Hydro-quebec

Canadian Patents & Development Ltd.

Jean-Paul Boillot

Raynald Simoneau

Jean-Luc Fihey

Jean-Marc Pelletier

Antonio Di Vincenzo

N Alexandrov

A Di Vincenzo

Ghislain Begin

Denis Villemure

A real time control system and process for controlling predetermined operating characteristics of a welding mechanism movable along a workpiece joint to be welded, the workpiece joint having two opposed edges. A thermal radiation sensing device is responsive to thermal radiation energy emanating from a heated workpiece joint. The sensing device is positioned along a travelling path of a welding element of the welding mechanism, ahead of and in close proximity to the welding element, the sensing device and welding element being disposed on a common side relative to the workpiece joint. The thermal radiation sensing device is caused to scan the workpiece joint along a line transverse to the travelling path so as to allow the sensing device to sense a thermal radiation profile along the transverse scanning line and to provide peak signals representative of the relative position of the edges of the workpiece joint in accordance with the thermal radiation profile sensed, thereby defining the actual width of the joint. Circuitry is provided for processing the peak signals provided by the radiation sensing device to issue command signals for controlling the predetermined operating characteristics of the welding mechanism.

Real time control system and process for controlling predetermined

A circuit for controlling the power supply to an electrode of the shielded type, such as that used in a shielded metal arc welding process (SMAW) whereby to protect a user from electric shocks. The control circuit is a protection circuit which serves to protect welders against electric shocks by decreasing the circuit voltage between the electrode tip and the workpiece to be welded. An AC or DC power supply may be used to feed the electrode. The control circuit is comprised of a high impedance voltage source applied to the electrode, a detection circuit for determining the level value of the impedance appearing between the electrode and the workpiece. The detection circuit compares the impedance thus detected with a threshold impedance and generates a control signal when the detected impedance is lower than the threshold impedance. The control signal operates a driver circuit which energizes a power feed device serially connected between the electrode power supply and the electrode itself. The predetermined threshold impedance value is set at about 500 ohms whereby a wet human body will not be subjected to an electric shock by contacting the electrode and the workpiece simultaneously.

Protection circuit against electric shocks during welding

Growing community of inventors

Beloeil, Canada

Jean-Paul Boillot