| 摘要 |
<p>1,040,685. Lining and covering pipes. BABBITT PIPE CO. Inc., and LES FORGES DE ZEEBRUGGE S.A. Jan. 12, 1965, No. 1275/65. Heading F2P. A method of forming a thermoplastic tube 62 within a metal tube 35 consists in inserting the one inside the other, applying an internal fluid pressure to the plastic tube which is greater than that which the metal tube 35 can withstand, simultaneously applying external pressure to balance the excess internal pressure and heating the pressure fluid to cure the plastic material. The metal tube 35 is thin walled, but is thicker at 36 than at 37 (Fig. 2) and can be flexed outwards without damage. The plastic tube consists of a number of plies of convolutely or spirally wound asbestos treated with thermosetting resin, preferably phenolic, cured to the " B " stage. The apparatus for bonding the plastic to the metal tube consists of a metal casing 1 having an inlet and an outlet for hydraulic pressure, each controllable externally by a valve, the casing 1 being radially spaced from a hollow core 48 upon the throat 47 of which is mounted the metal tube 35 and the plastic tube 62 with an expansible rubber diaphragm 49 inside them. Both ends of the apparatus are closed by fluid-tight seals on members such as 2 and 64 which are supported against internal pressure by yokes 15 on arms 14. The far end of the core 48 is perforated (Fig. 2a, not shown) so that fluid controlled by valves 56-61 which enters it from the tube 53 can flow back outside it to leave by the tube 60. The plastic tube is first expanded out into the metal tube by air pressure. The tubes are then mounted in the apparatus as shown in Fig. 2 and subjected to hydraulic pressure inside and out; first cool, then hot. The casing 1 is mounted on trunnions and can be tilted to expel gas formed during operation. A plastic cover can be applied to a metal pipe by similar means.</p> |
