WESMAN BURNERS

In a furnace the re-circulation of products of combustion can substantially contribute to the speed of heating and temperature uniformity. For low temperature ovens and dryers, suitable re-circulating fans are generally provided to achieve temperature uniformity. However, fans are not practical for high temperature furnaces and kilns.
Excess air can help in re-circulation but this will result in wastage of fuel. 30% excess air for a 1100 degree centigrade furnace will require additional 24% fuel than stoichiometric firing. In comparison, high velocity gases entrain and re-circulate more than seven times of own volume will eliminate need for fans or excess air.