JPH05171610A - Road heater and controlling thereof - Google Patents

Abstract

PURPOSE:To cut down the cost of electric power by a method in which the first heaters and the second heaters of high resistance values are set at an equal interval in parallel in blocks forming the road surface and connected to the power source through a switch, the first heaters are first heated by supply of electricity for quick heating, and electricity is then supplied to the second heaters for retaining the temperature. CONSTITUTION:The small and long bar-like first heaters 1 and the second heaters 2 having a higher resistance value than the first heater are set in parallel at an equal interval in a concrete heating block 8 forming the road surface. The number of the second heaters 2 may be reduced compared to the first heaters 1. The terminals (a), (b), and (c) of the block 8 are connected to power source 6 through a switch 7. At first, the first heater 1 are quickly heated by supply of electricity until a fixed temperature is reached, and the supply of electricity is switched to the second heaters 2 to keep the temperature of the road surface at a temperature suitable for thawing snow. The cost of electric power can thus be cut down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road heating apparatus applied to roads, outdoor stairs, etc., and particularly to an effective road heating apparatus and a control method thereof as a measure against snowfall in cold regions and heavy snow regions. ..

[0002]

2. Description of the Related Art In automatic snow melting operation by road heating, a road heating device installed on a road surface according to detection signals from various detection sensors such as a snowfall sensor, a snow cover sensor, an air temperature sensor, and a road surface condition sensor. The start and stop of the operation of the.

In the snow melting operation by the road heating, it is required that the road surface temperature reaches an appropriate temperature for the snow melting within the shortest possible time from the start of the operation.
Further, after the road surface temperature reaches the appropriate snow melting temperature, it is necessary to continue to maintain the road surface temperature until the road surface condition is allowed.

Conventionally, in this road heating, a large number of heating elements are buried under the road surface along the road surface, and the snow is melted on the road surface by heat generated by supplying electric power to the plurality of heating elements.

[0005]

However, in the above-mentioned conventional technique, the power supply amount per unit time is almost constant during the period from the start to the end of the snow melting operation, and therefore the snow melting operation is started. If the power supply to the road heating device is set to reach the appropriate temperature for melting the snow on the road surface within the shortest possible time,
Certainly, the road surface temperature can reach the appropriate snow melting temperature within a short time, but during the snow melting appropriate temperature maintenance operation period after this snow melting appropriate temperature reaching operation, it will continue to supply more power than necessary, and it will be huge. There was a problem that it would waste unnecessary power.

On the contrary, when the electric power supplied to the road heating device is set so as to be adapted to the operation for maintaining the appropriate temperature of snow melting, it is possible to suppress the wasteful consumption of electric power, but it is possible to start the snow melting operation. It will take a long time for the temperature to reach the appropriate temperature for snow melting, and it will not be possible to quickly restore the road condition to a safe state, and it will not be possible to satisfy the requirements for automatic snow melting operation by road heating. There's a problem.

Further, a means for switching the electric power supplied to the load heating device between the snow-melting proper temperature reaching operation period and the snow-melting proper temperature maintaining operation period on the power supply side has been considered, but it is expensive to supply a large number of power supply devices. Providing a power switching device will make the equipment cost of the load heating equipment enormous, and if the supply power is reduced, the extent to which the snow melting capacity of the load heating device is reduced is Since it is much larger than the degree, there is a problem in that the degree of reduction of the power supply that can be actually implemented is insignificant and almost no effect of reducing the power consumption can be obtained.

Therefore, the present invention was devised to solve the above-mentioned problems in the prior art, and compared with the operation period for reaching the appropriate snow melting temperature without lowering the operating efficiency of the heating element as a load. It is a technical subject to significantly reduce the power consumption during the snow melting appropriate temperature maintenance operation period, and to achieve a significant reduction in the electricity charge required for road heating and to obtain a good snow melting operation.

[0009]

Means for Solving the Problems The means of the present invention for solving the above-mentioned technical problem is to provide a plurality of elongated rod-shaped first members that are embedded along a road surface below the road surface in parallel at equal intervals. Having a heating element, having a plurality of elongated rod-shaped second heating elements embedded adjacent to the first heating element, and using one terminal of each of the first heating element and the second heating element as a power source. Commonly connected to the connected ground wire, and connecting the other terminal of each first heating element to the first wire connected to the first contact, which is one of the contacts of the switch connected to the power supply. The second terminal of each second heating element is connected to the second electric wire connected to the second contact which is the other contact of the switch connected to the power supply.

A desired number of the first heating element and the second heating element, a ground electric wire, a first electric wire and a second electric wire are embedded in a concrete block forming a road surface, and each electric wire is connected outside the concrete block. A heating block is configured by exposing the terminals for use, and a road surface is formed by spreading the many heating blocks, and the terminals of each electric wire make electrical connection between many heating blocks and with the power source. It is useful to achieve and configure a load heating device.

It is preferable that the resistance value of the second heating element is larger than that of the first heating element, and that the number of the second heating elements is smaller than that of the first heating element.

As the first heating element and the second heating element, a cylinder made of a heat-resistant electric insulating material is filled with a carbon solid material obtained by kneading carbon powder and electric insulating material powder into a solid state. It is extremely effective to use a carbon heating element having the following structure.

As the control means of the road heating device, the first electric wire is connected to the power source to operate the first heating element to start the snow melting operation according to the snow melting operation start command signal, and the road surface temperature is suitable for the snow melting operation. After a certain time set in advance, the connection to the power supply is switched from the first electric wire to the second electric wire, and instead of stopping the operation of the first heating element, the second heating element is operated and the road surface temperature is adjusted to the optimum snow melting temperature To hold in.

As another control means of the road heating device, the first electric wire and the second electric wire are connected to a power source in accordance with a snow melting operation start command signal to operate the first heating element and the second heating element together to melt snow. Starting operation, after a preset time when the road surface temperature reaches the low snow melting temperature, the first electric wire is disconnected from the power source to stop the operation of the first heating element, and only the second heating element is applied to the road surface. Keeping the temperature at the proper temperature for melting snow.

[0015]

[Function] Snowfall sensor, snowfall sensor, temperature sensor,
According to the snow melting operation start signal from various detection sensors such as the ground temperature sensor and further the road surface condition sensor, by operating the switch, the first electric wire is connected to the power source to perform the snow melting appropriate temperature reaching operation only with the first heating element, Alternatively, the first electric wire and the second electric wire are connected to a power source, and both the first heating element and the second heating element are operated to reach the appropriate snow melting temperature.

When the operation for reaching the appropriate snow melting temperature is performed only by the first heating element, the connection from the first electric wire to the second electric wire is performed after the preset time when the road surface temperature reaches the appropriate snow melting temperature. The second heating element is operated by switching to, and the snow melting proper temperature maintaining operation is performed only by this second heating element.

In this case, since the snow-melting proper temperature reaching operation for rapidly heating and raising the road surface temperature from the unheated state to a temperature suitable for snow-melting must be achieved only by the first heating element, compared with the second heating element. To reduce its resistance,
The number of installations is larger than that of the second heating element,
It is necessary to increase the amount of heat generation per unit time, and as a result, naturally, the power consumption per unit time becomes maximum during this snow melting appropriate temperature reaching operation.

Further, when the first heat generating element and the second heat generating element are driven together to perform the operation for reaching the appropriate snow melting temperature, after a preset time when the road surface temperature reaches the appropriate snow melting temperature, Only the first electric wire is cut off from the power supply, and the snow-melting proper temperature maintenance operation is performed only by the second heating element.

In this case, since the operation for reaching the appropriate snow melting temperature is performed by both the first heating element and the second heating element, it is inevitable that the calorific value per unit time can be increased, so that the appropriate snow melting temperature can be obtained. Although the ultimate operation can be achieved more effectively, the power consumption per unit time increases, and the contracted electricity charge increases accordingly.

In order to construct a load heating device with heating blocks, a large number of heating blocks spread vertically and horizontally in a form of forming a flat road surface are properly connected in series and parallel using their terminals, and a switch is provided. To the power supply via. In this case, since the numbers of the first heating elements and the second heating elements constituting each heating block and the connection form thereof are common and constant, one heating block can be treated as one load, This simplifies electrical calculations and handling of the load heating device.

In the carbon heating elements as the first and second heating elements, when the carbon fixed material, which is the main body, is heated by energization, the powder of the electrically insulating material kneaded with the carbon powder expands to increase the density of the carbon powder. Since it has a self-current control function that roughens and increases the substantial electrical resistance to limit the amount of flowing current, if the power is supplied to the heating element while the voltage is kept constant, the heating element enters the steady operation state. As a result, the power consumption is minimized.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a heating block 8 according to the present invention.
In the example shown in Fig. 4, the first heating element 1 using 8 carbon heating elements and the second heating element 2 using 8 carbon heating elements are alternately arranged in parallel. Adjacent first heating element 1 and second heating element 2 arranged in parallel
One heating element is electrically configured by short-circuiting one end with a connecting line. Therefore, the embodiment shown in FIG. 1 has four first heating elements 1 and four second heating elements 2.

One terminal at the other end of each heating element 1 and 2 is commonly connected to one ground wire 3, and the other terminal at the other end of the first heating element 1 is connected to the first wire 4. The other terminal of the other end of the second heating element 2 is connected to the second electric wire 5, so that each first heating element 1 is connected to the ground electric wire 3
And the first electric wire 4 are connected in parallel, and each second heating element 2 is connected in parallel between the ground electric wire 3 and the second electric wire 5.

Both terminals a of the ground electric wire 3, both terminals b of the first electric wire 4, and both terminals c of the second electric wire 5 are exposed outside the heating block 8 and are adjacent to each other. By connecting the terminals a, b, and c to each other, the adjacent heating blocks 8 are connected in series.

The terminal a of the ground wire 3 is directly connected to one output terminal of the power source 6 which is a commercial power source, and the other output terminal of the power source 6 is a switching contact 7a of a switch 7 which is a switching switch. Side is connected, the first wire 4
The terminal b of the switch 7 is connected to the first contact 7b of the switch 7, and the terminal c of the second electric wire 5 is connected to the second contact 7c which is the remaining contact of the switch 7, so that the changeover switch 7 is changed over. Thus, the operating heating element group is switched between the first heating element group 1 and the second heating element group 2.

A commercial power source of 200 V is used as the power source 6,
When four each of the first heating element 1 having a resistance value of 1400Ω and the second heating element 2 having a resistance value of 2000Ω are used, the changeover switch 7 is switched to the first contact 7b, that is, the first heating element group 1 The power consumption is 114 W in the operating state, and 8 in the state in which the changeover switch 7 is switched to the second contact 7c, that is, in the state in which the second heating element group 2 is operating.
The power consumption is 0 W, and the power consumption during the appropriate snow melting temperature maintaining operation is significantly reduced compared to during the snow melting appropriate temperature reaching operation. The above values are per 1 m ² .

FIG. 2 shows an example of the structure of the heating block 8 embodying the present invention, in which a plurality of decorative plates 13 are provided on the upper surface forming the road surface and a plurality of lower surfaces of the concrete plate 9 are reinforced by the reinforcing material 10. The heat storage mortar 11 in which the first heating element 1 and the second heating element 2 are embedded in the parallel posture shown in FIG. 1 is positioned, and the heat insulating mortar 12 is arranged on the lower surface of the heat storage mortar 11.

The heating block 8 is constructed by laying gravel 15 on the ground, laying a thick cushion sand 14 on it, and laying a number of heating blocks 8 vertically and horizontally on the cushion sand 14.

In the embodiment shown in FIG. 1, when the same number of the first heating element 1 and the second heating element 2 are provided and the resistance value of the second heating element 2 is set to be larger than that of the first heating element 1. In addition to this, the resistance values of the first heating element 1 and the second heating element 2 are made equal, and the number of the second heating elements 2 is made smaller than that of the first heating element 1, or both are combined. A combination of reducing the number of second heating elements and increasing the resistance value with respect to the first heating elements is possible.

For example, when a heating block 8 having a road surface area of 1.5 m ² is manufactured from nine first heating elements 1 having a resistance of 1500Ω and six second heating elements 2 having a resistance of 1800Ω, At the commercial voltage of 200 V, the first heating element group 1 has 23
Power consumption of 9.4W, and the second heating element group 2 is 13
The power consumption is 3.2 W, and in this case as well, the power consumption during the appropriate snow melting temperature maintaining operation is significantly reduced compared to during the appropriate snow melting temperature reaching operation.

[0031]

Since the present invention has the above-mentioned structure, it has the following effects. Providing two heating element groups,
By switching the connection form to the power supply of these two heating element groups during the operation for reaching the appropriate temperature for melting snow and for the operation for maintaining the appropriate temperature for melting snow, the power consumption during the operation for maintaining appropriate temperature for melting snow is improved compared to the operation for achieving the appropriate temperature for melting It is possible to significantly reduce the power consumption, and thus it is possible to obtain a significant reduction in the electric power cost required for the snow melting operation, so that the electric power can be effectively used for the snow melting operation.

Switching between the snow melting appropriate temperature reaching operation and the snow melting appropriate temperature maintaining operation and the power consumption can be achieved only by switching the connection of the heating element, which is a load, to the power source. There is no need to prepare,
In addition, since the rated power is supplied to each heating element that is a load, each heating element can perform heat generation operation in an efficient state, which reduces the equipment cost as a device and reduces power consumption. Therefore, efficient snow melting operation can be obtained.

Electric power consumed by operating the first heating element having a large calorific value during the operation for reaching the appropriate snow melting temperature and operating the second heating element having a small calorific value but low power consumption during the operation for maintaining the appropriate snow melting temperature. The instantaneous maximum value can be reduced, and the contract electricity charge can be reduced, so that a significant reduction in the electricity charge can be obtained.

[Brief description of drawings]

FIG. 1 is an electrical connection procedure diagram showing an embodiment in which the present invention is applied to a heating block.

FIG. 2 is an overall vertical sectional view showing an example of a heating block embodying the present invention.

[Explanation of symbols]

 1; First heating element 2; Second heating element 3; Ground wire 4; First wire 5; Second wire 6; Power supply 7; Switch 7a; Switching contact 7b; First contact 7c; Second contact 8; Concrete block 10; Reinforcement material 11; Heat storage mortar 12; Thermal insulation mortar 13; Decorative board 14; Cushion sand 15; Gravel a; Ground wire terminal b; First wire terminal c; Second wire terminal

Claims (7)

[Claims] 1. A plurality of elongated rod-shaped first heating elements (1) embedded along a road surface below the road surface in parallel at equal intervals.
And a plurality of elongated rod-shaped second heating elements (2) embedded adjacent to the first heating elements (1), and each of the first heating elements (1)
And one terminal of the second heating element (2) is connected to the ground wire (3) connected to the power source (6), and the other terminal of each of the first heating elements (1) is connected to the power source (6). Switch connected to (7)
The first electric wire connected to the first contact (7b), which is one of the contacts
(4), the other terminal of each of the second heating element (2),
A load heating device comprising a second electric wire (5) connected to a second contact (7c) which is the other contact of the switch (7). 2. A desired number of first heating elements (1) and second heating elements (2), a ground wire (3), a first wire (4) and a second wire.
(5) is embedded in a concrete block forming a road surface, and each of the electric wires (3) and (4) is provided outside the concrete block.
The heating block (8) is formed by exposing the terminals (a), (b), and (c) for connection of (5), and the road surface is formed by spreading the heating blocks (8). Terminal
(a) (b) (c) by the number of heating blocks (8)
2. The load heating device according to claim 1, wherein an electrical connection between the two and an electric power source (6) is achieved. 3. The resistance value of the second heating element (2) is set to the first heating element.
The load heating device according to claim 1 or 2, wherein the resistance value is larger than the resistance value of (1). 4. The second heating element (2) with respect to the first heating element (1)
The load heating device according to claim 1, 2 or 3, wherein the number of 5. The first heating element (1) and the second heating element (2) are solidified by kneading carbon powder and electric insulating powder into a cylindrical body made of a heat-resistant electric insulating material. 5. The load heating device according to claim 1, 2 or 3 or 4, wherein a carbon heating element configured by filling the above-mentioned carbon solid material is used. 6. The first electric wire according to a snowmelt operation start command signal
(4) is connected to the power supply (6) and the first heating element (1) is activated to start the snow melting operation, and after a preset time when the road surface temperature reaches the appropriate snow melting temperature, the power supply (6) The first wire (4) is switched to the second wire (5), and instead of stopping the operation of the first heating element (1), the second heating element (2) is operated to melt the road surface temperature. The method for controlling a load heating device according to claim 1, wherein the load heating device is maintained at an appropriate temperature. 7. The first electric wire according to a snowmelt operation start command signal
(4) and the second electric wire (5) are connected to the power supply (6), the first heating element (1) and the second heating element (2) are operated together to start the snow melting operation, and the road surface temperature melts. After a preset period of time reaching a low temperature, the first electric wire to the power source (6)
The road heating according to claim 1, wherein the connection of (4) is cut off to stop the operation of the first heating element (1), and the road surface temperature is maintained at an appropriate temperature for snow melting only by the second heating element (2). Device control method.