EXCESS AIR FUEL / GAS BURNER - 3422

Xcel Air Fuel / Gas Burner – 3422 3422 Fire All Dual-Fuel Burners are commonly used on heat treat and non-ferrous melting furnaces, kilns, ovens, air heaters, dryers, chemical process equipment, and other applications where superior temperature uniformity is required. These sealed-in, nozzle-mix burners for gas and/or distillate oil are stable on stoichiometric ratio, with large amounts of Xces air, or with up to 50% Xces fuel (provided additional air for combustion is in the furnace near the burner).

WORKING NATURE

Burners can be lighted at rich, lean, or correct air/fuel ratio, then immediately turned to high fire. Required gas pressures are low: 2”wg at the burner for coke oven gas, less for natural gas. Required oil pressure at the burner is nearly zero, but a pressure drop of about 10psi should be taken across the Precise OilControl Valve.

The most common ratio control system for 3422 Burners uses a cross-connectedregulator and Ratio Controller. When appropriate for the application, flow balancing systems or fuel only control (see “Xces Air” paragraph) is very satisfactory. If furnace temperatures after shutdown rise above 1000^oC, pass some air through burner to prevent overheating. During gas operation, use at least 7”wg atomizing air to cool atomizer (full atomizing air may be used); or for extended periods of operation on gas, atomizer can be withdrawn and stored: Use a back plate and gasket to seal rear of burner.

LIGHTING / FLAME SUPERVISION

A Pilot Set normally is used to light 3422 Burners. On gas, direct spark ignition of the burner is available. A manual torch can be used in some pplications. Burners accept ultraviolet (UV) scanners for monitoring pilot or main flame. A flame rod can be used to monitor pilot or main gas fire. When using flame supervision, an interrupted pilot is required–do not use constant or intermittent pilots. If using direct spark ignition, turn off spark after burner lights. An observation port is furnished with all burners. Positions of pilot, flame detector, and observation port are interchangeable as long as pilot and flame detector are mounted in adjacent holes.

XCES AIR

Xces air can improve temperature uniformity by avoiding hot spots in front of burners, by churning furnace atmosphere to reduce stratification, and by creating positive furnace pressure to eliminate cold air infiltration. Xces air can give very high effective burner turndown. Thus a furnace used for high temperature work (such as heat treating at 1000^oC) with burners firing on air/fuel ratio can also be used for low temperature jobs (such as drawing or drying at 300^oC) with burners firing on lean ratio.

APPLICATION TEMPERATURE

The 3422 burners can be used with chamber temperatures upto 1100^oC. If furnace temperature could rise above 850^oC after shutdown, some air should be maintained through the burner to prevent over heating.

CONSTRUCTION FEATURES

Air and gas inlets can be rotated in 90° (both CW & ACW Direction), but air and gas pipes should be brought in from the top or side to prevent oil dripping into them. Mounting plates are cast iron. Burner Blocks are 9″ long for thicker furnace walls, lining beyond end of tile should be flared at least 30° included angle, starting at tile OD. Extension tiles are not recommended. For installation convenience, burner body can be separated from the mounting plate and tile assembly. But burner block must be set in the wall with pilot and flame detector notches in proper location relative to intended burner body position.

JACKETED BURNER BLOCKS: 3422 Burners have a carbon steel jacket around the burner block for applications where there is no furnace refractory to support tiles and where temperatures.

List I. AIR CAPACITIES* Scfh (Standard Cubic Feet per Hour)
Burner designation	27”wg air at burner
3422-2A	2 600
3422-3A	4 100
3422-4A	6 300
3422-5A	10 300
3422-6A	15 700
3422-7AA	27 000
3422-8AA	33 500
3422-9AA	44 800
* Includes primary and secondary air.

List II. COMBUSTION AIR CAPACITITES in scfh (not including atomizing air)
Burner Designation	Air Pressure Drop Across Burner in inches of WGP							Approx. flame lengths in mm with 27”wg Main air (in open furnace)
Burner Designation	1	2	8	10	14	21	28	Gas	Oil
3422-2A	160	520	1160	1270	1470	1800	2100	152	456
3422-3A	280	890	1980	2160	2500	3050	3550	456	608
3422-4A	460	1450	3240	3540	4100	5000	5800	608	760
3422-5A	750	2370	5300	5800	6700	8150	9450	760	760
3422-6A	1180	3700	8300	9100	10500	12900	14800	912	1216
3422-7AA	2070	6550	14600	16000	18500	22700	26200	1824	1824
3422-8AA	2580	8150	18200	19900	23000	28200	32600	1824	1520
3422-9AA	3320	10500	23500	25800	29700	36400	42000	2128	1824

List III. ATOMIZING AIR CAPACITITES in scfh
Burner Designation	Air pressure drop across burner in inches of WGP
Burner Designation	24	28	31	35	38	41
3422-2A, -3A,-4A	500	520	560	600	620	650
3422-5A	640	690	720	760	800	840
3422-6A	800	850	910	950	1000	1050
3422-7-AA, -8-AA	870	930	990	1040	1100	1150
3422-9-AA	2650	2840	3000	3170	3320	3580

EXCESS AIR FUEL / GAS BURNER - 3422