Phase angle controlled firing circuit for valves in multi-phase system

Claim 1

IN A LOAD CONTROL SYSTEM WHEREIN A PLURALITY OF PHASE LINES SUPPLY POWER FROM A POLYPHASE AC SOURCE TO A LOAD, EACH OF SAID PHASE LINES HAVING CONNECTED THEREIN A NORMALLY NON-CONDUCTIVE CONTROLLABLE ELECTRIC VALVE, EACH VALVE WHEN SUBJECTED TO VOLTAGE OF A PARTICULAR POLARITY BEING GATEABLE TO PASS LOAD CURRENT IN A PARTICULAR DIRECTION IN RESPONSE TO A GATING SIGNAL, AND WHEREIN EACH OF SAID VALVES HAS CONNECTED THEREACROSS UNDIRECTIONAL CURRENT CONDUCTION MEANS POLED TO PASS CURRENT IN THE OPPOSITE DIRECTION, A VALVE CONTROL CIRCUIT FOR EACH OF SAID VALVES COMPRISING MEANS FOR PRODUCING PERIODIC SPACED UNDIRECTIONAL WAVES HAVING A PHASE POSITION AND TIME DURATION SUCH THAT THEY ARE LONGER THAN THE HALF CYCLES OF SAID PARTICULAR POLARITY OF THE LINE-TO-NEUTRAL VOLTAGE OF THE PHASE IN WHICH THE ASSOCIATD VALVE IS CONNECTED AND EACH OF SAID HALF CYCLES IS COEXTENSIVE WITH A PORTION OF A DIFFERENT ONE OF SAID WAVES, PHASE ADJUSTABLE PULSE FORMING MEANS HAVING A POWER INPUT CIRCUIT ENERGIZED BY SAID WAVES AND ALSO HAVING ADJUSTABLE PHASE CONTROL MEANS, SAID PULSE FORMING MEANS BEING OPERABLE TO PRODUCE OUTPUT PULSES WHOSE PHASE POSITION MAY BE VARIED SUBSTANTIALLY ACROSS THE ANGULAR EXTENT OF SAID WAVES, AND WHOSE PARTICULARLY PHASE POSITIONS IS SELECTABLE IN RESPONSE TO ADJUSTMENT OF SAID PHASE CONTROL MEANS, AND MEANS FOR APPLYING SAID PULSES AS GATING SIGNALS TO THE VALUE SERVED BY THE CONTROL CIRCUIT.