GB1183141A - Welding Head with Hydraulic Position Regulation - Google Patents

Abstract

1,183,141. Welding by fusion. COMMISSARIAT A L'ENERGIE ATOMIQUE. 1 Jan., 1968 [17 Jan., 1967], No. 139/68. Heading B3R. [Also in Division G3] A welding head for, e.g., non-consumable electrode gas-shielded arc welding comprises a rear section, which is intended to be introduced and locked into position within a cavity inside which a weld is to be made arounda circular path 16, and a front section 4 intended to be set in rotation from the exterior of the cavity, e.g. by a motor, the welding head having an hydraulic control system comprising a servo-valve 6 actuable from the exterior of the cavity, a double-acting piston 9 driven by the servo-valve when actuated and secured to a support 10 mounting a welding torch 5, the welding head also comprising a link-arm 11 operable from the rear section and slidable in guides 12 secured to the support 10, the arrangement being such that the torch is capable of moving along its axis under the action of the piston and of performing oscillatory movement under the action of the link arm whereby the electrode is maintained at a constant distance from the weld. The servovalve is actuated by a current which is a function of the voltage V-V 0 , where V 0 is a reference voltage from a control potentiometer and V is the voltage from a variable potentiometer 17 operated by movement of a rack 20, attached to the support 10. Holes 19 in a shield member 13 direct shielding gas at the weld. The rear section (Fig. 1, not shown) is locked in position by balls (3) and expandable pads (2). Movement of the member 10 may be monitored by an endoscope (7) connected to a television camera. The head may be used for welding pressure tubes to the end-shields of a nuclear reactor tank.