Oy Kwh Pipe Ab

Jonas Holmlund

Stefan Slotte

Gunnar Blomqvist

Charlotta Risku

Mikael Finne

Charlotta Leppaenen

The invention concerns a method for manufacturing pipes coated with a peelable protection layer, wherein the core pipe () is produced by extruding and calibrating, after which the surface of core pipe () is heated before a protecting coating layer () is applied onto the core pipe () on passing through a coating die (), followed by cooling the applied coating layer () before the readily coated pipe () is drawn out of the process. The method is characterized in that the degree of adhesion between core pipe () and coating layer () is controlled by rapid and effective heating of the surface of the core pipe () to a predetermined temperature and by controlling welding time and stretching of the coating layer being applied onto the core pipe () by maintaining a controlled vacuum level inside the coating die () forcing the coating layer to hit the surface of the core pipe at an angle as steep as possibly, preferably between 45 and 90 degrees, most preferably between 60 and 80 degrees.

Method for manufacturing coated pipes

The invention relates to a method and a device for cooling an extruded thermoplastics pipe () by directing a gaseous cooling medium tangentially towards the inner surface of the thermoplastics pipe () along its whole periphery, whereby the interior of the thermoplastics pipe () is divided by means of a protecting pipe () into an outer ring-shaped flow channel () for the cooling medium along the inner surface of the thermoplastics pipe (), and a central return channel () through which a part of the cooling medium is intended to be sucked back influenced by the flow of cooling medium in the outer ring-shaped flow channel (), and to be redirected towards the inner surface of the thermoplastics pipe (). The invention is characterized in that the cooling medium is air, and that there is a cooling equipment () mounted in the return channel (), whereby temperature and flow rate at least of the cooling water led to the cooling equipment () and possibly also of the cooling air which is fed into the thermoplastics pipe () are adjusted and controlled based on dimension and extrusion rate of the thermoplastics pipe () being manufactured.

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Oravais, Finland

Jonas Holmlund