JPH07151865A - Snowfall detecting system - Google Patents

Abstract

PURPOSE:To detect snowfall surely in a broad temperature range in a snowfall detecting system for detecting the presence or absence of the snowfall. CONSTITUTION:The surface temperature of a substrate with a moisture sensor 3 is detected by a temperature detecting element 10 in order to remove the causes of the malfunction such as the overheating of the moisture sensor for detecting the presence or absence of moisture and the out of operation at a low temperature. Judgement is performed with a surface-temperature detecting and processing part 11 at a binary threshold, and the ON/OFF control of a moisture-sensor heating heater 12 is performed in this constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in a snow melting method for a satellite communication antenna used in a snowfall area and a sensor method for detecting snowfall for controlling power ON / OFF of a load heating device.

[0002]

2. Description of the Related Art Due to the recent development of satellite communication, the number of micro earth stations installed is increasing, and 5
The number of antennas of 0 cm to 1 m tends to increase. In this case, in the snowfall area, snow is reflected on the mirror surface of the antenna, the beam direction shifts, and the attenuation becomes large, resulting in disconnection of the line.

In a snowfall region, a road heating apparatus is used which melts snow and ice on roads in winter by applying heat such as electricity and gas. It is desirable to energize such an antenna snowmelt or road heating only when snowfall occurs. For this reason, snowfall detection devices have been studied.
FIG. 5 shows an example of a conventional snowfall detection system. The temperature sensor 2 processes the output of the temperature sensor 1 such as a thermistor that detects the snowfall possible temperature (about 3 ° C.), and outputs the output of the moisture sensor 3 as well. The water content is processed by the moisture detection unit 4, and both are input to the AND circuit 5. When the condition is satisfied, the relay 6 is controlled to turn on the switch, the power source V1 is supplied, and the heating element 7 such as the antenna snow melting material or the load heating unit is supplied. A heating control system was used.

The moisture sensor 3 is provided with a comb-shaped conductor 3a having a plurality of X-underline slits on the surface and a heater 3b for melting snow to water and the ambient temperature is, for example, 7 When the temperature drops below ℃, the heater 3b is turned on,
When the AND circuit 5 operates to prepare for melting the snow, the relay 6 is turned on and the heating element 7 such as an antenna is turned on.

[0005]

Conventionally, because of such a structure, it is difficult to adjust the amount of electric power supplied to the heater 3b. That is, if the electric power applied to the heater 3b is too large, the snow will melt instantly, moisture will not be detected, and the heater will not turn on. On the other hand, when the electric power applied to the heater 3b is too small, the temperature is low (for example, −10 ° C.
Even if there is snowfall at -30 ° C, etc., it does not completely melt and there is a drawback that it malfunctions because water is not detected.

[0006]

SUMMARY OF THE INVENTION In order to reliably detect snowfall in a wide temperature range, the present invention measures the surface temperature of a moisture sensor, and when this temperature falls below a certain temperature, the heater of the moisture sensor The characteristics are improved and the detection accuracy is improved by turning on the power and turning off the power when the temperature exceeds a certain temperature.

[0007]

In the snowfall detection system of the present invention, the surface temperature of the moisture sensor is provided with a binary threshold value, the operable temperature range is expanded to turn on / off the heater for heating the moisture sensor, and malfunction can be prevented. Has become.

[0008]

1 shows an improved snowfall detection system according to the present invention. According to the present invention, the moisture sensor is improved, and the control / processing unit 14 is downsized and highly reliable by using a microprocessor.

In FIG. 1, in order to eliminate the conventional defects such as overheating of the moisture sensor 3 and inoperability at low temperature, the temperature of a substrate constituting the moisture sensor 3 is detected and a temperature such as a thermistor is used for control. A detection element 10 is added to convert the surface temperature of the moisture sensor 3 into a change in the resistance value of the thermistor.
This signal is input to the surface temperature detecting / processing unit 11, and the heater 12 that determines the value and heats the substrate of the moisture sensor 3
The relay 13 for turning on / off the power source is driven to turn on / off the power source V2.

The temperature for heating the heater 12 has been experimentally determined, and it has been found that a good snow melting result can be obtained by setting the temperature to about 18 ° C to 20 ° C. Further, the electric power of the heater is determined by the lowest temperature used in this system, and if it is assumed to be about -30 ° C, about 14W is required. This power consumption becomes smaller as the minimum temperature is raised.

The structure of the moisture sensor 3 is shown in FIG.
The moisture sensor 3 has a polymer material casing 19 attached to a support column 20 having a diameter of about 25 cm, and has an upper surface inclined at about 30 to 45 degrees so that snow does not stay long. Comb-shaped electrodes 21 are arranged on the surface of the moisture sensor 3 to detect that the capacitance therebetween changes with moisture.

The comb electrode 21 is patterned by etching on a dielectric substrate 22 such as a glass epoxy substrate. The dielectric substrate 22 is arranged on a metal plate 23 such as an aluminum plate and enables a uniform heat distribution. A cement resistor or the like is arranged as a heater 24 below the metal plate 23 to heat the surface of the comb-shaped electrode 21 and quickly convert snow into water.

The metal plate 23 has a size larger than that of the polymer material housing 19 so as to protrude from the polymer material housing 19. By doing so, the snow melts, so there is no risk of malfunction due to unmelted snow. 2
6 is a temperature detecting element for detecting the surface temperature of the moisture sensor, 2
Reference numeral 7 is a cord for connecting to a power supply.

As shown in the sectional view of FIG. 3, inside the moisture sensor 3, a heater 24 composed of cement resistance or the like is arranged below the metal plate 23 and is fixed with an epoxy adhesive 25 or the like. The surface temperature of the dielectric substrate 22 is detected by a temperature detecting element 26 such as a thermistor, and is guided to the surface temperature detecting / processing unit 11 of the control / processing unit 14 by a code 27.
Based on the processing result of the surface temperature detecting / processing unit, the heater is energized and heated by the code 28. The remaining space of the moisture sensor 3 is filled with the caulking agent 29 and kept warm. The temperature sensor 30 for detecting the outside air temperature can also be arranged as shown in FIG.

In order to reduce the size and increase the reliability of the control / processing unit 14, it is preferable to use a microprocessor for the control / processing unit 14 in FIG.

As a result of conducting an experiment with such a structure, the operating temperature range and characteristics thereof have been greatly improved.
FIG. 6 shows the characteristics of a conventional snowfall sensor system.

In the conventional system, the heater 3b below the moisture sensor has a heater 3b when the outside air temperature is 10 ° C. or lower.
Snow temperature (for example, around + 3 ℃) to keep b ON
In order to prevent the surface temperature of the moisture sensor from becoming too high, the applied power is limited to about 1.8W. If applied more than this, the surface temperature of the moisture sensor rises too much, and the moisture in the snow evaporates too quickly, making the operation unstable.

As a result, the surface temperature of the moisture sensor becomes close to 5 ° C. when the outside air temperature becomes close to −7 ° C., and it becomes impossible to melt the snow when it becomes lower than this. For this reason, the outside air temperature becomes -7 ° C or lower, snow detection cannot be performed when there is snowfall, and serious malfunction occurs in the case of road heating or the like.

FIG. 4 shows the relationship of the moisture sensor surface temperature to the outside air temperature of the snowfall sensor according to the present invention. The surface temperature threshold value given to the program of the microprocessor constituting the surface temperature detecting / processing unit 11 is as follows.
Heater ON temperature is 18 ℃, Heater OFF temperature is 20
℃ is set. This temperature is not exact because it includes a measurement error. When the outside air temperature decreases and reaches 2 ° C. to 3 ° C., the snowfall temperature is reached, and when the temperature sensor 1 in FIG. 1 reaches this temperature, the snowfall detection system starts operating. When the temperature detecting element 26 (temperature detecting element 10 in FIG. 1) of FIG. 2 detects 18 ° C., the heater 24 (FIG.
Then, the heater 12) is energized to heat the surface of the moisture sensor. When the temperature detected by the temperature detecting element 26 reaches 20 ° C., the heater 24 stops energizing, and OF is kept until 18 ° C. is detected.
Repeat the procedure of turning on when the temperature becomes F and 18 ° C is detected.

In FIG. 4, the temperature at which the heater 24 is turned on is 16
Although the temperature is around ℃, the position of the temperature detecting element 26 for detecting the temperature of the substrate 22 and the position of the measuring thermistor (the temperature sensor 1 in FIG. 1) of FIG. 3 for measuring the outside air temperature are deviated. This is because.

If the temperature continues to decrease, the same control as described above is performed, but since the heat radiation from the surface increases, the temperature detected by the moisture sensor surface of the thermistor for measurement decreases.

As a result, even if the outside air temperature reaches -30 ° C, the surface temperature of the moisture sensor is maintained at about + 7 ° C, and snow melting can be performed. Further, when the surface temperature becomes 20 ° C. or more, the energization of the heater 24 is stopped, so that the malfunction of the surface of the moisture sensor being overheated, the snow is immediately evaporated and the moisture is not detected is avoided.

As described above, the snowfall sensor system according to the present invention can widen the operable temperature range of the related art by about three times, and the malfunction is eliminated.

These controls and processings can be performed by one microprocessor, and in this case, miniaturization and high reliability can be realized, and at the same time, mass production, uniform characteristics, reduction of production process, and low cost. Is possible.

In the description of FIG. 1, the detected temperature is only the outside air temperature. However, the temperature sensor 1 and the temperature detection unit can measure the ground temperature required for the load heating and the temperature of the heating portion for the load heating. This can be easily achieved by adding 2 more.

[0026]

As described above, in the snowfall sensor system according to the present invention, the surface temperature of the moisture sensor is provided with a binary threshold to turn on / off the heater for heating the moisture sensor.
In order to perform FF, there are the following effects.

(1) The moisture sensor surface temperature can be maintained at the snow melting temperature even if the outside air temperature decreases, and the usable temperature range can be expanded as compared with the conventional one.

(2) Since the moisture sensor surface heating heater can prevent the surface from reaching an excessively high temperature, it is possible to prevent an erroneous operation in which the surface is not detected despite snowfall.

(3) If a microprocessor is used for the control / processing section, the size and weight can be reduced, the reliability can be improved, the mass production can be facilitated, and the cost can be reduced. Be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a snowfall detection system according to the present invention.

FIG. 2 is a perspective view showing a configuration of a moisture sensor according to the present invention.

FIG. 3 is a simplified cross-sectional view of a moisture sensor according to the present invention.

FIG. 4 is a diagram showing the relationship between the outside air temperature and the moisture sensor surface temperature in the snowfall detection system according to the present invention.

FIG. 5 is a block diagram of a conventional snowfall detection system.

FIG. 6 is a diagram showing the relationship between the outside air temperature and the moisture sensor surface temperature in the conventional snowfall detection device.

[Explanation of reference numerals] 1, 30 Temperature sensor 2 Temperature detection unit 3 Moisture sensor 4 Moisture detector 5 AND circuit 6, 13 Relay 7 Heating element 10, 26 Temperature detection element 11 Surface temperature detection / processing unit 12, 24 Heater 14 Control Processing unit 19 Polymer material housing 21 Comb-like electrode 22 Dielectric substrate 23 Metal plate

Claims (4)

[Claims] Claim: What is claimed is: 1. A temperature sensor output for detecting a possible snowfall temperature is melted with snow to obtain moisture, and the output of a moisture sensor for detecting this moisture is ANDed to generate heat from a heating element for snow melting. In the snowfall detection system that is performed, a temperature detection element for detecting the surface temperature is arranged near the surface of the moisture sensor, and the detected temperature has a predetermined upper limit value,
A snowfall detection system characterized in that the surface temperature detection / processing unit controls the heater of the moisture sensor to be turned on / off so as to be kept between the lower limit values. 2. The moisture detection sensor according to claim 1, wherein the moisture detection sensor is about 30.
Place the comb-shaped electrode on the upper part of the metal plate inclined by 45 degrees
A snowfall detection system characterized in that a heater is arranged below the metal plate, and the heat is transmitted to the entire metal plate to melt the snow and detect moisture. 3. A snowfall detection system, wherein the metal plate of the moisture detection sensor according to claim 1 or 2 has a size larger than that of a lower polymeric material housing. 4. The snowfall detection system according to claim 1, wherein the predetermined upper limit value of the temperature is about 20 ° C. and the lower limit value is about 18 ° C.