| 摘要 |
564,845. Fibrous tubes. REID, E. S. March 2, 1943, No. 3441. Convention date, Sept. 5, 1942. [Classes 99 (i) and 99 (ii)] In a fibrous conduit comprising two or more tubes 10, 11 telescoped one within the other and displaced longitudinally to form at one end a socket 14 and at the other a plug 13 for connection-to a similar conduit, the tubes are bonded together by a water soluble sodium silicate or dextrine adhesive which is fluid at ordinary temperatures. Preferably, the tubes are of equal length and after bonding are impregnated with a waterproof thermoplastic adhesive such as pitch. The pitch is heated to 270‹ F.-300‹ F. and the.tubes are immersed therein first under sub-atmospheric and then super-atmospheric pressure, after which the' tubes are removed at about 290‹ F. to produce a smooth surface suitable for electric wire conduits or at about 270‹ F. to keep an excess of pitch on the ends, the ends being subsequently warmed so that the ends' of adjacent tubes become bonded together when the tubes are joined together. The ends of the tubes may have an inward taper to form sockets for joining to other forms of tubes and short lengths of the tubes be used as coupling members for the tubes. |
