Abstract: The invention concerns a method for manufacturing pipes coated with a peelable protection layer, wherein the core pipe (1) is produced by extruding and calibrating, after which the surface of core pipe (1) is heated before a protecting coating layer (7a) is applied onto the core pipe (1) on passing through a coating die (7), followed by cooling the applied coating layer (7a) before the readily coated pipe (9) is drawn out of the process. The method is characterized in that the degree of adhesion between core pipe (1) and coating layer (7a) is controlled by rapid and effective heating of the surface of the core pipe (1) to a predetermined temperature and by controlling welding time and stretching of the coating layer being applied onto the core pipe (1) by maintaining a controlled vacuum level inside the coating die (7) 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.

Abstract: The invention relates to a method and a device for cooling an extruded thermoplastics pipe (1) by directing a gaseous cooling medium tangentially towards the inner surface of the thermoplastics pipe (1) along its whole periphery, whereby the interior of the thermoplastics pipe (1) is divided by means of a protecting pipe (8) into an outer ring-shaped flow channel (9) for the cooling medium along the inner surface of the thermoplastics pipe (1), and a central return channel (10) 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 (9), and to be redirected towards the inner surface of the thermoplastics pipe (1).

Abstract: The invention relates to a method and a device for cooling an extruded thermoplastics pipe (1) by directing a gaseous cooling medium tangentially towards the inner surface of the thermoplastics pipe (1) along its whole periphery, whereby the interior of the thermoplastics pipe (1) is divided by means of a protecting pipe (8) into an outer ring-shaped flow channel (9) for the cooling medium along the inner surface of the thermoplastics pipe (1), and a central return channel (10) 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 (9), and to be redirected towards the inner surface of the thermoplastics pipe (1).

Abstract: The invention concerns a method for manufacturing pipes coated with a peelable protection layer, wherein the core pipe (1) is produced by extruding and calibrating, after which the surface of core pipe (1) is heated before a protecting coating layer (7a) is applied onto the core pipe (1) on passing through a coating die (7), followed by cooling the applied coating layer (7a) before the readily coated pipe (9) is drawn out of the process.

Abstract: A method for preparing an end of a thermoplastics tube (1) is provided, wherein the tube is manufactured by spirally winding and welding together of a hollow profile (1a) having a substantially rectangular cross section. The method includes the following steps: cutting the end of the tube by a planar transversal section; extruding a second hollow profile (2) having a rectangular cross section and an outer shape essentially similar to Fat of the hollow profile (1a) from which the tube (1) is manufactured; spirally winding the extruded second hollow profile (2) around a drum having a diameter corresponding to inner diameter of the tube (1); cutting a loop (2a) from the second hollow profile (2) in a length corresponding to circumference of the tube end; joining the ends of the loop (2a) to each other, whereby a ring (2b) is formed having the same inner and outer diameters as the spirally wound tube (1); placing the ring (2b) against the cut tube end; and welding the ring (2b) to the tube end.

Abstract: A method for joining thermoplastic pipes made by spiral winding a hollow profile with mainly rectangular cross section.