Product Overview | 4950 Flame Grid
FEATURES 4950 Flame Grid burners were developed to incinerate organic vapors from ovens and industrial processes. They are mounted on horizontal or vertical fume-carrying ducts (up-flow or down- flow) with the grid array inserted into the cross section of the duct. The grid array has multiple gas tubes covered with gas distribu- tion holes and grid plates to stabilize the flame. They are fed by the gas header positioned outside the duct. The grid plates can be adjusted to reset the effluent pressure drop across the burner to achieve efficient mixing of fumes and flames. Releasing heat uniformly across the duct, minimizes the gas needed to ignite combustible pollutants in the fumes. Incineration is completed in a suitably sized combustion chamber (user built) downstream of the burner. Since 4950 Flame Grids use combustion air from the effluent stream, no additional blower is required. see Figure 1 effluent oxygen requirement.
Over time the fasteners could seize and be difficult to loosen. It may be necessary to grind off the old fasteners and replace them with new ones to be able to adjust the grids.
DIRECT AIR HEATING
APPLICATION Flame Grid burners are suitable for the following conditions: Once combustion is complete, the bypassed air is mixed back in with the burner products of combustion to produce the desired temperature rise. 4950 Flame Grids can also be used in direct fired air heaters where the oxidant is clean air (with 21% O 2 ). In direct fired air heater applications where a small rise in temperature is desired it may be beneficial to bypass some of the clean air around the grid. This allows for a smaller burner operating at a higher flame temperature which better controls the amount of CO produced.
Fume temperature at burner inlet: 1100 °F (593 °C) maximum
Adjustable Grid Plate
Fixed Grid Plate
Temperature at burner outlet: 1200-1600 °F (650-870 °C) Temperature required de- pends on nature of fume or smoke being incinerated.
Temperature rise across burner: 200 °F (93 °C) minimum 1600°F (8701 °C) maximum
Fully Open Grid Assembly Partially Closed Grid Assembly
Duct pressure upstream of burner: 2.0"w.c. (5.0 mbar) maximum
RESETTING ADJUSTABLE GRID PLATES
Note: Engineered specials are available for up to 80"w.c. (200 mbar) duct pressure.
For most applications, if the correct size 4950 is initially chosen, the grid plates will never need to be adjusted. But, if the air flow through the duct is decreased so that the pressure drop across the burner is too low, the grids can be adjusted to increase the pressure drop. When the grids are set fully open they block about 50% of the duct, and at the minimum open setting they block about 75% of the duct area. In most cases each grid spans three (3) gas tubes. This is why the width of every 4950 is built in three (3) tube increments. Only the center fasteners on each plate should be screwed down tight. The rest should be assembled so that the SST washer is slightly loose.
Fume stream pressure drop across burner: 0.2"w.c. (0.5 mbar) minimum 2.0"w.c. (5.0 mbar) maximum
Minimum oxygen content of fume stream: See Figure 1.
Flame Grid burners are not suitable for halocarbons.
Bulletin 4950 Page 2
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