| 摘要 |
The process consists in automatically carrying out the phases of grinding (milling, facing) the ends of the tubes, heating them by means of a heating plate, joining the faces (fronts, heads) of the tubes with pressure until a weld rib is formed and cooling the tubes. All these phases are carried out under conditions of controlled temperature, pressure and time. The machine comprises a hydraulic pump 10 of variable flow rate, a hydraulic cylinder 6 whose rod 5 is integral with the movable flange (clamp) 4, an electric motor 11 which receives the signals from the electronic control device C and a variable-pressure valve 12 coupled to the aforesaid motor for providing the circuit with suitable pressure. It also comprises a control circuit for the pump 10 which includes a pump of fixed flow rate 16, a cylinder 17 and the valves 10, 20, 21. Greater homogeneity and reliability of the weld are achieved. <IMAGE>
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