| 摘要 |
1,224,010. Producing composite tubing by extrusion. STAUFFER - WACKER SILICONE CORP. 8 Oct., 1968, No. 47554/68. Heading B5A. A primed fibrous tube 10 is passed through an extruder crosshead to receive a coating, e.g. of natural or synthetic resin or an elastomer, and the coated tube is subjected to a radially directed constrictive force to secure the coating to the tube. As shown, this force is provided by an "0" ring 94 situated in an annular recess 92, but may be provided by a land on the converging inner surface of die part 84, e.g. as at (96<SP>1</SP>), Fig. 5 (not shown). Tube 10 is primed by passage through a bath (14), Fig. 1 (not shown), and subsequently passes through a squeeze block (16) and an evaporator (18) upstream of the extruder, and a curing oven (36) downstream thereof. The tube is opened by a ball 40, preferably made of P.T.F.E. In the crosshead, the coating material is distributed about tube 10 by means of a block 82 having an inlet 76 and distribution ducts (88, 90), Fig. 3 (not shown). Ducts 64 in the extruder barrel provide for the circulation of a heating or cooling medium. Tube 10 may be braided, knitted, woven or felted and materials mentioned are glass, asbestos, wool, cotton, nylon and rayon.
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