Method for making pipe reducers

Abstract

Abstract A method is described for making plastic pipe reducers, such as, for example, for large diameter polyvinyl chloride irrigation pipe employing the shape memory of extruded plastic irrigation pipe to full advantage. An appropriate length of extruded plastic pipe having a diameter approximately that of the smaller reducer diameter is cut from a length of extruded plastic pipe. A sufficient length of the cut piece to form the larger diameter end and the transition to the smaller diameter end is heated to the softening temperature of the thermoplastic material. Longitudinally extending fingers are forced radially outwardly to expand the length of pipe polygonally into the transition portion, and the pipe is cooled in its expanded condition. A circular mold having an outside diameter the same as the relatively larger inside diameter of the reducer is inserted in the expanded end, and that portion adjacent the old is heated to the softening temperature of the plastic so that the shaped memory of the plastic shrinks the material onto the mold. The mold is removed after the plastic material is cooled. A similar molding technique is employed for the smaller diameter end of the reducer, either before or after the larger end is formed.

Inventors

• 👤 Kay E Mc

Bibliographic Details