Improvements in frost-damage protection devices for orchards and the like

摘要

864,372. Influencing meteorological conditions; powder distributers. GARDENER, J. G. June 12, 1958 [March 13, 1957], No. 8252/57. Classes 6(1) and 6(2). [Also in Group XXVIII] Apparatus for the protection of orchards, sports grounds, and racing tracks from frost comprises an air heater 4, a fan drawing air over the heater and positioned in a casing 1, the outlet of which connects with flexible ducts 7 from which flexible branch ducts 9 distribute air through holes 10. The ducts, which are made of synthetic resin extend along the ground and are held both along their length and at their ends by pegs extending diametrically across them. Wooden blocks slidably mounted on the pegs surmount and steady the pipes when inflated and press them flat against the ground when deflated. A layer of paper or transparent plastics material may be laid over the pipes to maintain a blanket of warm air in contact with the ground. The ducts 7 may have a double skin to prevent heat losses. Insecticide powder may be introduced into the ducts to be blown on to trees or ground.