Product Overview | Hot Air Burners
CONSTRUCTION Heat resistant cast iron burner bodies including air connections are lined internally with vacuum-formed ceramic fiber insulation. Burner tiles are 3000°F castable with or without self-supporting construction and are easily replaceable in the field. Burner air tubes are high temperature alloy, protected by a refractory radiation shield. IGNITION/FLAME SUPERVISION A 4011-12 pilot set is recommended for individual burner igni- tion. When multiple burners share a single pilot pre-mix header, a 4021-12 pilot tip per burner with an appropriately sized air/gas mixer is recommended. For higher ambient temperatures specify a Honeywell C7035A UV with an 8837-F Adapter, which includes a Honeywell heat block #136733 (R130-5849) and a ¼ " fpt for 100 cfh cooling air. Fully metered flow control arrangements on the cold air side-- such as 7288 Regulators or 8096 Combustion Controllers--are satisfactory for the vast majority of installations. Because 6825 Burners are capable of lean starts on cold air, standard cross connected regulators and Ratiotrols can be used on many batch operations, as well as on continuous furnaces with constant preheated air temperatures. RECUPERATORS 6825 Burners are compatible with any recuperators, including North American's 8483, 8485, and 8486 units.
Continuous roller hearth furnace uses 1000°F preheated air in its (44) 4825 Gas Burners, which can be converted to 6825 Dual-Fuel™. Optional (recommended) Sensitrol ™ Oil Valve is not included in burner assembly, and must be ordered separately. 6825 Burners will handle 1200°F preheated combustion air firing car bottom, aluminum melting, forging, glass melting, heat treat- ing, and other furnaces where standard 6422 or 6425 Burners would be used if combustion air were not preheated. Burners provide stable combustion in cold tight furnaces on stoi- chiometric ratio, with excess air, or on moderately fuel-rich ratios. Air is evenly distributed around the fuel stream, creating uniform combustion and a well-defined flame pattern throughout a wide turndown range. Gas flames are clear to semi-luminous dependent on air tem- perature, firing rate, and air/fuel ratio. Oil flames are luminous at all rates and ratios. CONTROL Mass flow control systems with air temperature compensation provide the most reliable fuel efficiency.
CAPACITIES
All burners are nominally sized for a high fire rate of 8 osi main air at 1000°F but can be fired at 16 osi.
Atomizing air capacity
Main air capacity scfh at 8 osi
Burner
Main air pipe size
scfh at 14 osi
designation
Ambient 2 700 3 680 5 000 7 700 20 950 27 720 36 280 11 750
1000°F 1 600 2 200 3 000 4 600 7 000 12 500 16 500 21 600
Ambient
6825-2 6825-3 6825-4 6825-5 6825-6
4 4 4 4 4 6 6 6
400 400 400 400 400
6825-7-A 6825-7-B 6825-8-A
2400 2600 2700
Bulletin 6825 Page 2
Sheet 1148 describes manual hot air valves that can be used with -6, -7, and -8 burners.
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