October 2, 1914.

THE COLLIERY GUARDIAN.

731

To the lower part of the receivers are connected
three different feeding pipes g, glt g2. Each
feeding pipe has a main valve h, hx, h2 at the
inlet of the receiver. The two pipes g, gx are used for
taking the coal ont of the wagons, whilst the second
pipe g2 is used for taking the coal from the storage over
a total distance of 200 yards. The two pipes g, g} can
be raised or lowered by means of a mechanical winch.
They are generally composed of rigid portions of piping
flanged together, and flexible segments are inserted
wherever this is required for the convenient moving
of the pipe. The terminal ends of the pipes g,g^g2
consist of a flexible portion k, kx,k2 and of a suction
nozzle with suitable openings. The working of
the plant is as follows :—The double-cylinder air pump,
which runs at about 120 revolutions per minute, is
started up and forms a vacuum of about 10 in. When
this is reached, either of the valves h, h2 is opened,
but no more than one at a time. For instance, if it is
desired to take the coal from the storage ground, the
valves h, are kept closed and the valve h2 is opened.
After this the nozzle i2 is brought into the coal, the
movement of this nozzle being quite free, thanks to the
flexibility of the tubing k2. As a fact, this may be
executed by a single workman. The action of the air
pump is such that it forces the air through the filters
e, c, into the receiver b, and the mixture of small coal
and air will enter the nozzle i2 and travel along the
flexible piping k2, then through the piping g2 into the
receiver b. As soon as it enters the receiver, the coal
will fall by its own weight into the lower conical part of
same, and from here it will be transported by means of
the automatic airtight discharging arrangement I on to
an automatic balance m, where it is weighed and then
brought into the receiving bunker n, from which the
coal travels by means of the chutes o to the belt
conveyors p,pv The dust in suspension travels with
the air through the piping e, e} into the filters c, where
the dust is collected, and the remaining air, free from
dust, travels through the pipes/,/] on the pump d, and is
then led, through the exhaust, into the free atmosphere.
The dust collected into the filters escapes through an
automatic airtight arrangement similar to the one
described and marked ZP It then passes on to an
automatic balance and falls into the receiving
bunker n, where it is mixed with the coal. The
conveyors p,px transport the coal to the boiler bunkers
for feeding in the ordinary way. In case it is necessary
to take the coal from the wagons, the pipings g gx are
lowered into the trucks, and the plant works just as
described above with suitable opening and closing
valves. As the figure clearly shows, it is possible to
connect the flexible coupling to any part of the piping,
and, by means of this, suction pipes can be added at
almost any place. It is needless to remark that in order
to form the vacuum wanted, all pipes except the one
working have to be kept tightly closed, and in order to
do this, besides the valves of the receiver, whose action
has already been explained, a special airtight cover has
been arranged by the makers which is very easily and
very effectively worked, and perfectly closes all branches
which are not working.

Fig. 3 shows a plant which has been in operation over
six. months at an important paper-mill in Germany.
This plant is intended for feeding the boilers, the works
being one of the largest of its kind in Germany, and
having 15 boilers, which are now fitted with this
automatic stoking arrangement. This plant was built
for the purpose of bringing the coal direct from the
boats or barges into the factory without using railway
wagons, the whole distance being 160 yds. and the
maximum height about 110 ft. Taking into considera-
tion the particular position of the paper mills, which are
situated near to the River Elbe, it was necessary to use
a plant which could be easily removed in case of
flooding. The River Elbe generally floods in spring,
and, when indications of same appear, the part of the
plant within the danger zone, which, as wHll be seen
from the sketch, consists only of a pipe carried by a
rope hanging to supports, can be easily dismantled and
put in a safe place during the time the floods last. This
operation has been completely carried out in 12 hours.

It will be noted from the drawing that the boilers are
on one side of the building, whilst the river runs on the
other; and, therefore, the whole width of the factory
must be crossed in order to reach the fire-place.

In order to be prepared for floods, strikes or other
abnormal conditions which could temporarily suspend
the unloading of coal from the barges, the company has
also provided a large storage bunker O as well as the
coal stored on the ground, The pneumatic plant is
built in such a way that coal can also be taken from the
bunker or any of the ships by a suitable action of the
necessary piping.

The working of the plant is quite similar to that
already explained. The nozzle / together with the
flexible tubing, is brought into the hatch of the boat,
and, by means of the vacuum formed by the pump L,
the coal travels along the piping B until it reaches the
receiver C. where it is discharged in a, similar way to
that explained before. In other words, from the lower
conical part of the receiver the coal falls through the
automatic rotary outlet on to a distributing belt E
leading to the bunker F, where the coal is scattered.
The bunker F opens on to a conveyor G. which feeds
the different boiler hopper chutes. The return way of
the air is through the piping M. By means of the
pipes Bb B2, B3, the coal can be taken either from the
truck I or from the bunker O or different coal depots in
exactlv the same way.

In this special installation no filter is in operation in
connection with the receiver, as a special dry lubricating
pump has been introduced. Also the inside of the
receiver C is fitted with a patent cyclone device, and
there are two dust collectors D and N fitted into the
system, thus reducing to a minimum the quantity of
dust in suspension in the air when same reaches the

pump. As a matter of fact, practically no dust passes
out through the exhaust, and no loss of any importance
has been indicated. The pump in question produces
about 2,400 cu. ft. of air per minute, running at a speed
of about 150 revolutions per minute, and works under a
vacuum of 10 in. mercury gauge.

The capacity of this plant, if the coal is taken from
1 arges over a distance of 160 yds. and a height of 110 ft.,
is 25 tons per hour. If the coal is taken from the trucks
or from the stoiage bunker, the capacity varies according
to the distance, between 40 and 45 tons per hour.

The different sizes of the pipes all along the course
aie indicated on the drawing. The portion between the
suction nozzle and the receiver is carried by means of a
rope, which rests on suitable supports, the nearest
portion of same resting on the roof of the paper mill.

The power required for driving this plant is 65-horse
power, and the attendance required is one or two men
at the suction nozzle and one man to look after the
pump and mechanical parts. The saving of labour for
loading and unloading, also for traffic and shunting, is
therefore enormous, and it is calculated that this plant
will completely pay for itself in two years.

Another plant has been working at Aussig, near
Dresden, for four years in connection with an automatic-
stoking arrangement for a large brewery. The material
transported is brown coal of a very soft nature, and the
moisture reaches 6 per cent. It was really astonishing
to witness how this coal travelled on to the nozzle, and
the writer saw pieces of nut coal about 2 in. diameter
between the small going through the pipe. This was
one of the first pneumatic transporting plants built,
and, as mentioned, it has been in operation for four
years. Its capacity is 8 tons per hour, and it delivers
the coal over a maximum distance of 100 yards and a
height of about 70 ft. The power required is about
18-horse power.

The description and remarks above expressed have
fully shown the advantages that this system of
transporting presents. As in any other plant, however,
there are limits to its convenient use and conditions
under which its efficiency appears at the best. According
to the opinion of the writer, its usefulness appears best
when tne transport has to be effected over a distance of
from 100 to 30o yards. In other words, it proves useful
whenever the distance is too long for the installation of
an ordinary transporter and elevators, and too short to
pay for the loading and unloading of railway trucks.
Besides, it is of great advantage when, within a
comparatively short distance, a great height has to be
overcome, as is the case when same has to pass over a
building or small hill. It is exceedingly useful where
the transporting is only required occasionally, such as
in the taking of small coal from barges or boats, as,
the labour reduced to a minimum, there is not the
inconvenience of keeping a gang of men continually
coming and going. The two principal limits which are
fixed to its action depend on the size of the coal and its
moisture. As to the size, this may be practically fixed
to a maximum of 2 in., and, therefore, the coal which is
sold in Wales under the name of small coal, and the
size of which is under Ijin., provides a very suitable
material for pneumatic transport. Also the peas and
nuts and duff coal may offer a suitable application. The
moisture should not exceed 6 per cent.

There is perhaps one field where this apparatus has
not yet been introduced, and same is of great local
importance. This is the coal field, where this plant
could be used for lifting the small coal from the bottom
of the pit to the surface, or for collecting same at a
central station underground. Of course, the whole
ventilation of the pit would have to be regulated so- as
to allow for the great suction caused by this apparatus,
but, on the other hand, there would be the advantage
of a speedy suction and elimination of the dust, on
which point it would be superfluous to speak.

EXPLOSION FROM A STEAM-PIPE JOINT AT
THE CELYNEN COLLIERY.

A report has been published of a preliminary enquiry
conducted by the Board of Trade respecting an explosion
which occurred at about 2 a.m. on May 9, 1914, at the
Celynen Colliery North, Newbridge. Monmouthshire,
owned by the Newport Abercarn Black Vein Steam
Coal Company Limited.

The joint which failed was situated on a steam pipe,
3 in. diameter, and about 23 ft. in length. This pipe
formed part of a steam-pipe range wl ich extended irom
the main range on the surface to the pumps situated in
the shaft, a total distance, to where the explosion
occurred, of about 450 ft. (see fig. 1). The flanges, which
were screwed on to the pipes, were made of wrought
iron and were 7A in. external diam., and I in. in thick-
ness, being secured together by means of four bolts
£in. in diam., the diam. of the pitch circle being 6|in.
The jointing material was an asbestos ring 5 in. external
diam., 3 in. internil diam., and I in. in thickness.

The pit shaft in which this explosion occurred is
in the process of construction, and to cope with
the accumulating water temporary pumps have been
installed in lodge or pump rooms, excavated in the
sides of the pit shaft, at various depths. When installed
these pumps were worked by means of compressed air,
but in August 1913 the air-compressor on the surface
failed, and steam at 160 lb. per square inch was
substituted as the motive power, the existing pipes
being utilised for this purpose, with the exception of
new branch pipes. 3in. diameter, connecting the pumps
to the main s’eam range in the pit shaft (see fig. 1).
The pump room, at the entrance of which the explosion
occurred, is known as No. 8. and is about 219 ft. from
the surface. It is a chamber about 20 ft. in length by
12 ft. in width by 9 ft. in height, and the only means of
ingress and egress was by a bucket raised or lowered in
the shaft by the winding engine on the surface.

The joint which failed was re-made on Sunday, May 3

last, by J. H. Hobbs, one of the pump-men, assisted by
J. C. Walker, second sinker. They removed two of the
bolts and slacked the other two, and then inserted the
asbestos ring. The nuts on the four bolts were then
tightened up, care being taken—so the men thought—
to tighten the nuts equally. The final pressure was
then put on the nuts by two spanners, one working on
the jaw of the other so as to obtain more leverage.
Steam was then admitted into the pipes, and W. II.
Winters, foreman sinker, went around the nuts again
and hardened them up. The joint, in conjunction with
the other gear in the pit shaft, was subsequently
examined daily by him, and found to be tight.

On Saturday, May 9, at about 2 a.m., a noise of
escaping steam was heard in the pit shaft; steam was,
therefore, shut off the pipes, but the interval from the
first alarm was about 10 minutes. The steam pressure
at the time is stated to have been 1401b. per square inch.
The safety valves on the boilers supplying steam to the
pumps were loaded to a pressure of 160 lb. per square
inch. An examination of the pipe range in the pit shaft
was then made, and it was found that the joint in the
steam-pipe range leading to No. 8 pump-ioom, which
had been re-made on May 3, had again failed, a piece of
the jointing material, about 1 in. by T%in., having been
forced out from between the flanges. The opening

'To Mam Steam Range
about 230f'

Surface

Stop Va/ve .
used to shut offW^'

Bottom



219 f? from Surface

Pit | Shaft

Fig. 1

3 Branch
to pump

Fig .2.

faced into No. 8 pump-room, and the escape of steam
into that space unfortunately caused the death of
W. Tedstone, pump-man, whose body was subsequently
found at the back of the water tank. The joint had not
been properly made, insomuch that the joint ring had
not been equally compressed (see fig. 2). The com-
pression on the thick portion being insufficient to pre-
vent a part of the ring being forced out by the pressure
of steam when the ring had become softened by
moisture, which the insufficient compression would allow.

The explosion was not of a violent character. Since
the explosion a baffle plate has been fixed near this joint
so that, in the event of the joint again failing, the
escaping steam will be projected into the pit shaft. As
a further precaution against failure of this kind, the
pipe flanges in the pump-room are fitted with band clips
to prevent the jointing material being forced out.