GB822369A - Improvements in or relating to balsa wood structures and members - Google Patents

Abstract

822,369. Laminates. PLANTATION WOOD (LANCING) Ltd., and INSULARBO Ltd. Nov. 25, 1957 [Nov. 23, 1956; Feb. 26, 1957], Nos. 35852/56 and 6485/57. Class 140. [Also in Groups XXIII and XXVIII] A balsa wood batten or sheet formed with interrupted or blocked grooves 13 parallel to the grain in one face or two opposed faces is used for thermal and acoustic insulation as a structure built up of two or more superimposed layers glued together and having, particularly if thermal insulation is especially desired, interposed thin sheets of insulating material such as brown paper, balsa, synthetic plastic or metal. The grooved battens or sheets may be enlarged by pulling them to open up the grooves and by inserting spacers, such as the comb 26, of wood, synthetic plastic or laminated material, into the grooves to maintain them in this condition. The combs block the grooves and prevent circulating convection currents from being set up in individual grooves but this may also be prevented by decreasing the depth of the grooves, preferably to zero, at intervals along their lengths or by filling the grooves with balsa wood dust, or a powdered synthetic plastic or mineral material, and binding the material in the grooves by spraying the surface with cellulose acetate or sodium silicate. The layers may be arranged with grooves running either parallel or mutually perpendicular to each other in adjacent layers and the two outer layers may be ungrooved on their outer faces. Panels may be glued side byside with a plain butt joint or with a zig-zag joint strengthened by a dowel running into both panels at an angle across the joint. For thermal insulation, a structure comprising one or more layers may be glued or otherwise secured to the external surface of a tank, pipeline or refrigeration space or it may be used as an internal lining and, if fluid is to be stored and the balsa wood itself is insufficiently impermeable, an inner caul of plastic material or thin metal sheet may be provided.