Question

Why are the blades of shaft in spreader stoker twisted?

(a) For supporting combustion by supplying more amount of air

(b) To draw in large amount of coal

(c) For uniform distribution of coal

(d) To restrict the supply of coal

The question was posed to me in examination.

My enquiry is from Type of Stokers in portion Steam Power Plant of Energy Engineering

Answer 1

Correct choice is (c) For uniform distribution of coal

Easy explanation: Spreader consists of rapidly rotating shaft carrying blades. These blades are twisted to provide uniform distribution of the coal over the grate. The fast rotating blades hit the coal particles coming from the feeder and throw into the furnace. The distribution of coal over the grate depends on the rotating speed of the spreader and on the size of the coal.