Cool Flame series XDF dual fuel excess air burners are nozzle mixing oil or gas units designed for up to 350% excess air or ''on-ratio'' firing. A unique stepped tunnel design produces excellent flame stability at all firing rates. All sizes are designed for turndown of ten to one ''on-ratio'' with 16 oz. combustion air pressure. Pressure balancing of gas zero governors and oil-air ratio regulators provide constant fuel to air mixes for ''on-ratio'' firing over the turndown range. The burner is designed for sealed firing in positive, neutral or negative pressure combustion chambers. EXCESS AIR OPERATION High speed heat transfer will occur in convection systems with maximum turbulence and scrubbing action of the hot gases against the work pieces. High discharge velocities from burners increases furnace hot gas circulation and promotes rapid heat transfer. Shorter firing cycles and lower fuel consumption result from better temperature uniformity requiring less soak time. ''On-ratio'' firing systems can produce the required velocities on high fire but drop to 10% to 15% of this velocity on low fire. Excess air systems use a constant air flow and ''on-ratio'' combustion at high fire. Only the fuel flow is varied for heat input turndown. The total volume of hot gases and velocity remains nearly constant at all firing rates. Furnace pressures, turbulence and heat transfer rates are uniform. Excess Air Burners are variable temperature air heaters. At high fire flame temperatures may be 2500?F or higher. As fuel only is decreased, exit gas temperatures drop to as low as 1200?F with 350% excess air. ORDERING INFO   With Standard Refractory less Jacket 3000°F With Hi-Temperature Refractory Less Jacket 3300°F With Alloy Jacket & Standard Refractory 3000°F With Alloy Jacket & Hi-Temperature Refractory 3300°F With Short Alloy Jacket & Standard Refractory 3000°F With Short Alloy Jacket & Hi-Temperature Refractory 3300°F   FEATURES   Burns all fuel gases or light oils Nozzle mix design for ''on-ratio'' control or excess air 350% excess air all sizes on gas or oil Turndown 10:1 on ratio with single air valve control Excellent flame stability instant lighting with either fuel Sealed construction for back pressure firing to 10 psig Pilot, flame rod and U.V. scanner mountings in tapped holes Unique stepped tunnel design Patented atomization Simplified construction - no moving parts   CAPACITY TABLE - ON RATIO FIRING   16 osi AIR 24 osi AIR Catalog Number Air Pipe Sizes Atomizing Air Flow CFH* Oil Flow GPH Combustion Air Flow CFH Gas Input 1000's BTU/hr. Atomizing Air Flow CFH Oil Flow GPH Combustion Air Flow CFH Gas Input 1000's BTU/hr. 16 XDF 2" 700 5 6300 630 850 6 7800 780 24 XDF 3" 1400 10 12600 1260 1700 12 15600 1560 32 XDF 4" 2800 20 25200 2520 3400 24 31000 3100 48 XDF 6" 5600 40 50400 5000 6800 49 62000 6200   Note 1 Gas pressure required at inlet to Balanced Zero Governor 4" W. C. minimum with oil lances retracted to stops. With gas pressure 2 osi higher than air pressure oil lances need not be retracted. Gas pressure must be higher than air pressure for all positive pressure combustion chamber firing. Oil pressure required at inlet to Oil-Air Ratio Regulator 40 to 50 psig. Note 2 Minimum recommended atomizing air pressure is 20 osi   CAPACITY TABLE - EXCESS AIR FIRING Catalog Number Air Pipe Size Gas Operation   Oil Operation   Air Flow SCFH 1000's BTU/hr. Gas Atomizing Air SCFH Combustion Air SCFH Oil Flow GPH Max. Min. Max. Min. 16 XDF 2" 6300 630 30 700 6300 5 0.5 24 XDF 3" 12600 1260 60 1400 12600 10 1 32 XDF 4" 25200 2520 120 2800 25200 20 2 48 XDF 6" 50400 5040 250 5600 50400 40 4   Note Capacities are for 16 osi air pressure, 3 osi gas pressure and 20 psig oil pressure delivered to the burner at maximum firing rates. Air flows remain constant at all firing rates. Only fuel flow is varied.