JPH1152065A - Snowfall detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snowfall detector capable of maintaining the temperature of a snow receiver plate always at a specific temperature regardless of variation of external conditions such as external air temperature and wind strength. SOLUTION: First and second reference temperatures for the detected temperature of an external air temperature sensor 4 and first and second set temperatures for the heated temperature of a snow receiver plate 1 and the heated temperature of the snow receiver plate 1 are switched to any one of each set temperatures based on the reference temperatures in the constitution. By controlling the drive power of a heater 2 so that the heated temperature of the snow receiver plate 1 becomes the set temperature based on the detected temperature of a snow receiver plate temperature sensor 3, the heated temperature of the snow receiver plate 1 is maintained constant at each of the set temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snowfall detecting device for a snowmelting device used on a road in a snowfall zone.

[0002]

2. Description of the Related Art Conventionally, as this type of snowfall detection device,
For example, as described in Japanese Utility Model Publication No. Sho 62-37183, a snow plate having a pair of electrodes on the surface, a moisture detecting unit that detects moisture attached to the snow plate with each electrode,
2. Description of the Related Art There is known an outdoor air temperature sensor that detects an outdoor air temperature, a snow plate temperature sensor that detects a temperature of a snow plate, and a heater that heats the snow plate. In this snowfall detection device, when it is detected that the temperature detected by the outside air temperature sensor becomes equal to or lower than the temperature at which snowfall is possible and the snow falls on the snow receiving plate and the respective electrodes are connected to each other by the moisture of the snow, a predetermined snowmelting device is used. Is activated. The snowfall detection device also includes a heater for melting snow falling on the snowboard as moisture, and when the temperature detected by the outside air temperature sensor falls below a predetermined first reference temperature, or When each of the electrodes detects moisture, the heater is driven with low power, the temperature detected by the outside air temperature sensor falls below the second reference temperature at which snow can fall, and each electrode of the snow plate detects moisture. In such a case, the heater is driven with high power. In other words, at the beginning of snowfall, the water in the snow-receiving plate tends to evaporate, so that the snow-receiving plate is heated at a relatively low temperature before falling snow, and the snow-receiving plate is heated at a relatively high temperature during the snowfall. We make sure snow does not accumulate on the snow plate.

[0003]

By the way, in the conventional snowfall detecting device, the heater is driven with low power when the snow plate is heated at a low temperature, and the heater is driven when the snow plate is heated at a high temperature. Although the heater is driven at high power, only a constant drive power is supplied to the heater even at low power and high power, so if external conditions such as outside air temperature and wind intensity change, the snow plate will be driven. There was a problem that the temperature was not constant, and the snow falling on the snow receiving plate could not always be accurately melted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to always maintain the temperature of the snow plate even when external conditions such as the outside air temperature and wind intensity change. An object of the present invention is to provide a snowfall detection device capable of maintaining a predetermined temperature.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a snow plate having a surface facing upward,
A pair of electrodes formed on the surface of the snow receiving plate, an outside air temperature detecting means for detecting the outside air temperature, a heating means for heating the snow receiving plate, and moisture attached to the snow receiving plate are detected by conduction of each electrode. A snowfall detection device comprising: a determination unit that determines snowfall when the outside air temperature is lower than a predetermined temperature.
A snow plate temperature detecting unit for detecting the temperature of the snow plate, a heating amount control unit for controlling a heating amount of the heating unit, an outside air temperature lower than a predetermined reference temperature, and moisture in the snow plate is detected. When the temperature is not set, the heating temperature of the snow plate is set to the first set temperature. When the outside air temperature is lower than the reference temperature, and when the moisture of the snow plate is detected, the heating temperature of the snow plate is set to the first temperature. And control means for controlling the heating amount of the heating means based on the temperature detected by the snow plate temperature detecting means so that the heating temperature of the snow plate is set to each of the set temperatures. Thus, since the heating amount of the heating unit is controlled based on the temperature detected by the snow plate temperature detecting unit, the heating of the snow plate can be performed even when external conditions such as the outside air temperature and wind strength change. The temperature is controlled so as to be constant at each set temperature.

[0006]

1 to 4 show an embodiment of the present invention. FIG. 1 is a schematic structural view of a snowfall detecting device, FIG. 2 is an exploded perspective view of a main part thereof, FIGS. 3 and 4. 6 is a flowchart showing the operation of the control unit.

This snowfall detection device comprises a snow plate 1 for detecting moisture attached to the surface, and a heater 2 for heating the snow plate 1.
A snow plate temperature sensor 3 for detecting the temperature of the snow plate 1;
An outside air temperature sensor 4 for detecting the outside air temperature, a moisture detection circuit 5 for detecting that moisture has adhered to the snow plate 1, and a temperature detection circuit for detecting the temperatures of the snow plate temperature sensor 3 and the outside temperature sensor 4, respectively. 6, a heater control circuit 7 as a heating amount control means for controlling the heater 2 based on the temperature detected by the snow plate temperature sensor 3, and a detection result of the moisture detection circuit 5 and a temperature detected by the temperature detection circuit 6. It comprises a discriminating circuit 8 for detecting snowfall, and a control unit 9 including a moisture detecting circuit 5, a temperature detecting circuit 6, a heater control circuit 7, and a discriminating circuit 8.

The snow receiving plate 1 has a pair of electrodes 1a and 1b on the surface. The electrodes 1a and 1b are formed in a comb shape so as to be close to each other, and are connected to the moisture detecting circuit 5, respectively.
The snow plate 1 includes a box-shaped case 1c.
It is assembled so that the surfaces of a and 1b are outside and covers the upper opening of the case 1c.

The heater 2 is composed of a plurality of heating elements that generate heat by power from a power supply (not shown), and is attached to a heat transfer plate 2a that is in surface contact with the back surface of the snow plate 1 and the inner side surface of the case 1c. , The snow plate 1 is heated.

The snow plate temperature sensor 3 comprises a temperature detecting element such as a thermistor for detecting the temperature as an electric signal, and is connected to the temperature detecting circuit 6.

The outside air temperature sensor 4 comprises a temperature detecting element such as a thermistor for detecting the temperature as an electric signal.
It is connected to the temperature detection circuit 6.

The moisture detecting circuit 5 includes the electrodes 1a,
1b, and detects that the electrodes 1a and 1b are electrically connected to each other due to moisture attached to the snow plate 1.

The temperature detecting circuit 6 is connected to the snow plate temperature sensor 3 and the outside air temperature sensor 4, and detects the temperatures of the snow plate temperature sensor 3 and the outside air temperature sensor 4 based on the detection signals of the temperature sensors 3 and 4. It has become.

The heater control circuit 7 is connected to the heater 2 and the temperature detection circuit 6, and based on the temperature detected by the snow plate temperature sensor 3 and the temperature detected by the outside air sensor 4 detected by the temperature detection circuit 6. The driving power is changed.

The discriminating circuit 8 is connected to the moisture detecting circuit 5 and the temperature detecting circuit 6. The moisture detecting circuit 5 detects the moisture of the snow receiving plate 1, and the temperature detecting circuit 6 detects snow based on the temperature detected by the outside air temperature sensor 5. And outputs a snowfall detection signal to a snow melting device (not shown).

The controller 9 controls the first and second reference temperatures T1, T2 (T1>) with respect to the temperature T detected by the outside air temperature sensor 5.
T2) and the first and second with respect to the heating temperature t of the snow plate 1.
Are set, and the heating temperature t of the snow receiving plate 1 is switched to one of the set temperatures t1 and t2 based on the reference temperatures T1 and T2. ing. In this case, the second reference temperature T2 indicates a snowfall-possible temperature empirically determined according to weather conditions and the like. The controller 9 controls the driving power of the heater 2 based on the detected temperature tj of the snow plate temperature sensor 3 so that the heating temperature t of the snow plate 1 becomes the set temperatures t1 and t2. ing.

In the snowfall detecting device configured as described above, the control unit 9 operates as follows. That is, as shown in the flowchart of FIG. 3, when the detected temperature T of the outside air temperature sensor 5 becomes lower than the first reference temperature T1 (S1), the heater 2 is activated (S2), and the heating temperature of the snow receiving plate 1 is increased. Let t be the first set temperature t1 (S3). As a result, the snow receiving plate 1 is heated at a relatively low temperature at the beginning of falling snow where the water in the snow receiving plate 1 tends to evaporate. Next, when moisture is detected by the electrodes 1a and 1b of the snow plate 1, (S
4) The heating temperature t of the snow plate 1 is set to the second set temperature t2 (S5). Thereby, the snow plate 1 is heated at a relatively high temperature so that snow does not accumulate after the start of snowfall. At this time, if the moisture in the snow receiving plate 1 is not detected in step S4 and the temperature T detected by the outside air temperature sensor 5 does not become lower than the first reference temperature T1 (S6), the heater 2 is stopped (S6). S7), returning to step S1. If the temperature T detected by the outside air temperature sensor 5 is lower than the second reference temperature T2 after the heating temperature t of the snow plate 1 is set to the second set temperature t2 in step S5 (S8), It is determined that there is snowfall (S9), and a snowfall detection signal is output to a snow melting device (not shown). At this time, when the detected temperature T of the outside air temperature sensor 5 does not become lower than the second reference temperature T2 in step S8, and the moisture of the snow receiving plate 1 is no longer detected (S8).
10), the heating temperature t of the snow plate 1 is returned to the first set temperature t1 (S11), and the process returns to step S4. After it is determined in step S9 that there is snowfall, the outside air temperature sensor 5
If the detected temperature T is not lower than the second reference temperature T2 (S12), or if the water content of the snow receiving plate 1 is no longer detected (S13), it is determined that there is no snowfall (S1).
4), canceling the snowfall detection signal to the snow melting device and step S
Return to 8.

Further, in the above-described operation, the heater 2 operates as shown in the flowchart of FIG. 4 regardless of the set temperature t1 or t2 of the heating temperature t of the snow plate 1 (FIG. 4). S15) When the detected temperature tj of the snow plate temperature sensor 3 is lower than the heating temperature t of the snow plate 1 (S15).
16), the drive power of the heater 2 is increased (S17), and the process returns to step S16. In step S16, the detected temperature tj of the snow plate temperature sensor 3 is not lower than the heating temperature t of the snow plate 1 and the detected temperature tj of the snow plate temperature sensor 3
Is higher than the heating temperature t of the snow plate 1 (S1
8) The driving power of the heater 2 is reduced (S19), and the process returns to step S16.

As described above, according to the snowfall detecting device of the present embodiment, by controlling the driving power of the heater 2 based on the temperature tj detected by the temperature sensor 3 for the snow plate, the heating temperature t of the snow plate 1 is controlled. Is set to be constant at each of the set temperatures t1 and t2, so that the heating temperature t of the snow plate 1 is always set to the set temperatures t1 and t2 even when external conditions such as the outside air temperature and wind strength change. It can be kept at t2.

[0020]

As described above, according to the snowfall detection device of the present invention, even when external conditions such as the outside air temperature and the strength of the wind change, the heating temperature of the snow plate is always kept at the predetermined temperature. Since it can be kept, it is possible to reliably detect snowfall.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a snowfall detection device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of the snowfall detection device.

FIG. 3 is a flowchart illustrating an operation of a control unit.

FIG. 4 is a flowchart showing an operation of a control unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Snow plate, 2 ... Heater, 3 ... Snow plate temperature sensor, 4 ...
Outside air temperature sensor, 7: heater control circuit, 8: discrimination circuit,
9 ... Control unit.

Claims (1)

[Claims] 1. A snow plate arranged with its surface facing upward, a pair of electrodes formed on the surface of the snow plate, an outside air temperature detecting means for detecting the outside air temperature, and heating the snow plate. A snowfall detection device comprising: a heating unit; and a determination unit configured to determine whether snowfall has occurred when the outside air temperature is lower than a predetermined temperature by detecting the moisture attached to the snow plate by conduction of the electrodes. A snow receiving plate temperature detecting means for detecting a temperature of the plate; a heating amount controlling means for controlling a heating amount of the heating means; and when the outside air temperature is lower than a predetermined reference temperature and no moisture is detected in the snow receiving plate. Sets the heating temperature of the snow receiving plate to the first set temperature, and sets the heating temperature of the snow receiving plate to the second setting when the outside air temperature is lower than the reference temperature and when the moisture of the snow receiving plate is detected. Set the temperature and set the heating means so that the heating temperature of the snow plate will reach the set temperature. Control means for controlling the amount of heating of the base plate based on the temperature detected by the snow plate temperature detecting means.