Home  

CHAPTER X.

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 BETWEEN STATIONS.
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 pump unreliable.

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.


Contents Page | Table of Contents

Home
Do you have any information you'd like to share on this subject? Please email me!
The Catskill Archive website and all contents, unless otherwise specified,
are 1996-2010 Timothy J. Mallery