IMPROVEMENTS IN APPARATUS OR MACHINERY FOR. VENTILATING MINES, SHAFTS, AND TUNNELS
Year: 1877

page_text: LETTERS PATENT to William Henry Thwaites, of Vulcan Iron Works, Bradford,
in the County of York, and Alexander Stewart, Manager of the said Works,
for the Invention of "IMPROVEMENTS IN APPARATUS OR MACHINERY FOR.
VENTILATING MINES, SHAFTS, AND TUNNELS." Partly a communication from
abroad by Edward Hamer Carbutt, of Vulcan Iron Works aforesaid, now
temporarily residing at Interlachen, Switzerland.
PROVISIONAL SPECIFICATION left by the said William Henry Thwaites and
Alexander Stewart at the Office of the Commissioners of Patents on the
30th May 1877.
WILLIAM HENRY THWAITES, of Vulcan Iron Works, Bradford, in the County of
York, and ALEXANDER STEWART, Manager of the said Works, "IMPROVEMENTS IN
APPARATUS OR MACHINERY FOR VENTILATING MINES, SHAFTS, AND TUNNELS."
[Partly a communication from abroad by Edward Hamer Carbutt, of Vulcan Iron
Works aforesaid, now temporarily residing at Interlachen, Switzerland.]
The said Invention relates to improvements in the apparatus or machines
commonly known as Root's blowers, and consists in the novel construction and
arrangement of the parts of the said blowers for the purpose of adapting them to be
used advantageously for the ventilation of mines, shafts, and tunnels.
The said Invention is carried into practise as follows, that is to say:-Our
improved blower has two rotary parts, which we term pistons, secured upon shafts
of steel or other suitable metal; upon each shaft are keyed cast-iron discs or plates.
We prefer to have five of them. The said discs or plates have flanges at their
circumference or periphery. In each disc plate there are wrought-iron bars,
preferably three, fixed on each side of the centre and extending to the outside of the
rotary piston. Recesses are provided in the discs to receive the said bars, which
are also secured by bolts well fitted in the same.

page_text: The outer portions of the pistons are formed by bending angle iron to a curve or
part of a circle of the required radius, and rivetting the same to the outer
extremities of the said bars. These angle irons are covered with sheet iron. The
sides or radial portions of the said pistons are covered with wood.
The shafts of the said rotary pistons rotate in bearings secured upon strong
girders, which form part of the framework of the ventilator pit. The said pistons
are equally balanced.
In suitable positions we arrange in combination with the said pistons adjustable
packing blocks mounted on hinged metal frames; these blocks can be easily set
up to the surface of the pistons by screws and nuts; these blocks serve to keep the
pistons tight; between the said packing blocks the ventilator pit is lined with
cement.
The piston shafts are geared
with engines for driving them.
by bevil wheels, or otherwise suitably connected
The top of the ventilator casing is left open.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by. the said William Henry Thwaites and Alexander Stewart in. the Great
Seal Patent Office on the 30th November 1877.
WILLIAM HENRY THWAITES, of Vulcan Iron Works, Bradford, in the County of
York, and ALEXANDER STEWART, Manager of the said Works. "IMPROVEMENTS IN
APPARATUS OR MACHINERY FOR VENTILATING MINES, SHAFTS, AND TUNNELS."
Partly a communication_from_abroad by Edward Hamer Carbutt, of Vulcan Iron
Works aforesaid, now temporarily residing at Interlachen, Switzerland.
This Invention relates to improvements in the apparatus or machines commonly
known as "Root's blowers," and consists in the novel construction and arrangement
of the parts of the said blowers, and in. the method. of driving these machines for
the purpose of adapting them to be used advantageously for the ventilation of
mines, shafts, and tunnels.
The said Invention is carried into practice as follows, that is to say Our
improved blower and exhauster has two rotary parts, which we term revolving
pistons, built and secured upon a main shaft of steel, or other suitable material as
herein-after described.
The main shafts of the said revolving pistons rotate in bearings or pedestals,
which are adjustable and securely fixed upon strong girders that form the frame-
work of the ventilator pit: The said pistons are equally balanced and adjusted by
the pedestals to the proper distance between the centres of the main shafts..
In suitable, positions-we arrange in combination with the said pistons adjustable
or fixed packing blocks mounted on hinged metal frames; these blocks can be
easily set up to the surface of the revolving pistons by screws and nuts. These
packing blocks serve to break the communication between the bottom and top-side
of the revolving-pistons, -and-prevent-the-air that is being forced forward from
returning or leaking through or between these parts. The ventilator pit is formed
at the top with girders.resting upon brickwork.
The piston shafts are geared together by bevil, spur, or worm wheels this gearing

page_text: 1
retains the revolving pistons in their proper relative positions, and thereby prevents
their touching each other when revolving.
The gearing is so arranged that the pistons move towards each other when
the air is to be forced downwards and away from each other when the air is to be
exhausted upwards.
The piston shafts are connected with engines for driving the ventilating apparatus.
We may use compound, high and low pressure, condensing, or any other suitable
engines for this purpose. The engines are provided with reversing mechanism to
be used in case of emergency, so that the ventilator can be run in either direction,
that is to say, the ventilator can at any time be used either to force air into the
mine shaft, or tunnel, or to exhaust the air from the same, This arrangement will
be found of great advantage in case of an explosion. The top of the ventilator.is
covered with a brick or galvanized iron house with a galvanized iron roof con-
structed with suitable openings for the inlet or exit of air. These openings should
be of large area to allow the air to pass through at a low velocity.
The superiority of this ventilator over the fans.commonly used for ventilating
mines, will be found to consist in their greater exhausting or forcing power that
will be.available through the diminished area of air passages. in a mine that.has
become disarranged from an explosion. Moreover, as we are able with our improved
apparatus to force or exhaust the air instantaneously in either direction, we can
quickly restore the ventilation. Fans that serve moderately well the ordinary
requirements of ventilation are in some cases of little use when the airways are
interfered with, and in most cases the airways must be cleared before such fans can
restore ventilation.
According to this Invention, we construct the ventilator to either exhaust or force
air, according to the direction in which the ventilator runs; but for the ventilation
of mines, shafts, or tunnels, we prefer to use our Invention to force air into the
mine to be ventilated for the following reasons, namely, in the method. of exhausting
at present in use the. exhaustion of the air to a density less than that of the
atmosphere will assist the gas set at liberty in a fissure to escape and readily mix
with the air being exhausted through the mine and form an explosive mixturé.
But on the other hand if the air is forced down or compressed to a density above
that of the atmosphere, as in the use of this Invention, the. gas escaping from a
fissure will more slowly escape into the compressed air that is being forced into the
inine, and the larger volume of compressed air will by mixing or dilution with the
gas take longer tinic to form the explosive mixture, and thereby afford a better
opportunity of discovering the presence of gas, and by. regulating the speed of our
improved ventilator the gas may be allowed to pass away from the mine in a
sufficiently diluted state to render the presence of the gas harmless, and increase
the safety of working fiery or dangerous mines. And to further carry into effect
this principle, we propose to force air with apparatus constructed according to this
Invention up to a considerable pressure, say 3 lbs per square inch, if necessary, and
to convey the compressed air at the above named pressure to the extreme ends of
the workings, and drive all the vitiated air forward, and by these means.effectually
clear out all sudden outbursts of gas.
"
Figure 1 is a transverse vertical section of the aforesaid ventilating apparatus ;
Figure 2 is a longitudinal section; and Figure 3, a.plan of the same, with the driving
engines.
Figure 4 is an elevation of the engine and ventilator house showing the con-
struction of the roof; Figures 5 and 6: are an end view and. transverse section
drawn to an enlarged scale of the revolving pistons.
A, A, are the pistons which are constructed and mounted upon the. shafts Bas
follows: Upon each of the said shafts are keyed cast-iron discs or plates C, which
have at their circumference flanges, all of which are accurately turned to the sanie
diameter. With each disc or plate there are three wrought-iron bars D fixed on
each side of the centre-axis. B, and reaching to the external periphery of the

page_text: revolving piston at E, E. Planed recesses c¹ are provided in the discs or plates C
to receive the bars D, which are also secured to the discs or plates in these recesses
by bolts c² turned to fit well in their holes. The outer ends of the bars Dare
widened at D1 and marked and slotted to correspond with the outer circle-E, E;
angle or L irons are bent to conform to the said outer circle E and rivetted to the
extremities of the bars at D!; these angle irons are covered with sheet iron G.
The inner or centre circles A¹ are formed by covering the discs or plates C.with
sheet iron plates G. The sides H, H, of the revolving pistons are covered with
galvanized sheet iron, or with wood, or other suitable material, and the ends of the
said pistons are covered with sheet iron. The cross bars I are provided. to stiffen
laterally the framework of the said revolving pistons.
The main shafts B, B, revolve in adjustable bearings J, J, which are fixed upon
girders K, K, of cast iron or other suitable material, forming the mouth of the
ventilator pit. The girders K are connected at their ends with cross girders L, L.
Upon the girders K, K, are fixed side plates-M, M, of cast iron or other suitable
material. The side-plates and girders are all planed accurately on their sides
towards the ventilator pit, and the stonework is dressed off level with the planed
girders.
·
"
At each end of the ventilator pit, and at the bottom, on each side of the inlet from
the mine, are arranged adjustable packing blocks of timber N, N, fixed upon
hinged iron frames N, N¹; which can be adjusted with screws and nuts n, n.
These packing blocks are set up closely to the periphery of the revolving pistons A
Between the packing blocks N, N, the ventilator pit is dug out and built in the
form of an inverted arch n¹, n¹, on each side of the inlet. This brickwork is faced
with cement, but it will be seen that there is considerable space n³, n³, between the
facing of cement and the outside circle of revolving pistons, and we depend only
upon the packing blocks N, N, to maintain the tightness of the revolving
pistons with the ventilator pit, and to prevent communication of the air from one
side to the other of the said revolving pistons.
•
The arrangement of the engine house and ventilator building is shown in Figures
1, 2, and 4.
The discharge air escapes through perforated openings o, o, in the roof, and by
reason of the very large area of the outlet from the ventilator, the top of the
ventilator pit being left entirely open, the air that is being exhausted from the pit
must necessarily be delivered into the atmosphere at a lower velocity than is usual
with other ventilating machinery or apparatus.
Although the above particular method of building up the revolving pistons with
cast-iron discs or plates and wrought-iron bars will be found very advantageous in
some cases, we prefer to use cross heads made entirely of cast iron, plato iron, or
other suitable material, and to dispense with the wrought-iron bars D.
-In Figures 1, 2, and 3 the ventilator is shown in connection with a pair of high-
pressure horizontal engines with adjustable cut-off valves and reversing motion.
These engines are geared with the ventilator main shafts by bevel wheels, the
engines being arranged at right angles to the ventilator. Two bevel wheels Q, Q,
are geared with bevel wheels Q1, Q, on the ventilator main shafts.
The arrows indicate the direction or course of the air; the ventilator in this case-
is shown to be exhausting-the air from the mine, shaft,-or-tunnel, but by reversing
the engine, by means of the mechanism provided for this purpose, the course of the
air would-be in a contrary direction to the arrows, and the air would be forced into
the mine, shaft, or tunnel.
By forcing in, instead of exhausting the air, we obtain a more effectual and
economical-system-of ventilation than could otherwise be obtained. And, further
more,-by-the-reversing of the engines and ventilator, the course or direction of the
air can be instantly changed. This capability of reversing will be of immense
advantage in cases of emergency, such as an explosion, when the air ways are
interfered with. The present best known methods of ventilation are useless under
.

page_text: such circumstances, being only able to carry the air in one direction, and of limited
exhausting power; any obstruction in the air ways renders them inoperative.
until such obstruction is cleared away.
We will now describe the modification of our engines and machinery for driving
these ventilators, and which, in combination with the said ventilators, form part
of this Invention.
Figures 7, 8, and 9 are longitudinal and transverse sections and a plan shewing
the ventilator driven by a horizontal engine working directly upon the main shaft
K₁ of the revolving pistons A, and provision upon the opposite side for a duplicate
engine J working upon the other main shaft K' of the revolving piston. In these
Figúres the ventilator, as shown by the arrows, is forcing the air into the mine, shaft,
or tunnel.
Figures 10, 11, and 12 are similar views showing an arrangement of direct-acting
engines connected with one main cross head H³, this main cross head having two
connecting rods I working directly upon the main shafts of the revolving pistons.
In this arrangement the engines are compound, the steam of the high-pressure
cylinders E¹, E, passing into the low-pressure cylinders F¹, F; and afterwards
passing to the condensor G¹. In this arrangement no wheel gearing will be
necessary, the connecting rods I' and cranks on main shafts K₁will keep the
revolving pistons in their proper relative positions..
Figures 13, 14, and 15 are similar views, showing an..arrangement of engines
with a high-pressure cylinder E¹ fixed above a low-pressure cylinder F, each of
these cylinders having connecting rods working directly upon the main shafts K¹.
In this case the spur. wheels B¹, B', are keyed on the main shafts.
Figures 16, 17, and 18 are similar views showing the ventilator driven with
worm wheels .C, C*, fixed upon the main shafts of the revolving pistons, and
actuated by right and left hand worms C¹, C¹, fixed upon an auxiliary shaft L¹,
which is driven by the spur wheel B¹ gearing into the spur pinion B³. The spur
wheel B is fixed upon the engine shaft, and driven with either one engine or
duplicate engines, as shown in Figure 18. In this arrangement we depend upon
the worm wheels and worms to maintain the revolving pistons in their proper
relative positions.
Figures 19, 20, and 21 are similar views showing an arrangement of a single
cylinder engine driving the ventilating apparatus. The cylinder E¹ has the piston
rod connected with the cross head H. From the cross head H¹ the two connecting
rods I', 1', extend up, and are connected to crank plates L³, L³, fixed upon the
auxiliary shafts L³, Ls; these shafts are geared with spur wheels B', B', and by means
of two other connecting rods 12, 1, act directly upon crank plates M', M², fixed upon
the ends of the main shafts K¹, K', of the revolving pistons.
Figures 22, 23, and 24 are similar views showing another modification for driving
the ventilator with a single engine and double connecting rods, but in this case we
fix spur wheels B', B', on the main shafts K¹, K, of the revolving pistons.
Having thus fully described our said Invention, and shown how the same may be
conveniently and advantageously carried into practice, we wish it to be understood
that we do not confine ourselves to the precise details herein-before described and
illustrated in the accompanying Drawings, as the same may be varied without
departing from the nature of the said Invention, and we further wish it to
be understood that we claim,-
First. In an apparatus or machine termed a "Root's blower," the improvements in
the construction of the rotating parts or pistons, in combination with the other parts.
of the said blower, as above set forth and for the purposes specified.
Second. The combination with the said apparatus or machine of an engine or
engines provided with reversing mechanism, whereby the ventilation may be
effected in either direction, and by exhausting or forcing in air, and whereby an
instantaneous reversal of direction may be obtained, as above set forth.
"
Third. The arrangement of the said "Root's blower or ventilator with either of

page_text: the driving engines illustrated in the accompanying Drawings, and in connection
with the mine, shaft, or tunnel to be ventilated. so that the air may be either forced
in or exhausted from the said mine, shaft, or tunnel, and may be forced in aț
a comparatively high pressure, as above set forth.
In witness whereof, we, the said William Henry Thwaites and Alexander
Stewart, have hereunto set our hands and seals, this Twenty-eighth day
of November, in the year of our Lord One thousand eight hundred and
seventy-seven.