Patent GB-970724-A (GB)
Title: Thermal insulation and method of forming same
IPC: F16L59/10
Filed: 1961-02-28
Abstract: 970,724. Thermal insulation for apparatus such as aircraft, refrigerators and tubes. JOHNS-MANVILLE CORPORATION. Feb. 28, 1961 [Feb. 29, 1960], No.7259/61. Headings F2P and F2X. In the making of a thermal insulation unit described particularly for use in aircraft and in refrigerators, heat insulating material which in its initial condition is a reshapeable mass but in its operational condition is rigid, but relatively fragile or brittle, is placed in a container or casing which in its initial condition is flexible and pliable, and which when filled is initially of generally circular cross-section, and which also in its operational condition possesses structural rigidity, the whole then being deformed by heat and pressure to the operational shape required and in such manner that the container and insulating material are fused together and the cross-sectional area is decreased whilst the length of the perimeter of the casing remains substantially constant. Examples of suitable heat insulating materials mentioned are fibrous potassium titanate, crushed lime silicate, crushed magnesia, macerated mineral or glass wool, expandable or foamable polystyrene. The filler material may be particulate with a diameter finer than 100 millimicrons, with a binder, and may be reinforced with an organic or inorganic fibre. The tubular container or casing may comprise a reinforcing material secured to or between sheets of surfacing material such as resin-impregnated asbestos paper. The reinforcing material may, for example, be asbestos or glass fibre in the form of a cloth, paper, mat or loose fibres impregnated with any organic or inorganic binder. On the " cold " side of the insulating unit the surfacing material may be of steel, aluminium or other metal sheeting secured to other parts of the thermal insulation. Figs. 18, 19 show one form of thermal insulating unit. A sheet 35 of resinimpregnated glass cloth is formed to provide tubular containers 36 (Fig. 18) extending from a base 35a. Rigid bars 37 of resin impregnated asbestos paper are placed between the containers 36 which are filled with the thermal insulating material. The assembly is then subjected to heat and pressure to deform the containers to the shape shown in Fig. 19 and may have an additional sheet of resin impregnated asbestos paper 38 positioned as shown. A plurality of layers of the containers may be formed (Fig. 21, not shown), the thermal insulating characteristics of the respective layers differing one from the other. The containers may be individually made and secured to the base by stitching. In a further form described the containers are made of thin flexible metal foil and the assembly reinforced by a layer of wire mesh (Fig. 35, not shown). Fig. 36 shows a filled tubular heat insulating container 111 wrapped helically around a cylindrical tube 110. A further tubular container 113 may be wound helically around the first, as shown. The containers are then subjected to heat and pressure to fuse the containers and their contents together and the assembly (see Fig. 37) may include an outer surfacing layer 116 of a material such as a resin impregnated asbestos paper.