| 摘要 |
1,176,906. Tubular foamed polyurethane. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 17 May, 1968, No. 23627/68. Heading B5A. A method of continuously producing tubular foamed polyurethane insulation comprises feeding a liquid foamed polyurethane-forming composition or its components to a rotary ring dispenser 11 mounted rotatably around a pipe 22 which is positioned coaxially within a flexible body formed from a plurality of overlapping sheets of paper 24, rotating the dispenser 11 around the pipe so that the liquid composition is discharged centrifugally from the dispenser as a spray on to the inner face of the flexible tubular body, while at the same time the dispenser and the tubular body are continuously movable relative to each other, allowing the liquid on the tubular body to foam and thereby expand radially to fill the space between the pipe and tubular body whilst supporting the tubular body at its outer face by means of a frusto-conical body 18 and calibration disc 21, and allowing the foamed polyurethane to harden to form a tubular body 25. To prevent sticking, the pipe 22 may be coated with polypropylene. To form an insulated pipe both the pipe 22 and flexible tubular body made up of sheets of paper 24 are moved together while the dispenser remains stationary. However to insulate a pipe in the field the dispenser together with the rest of the apparatus is moved over the pipe. To form tubular sections of insulation material only the flexible tubular body is moved, the pipe and dispenser remaining stationary and the tubular insulation formed is cut into sections by circular saws. |
