PURPOSE: To highly increase the efficiency of snow-melting operation, and to attain the energy-saving thereof, by a method wherein while road-preheating operation is being done or when the snow-melting operation is started, a large amount of electric power is supplied, and after a road surface is heated at a proper temperature, a small amount of the electric power being enough to keep at the proper temperature is supplied.
CONSTITUTION: When information that snow-melting operation is to be started is detected with a sensor 1 for soil temperature, an electromagnetic contactor 2 is closed and a road-preheating operation is started. At this time, heaters 7, 8 are connected in series by the use of a relay 3. After that, when information that road-heating operation is to be started is detected with a sensor 4 for snowfall, the relay 3 is controlled by a first control part 5 and the connection between the heaters 7, 8 are switched from series to parallel. As the result, the road-heating operation is started by a large amount of electric power and a road surface is heated at a temperature suitable for melting snow, in a short time. After a definite time passes away, the first control part 5 actuates a second control part 6 and the second control part 6 controls the relay 3 so as to switch the connection between the heaters 7, 8 from series to parallel, and vice versa at regular intervals. In this way, the snow-melting operation with a high-speed and with high efficiency can be obtained.
MIURA KENICHI
NISHIKAWA YASUNORI
SUDO MASAYOSHI
SAKAI YOSHIO
FUJII KK
| JPH05247907A | 1993-09-24 | |||
| JPS56135604A | 1981-10-23 |