Welding apparatus and process

Claim 1

ATMOSPHERIC CONTROL APPARATUS FOR DRAWN-ARC WELDING, COMPRISING, A HOOD BODY HAVING A BASE SURFACE, WALL SURFACES DEFINING A CHAMBER OPENING FROM SAID BASE SURFACE INTO SAID HOOD BODY, SAID CHAMBER BEING SUBSTANTIALLY CLOSEABLE BY ABUTMENT OF SAID BASE SURFACE AGAINST A WORKPIECE TO WHICH A WELDING ATTACHMENT IS TO BE MADE, A PASSAGEWAY FROM THE EXTERIOR OF SAID HOOD BODY TO SAID CHAMBER DEFINED BY WALL SURFACES SHAPED TO RECEIVE A WELDABLE ELEMENT, EXHAUST PORT MEANS FROM SAID CHAMBER TO ATMOSPHERE, CHAMBER GAS INLET MEANS THROUGH SAID WALL SURFACES OF THE CHAMBER, VALVE MEANS IN SAID GAS INLET MEANS VALVE ACTUATION MEANS, A GAS SUPPLY SOURCE OF PREDETERMINABLE MAXIMUM PRESSURE, A LENGTH OF SUPPORT CONDUIT BETWEEN SAID SOURCE AND SAID VALVE, SAID CONDUIT HAVING INTERNAL VOLUME TO HOLD A QUANTITY OF COMPRESSED GAS AT SAID MAXIMUM PRESSURE WHICH WILL EXPAND AT ATMOSPHERIC PRESSURE TO A VOLUME GREATER THAN THE COMBINED VOLUME OF THE SAID CHAMBER AND ALL GAS CONDUCTING MEMBERS TO AND FROM THE CHAMBER, INCLUDING THE SAID SUPPLY CONDUIT, AND AN ORIFICE THROAT IN SAID VALVE OF A SIZE RELATED TO SAID LENGTH OF HOSE TO THEREBY REDUCE THE FLOW FROM LONGER HOSES ACTING AS LARGER RESERVOIRS, WHEREBY SHIELDING GAS WILL FLOOD THE CHAMBER AND ESCAPE THROUGH SAID OUTLET PORT.