| 摘要 |
846,955. Joining plastic piping &c. SVENSKA METALLVERKEN A.B. Nov. 13, 1957 [Nov. 14, 1956], No. 35415/57. Class 87(2). [Also in Group XXVIII] Plastic parts are joined by bringing their contacting surfaces to abut against heated metal moulding members and retaining them there until the plastic material is brought into a molten or melting condition when the parts are removed from the moulding members and assembled. The invention is described with respect to the joining of plastic piping, e.g. of polyethylene or polypropylene, one of the pipes 1 being formed with a preformed sleeve 3 the inner surface 4 of which is shaped to be either conical or cylindrical, the outer surface of the other pipe 2 being similarly shaped. To this end the apparatus of Fig. 1 is used, this comprising pairs of cup-like members 19, 20 located opposite each other on plates 14, 15 between which extend heat transferring plates 21. The plates 21 are heated by the flame from burner 7 and transmit the heat by conduction and radiation to the members 19, 20. The pipes are introduced to the apparatus in the direction of arrows A, B, the sleeve 3 surrounding member 20 and the pipe 2 entering member 19, and when their surfaces are sufficiently molten, the pipes are assembled as shown at the top of Fig. 1. The melting should be to a depth of between zero and 35%, preferably 10 to 15%, of the total thickness of the plastic. In a modified form of apparatus, a pressure vessel containing heat transfer fluid such as water, oil, salt solution or the like may be used in place of plates 14, 15. |
