Sheet 6843-1
air pressure drop across the burner in osi
Burner
designation
0.5
1
2
4
9
16
30
scfh
psig
6843-3-25
540 780 1100 1590
2450 3340 4570 230 8
6843-4-25
920 1250 1830
2700
4050
5600 7700* 230 8
Air rates are for burners operating on natural gas on ratio. Cold air capacity when not burning will be approximately
7% greater.
6843-25 Hot Spot Burners are off ered in -3 and -4 sizes.
These burners produce short, intense fl ames when operating
on either natural gas or distillate oil. During oil fi ring, 8 psi of
compressed air is required at the burner for atomization. During
gas operation, 2 psi of compressed air is required to protect the
atomizer, but 8 psi can be used if it is necessary to maintain the
same burner capacity as during oil operation.
The 60% Alumina burner tiles withstand furnace temperatures to
2800°F, and are grooved to provide a tight seal when mounted
in either the furnace roof or wall. The tiles are reinforced with
stainless steel needles, and require suitable hand protection be
used during handling.
For natural gas operation, the pressure required at the gas
connection is approximately one half the main air pressure at the
air connection.
For oil operation, each burner must be equipped with an air/
oil Ratiotrol™ regulator and Sensitrol™ oil valve. This Sensitrol
oil valve is not included with the burner assembly and must
be ordered separately. As the atomizer nozzles are precision
machined, a 100 mesh strainer must be installed in the oil line
supplying the burners. In addition, to prevent damage, handling
of the atomizers should be kept to a minimum. When shutting
down the burners or switching over to gas operation, completely
purge the oil atomizers of oil to prevent coking.
Standard burners are supplied with a fl angeless mounting plate
for installation in a furnace roof. Optional fl anged mounting is
available (at additional cost) for installation in a furnace wall. Add
the letter "C" at the end of the burner designation when ordering
the fl ange, i.e. 6843-3-25-C.
A 4011-12 pilot set is recommended for individual burner ignition.
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. A UV Detector should be used for fl ame
supervision. While it is strongly recommended that the burners
be lit at low fi re, the maximum main air pressure for lighting
when fi ring oil is 8 osi.
The Dual-Fuel™ hot spot burners will perform well when coupled
with an air/fuel ratio control system that is capable of controlling
within the stability range of the burners. The extremely fast
mixing characteristics of this burner limit excess air, and excess
fuel should be limited to less than 10% Caution must be taken
when calculating burner inputs. Due to expansion changes in the
burner at diff erent fi ring rates, air fl ow dœ s not follow the square
root law. In addition, burner air fl ow decreases as the furnace
temperature increases, resulting in a change in air/fuel ratio. As
a result, the fi nal burner air/fuel ratio settings must be made with
the furnace at operating temperature. This results in the burners
fi rings lightly lean during a cold start-up and reaching ratio as
the furnace reaches temperature.
COMBUSTION AIR CAPACITIES in scfh
(for Btu/h HHV, multiply by 100)
*
Gas only. 16 osi is maximum air rate for oil on 6843-4-25
.
North American Dual-Fuel
™
Hot Spot Burners
WARNING:
Situations dangerous to personnel and property may exist with the operation and maintenance of any combustion equipment. The presence of fuels, oxidants, hot and cold combustion products, hot
surfaces, electrical power in control and ignition circuits, etc., are inherent with any combustion application. Components in combustion systems may exceed 160°F (71°C) surface temperatures and present hot
surface contact hazard. Fives North American Combustion, Inc. suggests the use of combustion systems that are in compliance with all Safety Codes, Standards, Regulations and Directives; and care in operation.
ENERG
Y | C
OMBUSITION
