Excerpt –
Pages 110 – 116
FRANKLIN INSTITUTE.
___________________
Use of Anthracite
Coal in Locomotives.
At
the monthly meeting of the Franklin Institute, held June 17th, 1847, the
following remarks on the use of Anthracite in Locomotives, were made by Professor
W. R. Johnson.
Since
the attainment of so complete a success, in using anthracite under the boilers
of stationary engines, and on board of all our principal river and sound steam
vessels, on the Atlantic coast, it has become a subject of much inquiry, to determine
why so little success has attended the efforts to introduce it into general use
upon railroads. Various trials, on the Columbia Road, and others on the Reading
Road, have, it is understood, been attended with so little promise of
advantage, as to cause, at present, the abandonment of that fuel, and an
adherence to wood, as the only available material. The cost of wood, alone, to
the Reading Railroad, during the last year, is put down, in the late annual
report, at $202,061, and, as the total quantity of coal brought to market, over
the road, was 1,188,258 gross tons, we have., after deducting the wood required
for passenger and freight trains, an expense of $191,569, for the wood required
to haul that quantity of coal 94 miles, and to take back the empty cars. It is
true, that the whole of this coal did not reach tide-water, but the computation
is based upon the fact, stated in the report of the Company, that the cost of
wood, Òper round trip of 188 miles," to haul 360 tons of coal, the above
distance, and Òback with empty cars," was 14.92 cords, costing $58.04. It
is estimated, by the President of the Railroad Company, that the introduction
of anthracite, instead of wood, would save the company $125,000 per annum.
Should it save half this sum, it is evident that great outlays, to effect the
purpose, would be warranted, and, consequently, the efforts heretofore made
would be fully justified. Mr. Nichols, the engineer, and general superintendent
of the Reading Road, has been, for some time, engaged in an effort to
accomplish this object, by placing the engine and boiler on separate carriages,
with a view to an enlargement of the fire surface of the latter. Mr. N. has, in
fact, used an ordinary locomotive, to which he has attached, on a separate
truck, a boiler, 16 feet long, and 4-1/2 feet wide, with a semi-cylindrical
arch running the whole length. This is connected, by jointed pipes, with the
engine. The blast is created by a fan, driven by a small engine. The escape
steam is thrown into what was the original boiler of the locomotive engine,
which is still retained, for the double purpose of serving as a condenser, and
of making weight on the driving wheels. If this plan of condensation shall be
found available, much time will be saved which is now consumed at water
stations, as a large portion of the water will be constantly circulating.
So
important to the Reading Railroad, has this item of expenditure of fuel become,
that, during the past year efforts have been made by the company to manufacture
an artificial fuel, with a basis of anthracite, as a substitute for wood. In
this, they are understood to have so far succeeded, as to have made some trips
with it. But still the desideratum is the use of anthracite alone.
Having
several times, within seven or eight years, witnessed the exclusive use of
anthracite, in all the locomotives on the Beaver Meadow, and Hazleton
Railroads, making round trips of thirty or forty miles, I have felt much
interest in tracing the causes of ill success elsewhere.
From
all the inquiries which I have been able to make, the following appear to be
regarded as the chief impediments to the use of anthracite in locomotives.
1.
The want of rapid ignition, and free, lively combustion.
2.
The intense, concentrated, local heat, which is said to destroy the grate bars,
to attack the rivets and laps of the fire box, and even to cause blisters to
rise in the plates of which it is composed; and, finally, to fuse the ashes
into a troublesome clinker.
3.
The sharp, angular particles of coal, projected by the violent, fitful blast of
the escape-steam, obliquely into the ends of copper tubes, cuts them away
within a few inches of the fire end. In the upper range of tubes, it is the
upper side which is chiefly attacked, and, as might be anticipated, in the
lower ranges, the lower sides are most worn away. The effect of this cutting is
usually limited to four or six inches or the length of the tubes.
4.
The difficulty of fitting in iron tubes, so as to make perfect joints, and, at
the same time, avoid irregularity in the form of the heads, and loosening one
tube while another is fastened.
As
the first of the above difficulties, the want of proper activity in the fire,
has been completely overcome in our steamboats., by the use of a steady fan
blast, it seems that an equivalent blast in the locomotive ought to produce the
same effect. The irregular, fitful current, generated by the waste steam, is
not in all respects an equivalent to the blast of a fan, but when that blast is
equalized, by projecting the escape steam, first into a receptacle of
considerable magnitude, and then through a number of small pipes, equally
distributed over the area of the chimney, the blast is so nearly equable, as to
answer completely the purpose of sustaining the fire in brisk and uniform
activity. This method of disposing of the escaping steam, originally invented
by Mr. Gurney, and applied in common road engines, to prevent the frightening
of horses, by the sudden, violent belching sound, was first introduced here by
Mr. Hopkins (sic) Thomas, now of Beaver Meadow, while a workman in the employ
of Messrs. Eastwick & Harrison. His object was a steady blast, not the mere
avoidance of disagreeable noise.
The
steam box used to equalize the draught, is cylindrical, 12 inches in diameter,
and11 inches deep; two tubes, each three inches in diameter, flanched at the
opposite ends to the steam chests of the two cylinders of the locomotive,
support the box in the interior of the dust chamber, and convey the escape
steam to its centre. A lid, ground to fit the top of the steam box, has 18 jet
pipes, rising two or three inches from its upper surface, drawn in at the top
to a diameter of half an inch. These are placed just beneath the base of the
chimney, and their purpose is to distribute the escaping steam throughout the
chimney, and, by limiting, to some extent, the rapidity of flow, to maintain
within the box a pressure approaching to uniformity.
Messrs.
Eastwick & Harrison founded, on a division of the receptacle into two
parts, a patent, which they applied in some engines built by themselves. But as
this evidently tended to make the action of the steam upon the air of the
chimney, in a degree partial and fitful again, the Beaver Meadow and Hazleton
Companies discarded this modification of GurneyÕs plan, and in all their
engines, which have constantly used anthracite for the last eight or nine
years, the draught is ample, the combustion regular, and the evaporation
vigorous and well sustained. The fire is, of course, kindled with wood, and
when this is well ignited, anthracite is added by little at a time, usually not
more than a single shovel full, and in lumps., commonly not above six inches in
diameter. If larger than this, they would remain too long in mass, dark and
ineffectual; if small egg or nut coal alone were used, it would, it is alleged,
by the jarring of the locomotive, spread over the whole fire at once, and check
the evaporation. While under way, the bed of coal upon the grate is kept at a
thickness of five, or at most, six inches. When fresh coal is added, care is
taken, that a single shovel full only is put on at once, and that this is
thrown on the part which appears thinnest. Much experience in watching the
indications of a manometre, while generating steam by anthracite, enables me
fully to appreciate the importance of these practical precautions. In some of
the attempts to use anthracite on the Reading Railroad, a bed of I18 inches
thick is said to have been allowed to accumulate on the grate. In such cases,
the whole engine is said to have become excessively overheated, and a flame to
have passed out at the chimney. This is easily understood, when we consider
that, in passing through so thick a mass of hot coal, the carbonic acid at
first formed, (CO2) by taking up a second proportional of carbon,
becomes CO + CO, or two proportionals of carbonic oxide. The atmospheric air to
ignite this compound, gains admittance partly through the chinks of the fire
door, and the dust box door, and is partly found near the chimney top, where the
intermitting blast through a single jet pipe, keeps the chimney alternately
receiving and emitting air.
The
second evil, that resulting from the highly concentrated heat, has been found
much more serious than the preceding. Grate bars were burned out in a few
weeks. Capt. A. H. Vancleve, who had charge of the Beaver Meadow Road, states
that, at one period, wrought iron bars were substituted for cast, but that it
required two smiths' fires to be in constant employ, to make grate bars for
four locomotive engines. The secret of preventing this occurrence, was stated
by a gentleman at Hazleton, to have been discovered by accident. A boulder, which
had rolled from a slope upon the track of the railroad, tore off the ash box of
the first engine which passed. As the damage did not interfere with the running
of the engine, and as it was not convenient, for some days, to return to the
machine shop, it was permitted to continue its trips for some days, without an
ash box. The over-heating and wasting of grate bars were so manifestly obviated
during the time, as to attract immediate attention. Ash boxes were successively
removed from other engines, and, from the adoption of this alteration to the
present time, the destruction of grate bars has ceased to be a source of
serious inconvenience. A set in the locomotive Franklin, were put in in June,
1846, and were in use, and in good order, at the end of May, 1847.
It
might be supposed that the wooden superstructure of the road, and particularly
that of bridges, would be endangered by the constant falling of sparks. In the
main, it maybe said, that this evil at length cures itself, for both road and
bridges, except the rails, become covered with a stratum of cinder, and fine
particles of coal, which effectually defends all beneath from danger of
igniting by particles of hot matter from the grate. Unlike particles of ignited
charcoal, these are, from their very weight, not liable to be easily raised and
blown about, by the currents of air created by the cars, which pass over them
after they reach the road. Hence the only precaution which has been found
necessary, is to place two sheets of iron, one on each side of the bottom of
the fire box, extending downwards about nine inches, and sloping inwards, to
confine the falling cinders to the central part of the track. At first a watch
was established at the bridges, but when the roadway became covered with
cinder, there was found to be very little danger from this source. The Hazleton
and Beaver Meadow Roads have wooden rails, laid with flat iron bars; where edge
or T rails are used, the danger would be manifestly less than in the case of
these roads, which have so long used anthracite without detriment.
The
concentrated heat of anthracite fires, generally affects injuriously only the
laps and rivets of the fire box, unless the iron of that part of the boiler be
of inferior quality. Hence the importance of selecting the very best of iron
for the fire box, and the probable utility, as suggested by Capt. Vancleve, of
subjecting it to a high temperature before using any plate for this purpose, in
order to detect blisters of imperfect welding, if such exist in the interior.
The number of pieces used in the lower part of a fire box, ought to be the
least possible, and the horizontal laps ought not to have their edges presented
downwards to the action of the rising flame. I see no practical difficulty in
the way of rolling sheets 18 inches wide, long enough to form the. entire
circuit of the lower part of afire box. Above that height there would be no
danger from this peculiar action of the fire. Nor do I know of any serious
objection to welding together the ends of such a sheet, especially if made
three-eighths of an inch, or more, in thickness, and thus forming a band in
which not a single joint or rivet should come in contact with the fire. All
other parts of the boiler would still be made in the ordinary manner.
The
locomotive Lehigh commenced running on the Hazleton Road in 1838. In 1844 it
was found necessary to renew a space of about 18 inches, in the lower part of
the fire box, and this is the only repair which that part has undergone since
the engine was put upon the road. I examined it in the latter part of May,
1847, and found the iron, to all appearance, sound and good, with no leaks at
the rivets, or elsewhere. Three or four of the upper rows of tubes in this
engine, have been in use since 1839, and the rest were renewed about two years
ago.
To
avoid the conversion of ashes into clinker, those anthracites should be
selected, which are free from slaty plies, and which contain the least of
sulphuret of iron, or other fusible impurities. Should any inconvenience be
found from clinker on a prolonged trip, it could easily be removed at a
watering station, by means of a forked fire hook, adapted to that peculiar
service. A small supply of wood may be carried, for re-kindling, in case of
unusual delays. But the experienced fireman will always be careful to clear
coal and clinker from his grate, before he attempts a renewal with wood.* Grates
may be hinged, with a view to the prompt discharge of their contents, and, with
that facility, the rekindling with wood may. take place even without stopping
the engine, especially if advantage be taken of a favorable grade of the road.
*This,
and the succeeding precaution, are suggested by Capt. Vancleve.
The
third point of difficulty, that resulting from the cutting away of copper
tubes, is fully obviated by the substitution of iron, with the farther
advantage of economy in the first cost. But this brings us to the fourth and
last difficulty-that of securing iron tubes to the heads of the boiler.
This
has been attempted in several different ways. One consists in cutting a screw
at each end of the tube, to enter corresponding threads cut in the heads of the
boiler, and then riveting over the projecting edges of the tubes. That on which
Mr. Baldwin has founded a patent, consists in brazing a short piece of copper
tube to each end of the iron one, and then connecting the former with the head
of the boiler, in the same manner as he puts in copper tubes. But that which
seems the most simple, and which is quite effectual, as proved at Beaver Meadow
and Hazleton, for a course of years, is the turning off of the iron tubes, on
the outside, at each end, in the form of the frustrum, of a cone, to the
distance of seven-tenths or an inch, by which the thickness of the tube at the
extremity is reduced about one-half. This conical part receives a ring of
copper, cylindrical within, conical without, and about half an inch wide,
Which, after the iron tube has been inserted in its place, is driven on to its
conical termination, filling the space between it and the edge of the aperture
in the head of the boiler. This copper ring, by its wedging effect, tightens
the iron tube, forms a close joint, and allows the edge of the iron tube to be
slightly opened out, and riveted, to form a very perfect juncture. The language
used in describing the result of this mode of fitting in the tubes, was, that
the Òjoints never leaked a drop." In rare instances, the welding of a
tube, (made by the same process as gas tubes is found slightly defective, but
this does not long put a stop to the use of the engine, for a very little labor
suffices to tap a screw in each end, and plug up a single defective tube, till
a convenient opportunity occurs for its removal. To clear dust of anthracite
from the tubes, a species of screw anger, with a sharp edge, like that of a chisel,
is occasionally employed.
The
quantity of anthracite commonly used in a round trip of 30 miles, on the
Hazleton Road, is from a ton to a ton and a half, hauling 35 to 40 cars, and
conveying from 100 to 120 tons of coal. The grades on this road are heavy, - 60,
80, and 140 feet per mile,- all in
the direction of the trade. The severest labor is, consequently, encountered,
in taking back the empty trains. In two experiments, conducted by Capt.
Vancleve, over the Beaver Meadow Road, reducing its grades by Pambour's
formula. to the condition of a level, he found that the seven ton engine
required 1-1/2 pounds of anthracite per ton, per mile of freight and cars
hauled, and the 13 ton engine took but one pound, for the same labor. The small
engine was subject to slipping of its wheels, on the high grades, which, of
course, impaired the efficiency of its fuel.
Those
who are most familiar with this subject, attribute to the early, persevering,
and well directed efforts of the Hon. Samuel D. Ingham, formerly President of
the Beaver Meadow Railroad Company, much of the credit of urging on to final
success, the experiments which have proved so important to the interests of
that coal region.
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