Patent ID: 8365572
Filing Date: 2013-02-05
Classification: B21C,B21D

Abstract:
1. Method for manufacturing bimetallic pipes starting from an outer pipe and an inner pipe telescopically inserted with clearance inside the outer pipe, characterised in that it comprises the following steps: providing a movable head and a fixed head, internally provided with clamping members suitable for the attachment with a respective end of the pipes, the fixed head being provided with an inlet for the supply of a suitable fluid from a respective vat and the movable head being provided with an outlet for the discharge of the fluid; providing an elastic abutment inside both the movable head and the fixed head, for the positioning of the ends of the pipes; providing a hydraulic piston controlled by a valve for setting the movable head in motion; moving the moveable head forward by means of the piston and, simultaneously, guiding the free end of the pipe to be made inside the fixed head up to the contact of the inner pipe with the respective abutment up to obtaining equilibrium between the elastic force exerted by the elastic abutment and the hydraulic force applied by the piston, in order to avoid damaging or bending the pipe to be made; clamping the outer pipe by means of hydraulic closure of the clamping members present inside the fixed head and inside the moveable head; and compressing the fluid volume isolated inside the pipe to be made, by means of a pressure multiplier.