PROCESS AND COMPLEX INSTALLATION FOR DRAWING THERMALLY CONTRACTABLE TUBES

The invention relates to a process and an installation for drawing thermally contractable tubes having a diameter of 50...90 mm, in a die. According to the invention, the process comprises the continuous drawing of the thermally contractable tubes, one by one, in a die made of aluminium pipe and cooled with flowing water under pressure, allowing the inflation of the tube due to the connection to a source of pressurized air; finally the die is removed and the support on which the drawn tube rests is also displaced with one pitch, thereby making possible the insertion of the next support, with another tube to be drawn, into the die. The claimed installation for applying the process comprises a support (1) on which a rotating disk (A) is mounted, said disk being sustained by some bearings (B) and allowing the fast coupling with an assembly (C) of rods bearing some thermally contractable tubes, the disk (A) being indexed by means of a limiter (2) and the drawing die (D) being carried by an elevator (F); the assembly (C) is introduced into a tunnel-like furnace (E) wherein said tubes are continuously rotated, said rods being in contact with some feelers (G), the displacemnt of the assembly (C) being automatically controlled from a switch cabinet (H) to a drawing area where the said rods are coupled with some pressure air injection heads (3) which, in their turn, are mounted onto some pneumatic cylinders (4), the pressurized air is supplied by a compressor (I) provided with a tank and is conveyed by an air drying element (J) to some electrically-operated valves (51) distributing the air required for drawing the tubes, the die (D) being cooled with water from a line (L), the cylinders (4) being driven by the pressurized air from a line (M). Invenţia se referă la un procedeu şi la o instalaţie pentru etirat tuburi termocontractabile, cu un diametru de 50...90 mm, într-o matriţă. Procedeul conform invenţiei cuprinde etirarea în flux continuu a câte unui tub termocontractabil într-o matriţă confecţionată din ţeavă de aluminiu şi răcită cu apă curentă sub presiune, ceea ce permite umflarea tubului prin legarea la o sursă de aer sub presiune; în final, matriţa este deplasată, iar un suport pe care se află tubul etirat este deplasat cu un pas, astfel că este posibilă introducerea în matriţă a următorului suport pe care se află un alt tub, care urmează a fi umflat. Instalaţia conform invenţiei, pentru aplicarea procedeului, cuprinde un suport (1) pe care se află montat