SHORTNESS OF WATER. PUMP DISORDERS.
TROUBLE DEVELOPS NATURAL ENERGY.
TROUBLE; and affliction are known to have a purifying
and elevating effect upon human character; difficulties encountered
in the execution of work, develop the skill of the true artisan;
and trouble on the road, or accidents to locomotives, furnish
the engineer with opportunities for developing natural energy,
ingenuity, and perseverance, if these attributes are in him, or
they publish to his employers his lack of these important qualities.
One of the most serious sources of trouble that an engineer
can meet with on the road, is shortness of water.
SHORTNESS OF WATER A SERIOUS PREDICAMENT.
Deficiency of steam with a locomotive that is expected
to get a train along on time, is a very trying condition for an
engineer to endure. But a more trying and more dangerous ordeal,
is want of water. Where steam is employed as a means of applying
power, water must be kept constantly over the heating surfaces
while the fire is incandescent, or their destruction is inevitable.
With a boiler which evaporates water rapidly, and in such large
quantities as that of the locomotive, the most perfect feeding
apparatus is necessary. Nearly all locomotives are well supplied
in this respect. Good pumps or efficient injectors provide the
engineer with excellent appliances for feeding the boiler under
ordinary circumstances. But conditions sometimes occur where the
best of pumps, or the most reliable of injectors, fail to force
water into the boiler.
HOW TO DEAL WITH SHORTNESS OF WATER.
When from any cause he finds the boiler getting short
of water, the engineer should resort to all known methods within
his power to overcome the difficulty, by removing the obstacle
that is preventing the feeding apparatus from operating. But,
while doing so, the safety of his fire-box and flues should not
be overlooked for a moment. The utmost care must be taken to quench
the fire before the water gets below the crown-sheet. This can
be performed most effectually by knocking the fire out; but sometimes
the temporary increase of heat, occasioned by the act of drawing
the fire, is undesirable; and, in such a case, the safest plan
is to dampen the fire by throwing wet earth, or fine coal saturated
with water, upon it. Or a more urgent case still may intervene,
when drenching the fire with water is the only means of saving
the sheets from destruction. This should be a last resort, however;
for it is a very clumsy way of saving the fire-box, and is liable
to do no small amount of mischief. Cold water thrown upon hot
steel sheets, causes such sudden contraction, that cracks, or
even rupture, may ensue.
WATCHING THE WATER-GAUGES.
As "burning his engine" is the greatest disgrace
that can professionally befall an engineer, every man worthy of
the name guards against a possibility of being caught short of
water unawares, by frequent testing of the gauge-cocks. It is
not enough to have a good-working water-glass. If an engineer
is ambitious to avoid trouble, he runs by the gauge-cocks, using
the glass as an auxiliary. Careful experiments have demonstrated
the fact, that the water-glass, working properly, is a more certain
indication of the water-level than gauge-cocks; for, when the
boiler is dirty, the water rises above its natural level, and
rushes at the open gauge-cock. This can be proved when water is
just below a gauge-cock level. If the cock is opened slightly,
steam alone passes out; but, when the full opening is made, water
comes. But water will not come through a gauge-cock, unless the
water-level is in its proximity; and an engineer can tell, when
his gauge shows a mixture of steam, that the water shown is not
to be relied upon. It is not "solid." On the other hand,
a water-glass out of order sometimes shows a full head of water
when the crown-sheet is red-hot.
WHAT TO DO WHEN THE TENDER IS FOUND EMPTY
The most natural cause for pumps or injectors ceasing to work,
is absence of water from the tender. This condition comes round
on the road occasionally, where engineers neglect to fill up at
water-stations, or where there are long runs between points of
water-supply. When an engineer finds himself short of water, and
the means of replenishing his tank too distant to reach, even
with the empty engine, he should bank or smother the fire, and
retain sufficient water in the boiler to raise steam on when he
has been assisted to the nearest water-tank. This will save tedious
delay, especially where an engine has no pumps. Occasionally,
from miscalculations or through accidents, the fire has to be
quenched, and insufficient water is left in the boiler to start
a fire on safely. In this event, buckets can be resorted to, and
the boiler filled at the safety-valves, should there be no assistance,
or means of pumping up. Every possible means should be exhausted
to get the engine in steam, before a runner requests to have his
engine towed in cold.
A TRYING POSITION.
I once knew a case where an engineer inadvertently
passed a water-tank without filling his tender. He had a heavy
train, and was pushing along with a heavy fire, on a severe, frosty
night, when every creek and slough by the wayside was lost in
heavy ice. Presently his pump stopped working, and he spent some
time trying to start it before he discovered that the tender was
empty. By the time this fact became known, his boiler water was
low, and a heavy fire kept the steam screaming at the safety-valves.
He had no dump-grate, and the fire was too heavy to draw. It seemed
a clear case of destroying the fire-box and flues. But he was
a man of many resources. First, he tried to get water through
the gauge-cock he had only one gauge to quench the
fire, but found the plan would not work. Then he filled up the
fire-box nearly to the crown-sheet with the smallest coal on the
tender, and partly smothered the fire. He then partly opened the
smoke-box door, and started for the water-station. After getting
the engine going, he hooked the reverse-lever in the center, and
kept the throttle wide open, to make the most of the steam-supply.
He saved his engine.
WATCHING THE STRAINERS.
When the top of a tank is in bad order, and permits
cinders and small pieces of coal to fall through rivet holes,
or through seams, the engineer may look out for grief with his
pumps or injectors. On the first signs of the water failing, he
should examine the strainers; and he will probably find that these
copper perforations, which stand like wardens guarding the safety
of the pumps and injectors, have accumulated a mass of cinders
that obstructs the flow of the water.
CARE OF PUMPS.
Mechanical prognostications seem to indicate that pumps,
as locomotive attachments, have outgrown their usefulness, and
that their days are numbered. They have done good service while
no better method of feeding locomotive boilers was known; but,
since the advent of injectors, pumps have begun to disappear.
They still hold their own, however, on a great many roads; and
a description of their management will be of general interest.
HOW THE CONDITION OF PUMPS CAN BE TESTED.
If an engineer is in the habit of pumping regularly,
and of watching his engine closely, he can tell immediately from
the steam when the pump stops working. Then he will open the pet-cock;
and its action will indicate, to some extent, where the trouble
lies. If the pet-cock throws a feeble stream of water, the trouble
probably is in the lower valve. If that sticks up, or part of
the bottom cage breaks, the plunger will push the water back into
the feed-pipe on the return stroke, consequently there will be
no pressure to throw a strong stream through the pet-cock. When
the upper or pressure-valve is damaged, or is stuck up, the pet-cock
will throw a full stream during the inward stroke of the plunger;
but, on the outward stroke, the plunger will draw the water out
of the branch-pipe, and air will be sucked in at the open pet-cock.
When the check-valve is damaged, or stuck up, steam and water
will blow back through the branch-pipe when the pet-cock is left
open. If the steam thus escaping from the check-valves heats the
pump and valves to a high temperature, it will be prevented from
working, from several causes. The heat generates a low form of
steam, which fills up the space behind the plunger; therefore,
no vacuum is formed to draw the water. Not infrequently the pump-valves
expand so much from the heat, that they stick fast away from their
seats. If the pump has stopped through the presence of impurities
on either of the valves or cages, the engineer knows that he may
remove the obstruction by steam-pressure; so, after letting the
feed-pipe fill with water, he opens the heater-cock, and closes
the foot-cock, letting the steam and water blow through the pump.
If he considers the obstruction to be in the strainer, and has
not time to stop and take it down, he blows steam from the heater
through to the tender, which gives temporary relief. If any of
the pump-valves are stuck up, and can not be got back to their
seats by blowing water and steam through them, the engineer will
take a soft hammer, and tap the seats lightly, with good prospects
of remedying the defect. In case no improvement can be effected
in that way, and there is no other feeding-medium to rely upon,
the engineer can take down the top or bottom chamber in a few
minutes to remove any impurities that may be keeping the pump
from working. He will then be likely to find a piece of packing
that has passed through the pump, bushing, or some other foreign
substance, jammed between the cage and the valve, keeping the
latter immovable. Or the trouble may be a broken valve or cage,
which will render the pump useless till repaired.
LIFT OF PUMP-VALVES.
When a pump-valve has much lift, it is very liable to pound itself
or the cage so heavily that breakage occurs. The proper lift required
for pump-valves depends to some extent upon the diameter of the
valves themselves, those of liberal thickness requiring less lift
than a valve of narrow compass. The engine pulling our train has
pump-valves two and one-half inches in diameter: the pump-plunger,
being worked from the cross-head, has a diameter of two inches.
The bottom valve has three-thirty-seconds of an inch of lift,
the middle valve has one-eighth of an inch of lift, and the check-valve
rises one-fourth of an inch. These dimensions produce very satisfactory
results for all speeds. The pump performs its work with remarkable
smoothness, is free from pounding or fluctuating, and gives no
trouble about repairs. Engines employed on fast passenger service
have their valve-lifts one-thirty-second of an inch less than
this one, and slow freight engines are regulated to rise one-sixteenth
of an inch more than the dimensions given.
KEEP PIPES TIGHT, AND PACKING IN ORDER.
In order to insure the regular and satisfactory working
of a pump, care should be taken to prevent leaks about the feed-pipes
or heater-pipes: the packing should be kept in good order, and
the chamber-joints should be perfectly air-tight. During the outward
stroke of the plunger, a vacuum should be produced inside the
pump, into which the water rushes. If this vacuum gets partly
filled with air or vapor, the working of the pump will be unsatisfactory.
Nothing is so liable to produce this undesirable condition as
badly packed glands or leaky joints. A poor pump can often be
made to produce fair work, by attention and care bestowed upon
its attachment; and lack of care will soon render the best constructed
SAND IN THE PUMP-CHAMBERS.
The pump has one arch-enemy, which comes off victor
in every conflict. That is sand. The railway idiom which uses
the word "sand" to express courage, originated in the
knowledge of how certainly and quickly a handful of sand would
vanquish the best pump that mechanical skill might produce. The
grit works its way among the packing, and tears and cuts the plunger
out of shape: it insinuates itself up between the cages and valves,
and holds the latter so fast that hard hammering is often needed
to dissolve the compact. Proper washing out of the tank, cleansing
of feed-pipes, and the use of water free from sand, is the only
sure remedy for this evil. Where an engineer is situated so that
he must take water containing sand in suspension, partial relief
will be obtained by giving the valves free side-room in the cages;
but an injector will be found much superior to a pump as a means
of putting sand-contaminated water into a boiler.
DELIVERY ORIFICE CHOKED WITH LIME SEDIMENT.
When a pump begins to show distress from overpressure,
which will be indicated by the breaking out of joints,
the rejection of stuffing and box-packing, and the bursting of
branch-pipe, the orifice between the check and the boiler
should be examined; for that aperture often becomes almost closed
by the accumulation of lime-salts.
MINOR PUMP TROUBLES.
Where the feed-pipes and other connections are perfectly
air-tight, some pumps will pound badly when the water is shut
off. This can be prevented by making a minute hole in the feed-pipe;
or a more convenient place is the upper part of the heater-pipe,
away above the water-level.
Should the valves of a pump be leaky on their seats, the pump
will not work satisfactorily. Where the lower valve is not properly
ground on the seat, the plunger sucks air from the feed-pipe,
or through the joints or packing, and, at the return stroke, compresses
part of the air in the pump, and forces the remainder back into
the feed-pipe through the leaky valve. This process goes on after
the feed is put on; the accumulated air stands like a cushion
between the plunger and the water; and the pump will not go to
work until the petcock is opened, when the air rushes out, permitting
the water to flow in. Engineers having pumps that will not work
till the pet-cock is opened, should have the suction-valve ground
in; and they will find a decided improvement from the operation.
For slow train service, pumps perform the service of boiler-feeding
fairly well; but, for fast passenger trains, a pump should not
be tolerated. A pump can not be constructed for high-speed engines
that will throw water regularly at high velocity of stroke.
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