August 4, 1916.

THE COLLIERY GUARDIAN.

213

CURRENT SCIENCE

Electrical Charging Wagons for Coke Ovens.

Until recently, coke ovens were universally charged
by hand with small tip wagons or by overhead cable-
ways, requiring a large number of workers, both at the
ovens and at the coal bins. In some more modem
plants the charging is done by means of large electric-
ally-driven wagons, each holding a complete charge of
from 8 to 12 tons, but this system has not in the past
been applied to existing plants, as the ovens themselves
are not generally easily adapted to it. The oven walls
must be strong enough to bear the weight of the loaded
wagon (18 to 25 tons), and the wagons nre so wide that
it is necessary that the condensers for recovering the
tar, etc., should be placed at the side instead of at the
top of the furnace.

Recently, however, this system has been applied with
success to existing coke oven plants, with very little
re-construction of the furnace structure and wagon
track, by adopting small wagons. Details of one such
installation are given in Gliickauf. This installation
comprises a battery of 60 eoke ovens, which are kept
charged by one man instead of the 10 or 12 required oy
the old method. The coal bins are not in a direct line
with the axis of the track over the charging hoppers,
but the small wagons can take curves down to 5 m.
radius. The charging set comprises three wagons of
about three tons capacity each. Each wagon is 4 m.
long by 1’2 m. wide and 1-7 m. high, and is divided
into two parts, with the usual drop bottoms. Between
the two hoppers is the driving motor of 4 kw. capacity,
which, together with the starting and other switchgear,
is enclosed in .a dustproof compartment. Power is taken
from an overhead trolley wire, and the motor is con-
trolled by. a lever. After the three wagons have been
filled under the coal bins, they are sent along in succes-
sion under their own power towards the ovens, the
operator following on the last. When the wagons reach
the coke oven platform their motors are switched off
automatically, and the brakes applied by means of stops
projecting up from the track. These stops are placed
by the operator at the particular oven it is desired to
charge. The wagons are brought into the correct posi-
tion, and emptied by the operator, who then sends them
back on their own power, and returns himself on the
last, after having closed the top of the filled oven, and
moved the stops to the next oven to be filled.

Recording Boiler Performances.

In the Journal of the American 'Society of Mechanical
Engineers, Mr. G. B. Willcox gives particulars of an
instrument for the performance of boilers to be ascer-
tained hour by hour, without the necessity of analysing in
detail the figures of the daily coal and water logs.

The instrument (econograph) may be located in the
manager’s office, and produces a daily chart that shows
by separate lines, but simultaneously, the water rate, the
coal rate, and whether the ratio of water to coal has
fallen below the assumed standard. The chart not only
shows whether the desired degree of economy has been
maintained, but also, in the event of the economy falling
below the desired standard, the time of day when the
drop occurred, and for what length of time the boilers
were run at a degree of economy lower than the assumed
standard. It also assists in locating the cause of falling'
off, that is, it indicates whether the poor economy was
due to decrease in evaporation or to unusual increase in
fuel.

The daily chart consists of four lines or curves coinci-
dent as to time, but independently recorded on the chart
as follows : (1) A line showing the amount of water fed
to the boilers; (2) a line showing the fuel fired; (3) a line
showing the time at which unevaporated water was
withdrawn from the boiler, through the blow-off or other-
wise ; (4) a line showing the time at which the economy
of steam production fell below the assumed standard of
performance which was expected to be maintained, and
the time when the desired standard was regained.

The water line on the chart gives, to scale, the total
. water fed to the boilers at any given hour, in thousands
of pounds. The inclination of this line from the hori-
zontal shows approximately the rate at which water was
being supplied at any .given time, and shows fluctuations
in the rate of water supply. The fuel line shows the total
fuel fired at any given time, and the rate of firing. Thus
the slope of the water and fuel lines indicates at a
glance the probable cause of any change in economy.

The hour at which an apparent change occurs is auto-
matically shown, so that the time of commencement and
the end of a period of inefficient operation on the day
shift, night shift, or at any time, is recorded beyond
dispute. If standard economy or better is being main-
tained, the chart shows it, indicating that there is no
necessity for analysis of the water and coal logs, but if
economy drops, the time at which the drop occurs is
definitely fixed, and an .analysis of the coal and water
logs for that period of time should be made to locate the
fault.

The instrument comprises a clockwork drum carrying
a sheet of paper, on which four pointers draw indepen-
dently the lines above referred to. One of the pointers
i<s connected, through a train of gears and an electrically-
operated tripping mechanism, with a contact switch
connected to a water weigher or to the recording device
of a flow meter that measures the amount of water fed
to the boilers, or it may be connected with the recorder
of a steam-flow meter.

The second pointer is connected through a similar set
of gears and an electric tripping device with a moving
part of the stoker, or with an automatic coal scale, or
with a contact device actuated by the wheelbarrows or
carts delivering coal to the boilers, as the case may be,
or, if gas or oil is used for fuel, the pointer is actuated by
contacts on the indicator of the fuel meter.

AND TECHNOLOGY.

The-third pointer draws a straight horizontal line so
long as the ratio between water and fuel is equal to or
greater than the standard which it is desired to maintain,
but when the ratio of water or coal drops below the
standard this pointer makes a break in the diagram at the
hour when the drop occurred, and the line remains
broken until such time as efficiency again reaches
standard. This broken line gives unmistakable notice
to the plant manager, who can refer to the water .and
fuel lines directly above to ascertain the probable cause,
and he can then make the usual analysis of his boiler-
room water log and coal log covering the time in
question, and can institute proper enquiries in the fire-
room. The third pointer does not draw attention to
economy that is better than standard, because it has
been found impracticable to attempt to record diagram-
matically minute fluctuations in the ratio of coal and
water, and it is sufficient for ordinary purposes to indi-
cate sharply, as by the broken line, only those times
when performance falls below standard.

The fourth pointer is connected by an independent
circuit to the blow-off valve of the boiler, and shows
by a break or jog in its line the hour at which the blow-
off valve is opened, and the length of time it remains
open, to direct attention on the diagram to the time at
which unevaporated water was removed from the
boilers, in order that it may not be inadvertently figured
as having been evaporated.

The instrument is not intended to take the place of
the technical knowledge requisite to maintain high
boiler economy, but it minimises the tedious work of
analysing boiler data, and calls attention to those times
of poor economy which it is profitable for the engineer
in charge to study, referring back to his log data.

Substitutes for Coal in Gas Making : A French Report.

At the. annual meeting of the Societe Technique de
1’Industrie du Gaz en France, the committee on gas
manufacture reported on the possible substitutes for coal
in gasmaking.

Wood.—Wood gas was formerly used in Switzerland
and Bavaria, under the name of Pettenkofer gas.
Wurtz’s dictionary gives interesting details. The wood
was distilled in long iron retorts heated by peat fire; the
charges were 1-cwt. of dry deal wood, which yielded, in
90 minutes, 706 cu. ft. of gas, 20 per cent, of wood
charcoal, and 5 to 7 per cent, of very good tar. The gas
contained about 25 per cent, of carbonic acid, which had
to be removed by lime, about J cwt. per 1,000 cu. ft. of
gas; what was left contained 18*5 per cent, of hydrogen,
62-0 carbonic oxide, 9-5 of methane, and 7*7 per cent, of
other hydrocarbons. The lighting power was, it was
claimed,.at least equal to that of coal gas; but the gas
always had to be burned in burners with wide slits, by
reason of its density.

The researches made in connection with Riche gas
showed that a good engine gas could be made from wood.

Eucalyptus Wood.—In Algeria a good deal of euca-
lyptus wood is used, in conjunction'with 20 per cent, of
coal. The wood used is white eucalyptus, specific
gravity of 0-945 (not the red eucalyptus (specific
gravity 0’585). It is cut into blocks not exceeding 4 in.
in thickness; in two hours these give about 11,650 cu. ft.
per ton of a rather poor gas. The heat applied is
relatively low. The wrood charcoal is hard; but if the
blocks exceed 4 in. in thickness, the distillation has to
be prolonged and the wood charcoal then crumbles away.
The return in wood charcoal is about 24 per cent.
Charging and quenching are effected as rapidly as
possible..

An important works in Russia has, since the outbreak
of war, been using wood (not specified) with an admix-
ture of coal. With 35 per cent, of coal, 64 of wood and
1 of “ mazout ” (petroleum residue) the yield was 31-82
per cent, of gas, 60 of coke, and 15 of wood charcoal;
with 21 per cent, of coal, 78 of wood and 1 of mazout, the
yield was 33-2 per cent, of gas, 60 of coke, and 15 of
wood charcoal. The mixture of coke and wood charcoal
obtained is not very good for heating retorts, but a part
of the wood charcoal can be readily removed. In any
ease, the temperature of distillation'need not be as high
as when coal alone is used. The gas is passed first over
oxide of iron, then over lime. The gas is heavy, so
that higher pressures must be put on and the burners
must be adjusted.

Resinous Woods.—Anjou pine,dried so as to lose 35 per
cent of its weight, distilled for three hours in 2-6-cwt.
charges in 20 ft. retorts, gives a gas which does not
appear to affect the quality of ordinary coal gas to which
it is added. Landes pine (ordinarily tapped for resin)
gives about 25 per cent, of its weight in gas; distillation 3
hours, retorts 10 ft.; gas rather poor; wood charcoal 25
per cent., whereof one-third fell to dust.

Resinous Residues.—Obtained when pine trees are
tapped for resin and the resin obtained is strained
through a filter. The distillation is very rapid, and leaves
practically no carbon or ash. 35 per cent, of the material
appears in the form of gas of very high illuminating
power. Unfortunately, the price of this material is very
high (.£6 8s. per ton), and the quantity.available is very
small.

Olive Oil Residues.—These have been tried in various
works in the South of France. They consist of the
squeezed pulp of the fruit, with or without the stones.
The pulp without stones gives, in two hours, in charges
of 1’6 cwt. per 10-foot retort at a clear cherry red heat,
41 per cent, of gas and 28 per cent, of charcoal powder,
which with tar makes good briquettes for firing retorts.
The gas has a high illuminating power (73’5 Litres for one
carcel). With the stones the distillation takes longer,
four hours instead of two, and the yield of gas is 33-3
per cent, (average 107-6, minimum 94 litres per carcel),
with 24 per cent, of charcoal powder.

The committee concludes that there is not at present
any real substitute for coal. The use of wood, etc., may
be serviceable locally, and for a time, but if it became
general, prices would go up and supplies would fail.
Wood distilled alone produces an acid gas (chiefly acetic
acid) which corrodes the ironwork. The addition of coal
to the wood produces ammonia, which neutralitses the
acids formed, so that there is no trouble occasioned by
any corrosion.

The density of wood gas being high, the addition of
wood gas to coal gas would necessitate an adjustment of
the burners.—Gas World.

THE GERMAN COAL AND IRON
TRADES.

We give below further extracts from German
periodicals that have reached us, showing the course of
the coal and iron trades in Germany :—

Coal Syndicate Report for June.

Total coal raised, 7,347,464 tons (8,435,478 tons in
May), or 328,378 tons per working day. Calculated dis-
tribution, 5,652,811 tons (6,700,816 tons), or 261,578 tons
(248,178 tons) per working day, being 72-36 per cent.
(68’66 per cent.) of the participation. Total coal distri-
bution, 7,589,623 tons (8,548,787 tons), or 339,201 tons
(316,622 tons) per working day. Deliveries, including
local sales, miners’ house coal, and supplies to pits’ own
iron works: Coal, 3,884,853 tons (4,700,648 tons), or
173,625 tons (174,098 tons) per working day; coke,
2,249,839 tons (2,276,700 tons), or 74,995 tons (73,442
tons) per working day; briquettes, 294,357 tons (350,568
tons), or 13,156 tons (12,984 tons) per working day.

Steel Union Deliveries in June.

The total deliveries, in weight of raw steel, during
June amounted to 298,752 tons (311,620 tons in May),
of which 77,483 tons (80,765 tons) were semi-manufac-
tured products, 134,584 tons (142,347 tons) railway
material, and 86,686 tons (88,528 tons) sections.

Coal Syndicate Renewal.

The Prussian Minister of Commerce has issued a
Decree, under the Law of July 12, 1915, notifying the
coal owners in (1) the Dortmund district, except the
Ibbenburen Colliery and the State Colliery at Klus; (2)
the Crefeld (Bonn) district; that they must form asso-
ciations, in accordance with the said Law, by October 15.
If this is not done, the Government will establish com-
pulsory syndicates. The present voluntary arrangement
in Westphalia is due to expire on December 31, so that,
by fixing October 15, the Minister apparently wishes to
gain time for arranging the compulsory syndicate should
the voluntary negotiations fail.

Rhine Traffic.

At the end of July the traffic difficulties produced by
the recent flood water had not been entirely overcome,
though the position was improving. Increased consign-
ments of coal were coming forward to the Ruhr har-
bours, and larger shipments were being made both up
and down the river, there being a sufficiency of craft
and little delay in loading. Whilst the river was deep
enough to allow full loading, towage was still difficult
owing to the strong current, so that supplies to the
Upper Rhine were being delayed. Most of the up-river
shipments of late have passed direct into consumption,
leaving very little for stock.

TRADE AND THE WAR.

Messrs. A. A. Embiricos and Company, steamship owners,
have removed from 14, St. Mary Axe‘, to more commodious
premises at 6, Grosby-square, London, E.C.

The Board of Trade is winding up the Glasgow Metal
Company Limited, dealers in tin scrap, Victoria Works,
Coatbridge.

Over 250 firms connected with engineering in different
parts of Scotland have accepted the invitation of the Lord
Provost of Glasgow to the conference to-day (Friday).
Many of the leading men connected with the engineering
industry have signified their intention of being present.

The railway and steamboat companies have increased their
artes on goods traffic between Dublin and any station in
England. The increase on iron and steel to or from Dublin
is 5d. per ton, at rates including cartage in England only, or
in Dublin only. The increase on all other goods traffic is 5d.
per ton at station-to-station rates, and Is. 3d. per ton at rates
including cartage. In the case of interior Irish stations
(to or from) the increase is 5d. per ton on all goods traffic at
station-to-station rates, and lid. per ton on all goods traffic
at rates including collection or delivery.

Two Monmouthshire collieries have been idle since Tuesday
owing to disputes.

The shortage of tonnage for American coastwise business
becomes more acute as the season advances. Coal men are
convinced that radical advances are likely to occur.

The East, of Scotland Association of Engineers passed a
resolution expressing the opinion that all engineering firms
in England and Scotland should unite under a strong central
organisation for the purpose of dealing with questions which
will arise in the near future.

According to reports made by mining engineers, there exists
at Maissade. Arrondissement of Hinche, on the line of the
National Railway of Hayti, an extensive deposit of lignite of
good quality. Another lignite deposit exists in the Arron-
dissement of Mirebalais, Department of the West. The loca-
tion has been visited by foreign engineers, who have reported
favourably on the. deposit and the quality of the coal. The
Board of Trade Journal states that at Camp Perrin, in the
southern district, 2£ miles from the city of Aux Caves on a
level road, there is a deposit of two or three layers of good
lignite. Seven tons of surface coal were given for trial to
one of the steamers of the Hamburg-American Line, and it
was found that the coal burned very well, but left much
residue.