Method and apparatus for making a plastic pipe

A method of making a plastic pipe;

• comprising the steps of:
• continuously advancing an extruded tubular melt strand through a production line;
• selecting a sizing sleeve from a plurality of sizing sleeves;
• swinging segments of the selected one of the sizing sleeves outwards to allow attachment of the sizing sleeve to the melt strand before placement in a sizing chamber;
• swinging the segments inwards to fully embrace the melt strand;
• locking the segments of the sizing sleeve;
• and
• transferring the sizing sleeve into the sizing chamber for calibrating an outer diameter of the melt strand to provide a pipe with a desired dimension.

A method of making a plastic pipe;

• comprising the steps of:
• advancing an extruded tubular melt strand through a production line;
• selecting a sizing sleeve from a plurality of sizing sleeves;
• stopping the production line while cutting the melt strand to allow attachment of the selected one of the sizing sleeves to the melt strand before placement in a sizing chamber;
• and
• transferring the sizing sleeve into the sizing chamber for calibrating an outer diameter of the melt strand to provide a pipe with a desired dimension.

Apparatus for making a plastic pipe, comprising:

• an extruder terminating in production direction in an adjustable pipe head for discharging a melt strand;
• a vacuum suction device receiving the melt strand from the pipe head and controllable to form a pipe with a preliminary outer diameter;
• a sizing chamber;
• and
• a plurality of sizing sleeves having different inner diameter for selective placement in the sizing chamber for calibrating the pipe to have a desired outer diameter.