Q. What class of boilers are generally used in a threshing
engine?
A. The flue boiler and the tubular boiler.
Q. About what amount of heating and grate surface is required per horse power in a flue boiler. A. About 15 square feet of heating surface and 3/4 square feet of grate surface.
Q. What would you consider a fair evaporation in a flue
boiler?
A. Six pounds of water to I pound of coal.
Q. How do these dimensions compare in a tubular boiler. A. A tubular boiler will require I/4 less grate surface, and will evaporate about 8 pounds of water to I pound of coal.
Q. Which do you consider the most available?
A. The tubular boiler.
Q. Why?
A. It is more economical and is less liable to "collapse?"
Q. What do you mean by "collapse?"
A. It is a crushing in of a flue by external pressure.
Q. Is a tube of a large diameter more liable to collapse than one of small diameter? A. Yes.
Q. Why? A. Because its power of resistance is much less than a tube of small diameter.
Q. Is the pressure on the shell of a boiler the same as on the
tubes?
A. No.