Oy Kwh Pipe Ab

Seppo Takala

Marek Warcholinski

A method for producing a lightweight end wall of a containers characterized by the following stages: manufacturing a large size lightweight thermoplastics tube by spirally winding and joining together a hollow profile of thermoplastics, cutting a piece from such a tube to form a pre-form of an end wall, heating the pre-form into a mouldable state, pressing the pre-form into a dome shaped piece between a male and a female mould-half, cooling the dome shaped piece while pressed between the mould-halves, maching-tooling the edges of the cooled piece to match the cross-sectional surface of the tube mantle, and joining the mantle and the end wall together by welding.

Method for manufacturing a container end wall of lightweight construction and a container provided with such an end wall

This invention concerns a method and an apparatus for making a spirally-wound tube from a hollow thermoplastic profile () having a substantially rectangular cross-section, which method comprises the steps of: winding the thermoplastic profile () around a drum () and joining adjacent loops together by welding, and smoothing the outer weld joint () by means of extra heat and a smoothing body resting against the weld joint (). The invention is characterized in that the thermoplastic profile (), when fed to the drum (), comes onto a stationary first section () comprising spaced sliding means () arranged along the periphery, on which section welding is performed, after which an inner weld joint () thus formed is arranged to run along a spiral groove () running around the stationary first section (), whereby the inner weld joint (), as well as the outer weld joint (), are treated by using extra heat and a stationary smoothing body () resting against it, and that the tube, once both of the welded surfaces () have been smoothed, is transferred to a rotary driven drum section () causing the tube to rotate and generating the winding motion of the thermoplastic profile ().

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Belchatow, Poland

Seppo Takala