The Locomotive - Lighthouse Survival Blog

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PUBLISHED BY THE HARTFORD STEAM BOILER INSPECTION AND INSURANCE COMPANY.
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Nknn Sekies Vol. XV. BARTFORD, CONN., OCTOBER, L894. No. 10.
Concerning' Blow-off Pipes.
In tlu- September issue of The Locomotive, in speaking of the deposit of sediment
and the formation of scale in pipes, we referred to the use of straight-way valves
on blow-offs, and stated that the opening in such valves should be fully equal to the
sectional area of the blow-oif pipe itself. As the importance of this point is not always
Fig. 1. — A Globe Valve applied to a Blow-off Pipe.
thoroughly appreciated, we herewith present two cuts (Figs. 1 and 2) which will suf-
fice, it is hoped, to make the matter clear. Fig. 1 represents a globe valve as applied to
a blow-off pipe, and we have endeavored to illustrate the fact that such a valve is liable
to trap pieces of scale that have flaked off from the shell (or tubes) of the boiler. The
same action may take place with any other form of valve in which the passage is not
straight, or which has an opening of less area than the blow-off pipe itself. Fig. 2
illustrates a straight-way valve having an opening a trifle greater than the area of the