Patent ID: 7625196

Claim:
A device for manufacturing a double-walled, thermoplastic tube with a connecting sleeve, the device comprising: A) a mould tunnel ( 4 ) that comprises at least one row of moulds ( 5 ) guided on a path, has a corrugated mould wall ( 13 ) in at least one first section and a sleeve recess ( 12 ) corresponding to the connecting sleeve in at least one second section, B) an extruder equipped with an extrusion head ( 3 ), where the extrusion head ( 3 ) has a first die ( 2 ) for extruding a first tube ( 1 ) into the mould tunnel ( 4 ) and a second die ( 7 ) located downstream in the direction of motion of the moulds ( 5 ) in the mould tunnel ( 4 ) for extruding a second tube ( 6 ), C) a first gas duct ( 10 ) located between the two dies ( 2 , 7 ) and a second gas duct ( 14 ) opening downstream of the second die ( 7 ) in the direction of motion of the moulds ( 5 ) of the mould tunnel ( 4 ), E) a compressed gas controller ( 15 ) connected to the first gas duct ( 10 ) for generating a pressure p 1 and essentially constant pressure p 2 ≦p 1 , or a variable, but not continuously declining pressure p 2 with the compressed gas flowing out of the mouth of the first gas duct ( 10 ) in the space between the two tubes ( 1 , 6 ), where p 1 and p 2 are above atmospheric pressure, F) a compressed gas controller ( 16 ) connected to the second gas duct ( 14 ) for generating a pressure p 3 that is above atmospheric pressure on the inside of the second tube ( 6 ) with the compressed gas flowing out of the mouth of the second gas duct ( 14 ), and G) a controller ( 17 ) for controlling the compressed gas controllers ( 15 , 16 ).