On small stoker burner boilers ther

On small stoker burner boilers there may be
only one combustion fan as shown in Figure
12, which means that it is very difficult to
separate the primary air supply to the
grate from that in the final combustion
zone above the grate. As a result
the potential for overheating and
subsequent slag formation on
the grate is very high, and some
boiler manufacturers have
included a water cooling
circuit within the grate as a
preventative measure.