IMPROVEMENTS IN THE MEANS, MACHINERY, OR APPARATUS USED IN THE PROPULSION OF TRAINS BY CURRENTS OF AIR, PARTS OF SAID IMPROVEMENTS BEING APPLICABLE TO OTHER PURPOSES WHERE BLOWING AND EXHAUSTING OR RE- PRIGERATING APPARATUS OR PULLEY ARRANGEMENTS ARE REQUIRED
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by John Hawkins Simpson at the
Office of the Commissioners of Patents, with his Petition, on the
27th April 1869.
I, JOHN HAWKINS SIMPSON, of Bolton Street, Piccadilly, in the
County of Middlesex, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN THE MEANS, MACHINERY, OR APPARATUS USED IN
THE PROPULSION OF TRAINS BY CURRENTS OF AIR, PARTS OF SAID IMPROVEMENTS
BEING APPLICABLE TO OTHER PURPOSES WHERE BLOWING AND EXHAUSTING OR RE-
PRIGERATING APPARATUS OR PULLEY ARRANGEMENTS ARE REQUIRED," to be as
follows:-
In or about the year 1810, a Danish engineer named Medhurst
invented a system of propelling passenger trains through tunnels by
allowing the pressure of atmospheric air when in motion to act upon
them as upon moveable pistons, the tunnels proposed by him were to be
built of brick and supplied with a pair of rails to support and guide the
wheels of the trains, and the means of forcing the air into the tunnels
behind the trains or of expelling it before them was by the employment
of pumping apparatus. Further Letters Patent for England were in the
year 1824 (No. 4905) granted to John Vallance, of Brighton, for certain

page_text: methods of propelling passengers through cast-iron tubes, the carriage
being held and guided by rails or grooves on or in the bottom of the
tube, and the space between the interior of the tunnel or tube and the
outside of the carriage being filled up with soft material to prevent
leakage of air; the pneumatic pressure being applied over the entire
transverse area of the carriage, and many persons were it is reported so
conveyed through iron tubes erected in Brighton.
Now my Invention consists in using for the purposes of blowing air
into or extracting it from such brick or iron tunnels or tubes a rotary
blower or series of rotary blowers made according to the Specifications of
William Edward Newton, No. 1333, A.D. 1866, and Alfred Vincent
Newton, No. 1181, A.D. 1867. Although I recommend the use of
blowing apparatus which consists of a combination of the arrangements
described in those Specifications and those now herein-after described,
that is to say, for obtaining the motive power for propelling the trains as
herein-before referred to, or for supplying air for purposes of ventilation,
hitherto the pneumatic motive power has been obtained only by putting
a certain volume of atmospheric air into motion by means of a pump,
fan, jet, or otherwise regardless of density incidental thereto. I propose
utilizing the contraction and expansion of air due to forced changes of
temperature, in conjunction with fans, pumps, blowers, or already applied
means of putting the air into motion in order to obtain an increased
effect, and a quicker transit of trains, or supply of air for ventilation
without having to increase the dimensions or the velocity of the blowing
machine. For this purpose 1 insert in the air passage leading into
the blower a refrigerator or apparatus for automatically cooling the air,
by which means the volume of air is contracted. In its denser state it
is operated upon by the fan or other blower which is thus enabled to act
upon a greater weight of air with a constant velocity than it otherwise
would. If air is to be forced into the tube or tunnel or any passage or
room for ventilation the refrigerator is placed between the free atmo-
sphere and the blower, but if the air is to be exhausted from tube,
tunnel, passage, or room the refrigerator is placed between such tube
tunnels, passage, or room and the blower, or the passage of the air is
regulated in its directions, as above described, by air valves. Any refri-
gerator may be used for the purpose which offers little resistance to the
free passage of air and yet presents large and effective cooling surfaces,
but the form of refrigator which I recommend is one which depends for

page_text: its action upon the absorption of heat due to evaporation of liquids.
It consists of a vertical metal cylinder in which are a number of annular
funnel shaped divisions sloping down from the sides to within a short
distance from the axis. In the centre I erect a vertical revolving
shaft carrying a number of umbrella shaped discs, arranged alternately
between the annular divisions of the cylinder, and reaching to within a
short distance of the side of the cylinder. I then allow a liberal
stream of water to enter at the top. Falling upon the first revolving
umbrella the water is instantly accelerated into a rapid rotating
motion and is impelled by centrifugal force against the sides of the
cylinder; here it comes to rest and runs down the first funnel shaped
division on to the next revolving umbrella, which drives it off in the
same manner, and so on to the bottom. The interior of the cylinder
is thus occupied by strata of very finely distributed particles of water.
The air intended to be cooled and condensed passing through the finely
divided particles of water causes a slight evaporation from their surfaces
and a corresponding reduction of the temperature, which serves to keep
the water cold. The cold water as it runs out at the bottom is by a
suitable appliance elevated and re-enters at the top of the cylinder.
This refrigerator may be used as a means of supplying either cold air
or cold water or other liquids for a variety of purposes. I likewise use
for the propulsion of trains the caloric principle alone without the
intervention of any blowing apparatus by either expanding or both
expanding and contracting the air; to do this I employ a heating
apparatus which I prefer to construct in the form of a honeycomb of
brickwork, which is so built as to allow it to be heated at pleasure and
used at the same time for the passage of the air through it on its way to
the tube.
I use the following improved description of pulley for transmitting
motion to the vertical shaft in the refrigerator and to the rotary blower
herein-before referred to with the view to increase the friction of the
rope or wire used in communicating motion, that is, I employ upon the
circumference of the pulleys instead of a V or U shaped groove as is
customary, a series of pins slanting alternately outwards over the two
edges. These pins I prefer to fix in a series of suitable holes which are
drilled in a circle upon the periphery. The cord in passing upon the
pulley is forced between the pins to form a zig-zag line upon the peri-
phery and is prevented from slipping by its rigidity, it being bent

page_text: backwards and forwards. The above described pulley may be applied
in various cases where power has to be transmitted from point to
point.
Sometimes it is necessary to employ air doors where the tube enters a
station by two tunnels, and then I connect these air doors with the
points, so that when the door on one side is closed the points are held
automatically over to prevent a train by any possibility arriving at the
wrong platform or striking against a closed air door.
Instead of air doors at the entrances of end stations I also employ an
enlargement of the tube which is generally open to the air but may be
closed if necessary by means of valves. I also make the approach into
the station on an incline, so that when a train is blown towards the
station the guard by applying his break can arrest it easily within a few
yards of a given spot. This I prefer that he should do so as to leave
the end carriage in the mouth of the tube, which it thus fills up and acts
as door or valve, preventing any unpleasant rush of air into the station.
At starting I prefer the guard should make use of the gradient alone
whilst descending until he passes the enlargement just mentioned
when he meets the current of air which is to take him through.