Control valve for metal spraying guns

Claim 1

A CONTROL VALVE ARRANGEMENT FOR A METAL SPRAYING GUN AND THE LIKE, COMPRISING, IN COMBINATION, A VALVE BODY FORMED WITH TWO INLET PORTS AND TWO OUTLET PORTS, ONE OF SAID INLET PORTS BEING ADAPTED TO BE CONNECTED TO A SOURCE OF COMBUSTIBLE GAS AND A SOURCE OF COMBUSTION SUPPORTING GAS, RESPECTIVELY, EACH OF SAID INLET PORTS FORMING A PAIR OF PORTS WITH A CORRESPONDING OUTLET PORT, SAID VALVE BODY BEING FORMED WITH A BORE OF CIRCULAR CROSS SECTION, SAID PORTS HAVING ORIFICES IN SAID BORE; AND A VALVE PLUG MATING SAID BORE, SAID PLUG BEING FORMED WITH TWO MAIN DUCTS AND TWO AUXILIARY DUCTS THERETHROUGH AND ROTATABLE IN SAID BORE ABOUT AN AXIS BTWEEN A FIRST POSITION IN WHICH SAID MAIN DUCTS ARE ALIGNED WITH SAID ORIFICES TO RESPECTIVELY CONNECT SAID PAIRS OF PORTS, AND A SECOND POSITION IN WHICH SAID AUXILIARY DUCTS ARE ALIGNED WITH SAID ORIFICES TO RESPECTIVLY CONNECT SAID PAIRS OF PORTS; RESPECTIVE ONES OF SAID MAIN AND AUXILIARY DUCTS COINSTITUTING CORRESPONDING FIRST DUCTS FOR ALTERNATIVE PASSAGE OF COMBUSTIBLE GAS THERETHROUGH TO A FIRST ONE OF SAID OUTLET PORTS, AND THE OTHER DUCTS CONSTITUTING SECOND CORRESPONDING DUCTS FOR ALTERNATIVE PASSAGE OF COMBUSTION SUPPORTING GAS THERETHROUGH TO THE SECOND OUTLET PORT; EACH OF SAID AUXILIARY DUCTS HAVING A METERING PORTION OF A FLOW SECTION SUBSTANTIALLY SMALLER THAN THE FLOW SECTION OF THE CORRESPONDING MAIN DUCT, THE FLOW SECTION OF THE METERING PORTION OF SAID FIRST AUXILIARY DUCT BEING SUBSTANTIALLY SMALLER THAN THE FLOW SECTION OF THE METERING PORTION OF SAID SECOND AUXILIARY DUCT, SAID DUCTS HAVING RESPECTIVE RADIALLY EXTENDING AXES, THE AXES OF SID MAIN DUCTS AND OF SAID AUXILIARY DUCTS EXTENDING IN RESPECTIVE COMMON AXIAL PLANES, AND THE AXES OF SAID CORRESPONDING FIRST AND SECOND DUCTS EXTENDING IN RESPECTIVE FIRST AND SECOND RADIAL PLANES AXIALLY SPACED FROM EACH OTHER, SAID PLUG HAVING A SMALLER DIAMETER IN SAID FIRST RADIAL PLANE THAN IN SAID SECOND RADIAL PLANE, THE ORIFICES OF TWO RESPECTIVE PORTS OF SAID PAIRS OF PORTS HAVING SUBSTANTIALLY THE SAME CIRCUMFERENTIAL DIMENSIONS, SAID MAIN DUCTS FORMING APERTURES IN SAID PLUG, SAID APERTURES BEING ALIGNED WITH SAID LAST MENTIONED TWO PORTS RESPECTIVELY IN SAID FIRST POSITION OF SAID PLUG, AND OUT OF ALIGNMENT IN SAID SECOND POSITION OF SAID PLUG, THE CIRCUMFERENTIAL DIMENSIONS OF SAID APERTURES BEING SUBSTANTIALLY EQUAL, WHEREBY DURING ROTATION OF SAID PLUG FROM SAID SECOND TOWARD SAID FIRST POSITION THEREOF SAID FIRST MAIN DUCT IS ADAPTED TO CONDUCT COMBUSTIBLE GAS TO SAID FIRST OUTLET BEFORE THE SECOND MAIN DUCT IS ADAPTED TO CONDUCT COMBUSTION SUPPORTING GAS TO SAID SECOND OUTLET.