GB1433295A - Corrugating a mat of randomly-oriented fibres and thermally- insulating coverings made therefrom - Google Patents

Abstract

1433295 Corrugating; pipe insulation FIBERGLAS CANADA Ltd 12 March 1974 [4 May 1973] 11057/74 Heading B5A [Also in Divisions F2 and D1] A mat 28 (Fig. 1) transported along a straight path 26, is provided with one or more lines of weakening 32 extending parallel to said path, and is deformed to create one or more corrugations 38 also extending parallel to said path and having the line of weakening in the interior surface. A heat-insulating felt mat 28 impregnated with a thermosetting binder is fed and compressed by rollers 16 from a roll 14 (or from an accumulator continuously receiving the mat from a fibre producer and suction felting boxsee Figs. 13, 14 (not shown)). Upper and lower wheels or rollers 20 form staggered parallel depressions 32 in the upper and lower surfaces of the mat (see Fig. 2C). The mat is fed by a conveyer 18 between tapering guides (not shown) into the nip between two driven friction drums 34 that form the corrugations 38; archin is preventing by upper horizontal rollers (not shown). The corrugated mat is then fed between the corrugated and perforated platens 58, 60 (Fig. 4) of a moulding press which blows hot air 64 through the mat to cure the thermosetting binder and compresses the corrugations to a density of (3À5-10) lb/cu. ft. As the upper platen 58 rises after pressing, the corrugated mat is fed forward by rollers that move vertically to free the mat from the platens. A blower 72 forces air through the mat for cooling and defuming, whereafter the mat is cut to length transversely by a circular saw. Finally, a slitter saw 86 cuts the corrugations in half along a horizontal plane to form upper and lower matching portions 88, 90 (see Fig. 2G). The mat 28 can comprise two widths fed side-by-side for joining in the press (see Fig. 4, not shown). The press platens are interchangeable for different shapes and sizes of corrugations; Fig. 4 illustrates apparatus with intermittent feed-forward of the mat, but continuous feeding can occur if the press platens are carried by conveyers (Fig. 5). A relay control circuit for automatic control is shown in Fig. 12 (not shown). Heat control of Press.-Gas is heated to 1600‹ F. in a furnace 224 (Fig. 9) and fed by a fan 230 to the lower press platen 210 after mixing with recirculated gas 231 under a control 232 and damper D2. After pressing, cool air is drawn in through a damper D5. A fire-sensing thermocoupler is provided in line 233. Article and materials.-The matching portions 88, 90 (Fig. 4), of the mat are used in opposition as a conduit covering of circular, oval or rectangular cross-section. Glass fibres, mineral wool or asbestos fibres are impregnated with a phenolformaldehyde-amine copolymer.