COAL - Clpdigital.org

36 THE COAL TRADE BULLETIN.
DISCUSSION OF EXHAUST
STEAM FROM MINE PUMPS.
The disposition of exhaust steam from pumping
machinery in mines is a worthy subject ior serious
consideration. The use of long pipes to carry
off the exhaust is costly and very inconvenient at
Fig. 1.
times, owing to the frequent necessity for changing
positions of the pumps in the various parts of
the suaft. In mining operations large bodies of
water are frequently encountered, making it neces­
sary to have a pump that can be readily moved
about, and raised and lowered in the shaft in
the least possible time.
The most feasible and the best plan we know of
is a simple and inexpensive method of steam condensation
provided by the A. S. Cameron Steam
Works, foot of East 23rd street, New York, and
very often used in connection with their well
known "mine sinking pump," which meets with
universal favor, and is worthy of mention and
adoption. The accompanying illustrations and
descriptions fully explain their system:
Illustration, Fig. 1, shows one of the Cameron
vertical plunger sinking pumps, having the slings
attached by which it is hung in the shaft. The
darker portion of this reproduction shows the condenser,
together with the exhaust pipe leading
thereto, and directly bolted to the water valve
chest; which makes a very compact arrangement
without causing any resistance to the free inflow
of water, while at the same time it is exceedingly
effective in taking care of the exhaust steam by
condensing it, and permitting it to enter the pump,
as water, through the suction opening, from which
it is discharged to the surface.
In illustration. Fig. 2, a sectional view of the
condenser chamber is shown which clearly defines
the simple method of condensation. The constant
flow of water through the suction piping connected
to the bottom of the condenser wi.l naturally
cool the bronze sleeve which is arranged
within this chamber; so that when the exhaust
steam conies in contact Wi«.u the cool surface, part
of it will immediately lie condensed, and the remainder
passing through the annular opening,
will also be condensed after mixing with the water
passing through the suction.
It also has the additional aovantage of relieving
the steam piston of back pressure, as a partial
vacuum is formed proportionate to the neight of
the suction lift. It is necessary tnat the water
cylinder be fully charged before the exhaust steam
is turned into the condenser, by allowing the pump
to exhaust into the atmosphere until it has become
filled with water, then the three-way valve
may be turned and the exhaust steam admitted to
the condenser, but it should never be allowed to
enter except in combination with the water. In
some cases automatic floats are arranged to stop
the pumps when the water supply is down. An
air leak is fatal to the successful working of this
as of any other condensing apparatus, and tnerefore
must be guarded against.
The effective power of a steam pump depends
largely on the initial steam pressure pushing the
piston, but there is always a back pressure when
the steam is exhausting into the atmosphere.
From this it will readily be seen that more steam