| 摘要 |
PCT No. PCT/NO96/00012 Sec. 371 Date Oct. 14, 1997 Sec. 102(e) Date Oct. 14, 1997 PCT Filed Jan. 17, 1996 PCT Pub. No. WO96/22567 PCT Pub. Date Jul. 25, 1996An installation for melting of snow or ice, e.g. at roof downpipes on flat roofs, in gutters and the like, comprising a heating means (11), a temperature sensor means (4,6) and a control unit (1) for connecting and disconnecting the heating means (11) in dependence on sensed temperature. The temperature sensor means comprises a first temperature sensor (4) for sensing the surface temperature at the place of snow or ice melting, and a second temperature sensor (6) for sensing the air temperature at the topical place. On the surface there is further arranged a snow sensor (7) which is connected by the control unit (1) when the first temperature sensor (4) at a rising temperatures registers that the surface temperature rises above a chosen minus value, or when the second temperature sensor (6) at a falling temperature registers that the air temperature falls below a chosen plus value, the control unit (1) causing connection of the heating means (11) if the snow sensor (7) registers snow during a chosen time period, and further keeping the heating means (11) connected at least until the second temperature sensor (6) at a rising temperature registers that the air temperature rises above the chosen plus value, or at least until the first temperature sensor (4) at a falling temperature registers that the surface temperature falls below the chosen minus value, but in both cases only on the condition that the snow sensor (7) at intervals registers snow. |
