Q. Describe the construction of a Return Flue Boiler?
A. It has a cylindrical shell, with heads riveted at each end, in which
are placed a large main flue, and a number of small flues or tubes,
open at both ends. The top row of flues is placed below the water line.
One end of the main flue is used for the fire box, into which the fuel
is thrown through door at back end and the products of combustion pass
forward through this main flue to an ample smoke box in front end, and
return through the smaller flues or tubes to smoke box at rear end,
which is connected to the smoke stack. They are generally supplied with
steam dome and mud drum, and are used extensively in the construction
of traction engines where straw is used for fuel. They are also
furnished with several hand-holes placed in proper places for cleaning
the boiler.
[Illustration: Sectional View J. I. Case Return Flue Boiler.]
Q. What are the advantages of this style of boiler?
A. Large heating surface, easily repaired and cleaned, simplicity of
construction and compactness.