August 2000
FLAT FLAME
™ GAS BURNERS
Bulletin 4831
Core Burner Business Group
4831 Flat Flame Burners
transfer heat to the surrounding refractory wall or roof by highly turbulent
convection; the refractory then radiates heat uniformly to the load. Minimum forward velocity results
in uniform radiant heating with no flame inpingement.
Applications.
Successful applications of 4831 Flat Flame Burners
include:
Wire patenting furnaces: Roof-mounted burners provide more
uniform heating than side-fired installations.
Cover annealers: The excellent uniformity and fuel economy
characteristic of large cover annealing furnaces fired with 4832 Flat
Flame Burners have been duplicated with 4831’s on smaller units.
Strip annealers: The 4831’s small diameter flame is ideally
suited to long narrow furnaces.
High temperature single layer kilns.
Glass tank forehearths.
Performance.
4831 Flat Flame Burners are sealed-in. All combustion
air is provided through the air connection.
They are stable in cold, tight chambers, operating lean, rich, or on
correct ratio. This flexibility combines with flat flame characteristics
to produce superior uniform heating.
Flames stay flat down to 1 osi air pressure on correct air/gas ratio,
but are less flat with rich ratios. Even when visible flames are within
the tile throat, flow of combustion products is still flat.
Construction.
Burners are made of special low growth cast iron.
The standard 60% alumina refractory tile, suitable for furnaces up
to 3000 F, is available in 7" and 9" lengths. The refractory cover
plate should not be attached to the furnace shell.
Tiles, tapered on two sides, are available (at no extra cost) in
the 9" length only. These tile faces measure 63/4" ´ 71/2": Specify
"4831- -T".
Installation.
Burner tile face must be flush with the inside surface
of the furnace refractory. For convenience in piping burners in thick
walls, air and gas connections enter the back of the burner parallel
to its centerline. Two studs projecting from the cover plate permit
suspending the burner in a furnace roof. For more comprehensive
instructions, refer to Instructions 4832-2.
Flame Supervision.
Burners are compatible with certain makes
and models of flame supervisory equipment. Consult a North
American office for a satisfactory arrangement. Viewed from outside
the furnace, flame detector must be mounted clockwise from the
pilot. Interrupted pilots are required for maximum safety. If no flame
detector is specified, an observation port is furnished in the detector
opening.
Lighting
. Series 4831 Burners light smoothly with North American
gas pilots. Limit pilot input to 10 000 Btu/hr to avoid overheating
the mounting. Manual lighting with a torch also is possible, either
at the tile face or through the pilot opening in the burner. Pilot opening
must be closed after lighting.
COMBUSTION AIR CAPACITIES, scfh
(multiply by 100 to get Btu/hr)
Burner air pressure drop across the burner in osi min. gas
designation 1 5 6 8 12 16 pressure
4831-0
170 380 420 490 600 690 3.0 osi
4831-1
305 680 755 870 1070 1230 3.0 osi
With 10:1 air/gas ratio and 16 osi air. Lower gas pressure required at lower firing rates. Do
not use these figures to set air/gas ratio- -use an 8697 Metering Orifice.
l www.namfg.com Printed in USA NA800-B4831
OPERATING CHARACTERISTICS
Burner air pressure drop across the burner in osi
Flame description designation 1 4 6 8 12 16
Flame diameter, inches
. 4831-0 . 6 7 7 8 8
4831-1
. 8 8 9 12 12
Flame length (beyond tile), inches
. 4831-0 . 21/2 2 11/2 1 1
4831-1
. 2 2 2 1 1
Maximum % XSAir, with constant pilot air 4831-0
190 120 105 85 85
4831-1
130 100 90 80 75
Maximum % XSAir, without constant pilot air 4831-0
110 90 85 60 40
or direct spark 4831-1
75 70 65 50 45
Burner dimensions in inches Recommended Mixture Flame Wt,
designation A B pilot tip pressure rod length
. lb
4831-0 3/4 1/2 4021-12 0.8"wc 31/2" 44
4831-1
1 3/4 4021-12 0.8"wc 31/2" 44
.
With natural gas at 10:1 air/gas ratio.
.
Flame is entirely within tile.
.
From the outer boss of the flame rod connection.
To order, specify: 4831-(code for pipe size)-tile length or style (7 for 7", 9 for 9", T for 9" Tapered) Burner Complete.
Examples: 4831-0-9 3/4" Burner Complete with 9" Tile
4831-0-T 3/4" Burner Complete with Tapered 9" Tile
4831-0-BO 3/4" Burner Only
3
/4" fpt
30°
27/8"
PILOT
35/8"
23/4"
35/8"
1"
45°
30°
1
/8" fpt Air
Pressure Tap
3
/8" –16 N.C. Thr'd.
With pilot and flame detector bosses in position shown, gas inlet can be positioned at either 6 or 9 o'clock positions.
B–fpt for Gas Inlet
A– fpt
Combustion
Air Inlet
13/4" 129/32" 1"
321/32" 71/8" or 91/4"
71/2"
sq.
4831- -T Tile is tapered on two
45° 3/8" sides to 63/4" width at tile face.
2"
3
/4" fpt for
Flame Detector
or
Observation Port
DIMENSIONS
inches
DIMENSIONS SHOWN ARE SUBJECT TO CHANGE. PLEASE OBTAIN CERTIFIED PRINTS FROM NORTH AMERICAN MFG. CO.
IF SPACE LIMITATIONS OR OTHER CONSIDERATIONS MAKE EXACT DIMENSION(S) CRITICAL.
WARNING:
Situations dangerous to personnel and property can develop from incorrect operation of combustion equipment.
North American urges compliance with National Safety Standards and Insurance Underwriters recommendations, and care in operation.
Bulletin 4831
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