JP4237168B2 - Heating equipment and road heater - Google Patents

Description

  The present invention relates to a heating facility and a road surface heater. More specifically, the present invention relates to a heating facility and a road surface heater used for preventing freezing of roads and various planar objects, melting snow, and the like.

  As a conventional road surface heater, a mesh body woven in a grid pattern with carbon fiber or a mesh body woven in a grid pattern with a mixed fiber of carbon fiber and heat-resistant fiber is coated with a thermoplastic resin to form a mesh body. There is a road surface heater that generates heat when energized (Patent Document 1).

The amount of heat generated by the road surface heater is controlled by the amount of power supplied. As a technology for controlling the amount of power supplied, the following AC power adjustment device is generally used (Non-Patent Document 1).
The basic circuit for adjusting the AC power supplied to the load is a thyristor connected in reverse parallel as shown in FIG. Instead of using two thyristors, there are a type in which a thyristor and a diode are connected in reverse parallel, and a method in which one triac or reverse conducting element is used.
As shown in FIG. 5B, the current flowing through the element naturally becomes zero due to the change in polarity of the AC power supply voltage. Therefore, the thyristor is turned off at this time. In this way, when the AC power of the load is phase controlled or on / off switched using the natural annihilation (natural arcing) of the thyristor current, each of the peaks in the power waveform is partially cut off. It is possible to increase or decrease the amount of power supplied according to the cut amount.

  However, in the AC power adjustment technique as described above, as shown in FIG. In this case, since the temperature of the heater decreases between the peaks of the load current, it is necessary to increase the decrease, eventually resulting in an increase in power consumption and a high maintenance cost (electricity charge). There is a problem of becoming.

JP-A-7-34425 362 pages of color edition electrical encyclopedia August 10, 1982 Ohm Co., Ltd.

  In view of the above circumstances, an object of the present invention is to provide a road heating facility and a road surface heater that consume less power.

A road surface heater according to a first aspect of the present invention is a road surface heater constituting a heating facility, wherein the road surface heater has a plurality of first heating wires and a plurality of second heating wires arranged so as to be orthogonal to each other. Comprising a power control device for supplying a constant power to the first heating wire and supplying only the power necessary for preventing a temperature drop from a target heating temperature to the second heating wire; The power control device obtains a differential voltage that is the difference between the target temperature and the detected temperature on the road surface, and outputs an inverted amplification voltage obtained by inverting the polarity of a voltage that is lower than 0 V with respect to 0 V. The inverting amplification voltage is compared with the pulsating rectification obtained by rectifying the AC power supply, and the comparison output is output only at the portion where the inverting amplification voltage exceeds the pulsating rectification, while the comparison output is being output. Only supply pulsating rectification as load power And butterflies.
A road surface heater according to a second aspect of the present invention is a road surface heater that constitutes a heating facility, and the road surface heater is arranged such that a plurality of first heating wires and a plurality of second heating wires are orthogonal to each other. Comprising a power control device configured to supply the first heat generating wire and the second heat generating wire with electric power necessary to match the detected temperature of the road surface with the heating target temperature, A differential voltage that is the difference between the target temperature on the road surface and the detected temperature is obtained, and an inverted amplified voltage obtained by inverting the polarity of a voltage lower than 0 V with respect to 0 V as a reference is output. Compared with pulsating rectification obtained by rectifying an AC power supply, a comparison output is output only at a portion where the inverted amplification voltage exceeds the pulsating rectification, and only as long as the comparison output is output, the pulse power is output as a load power. It is characterized by supplying current rectification.

According to the first aspect of the invention, the temperature is controlled by a part of the heating wires constituting the road surface heater, so that the fluctuation range of the supplied power is reduced and the power consumption is also reduced. In addition, when the temperature rise control is performed, the lower the detected temperature is, the wider the energization time period is compared to when the detected temperature is high. This is because, when the detection temperature is low, the inverted amplification voltage becomes high, the position intersecting the pulsating rectification peak becomes high, the width of the valley is widened, and the power supply amount is increased. On the other hand, when the detected temperature is high, the energization time period is conversely narrowed and the power supply amount is reduced. As described above, even when the detected temperature is lower than the target temperature, the energization time is increased or decreased in proportion to the lower temperature, so that smooth temperature control can be performed without using wasteful power for temperature increase. .
According to the second aspect of the invention, since the temperature is controlled by all the heating wires constituting the road surface heater, the temperature raising / lowering speed is fast and the target temperature is easily maintained. In addition, when the temperature rise control is performed, the lower the detected temperature is, the wider the energization time period is compared to when the detected temperature is high. This is because, when the detection temperature is low, the inverted amplification voltage becomes high, the position intersecting the pulsating rectification peak becomes high, the width of the valley is widened, and the power supply amount is increased. On the other hand, when the detected temperature is high, the energization time period is conversely narrowed and the power supply amount is reduced. As described above, even when the detected temperature is lower than the target temperature, the energization time is increased or decreased in proportion to the lower temperature, so that smooth temperature control can be performed without using wasteful power for temperature increase. .

Next, an embodiment of the present invention will be described with reference to the drawings.
(Configuration of road heater)
FIG. 1 is a plan view of a road surface heater 10 of the present embodiment. As shown in the figure, the road surface heater 10 of this embodiment is rectangular, and electrodes 1 and 1 are provided on the upper and lower short sides, and electrodes 2 and 2 are attached on the left and right long sides. The electrodes 1 and 2 are, for example, true casting, but may be a copper plate, copper foil, aluminum, or the like.

Between the upper and lower electrodes 1, 1, an appropriate number of first heating wires 3, for example, 10 are attached in parallel. The left and right electrodes 2 are three times as long as the electrode 1. The electrode 2 may be the same one as the electrode 1 connected in series, or may be one that is three times as long. An appropriate number of second heating wires 4, for example, 30 are attached in parallel between the electrodes 2 and 2. The heating wires 3 and 4 are bonded to each other at the intersections by an adhesive, pressure bonding, fusion bonding, or the like. In this way, since they are alternately overlapped at the intersections and are carved, it is possible to prevent them from being separated apart. The heating wires 3 and 4 may not be knitted in the cage, but may be simply superimposed.
The cross-shaped space surrounded by the intersecting exothermic wires 3 and 3 and exothermic wires 4 and 4 functions as an adhesion gap for adhering the road surface base material and the surface layer material when constructing on the road surface.

  Since the width and length of the road heater 10 are substantially proportional to the length and number of the electrodes 1 and 2, the short side width W is 1 m and the long side length L is 3 m. This is because the road width is generally 3.5 m, and if the width of the short side is 1 m, one side lane can be installed by arranging three road surface heaters 10 in parallel. The reason that the long side is 3 m is for the convenience of construction on the road surface. If it is too short, it will only increase the number of man-hours. If it is too long, it will be inconvenient to handle and difficult to apply to curved roads.

  In addition to paved roads, various road surface objects such as paved parking lots, paved bicycle parking lots, concrete walls, building floors, building wall materials, roofing materials, steel materials, signboards, signs, etc., are adopted for road heaters 10 without restriction. Yes. Further, the length and width of the road surface heater 10 and the number of the first and second heating wires 3 and 4 may be arbitrarily changed according to these application targets.

(Heating wire)
Each of the first and second heating wires 3 and 4 is a heating wire in which ultrafine carbon fibers that emit far infrared rays when energized are bundled. For example, one carbon fiber has a diameter of 7 μm and a bundle of nearly 50,000 carbon fibers is used as the heating wires 3 and 4 of the present invention. A pulsating current rectified in one direction is supplied to the carbon fiber to generate heat. In other words, carbon fiber has a characteristic that when a current is applied in the opposite direction, the flow of molecules is not constant, and it is difficult to generate heat.

  Each of the heat generating wires 3 and 4 covers a bundle of carbon fibers with a protective film of a synthetic resin such as vinyl resin. This coating is for protecting from crushed stone and the like, and rubber or the like can be used as the protective film. In addition, as a physical characteristic, it has the advantage that it is very strong with respect to a tensile force, and it is difficult to cut even if it receives the impact by driving | running | working of a motor vehicle after laying on the road surface.

  The first heating wire 3 is coated around a bundle of carbon fibers with a metal film such as nickel, tin, copper, or aluminum. In this case, since the electrical resistance is lowered by the metal film, the length is three times that of the second heating wire 4, but the resistance value can be the same level as that of the second heating wire 4 not covered with the metal film. In this way, by setting the resistance value to the same level, the same voltage can be applied to flow the same current, so the same power source can be used and the equipment is simplified.

(Power supply system)
The first heat generating wire 3 in the vertical direction and the second heat generating wire 4 in the horizontal direction are supplied with power by the independent power control devices CD1 and CD2.
A power source 13 is connected to the electrodes 1 and 1 of the first heating wire 3 via a first power control device CD1, and a constant voltage is supplied to the first heating wire 3 to give a constant amount of heat to the road surface. It is like that.
A power source 13 is connected to the electrodes 2 and 2 of the second heating wire 4 via a second power control device CD2. The second power control device CD2 adjusts the supplied power amount so as to keep it at a constant temperature by adjusting the amount of supplied power in accordance with the actual road surface temperature caused by fluctuations in the weather and the outside air temperature. That is, electric power necessary to prevent a temperature drop from the target heating temperature is supplied.

(Power control device)
Next, the power control device CD2 that performs temperature adjustment will be described.
FIG. 2 is a block diagram of the power control device CD2. The temperature sensor 31 detects the actual road surface temperature as the detection temperature B. The temperature sensor 31 is provided on the surface of a paved road or the like to be detected. As the power source 13, a battery, solar power, wind power generation or the like is used, and the type of power source is not particularly limited.
The power control device CD2 of the present embodiment controls the voltage applied to the road heater 10 so that the difference between the detected temperature B detected by the temperature sensor 31 and the set target temperature A becomes zero, It is a control device that adjusts the supplied power.

  As shown in FIG. 2, the power control device CD <b> 2 includes a differential amplifier 41, an inverting amplifier 42, a rectification synchronization circuit 43, a comparison circuit 45, and a power control element 46. The power control element 46 includes various transistors such as a thyristor, a field effect transistor, and an IGBT (insulated gate bipolar transistor).

Hereinafter, description will be made with reference to FIG. 2 and FIGS. 3 and 4 together.
The set target temperature A and the detected temperature B detected by the temperature sensor 31 (see FIG. 3I) are input to the differential amplifier 41. Then, the differential amplifier 41 outputs a difference between the detected temperature and the portion exceeding the target temperature A by the following calculation (see FIG. 3 (II)).
Differential voltage C = (detection temperature B−target temperature A)
Note that the set temperature (target temperature A) on the road surface and the like for preventing freezing is generally set to about 5 ° C. Therefore, if the actual road surface temperature fluctuates between 2 ° C. and 6 ° C., the difference temperature is controlled between −3 and + 1 ° C.

  The inverting amplifier 42 outputs an inverting amplification voltage E obtained by inverting the polarity of the voltage lower than 0V with respect to the differential voltage C output from the differential amplifier 41 with reference to 0V (see FIG. 3 (III)). .

  The rectification synchronization circuit 43 is supplied with an AC voltage F (see FIG. 4 (IV)) from the power supply 13 and outputs a pulsating flow rectification G (see FIG. 4 (V)) rectified so as to flow in one direction. is there. As a result, it is possible to supply a current in the same direction in which the carbon fiber easily generates heat.

The comparison circuit 45 compares the inverted amplification voltage E output from the inverting amplifier 42 with the pulsating flow rectification G output from the rectification synchronization circuit 43 (see FIG. 4 (VI)), and compares them by the following calculation. The output I is output.
When the inverting amplification voltage E exceeds the pulsating rectification G, the comparison output I is output as a rectangular wave (ON). When the inverting amplification voltage E is lower than the pulsating rectification G, the comparison output I is set to 0 (OFF). ). As a result, the width of the comparison output I coincides with the time when the inverted amplification voltage E exceeds the pulsating rectification G. In other words, the time when the comparison output is 0 coincides with the time when the inverted amplification voltage E is below the pulsating flow rectification G (see FIG. 4 (VII)).

The power control element 46 outputs the load voltage J from the comparison output I output from the comparison circuit 45 and the pulsating flow rectification G output from the rectification circuit 43 by the following calculation.
When the comparison output I is ON, the load voltage J is supplied, and when the comparison output I is OFF, the load voltage J is not output (see FIG. 4 (VIII)).
As a result of the control as described above, when the inverted amplification voltage E exceeds the pulsating flow rectification G, power is supplied to the road surface heater 10 so that the actual temperature of the road surface matches the target temperature. Then, the load power is supplied not in the middle of the pulsating mountain, but in the portion between the bases of adjacent mountains (see FIG. 4 (VIII)).

(Temperature control method)
Next, a temperature control method will be described.
In FIG. 4 (VIII), Hi indicates a region where the actual detected temperature B is above the target temperature A, and Lo indicates a region where the detected temperature is below the target temperature. And the code | symbol a shows the electric power supply time slot | zone, and the area | region which does not attach | subject the code | symbol shows the non-supply time slot | zone.
In the region Hi where the detected temperature B exceeds the target temperature A, no power is supplied, so the amount of heat generated by the road surface heater 10 decreases and the road surface temperature also decreases. Then, the target temperature A is settled.
When the temperature falls below the target temperature A, the temperature rise is controlled as follows.

When the detected temperature B is lower than the target temperature A, power is supplied in the time zone indicated by the symbol a, the amount of heat generated by the road surface heater 10 increases, the road surface temperature also increases, and finally the target temperature. A will be reached.
Further, when the temperature rise control is performed in this way, the lower the detected temperature B, the wider the energization time zone a (corresponding to θa to θb) than when the detected temperature B is high. This is because, when the detection temperature B is low, the inverted amplification voltage E becomes high, the position where it intersects the peak of the pulsating rectification G is high, and the width of the valley is widened. In this case, the amount of power supply increases.
This means that when the detected temperature B is high, the energization time zone a becomes narrower. In this case, the power supply amount is small.
As described above, even when the detected temperature B is lower than the target temperature A, the energization time is increased or decreased in proportion to the lowering temperature, so that smooth temperature control is possible without using wasted power for temperature increase. It becomes.

The control method of the present invention has the following advantages.
1) Advantage 1
A constant amount of power is constantly supplied to the first heating wire 3 by a normal power control device CD1, and when a temperature difference occurs, the second heating wire 4 is kept warm by the temperature control device CD2 of the above embodiment. Adjustments can be made. As described above, since the temperature control is performed only with some of the heating wires constituting the road surface heater 10, the fluctuation range of the supplied power amount is reduced. For this reason, the fluctuation | variation of electric power consumption becomes small and energy saving is attained.
However, the present invention is not limited to this type, and both the first heat generating wire 3 and the second heat generating wire 4 may be temperature-controlled by the temperature control device CD2 of the above embodiment.

2) Advantage 2
According to the control of the present invention, there is an advantage that it is easy to prevent a temperature drop of the heater. FIG. 5A shows a power supply state according to the present invention, and FIG. 5B shows a power supply state under the control of the prior art. In both cases, the hatched portion is a power supply time zone.
(B) As shown in the figure, with the control of the prior art, the interval between the non-feeding bands b is wide, and the temperature of the heater itself or the road surface is likely to drop between the non-feeding bands b. On the other hand, as shown in FIG. (A), in the control of the present invention, the feeding band a itself is divided into two adjacent peaks, but the first peak in the power waveform goes down to zero voltage. But the mountain in the second half has resumed power supply. In this case, even when the power supply becomes 0, the temperature itself does not decrease to 0, but maintains a certain temperature, and the temperature is heated again in the latter half. There is an advantage that less power consumption is required than when heating. Therefore, according to the present invention, the electricity bill can be reduced and energy saving can be achieved.

3) Advantage 3
The reason why the comparison with the synchronous voltage H is not the differential voltage C itself but the inverted amplification voltage E is for the following reason.
As shown in FIG. 6, when the synchronous voltage H describing the sine wave is compared with the differential voltage C, the differential voltage C increases as the temperature exceeds the target temperature, and the valley between adjacent sine waves increases. Since the width is wide (see (VI)), the width of the comparison output I is widened (see (VII)), and extra power is supplied. For this reason, the temperature difference is further widened without lowering to the target temperature. On the other hand, when the inverted amplification voltage E is superimposed on the synchronous voltage H as in the present invention, since it intersects in the vicinity of the base (see (VI)), the width of the valley becomes narrow and the width of the comparison output I becomes narrow (( See VII). For this reason, as the detected temperature B exceeds the target temperature A, the width of the comparison output I becomes narrower. For this reason, the temperature can be lowered to the target temperature, and as a result, the amount of power used can be reduced.

(Road heating equipment)
As shown in FIG. 7, a plurality of, for example, three road surface heaters 10 of the present invention are installed in parallel in the width RW direction of the road surface.
Further, the road surface heater 10 is repeatedly installed in the length direction of the road in the same manner, and a snow melting road can be formed over a desired distance.

(Energization sequence control)
The group of road heaters 10 arranged in parallel as shown in FIG. 7, for example, the three road heaters No. 1 to No. 3 are preferably subjected to energization order control.
FIG. 8 shows a control circuit for energization sequence control. The basic configuration of the power control device CD2 is the same as that in FIG. 2, and a circuit indicated by the symbol K is added.
Six power control elements 46 are provided in accordance with the first and second heating wires 3 and 4 of the three road surface heaters 10 (No. 1 to No. 3). The power control element 46 is provided in parallel to the output from the comparison circuit 45 via the AND circuit 48. A ring counter 47 is interposed between the rectification synchronization circuit 43 and each AND circuit 48. The ring counter 47 has a function of dividing a mountain of the rectifying pulsating flow G and sending it to the individual road surface heaters 10. That is, the first peak of the rectifying pulsating flow G is sent to the No. 1 road heater 10, the second peak is sent to the No. 2 road heater 10, and the third peak is sent to the No. 3 road heater 10. It has a function to repeat the order.
The AND circuit 48 is provided to synchronize the comparison output I (see VII in FIG. 4) and the load power J (see VIII in FIG. 4). Due to this synchronization, large power can be extracted effectively.

With the above configuration, power is sequentially and intermittently supplied to No. 1 to No. 3 road surface sheets 10. For example, if power is supplied to No. 1 and the supply is cut off, it is immediately supplied to the next No. 2, and if the supply to No. 2 is cut off, it is immediately supplied to the next No. 3. When the supply to No. 3 is cut off, the supply to No. 1 is started again, and this operation is repeated thereafter.
The supply time is 10 msec per operation in the 50 Hz region of commercial power and 8.33 msec per operation in the 60 Hz region.

  Even if power is sequentially applied as described above, the road surface temperature does not decrease immediately, so the road surface temperature can be maintained. Therefore, power consumption is reduced and it is economical.

It is a schematic plan view of the road surface heater which concerns on one Embodiment of this invention. It is a circuit diagram of the electric power control apparatus of the road surface heater which concerns on one Embodiment of this invention. It is explanatory drawing of control operation | movement I-III by the electric power control apparatus of FIG. It is explanatory drawing of control operation IV-VIII by the same electric power control apparatus. It is explanatory drawing which contrasted the power control of this invention, and the conventional power control. In this invention, it is a comparison explanatory drawing with the case where it does not use with the case where an inversion amplification voltage is used. It is explanatory drawing of the arrangement pattern to the road surface of the road surface heater of this invention. It is a circuit diagram of an energization order control circuit. It is explanatory drawing of the conventional alternating current power adjusting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode 2 Electrode 3 1st heat generating wire 4 2nd heat generating wire 10 Road surface heater 13 Power supply
CD1 1st power controller
CD2 Second power control device 41 Differential amplifier 42 Inverting amplifier 43 Rectification synchronization circuit 45 Comparison circuit 46 Power control element 47 Ring counter 48 AND circuit

Claims (2)

A road surface heater constituting a heating facility,
The road surface heater is configured by arranging a plurality of first heating wires and a plurality of second heating wires so as to be orthogonal to each other,
A constant power is supplied to the first heating wire,
The second heating wire includes a power control device that supplies only power necessary to prevent a temperature decrease from the heating target temperature,
The power control device
Find the differential voltage, which is the difference between the target temperature on the road surface and the detected temperature,
The differential voltage is output as an inverted amplification voltage obtained by inverting the polarity of a voltage lower than 0V with reference to 0V,
Comparing the inverted amplified voltage with the pulsating rectification obtained by rectifying the AC power supply, and outputting a comparison output only at a portion where the inverted amplified voltage exceeds the pulsating rectification,
A road surface heater that supplies pulsating flow rectification as load power only while the comparison output is being output. A road surface heater constituting a heating facility,
The road surface heater is configured by arranging a plurality of first heating wires and a plurality of second heating wires so as to be orthogonal to each other,
The first heating wire and the second heating wire are provided with a power control device that supplies power necessary for matching the detected temperature of the road surface to the heating target temperature,
The power control device
Find the differential voltage, which is the difference between the target temperature on the road surface and the detected temperature,
The differential voltage is output as an inverted amplification voltage obtained by inverting the polarity of a voltage lower than 0V with reference to 0V,
Comparing the inverted amplified voltage with the pulsating rectification obtained by rectifying the AC power supply, and outputting a comparison output only at a portion where the inverted amplified voltage exceeds the pulsating rectification,
A road surface heater that supplies pulsating flow rectification as load power only while the comparison output is being output.

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