The Locomotive - Lighthouse Survival Blog

1893.
THE LOCOMOTIVE.
prevent the water in one boiler from buckiiiy up into tlie otlier ono, if tlit-n; sliouhl
beany diflTerence in pressure iu tlie two boilers. Such a diflerence in pressure mifrlit
easily arise from :i variety of causes; for instance, if the stop-valve in the steam pipe
leading from either boiler were closed, a dit!erenee in pressure would immediately nrsuit.
:md a change in the relative water levels in the two boilers would follow, unless one
of the valves FT were also closed; and as these valves are at the back end of the set-
ting, it would not be strange if the fireman should occasionally forget to attend to them,
especially if he left them open habitually, as in the present case. It is also found, in prac-
tice, that if the fire in one of the furnaces is brighter than that in the other one, water is
apt to back out of the hotter boiler, even when the steam valves are both open, and the
pressure apparently equal throughout the system. In any case, the arrangement is a
dangerous one, and should not be tolerated when safety can be so easily secured. While
we do not approve of the feed entering the boiler at the bottom, as shown in the cut, we
Fio. — AXOTHER DaXGEROFS FeED CONNECTION.
may suggest that the greater part of the danger can l)e removed by putting in check-
valves at AA, for by this simple change the backing out of water from either boiler
can be effectually prevented.
Fig. 2 shows a somewhat similar arrangement, excc])t that in this case there was no
check-valve at all, and the pump-valves had to hold the direct boiler pressure all the
time. The valves shown at BB were only used when blowing ofi", and were kept closed
at other times. Valves AAA were ordinarily left open. The boilers were set over se|>-
arate furnaces, as before, and all the objections that apply to Fig. 1 are equally appli-