate circuit 11 corresponds to FIG.
With reference to the AC waveform shown in (A), the output timing of the gate voltage is synchronized with the zero cross point P in the AC waveform in FIG. . That is, application of an excessive voltage to the heater body 1 can be prevented, and the life of the heater body can be extended.

The output time t ₁ of the gate voltage is determined by the operational amplifier 14. More specifically, as described above, the operational amplifier compares the temperature detected by the temperature sensor 8 with the set temperature, and based on the result of the comparison. The output time t ₁ is determined, and the gate voltage is output from the trigger 15 to the switch circuit 12 only during the output time t ₁ .

FIG. 3 (C) shows the voltage waveform between the input ends of the rectifier circuit 13, i.e., the output terminal T ₂ of the switch circuit shows the voltage waveform between the secondary ac line 5b, the output time of the gate voltage t ₁ During this time, an AC voltage having a waveform similar to that shown in FIG.

FIG. 3D shows a theoretical waveform of the voltage between the output terminals of the rectifier circuit 13, and a voltage waveform rectified by the rectifier circuit 13 is obtained. Although the voltage waveform is a pulsating current in FIG.
The measured waveform of the voltage between the output terminals of No. 3 is smoothed as shown in FIG. This is considered that since the electrodes 6a, 6b, 6c of the heater body 1 are arranged on the heat generating member 7 so as to be parallel to each other, the heater body acts as a capacitor, and the total length of the heater body is reduced. The longer the length, the smoother the measured waveform can be obtained.

In the above-described embodiment of the electric heater device, the heat generating member of the heater body is formed in a sheet shape. However, an electric heater having a different shape may be used depending on the purpose of use of the electric heater. In some cases, another heater body such as a nichrome wire heater may be used.

Next, a method for manufacturing a heater body for an electric heating device according to the present invention, particularly a heater body suitable for road heating for snow melting will be described with reference to FIG. In the figure, reference numeral 17 denotes a base roll, which is a roll around which a base material 18 serving as a base of the heat-generating member 7 is wound. This is a mesh-like long cloth made of an insulating material woven so as to be parallel to each other and having a width of, for example, about 30 cm.

The base material 18 fed from the base roll 17 is squeezed from above and below by a squeezing roll 21 through an immersion tank 20 filled with a conductive ink 19 containing conductive particles, for example, a carbon ink, to thereby generate excess conductive material. The volatile ink is removed and sent to the dryer 22 to be dried.

By appropriately setting the concentration of the conductive ink in the immersion tank 20 and the pressing pressure of the pressing roll 21, the amount of the conductive particles adhered to the base member 18 is adjusted, and the amount of the conductive particles adhered to the base material 18 is adjusted. Thus, the electric resistance value of the heat generating member 7 is determined.

That is, if the amount of the conductive particles attached is small, the electric resistance value is large, and a heat-generating member having a small heat value per unit area can be obtained. Is small, and a heat generating member having a large heat generation amount per unit area can be obtained.

The base member 18 dried by the dryer 22 is cut by the cutter 23 into a required length, for example, about 50 m for road heating, and becomes the heat generating member 7. In advance, the assembler 24 previously feeds the feed lines 3a, 3b to the ends of the electrodes 6a, 6b, 6c.
The electrode terminals 9a, 9b, and 9c to which the ends of are connected are connected, and the temperature sensor 8 to which the temperature detection line 4 is connected in advance is attached.

The heating member 7 for which wiring has been completed is the laminator 2
5, the whole is covered with an insulating film 10 a made of, for example, a polyester film by a laminating process in the laminator, and is wound around a product roll 26 as a completed product of the heater body 1.

Thus, the completed heater body 1 undergoes a wiring inspection and an electrical resistance measurement inspection to become a product. By the way, in the conventional heater body, since the calorific value of the heater body depends only on the electric resistance value, it is necessary to strictly control the electric resistance value. About 30%. On the other hand, in the electric heater device of the present invention, since the heating value is managed on the control device 2 side, it is not necessary to control the electric resistance value of the heater body so strictly. The inspection can be simplified and the product yield is good, so that the manufacturing cost of the heater body can be reduced.

[0037]

According to the electric heater device of the present invention,
The temperature of the heater, which is a heating element, is detected and fed back to the controller, and the controller supplies necessary power per unit time to the heater based on the detected temperature.

Therefore, even if the electric resistance value of the heat generating member in the heater body is not a required value, or if the heat generating member is deteriorated due to the lapse of use and its electric resistance value changes, the control device can reduce the required heat value. The corresponding power is supplied,
The required set temperature can be stably maintained.

Further, since the control device supplies only the power corresponding to the required heat value to the heater body, there is no danger of overheating, so that the power consumption can be minimized and energy saving can be achieved. Can be planned.

Further, since the control device applies a DC voltage to the heat generating member of the heater, there is no problem such as deterioration of the heat generating member caused by applying an AC voltage to the heat generating member unlike the conventional device. The life of the heater body can be extended.

Further, according to the method of the present invention, it is not necessary to strictly inspect the electric resistance value of the heater body as in the prior art, so that the inspection can be simplified, and in the past, the electric resistance value error caused by an error in the electric resistance value. Most of the accepted heaters can be used as products, and the product yield is good, so that the heaters can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electric heater device according to the present invention.

FIG. 2 is a graph showing a relationship between a supply voltage to a heater body and a temperature detected by a temperature sensor.

FIG. 3 is a graph showing voltage waveforms at various points in the control device, where (A) is an AC voltage waveform input to the control device;
(B) is a waveform of the gate voltage input to the switch circuit,
(C) shows the voltage waveform input to the rectifier circuit, (D) shows the theoretical waveform of the voltage between the output terminals of the rectifier circuit, and (D ') shows the measured waveform of the voltage between the output terminals of the rectifier circuit.

FIG. 4 is a process chart showing a method for manufacturing a method heater body according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heater body 2 Control device 3a, 3b Power supply line 4 Temperature detection line 5 AC line 6a, 6b, 6c
Electrode 7 Heating member 8 Temperature sensor 9a, 9b, 9c Electrode terminal plate 10 Insulating cover 11 Gate circuit 12 Switch circuit 13 Rectifier circuit 14 Operational amplifier 15 Trigger 16 Temperature setting circuit 17 Base roll 18 Base material 19 Conductive ink 20 Immersion tank 21 Compress Roll 22 Dryer 23 Cutter 24 Assembler 25 Laminator 26 Product roll

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D051 AA08 GA01 GB02 GB08 5H323 AA40 CA10 CB03 DA03 EE01 FF03 GG03 KK05 MM08 MM14

Claims (4)

[Claims] A heating unit having a heat-generating member that generates heat when a voltage is applied thereto; and a control unit for supplying electric power for heat generation to the heat-generating member of the heater unit. Applying a constant voltage DC voltage, and intermittently applying the DC voltage according to a temperature detected by a temperature sensor provided at an appropriate position of the heater body, thereby supplying a required amount of power per unit time to the heat generating member. Supply,
An electric heater device configured to maintain a temperature of a heater body at a predetermined temperature. 2. A heater having a heating member which generates heat when a voltage is applied thereto, and a control device for supplying power for heat generation to the heating member of the heater, wherein the control device includes an external AC power source. A gate circuit that outputs a pulsed gate voltage synchronized with the zero-cross point of the AC voltage with reference to the voltage waveform, and is normally OFF but ON while the gate voltage is being input from the gate circuit. A switch circuit, and a rectifier circuit for double-wave rectifying the output from the switch circuit, wherein the gate circuit sets a gate voltage for a required time according to a temperature detected by a temperature sensor provided at an appropriate position of the heater body. Output to turn on the switch circuit,
The output from the switch circuit is intermittently applied to the heat generating member via the rectifier circuit with a DC voltage to supply a required amount of power per unit time to the heat generating member and maintain the temperature of the heater body at a predetermined temperature. An electric heater device configured to drip. 3. A heater body having a heating member that generates heat when a voltage is applied thereto, and a control device for supplying power for heating to the heating member of the heater body, wherein the heater body is provided to the heating member. A gate circuit that includes electrodes that are parallel to each other and includes a temperature sensor in an appropriate position, and the control device outputs a pulse-like gate voltage synchronized with a zero-cross point of the AC voltage with reference to an external AC voltage waveform A switch circuit that is normally OFF but is ON while a gate voltage from the gate circuit is being input, and a rectifier circuit that performs double-wave rectification on the output from the switch circuit. Outputting a gate voltage for a required time in accordance with the temperature detected by the temperature sensor to turn on the switch circuit, and outputting the output from the switch circuit via the rectifier circuit. DC to the heating member voltage by supplying intermittently applied requirements of power per unit to the heating member time by, electric heater device comprising constructed such that the temperature of the heater body is maintained at a predetermined temperature. 4. A base material obtained by knitting a plurality of rows of electrodes made of conductive wires in a long mesh-like cloth made of an insulating material so as to be parallel to each other in a longitudinal direction, and a conductive ink containing conductive particles. After the base material is impregnated with the conductive ink by immersion in the stored immersion tank, excess conductive ink is removed, and then dried to form a heat generating member. A method for manufacturing a heater body for an electric heating device in which required wiring is provided at one end, a temperature sensor is provided at an appropriate position of a heating member, and the entire heating member is covered with a cover made of an insulating material.