i STEAM COAL - Clpdigital.org

THE COAL TRADE BULLETIN. 29
PROGRESS IN MINE PUMP CONSTRUCTION.
The proper drainage of a mine has always been
a serious problem, and only the last few decades
can show marked progress towards a really practical
solution of the problem. The early pumping
engines were exclusively overground working
pumps situated at different levels. Each of these
passed the water on to the one above besides dealing
with that collected on its own level. These
engines were of the beam type, without fly-wheels,
and constituted the flrst adaptation of steam as
Fig. 1—Steam End.
a motive power. It was on them that Newcomen,
Watt, Trevithick and Stephenson made their experiments
and most important inventions. In
a modified form, known as the Cornish engine,
they attained fame and general use: in fact, for
a long time they were the accepted standard for
pumping engines, and to this day there are not
a few of them either in actual use or standing in
reserve.
Electrically-driven pumps would seem to offer
a good modern substitute for ancient methods of
unwatering mines, but they are extremely expensive
in first cost and maintenance as well, and
present problems that have not, as yet, been fully
overcome in practice. Therefore, for the present
at least, and until electricity can be harnessed
and controlled and adapted to mining work at the
minimum expense, it is necessary that a thoroughly
reliable mine pump should work equally
well with compressed air as with steam, for the
use of air is much to be preferred to that of
steam.
It is a very general, though mistaken, idea that
the question of steam economy in an engine working
down a mine is not of importance. Managers
of mines should not lose sight of the fact that a
high consumption means more boiler power required,
larger pipes and increased cost of insulation,
besides the inconvenience of a higher temperature
in the mine and of warmer water due to
greater quantity of steam condensed. It cannot.
therefore, be considered true economy to put down
cheap and uneconomical machinery, as any saving
on this count is soon eaten up by the enhanced
cost of the accessories and fittings.
Among the few good pumps that can be safely
recommended as being thoroughly reliable and
effective when operated either by steam or air,
the Cameron is conceded to be one of the best.
The Cameron pump has stood for nearly half a
century for simplicity, compactness and strength
of construction; certainty of operation and reliability
in long-continued service. It has few
working parts and none exposed to external damage,
and yet careful and just consideration has
been given to minimizing the necessity for and
the cost of repairs, so that a part when worn out
can be renewed readily and cheaply and not involve
the purchase of well nigh an entire pump.
The construction of the Cameron is shown by
Fig. 1, a sectional view showing the steam end,
the piston complete and water end. Referring to
the steam end: The plunger is reversed by
means of two plain tappet valves, and the entire
mechanism thus consists of four stout pieces only.
Fig. 2—Water Valve Chest.
all working in direct line with the main piston.
It is simple and without delicate parts. A is the
steam cylinder; C, the piston; L, the steam chest;
F, the chest plunger, the right-hand end of which
is shown in section; G. the slide valve; H, a lever,
by means of which the steam-chest plunger F
may be reversed by hand when expedient; II are
reversing valves; KK are the reversing valve