A windbox is a large cavity pressurised by FD or forced draft fans from which individual burners take their combustion air. Generally a number of burners are fed (at different times) from this "box" so there is a need to balance the air flows through air registers. This is a situation on large boilers, but the same type of burner can be fitted singularly on smaller applications. Due to the nature of the air supply the burner performance with regard to flame shaping, efficiency, turndown is usually better than say a "gun" burner. These burners are also known as package burners or monobloc burners which are for lower capacities (but overlap into the larger ranges) but are characterised by compactness (everything....fan, fuel pump, fuel solenoids or valves, ignition system, flame scanner is on (or close to)the burner). Their flames aren't as compact (or adjustable) as the register burners and tend to be long, ideal for say firetube boilers. However this is not to say that by certain modifications (I have done many)package burners can be adapted to many uses that they weren't really meant for. Package burners are lower in cost than an equivalent register (or windbox) burners.
When you talk about burners for waste heat boilers, do you mean auxilliary burners to supplement or alternate with the waste heat?
If you require more specific information on burner choices I would be pleased to assist further. If you check my website you will see many examples of package burners and can compare them to the register burners also shown.
Regards, Rod Nissen.
Combustion & Engineering Diagnostics
nissenr@iprimus.com.au
