Product Overview | 4821 Air Burners
4821 Hot Air Magna-Flame ™ Burners operate with hot air from recuperators or other heat recovery devices to save energy on furnaces, such as steel reheat, aluminum melting, process heaters, and other high temperature applications. Normal capacities are rated at 1000°F air at a pressure of 10"w.c. CONSTRUCTION . Bodies featuring round mounting flanges are fabricated heavy-gauge carbon steel and lined with ceramic fiber and castable refractory. Internal parts are heat-resistant alloy and the stabilizing disc is faced with high alumina refractory. OPERATION. Gas flames are stable in cold, tight combustion chambers with ambient or high temperature combustion air. Under these conditions, the flame is semi-luminous. The 4821 burner incorporates a low fire air jet. Air (at 60°F) is supplied to the connection at 1.0 psi (27.7"w.c.) and is introduced into the center of the flame to enhance flame shape throughout turndown conditions. See table below for air jet capacities. For applications that benefit from high velocity, such as aluminum melters and holders, steel reheat furnaces or others, the 4821 is available in an "R-version". The refractory tile shape of the R version is reduced (converging) to produce high hot-gas exit velocities, resulting in increased convective heat transfer and at the same time entrainment of surrounding furnace gases resulting in low NOx emissions. For extremely low NOx applications, consult North American about combining the R-version burner with low NOx injection (LNI) technology.
CONTROL . The burner operates with main air pressures from 0.2 to 10"w.c. For stoichiometric firing, required natural gas pressure is a minimum 60 percent of the air pressure. Either a cross-connected regulator system or electronic mass flow control system can be used. IGNITION AND FLAME SUPERVISION . Magna-Flame™ burners should be pilot ignited . Pilot ignition must occur at 1"w.c. main air pressure or less. Appropriate 4014 gas-boosted pilots are to be used with this burner (sold separately), and are shown on the dimension table. Pilot operation must be interrupted to prevent overheating of the mounting. Self-checking UV scanners (sold separately) are recommended for flame supervision. See Bulletin 8832 for selection of UV adapters. It is possible for a UV scanner mounted on this burner to sight flame(s) of other burners in the same firing chamber. Consult North American for configuration guidance on multiple burner applications. INSTALLATION . The burner does not include a tile. The tunnel shape shown on the dimension drawing (page 2) must be built into the combustion chamber wall. See Supplement DF-M1 for installation recommendations. REPLACEMENT AND SPARE PARTS. NOTE: In October, 2009, the 4821 burner was redesigned to change from a square mounting flange to round and replaced the threaded gas connection with a flanged gas tee. When replacing burners, or ordering parts, please inform your sales professional of the complete part number, sales order and/or manufactured date. This information is stamped on a tag located on the burner back plate.
COMBUSTION AIR CAPACITY, scfh (for Btu/h HHV capacity, multiply scfh by 100)
Burner
Jet Air, scfh
Flame Dimensions
Designation at 1000 F air Standard Tile Reduced Port Tile at 10"w.c. P at 10"w.c. P with 27.7"w.c. P Length Diameter 1000 F Air 60 F Air at 60 F
4821-9
4821-9-R
34,000 40,000 53,000 78,000 106,000 134,000 172,000 215,000 260,000
55,000 67,000 89,000 130,000 177,500 225,000 288,000 360,000 435,500
1,130 1,850 1,850 4,500 4,500 6,700 8,600 10,750 10,750
5' 5' 7' 9'
2' 2' 2' 3' 4' 4' 5' 5' 5'
4821-10-A 4821-10-B
4821-10-AR 4821-10-BR 4821-12-R 4821-14-R 4821-16-R 4821-18-R 4821-20-R 4821-22-R
4821-12 4821-14 4821-16 4821-18 4821-20 4821-22
10' 13' 16' 17 ' 20'
Because of postive pressure in the burners, it is difficult to light with a torch unless the air is turned very low and a strong pressure torch is used. Subtract 10% from flame dimensions shown for reduced port tile "R" version.
Bulletin 4821 Page 2
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