Method and apparatus for manufacturing non-round plastic tubing

A method of concurrently manufacturing a plurality of plastic tubing structures comprising:

• molding a corrugated generally tubular structure;
• splitting the molded generally tubular structure longitudinally into a plurality of tubing structures, each tubing structure having terminal edge areas adjacent the longitudinal split and corrugated side walls disposed between the terminal edge areas;
• and
• attaching a generally flat base longitudinally, generally along the terminal edge areas of each corrugated tubing structure.

A method of forming tubing which has corrugated side walls, the side walls being longitudinally joined near an apex area of the tubing by a hinge means, each side wall terminating opposite the hinge means at a longitudinal terminal edge area, the tubing further having a flexible base connecting the terminal edge areas whereby the side walls are adapted to fold about the hinge means to form a flattened, folded configuration with the terminal edge areas adjacent each other and an open configuration with the terminal edges displaced from each other by the width of the base, the method comprising:

• extruding a sleeve of plastic material;
• molding the sleeve to form a corrugated generally tubular structure comprising at least four corrugated side walls which are joined longitudinally by the hinge means and by terminal edge areas;
• longitudinally splitting the joined terminal edge areas whereby at least two pairs of hinged connected side walls are produced;
• and
• attaching a flexible material longitudinally along the terminal edge areas of at least one pair of hinged connected side walls to form a base, whereby the pair of hinged connected side walls and the flexible base connected between the terminal edge areas define the tubing.

An apparatus for manufacturing plastic tubing structures for conveying fluids, the tubing structure being hollow in a longitudinal direction and sufficiently rigid in cross section to withstand compressive loading forces when installed in subterranean locations, the apparatus comprising:

• extruding means for extruding a sleeve of plastic material;
• molding means for molding the extruded sleeve into a generally tubular structure, said molding means including a plurality of mold blocks, said mold blocks having an internal molding surfaces which are adapted to contact the sleeve, at least some of the internal molding surfaces having a generally semiround cross section and a projection to form a hinge means in an apex area of the tubing structure, the mold blocks being adapted to abut together adjacent said extruding means around the extruded sleeve, to travel away from the extruding means with the sleeve conforming to the blocks, and to separate away from the generally tubular structure, whereby the generally tubular structure includes at least two tubing structures having hinge means at their apices and longitudinally connected together adjacent terminal edge areas;
• and
• splitting means for splitting the generally tubular structure longitudinally substantially adjacent said terminal edge areas and substantially parallel to the hinge means, whereby the generally tubular structure is split into at least two hinged tubing structures.

An apparatus for manufacturing plastic tubing structures for conveying fluids, the tubing structures being hollow in a longitudinal direction and sufficiently rigid in cross section to withstand compressive loading forces when installed in subterranean locations, the apparatus comprising:

• extruding means for continuously extruding a sleeve of plastic material;
• molding means disposed adjacent the extruding means for continuously molding the extruded sleeve into a generally tubular structure, the generally tubular structure comprising at least two tubing structures longitudinally connected together adjacent terminal edge areas;
• splitting means disposed downstream from the molding means for continuously splitting the generally tubular structure longitudinally substantially adjacent said terminal edge areas, whereby the generally tubular structure is split into at least two tubing structures;
• and
• attaching means disposed downstream from the splitting means for continuously attaching a flexible strip of sheet-like material longitudinally generally along the terminal edges of each tubing structure.

An apparatus for manufacturing corrugated tubing structures, the tubing structures comprising corrugated side walls which are longitudinally connected by a hinge means, the side walls each having terminal edge areas extending longitudinally generally parallel to the hinge means, the side walls being moveable about said hinge means at least between a folded configuration in which the terminal edge areas are generally adjacent and an unfolded configuration in which the side walls define a channel for conveying a fluid, the apparatus comprising:

• extruding means for extruding a sleeve of plastic material;
• molding means for continuously molding the sleeve to form a generally tubular structure, the generally tubular structure comprising at least two tubing structures, each terminal edge area of each tubing structure being operatively connected with a terminal edge area of another of the tubing structures;
• splitting means for splitting the connected terminal edge areas, whereby at least two tubing structures are produced;
• and
• attaching means for attaching flexible material longitudinally generally adjacent the terminal edge areas of at least one of the tubing structures, whereby the flexible material forms a base for the tubing structure.

A method of forming generally triangular tubing which has corrugated sidewalls and a generally flat, flexible base, the sidewalls being longitudinally joined near an apex area of the tubing and the flexible base being connected with terminal edge areas of the sidewall which are disposed generally opposite the apex, the method comprising:

• extruding a sleeve of plastic material;
• molding the sleeve to form a corrugated, generally tubular structure comprising at least four corrugated sidewalls which are joined longitudinally generally at apex and terminal edge areas;
• longitudinally splitting the joined terminal edge areas, whereby at least two pairs of connected sidewalls are produced;
• and,
• attaching a flexible material longitudinally generally along the terminal edge areas of at least one pair of the longitudinally connected corrugated sidewalls to form the flexible base, whereby the generally triangular tubing with corrugated sidewalls and generally flat, flexible base is defined.

An apparatus for manufacturing corrugated, generally triangular tubing structures, the tubing structures comprising corrugated sidewalls which are longitudinally connected generally at an apex area and a generally flat, flexible base which is attached to the corrugated sidewalls generally at terminal edge areas which are disposed opposite the hinge area, the apparatus comprising:

• extruding means for extruding a sleeve of plastic material;
• molding means for continuously molding the sleeve to form a generally tubular structure, the generally tubular structure comprising at least four corrugated sidewalls longitudinally connected generally at apex and terminal edge areas;
• splitting means for splitting the sidewalls connected at terminal edge areas, whereby at least two tubing structures are produced;
• and,
• attaching means for attaching flexible material longitudinally generally adjacent the terminal edge areas of at least one of the tubing structures, whereby the flexible material forms the flexible base of the generally triangular tubing structure.