December 15, 1916.

THE COLLIERY GUARDIAN

1161

any of them to> be raised in the event of irregular settling
of the ground or foundation. The horizontal forces set
up by the pull of the rope and by the machinery are
taken up by ties in the engine and guide-pulley plat-
forms.

The pitbank is 9 m. above ground level, and projects
beyond the tower on two sides, so as to provide room for
the automatic circulation of the tubs. The full tubs
run down by gravity to the tipples, and the empties
pass thence to the automatic hoists, which raise them
to such a height that they can run down to the pit mouth
again. At about 36 m. from the ground, the sectional
dimensions of the tower are increased to 18 m. by
13-5 m. for the engine room.

Inside the engine room is mounted a 15-ton travelling
crane for handling the machinery; and below the engine
platform is a section stage (29 m. above ground level)
for the guide pulley. A wrought iron stair and a J-ton
electric hoist are provided as far as the engine platform.
Stiffening rings at intervals inside the tower are utilised
as footways for cleaning the windows, and an external
balcony on the level of the engine platform affords access
to the outside for repairs and cleaning.

The iron framework of the tower is faced with brick-
work, whilst the two internal platforms are of ferro-
concrete, and the roof is of ferro-pumice, covered with a
double layer of tarred felt.

The tower was constructed to stand the working pres-
sure of 24,050 kilogs., a breaking strain load of 22,600
kilogs. in both ropes, a wind pressure 'of 125 kilogs. per
sq. m. of tower surface, and the forces set up by the
engine reducing gear at different crank positions, in both
forward and reversed running.

The Winding Engine.

The double-cylinder engine has a cylinder diameter of
700 mm., stroke 1,000 mm., and drives a Koepe pulley
6 m. in diameter, the speed being reduced in the ratio
2*35 : 1. The maximum running speed of the engine is

Fig. 2.—Plan of Winding Engine.

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120 revolutions per minute; steam pressure, 10 to 11
atmospheres; temperature, 275 degs. Cent. A plan of
the engine is given in fig. 2.

The valve gear is operated by cams in preference to
slide valves, and is controlled by steam reversing gear
from a handle at the driver’s stand.

Great care was necessary to reduce to a minimum the
effects of the periodic swinging forces produced by the
reciprocating masses of the engine, so as to counteract
the swinging of the tower itself, especially in view of the
fact that, at some point during the acceleration, these
two movements would be certain to coincide. Actual
measurements taken with the engine running have
shown that, at a rope velocity up to 7|m. per second,
the tower remains steady, and though movement of the
tower set in between 7-J- and 8| m. per second, this dis-
appeared on the speed being still further increased, so
that, even .at maximum speed, the tower remains prac-
tically uninfluenced. External measurements taken on
the level of the engine platform have shown deviations
up to 5J mm. in the direction of the plane of the rope,
and up to about 4| mm. at right angles thereto. At
speeds exceeding 8 m. per second, however, the move-
ments diminished considerably, and practically dis-
appeared at a speed of 16 m., although the forces are
then almost four times as great as they are at 8 m. It
is therefore evident that the decisive factor is not the
dimensions of the forces themselves, but their periodi-
city; and after the carrying out of certain alterations in
the compensation of the reciprocating masses, the move-
ments of the tower have been completely suppressed,
whatever the speed of the engine.

The moving parts, pistons, piston nods, cross heads,
and connecting rods, are all of best material, and as
light as compatible with the strains they have to stand.
Power is transmitted from the crank shaft to the wind-
ing pulley by helicoidal gear, of open hearth steel with

milled teeth, which gear runs in an enclosed bath of oil
and fat, a special pump supplying the oil to the gear
teeth at the point of mutual contact.

The winding pulley has a diameter of 6 m., measured
at the rope centre, and is made of wrought iron with a
cast iron hub. The weight is as low as is consistent
with the strains set up by the rope and brakes, it being
unnecessary to give this pulley the weight it would
need to have, in order to act as a flywheel, in the case
of direct coupling. Since the arc of the pulley
embraced by the rope is one of about 230 degs., as com-
pared with the usual 180degs., the degree of security
against slip is increased by about 39 per cent. The
pulley shaft, which also carries the large gear wheel, is
very strong, and is carried by two bearings, which, like
the main frame of the engine, are supported direct on
the large girders of the tower framework. This method
of mounting renders the engine and pulley independent
of each other, to some extent, in relative position; but
the accurate engagement of the gear teeth can be
adjusted, vertically, by means of wedges under the
bearings.

In other respects, the engine combines the maximum
of reliability and economy, and is operated in an
extremely simple manner. The driver moves the lever
into starting position, and as soon as the prescribed
speed has been attained, the governors automatically set
the expansion to maintain that speed. At the final
stage of the wind, the driver returns the lever to its
middle position, thus shutting off steam. Should he
omit to do this at the proper time, steam is shut off
automatically by the safety appliance, according to the
speed and depth at the moment. The safety mechanism
prevents the engine from being started in the wrong
direction, without, however, preventing the driver from
operating the reversing gear; it automatically adjusts
the expansion to the degree required for full speed; pre-
vents the prescribed maximum speed being exceeded,
either for winding materials or men; and shuts off steam

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in the last stage of the wind, so that the speed diminishes
progressively as the cage nears bank, and finally stops
the cage gently, within a short space, if the latter should
pass the bank level. Overwinding is therefore precluded
entirely.

This last effect is produced by the co-action of the
governors and the depth curve. It is highly important
that the latter should be operated directly by the nuts
of the depth indicator, which must be properly adjusted
with relation to the position of the cage—an essential
matter when a rope pulley is used and rope slip must
be taken into account. Unless the curve members are
operated direct, a fresh adjustment is necessary every
time slip occurs—an operation that is easily overlooked
by the man in charge, and so the safety mechanism
becomes inoperative.

With regard to the steam consumption of the engine,
it may be mentioned that although there is a certain
amount of work lost in the gearing (about 3 to 4 per
cent, in the present instance), it is possible to run the
engine at a far higher speed than would otherwise be
the case, the piston velocity being 4 m. per second in
place of the usual average of 2’7; and this increased
speed means reduced steam consumption. Another
favourable influence on the steam consumption is that
the smaller cooling surfaces and dimensions lessen the
losses by radiation and leakage, whether the engine be
running or still. The reversal losses are also smaller.
Although the influences cannot be expressed in figures,
they combine to make the total steam consumption per
shaft horse-power and hour smaller than with direct
drive. The consumption, with the usual addition for
waste, stoppages, brake consumption, etc., is about
12*5 kilogs. for steam at 275 degs. Cent. The exhaust
steam is utilised for warming bath water and feed water,
and for heating the changing house. A steam accumu-
lator is provided for utilising the occasional surplus

exhaust steam, and this apparatus supplies low-pressure
steam for the boiler feed water and the wash house.

The boiler plant, which is close by the tower, com-
prises two Lancashire type boilers, each with a heating
surface of 105 sq.m., with superheaters of 40 sq.m.
area, supplying steam at a pressure of 12 atmospheres
and 300 degs. Cent. The boilers are fired with dried
coal sludge, mixed with coke breeze.

The total cost of the winding installation, including
the complete tower, winding engine, guide pulley, boiler
plant, with chimney stack and steam pipes, and founda-
tion work, was about 335,000 mk. (.£16,750), whereas
ah electrical plant for the same work (extension of the
existing power plant) would have cost at least 500,000
mk. (£25,000). Owing to the success of the plant, a
similar installation is in course of erection at the
Heinrich Colliery, Ueberruhr, for raising a net load of
1,300 kilogs. from a depth of 400 m.

MIDLAND INSTITUTE OF MINING, CIVIL
AND MECHANICAL ENGINEERS.

A general meeting of the Midland Institute of Mining,
Civil and Mechanical Engineers was held at the Univer-
sity of Sheffield on December 7, when interesting dis-
cussions took place on the action of fungi on pit timbers
and on the refractory materials of the South Yorkshire
coal field. The President (Mr. C. C. Ellison) presided.

On the proposition of Mr. R. Graham, seconded by
Mr. A. T. Thomson, Mr. Philip Brady Nicholson was
elected an associate member.

Some Causes of Decay of Timber in Mines.

Mr. Mitchell read his paper on the above subject.
(See page 1164.)

Discussion.

Mr. G. Blake Walker said they were all very much
indebted to their friends at the Imperial College of
Science and Technology for the visit of Mr. Mitchell.
The fact that the college was devoting itself to these
practical ways of helping them in the carrying on of their
work was very gratifying, and they ought to appreciate
it very much. The address to which they had listened
was an eminently practical one. It was not theoretical
with regard to the botanical aspects of the matter, but
dealt with facts as they actually had them, and pointed
the way to a simple and apparently effective remedy for
dealing with a trouble which affected them more perhaps
than they realised. Mr. Mitchell had for many years
been engaged on the rubber plantations of the Malay
States, where on some plantations 10 to 15 per cent, of
the trees were infected and killed. By washing them
with copper sulphate, however, that proportion had in
some cases been reduced to less than 1 per cent. The
climate of the Malay States was warm and humid, and
not unlike the temperature met with in mines, so that
they in the mining industry might well hope for similar
success. As to the cost of the treatment, he should say
it would be a matter for an old man, who was not able
to do much else, but who could just travel the mine, to
go round with a bucket and a cloth, removing the
growths, and rendering the spread of the infection
infinitely less. As Mr. Mitchell had told them, they
had a very considerable amount of this trouble already
existing in their mines. The work of dealing with it
would not be done in a day, a week, or a month, but
if they would take the matter in hand, and adopt a
reasonable system, it would not cost them very much,
and he thought it would materially prolong the life of
the timbers, especially in those cases where they had to
stand for yeans in return airways. He had not previously
been aware that there was much of this fungus in the
pits writh which he was connected, but they had been
able to find some very luxuriant growths for Mr.
Mitchell’s edification, among them being some very
interesting varieties. They were not particularly
interested in the varieties—all of which were injurious.
He had much pleasure in moving a very hearty vote of
thanks to Mr. Mitchell. He thought he might add that
they w’ould all be very pleased to give Mr. Mitchell all
the facilities he desired with regard to examining the
state of the timbers in their mines. They hoped that at
a future time he might be able to give them some further
advice, and that he might find that they were benefiting
by it.

The President, in seconding the vote of thanks, said
he would like some further information as to whether it
was possible to treat the timber in some economical
manner before it went into the mine. They all knew
that it could be treated at great cost, but it might be
possible to treat it more cheaply in such a way as would
stop the fungi. He would also like to know whether
these fungi attacked timber which was stored away and
kept for use in, say, two years’ time. If so, it was
quite possible that they had stacks of timber which were
gradually being destroyed without their knowing any-
thing at all about it. A practical point was the effect
of fungi on covering timbers which stayed in position
for years. This would cause as much trouble as any
case, because very often the diseased nature of the
timber could not be detected, and it led to large falls
of roof, which were not only dangerous, but very costly
indeed. There was a practical difficulty there in find-
ing out what was the matter, or, if they did find it out,
in attacking it.

Col. H. Rhodes said they were all using a great deal
of home-grown timber now, the bulk of it going down
the pit with the bark on, and a great deal of it being,
to say the least, unseasoned. There seemed to be a
good deal more breakage of this timber. No doubt this
was due to its being unseasoned, but, at the same time,
the fungus seemed to appear on it a great deal more
than used to be the case. He had in mind a little
outcrop mine working just outside Sheffield. They were