METHOD AND DEVICE FOR DE-ICING ROAD CARRIAGEWAYS INVOLVING THE RE-USE OF RECOVERED THAWING SOLUTION

摘要

A method and device are disclosed for the automated de-icing of road carriageways (1) to which an aqueous solution of thawing agent is applied as a way of lowering the freezing point. The solution runs off the carriageway as thaw water, possibly mixed with precipitation and melt water. This thaw water is collected, and its concentration of thawing agent measured (in 18), before being (at least partially) re-applied (via 11) to the road as aqueous thawing solution, if necessary topped up with fresh thawing agent. The proposed method and device are particularly economical and environmentally friendly in that, before its re-applications a thawing solution, the concentration of the thaw water destined for re-use is raised (in 26) in a separation stage in which partial streams are produced, consisting respectively of water containing little or no thawing agent (in 31) and of a highly concentrated solution (in 32), this allowing a higher proportion of the thaw water to be re-used. Stages to eliminate harmful substances can also be incorporated in this cycle.