GB1236314A - A thermally insulated metal pipe - Google Patents

Abstract

1,236,314. Thermally insulated pipe. VEREINIGTE DEUTSCHE METALLWERKE A.G. 14 March, 1969 [15 March, 1968], No. 13698/69. Heading F2P. A thermally insulated copper pipe 1, has an insulating sheath 2 comprising one, or more, hot-sealed, random, continuous filament fleeces each of which is composed of stretched continuous filaments of a thermoplastic synthetic material, e.g. polyester resins, pololefins, &c. which filaments are bonded together by compressing and heating e.g. on a hot cylindrical roll, the insulating sheath 2 having its outside and/or its inside either provided with an additional covering film of the same, or some other thermoplastic synthetic, material, or hot sealed. The fleeces can be formed by drawing continuous filaments away from spinnerets by means of a high velocity air stream flowing at a velocity between 50 and 350, and preferably 250, metres/sec. and generated in a blowing nozzle and simultaneously stretching the filaments. Then the filaments are deposited on a travelling band in random disposition and compressed between a heated roll and a co-operating pressure band which applies a pressure between 1-50, and preferably 3-6 Kg./sq. cm., at a temperature between 3-50‹ C., and preferably 5-30‹ C., for a time between 2-30, and preferably 5-15, seconds. The surface of the sheath can be sealed by the application of heat and pressure to create a porous skin, which allows the sheath to breath but prevents the ingress of water. The hot sealing may however be carried out to provide an air and watertight outer surface. Alternatively, a flame resistant, or anticorrosion, film may be bonded to the outer surface of the sheath, suitable films respectively being of polyvinyl chloride, polyester and polyethylene, or propylene. As shown in Fig. 4, the sheath 2 has been compressed only at discrete points to create protruberances 5 containing a large number of airoccluding pockets.