Burner Design Requirements
Sliding-can type air registers should be cast iron or steel plate of 10-gage minimum thickness. This is to provide resistance to warping and to improve long term operability. Roller bearings should be provided for easy register movement, and a positive locking device should be provided to prevent vibration from changing the register position. Butterfly-damper type air registers are preferred over the slidingcan type.
Today, many burners have to operate inside plenums for noise control. Air register controls must be operable from outside the plenum and should be equipped with position indicators which clearly show the register position from outside the plenum. Lighting and sighting ports should be positioned so that the operator can check the position of the burner register from the firing platform. Penetration for air register controls, oil gun, burner access plates, etc., must be positively sealed to prevent burner noise from coming out the gaps.
Burners enclosed in plenum chambers should be rigidly supported directly on the furnace case, not hung on the plenum. Merely bolting the burner to the plenum wall will not provide sufficient rigidity for adequate position control of gas and oil tips in the burner tile.
The heater design should provide sufficient space between burners and tubes to assure that flames will not impinge on the tubes even when the heater is operated at 125% of design. Compliance with this requirement should be demonstrated in tests at the burner supplier’s facility.
Burners should be furnished without pilots. Minimum gas bypasses provide much greater assurance of flame safety. Burners must be readily accessible for control and maintenance. Oil guns and gas tips must be easily removable during operation.
In order to avoid lighting off through plenum chambers and oil spilling hazards, all burners (both gas and oil) in floor-fired heaters should be ignited from above through side viewing ports. Port size and location must be sufficient to insert the lighting torch and observe the flame while lighting off the burners.
If burners are enclosed in plenum chambers, consider providing burner air control at the plenum chamber inlets, particularly if a large number of burners is enclosed in a common plenum. The idea is to provide more convenient (ganged) excess air control.