AN IMPROVED MODE OF VENTILATING RAILWAY TUNNELS
Year: 1869

page_text: LETTERS PATENT to John Ramsbottom, of Crewe, in the County of
Chester, Engineer, for the Invention of "AN IMPROVED MODE OF
VENTILATING RAILWAY TUNNELS."
Scaled the 27th July 1869, and dated the 18th March 1869.
PROVISIONAL SPECIFICATION left by the said John Ramsbottom at
the Office of the Commissioners of Patents, with his Petition, on
the 18th March 1869.
I, JOHN RAMSBOTTOM, of Crewe, in the County of Chester, Engineer,
do hereby declare the nature of the said Invention for "AN IMPROVED
MODE OF VENTILATING RAILWAY TUNNELS," to be as follows:-
My Invention consists in extracting the vitiated air from the tunnel
through one or more openings at or near the middle of its length,
by means of fans, pumps, or by the rarefaction of the air by heat in
an upcast shaft as is practised in mines; the vitiated air so exhausted
being replaced by fresh air from each end of the tunnel. In cases
where the vitiated air cannot be extracted sufficiently near the centre

page_text: of the length of the tunnel the velocity of the currents from each end
may be regulated by screens or other equivalents attached to the sides
or roof of the tunnel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Ramsbottom in the Great Seal Patent Office
on the 18th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
RAMSBOTTOM, of Crewe, in the County of Chester, Engineer, send
grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of March, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Ramsbottom, Her special
license that I, the said John Ramsbottom, my exccutors, administrators,
and assigns, or such others as I, the said John Ramsbottom, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully. might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED MODE OF VENTILATING RAILWAY TUNNELS," upon
the condition
(amongst others) that I, the said John Ramsbottom, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said John Ramsbottom, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in
and by the following statement (that is to say):
―
My Invention consists in extracting the vitiated air from the tunnel
through one or more openings at or near the middle of its length, by

page_text: means of fans or pumps, or by the rarefaction of the air by heat in an
upcast shaft as is practised in mines. The vitiated air so exhausted
being replaced by fresh air from each end of the tunnel. In cases where
the vitiated air cannot be extracted sufficiently near the centre of the
length of the tunnel the velocity of the currents from each end may
be regulated by screens or other equivalents attached to the sides or
roof of the tunnel..
And in order that my Invention may be fully understood and readily
carried into operation, I will proceed to describe the accompanying
two Sheets of Drawings, referen being had to the figures and letters.
marked thereon.
On Sheet 1, Figure 1, is a transverse section of the railway tunne!
to be ventilated, and of my improved mode of ventilating the same;
Figure 2 is another sectional elevation taken at right angles to Figure 1;
and Figure 3 is a plan of the same, also partly in section.
a is the railway tunnel, and 6 is a horizontal passage or cross
drift forming the communication between the tunnel a and the chamber c
in which is the exhausting fan d, this fan is keyed on the axle e, indi-
cated by a dotted line, and the steam engine for driving the fan is fixed
on the foundation stone f. The boilers for supplying steam to the engine
are placed in the boiler house g, and the steam is conveyed through
suitable pipes, not shewn in the Drawing, from the boilers to the steam
engine. The products of combustion from the furnaces of the boilers
are conveyed along the flucs h to the chimney i which is placed within
the upcast shaft k, and the waste steam from the engine will be dis-
charged through a suitable blast pipe placed in the bottom of the
chimney. As soon as the fan is set in motion the vitiated air from
the centre of the tunnel is drawn along the passage or cross drift b
and enters from both sides into the chamber c from which it is expelled
into the shaft k by the fan. When a partial vacuum is thus formed
in the tunnel by exhausting the vitiated air from about the centre of
the length thereof, fresh air enters from each end of the tunnel to.
occupy spaces at each end corresponding in volume with that of the
vitiated air which has been extracted, and these in-currents of fresh air
are kept up so long as the fan is in motion. The upcast shaft k is
made of sufficient height to carry off the vitiated air and distribute it
at a suitable elevation to avoid nuisance. When the fan is not in
motion the heated products from the furnaces of the boilers will to

page_text: some extent rarefy the air in the upcast shaft k, and so produce a slight
ventilating action in the tunnel, and to increase this action the passages
through the fan are made of large area.
In cases where the vitiated air cannot be exhausted from near
the centre of the length of the tunnel the velocity of the currents from
each end may be regulated by screens or other equivalents attached
to the sides or roof of the tunnel. These screens, which are placed in
the shorter length of the tunnel, are shewn in Figure 1, and their
number and size must be such as to produce the desired degree of
retardation.
In some cases it may be desirable to extract the vitiated air from
more than one opening near the centre of the tunnel, the openings
should then each be provided with an exhausting apparatus, or, if it not
too far apart the openings are connected with one common exhausting
apparatus, so that the vitiated air may be extracted from one or the
other, or from both, according to the direction and force of the wind.
On Sheet 2, Figure 4, is an elevation in section of a double acting
pumping engine which may be employed for extracting the vitiated air
from a railway tunnel. In this view represent a large cylinder, which
is made by preference of glazed bricks. In this cylinder are the two
pump buckets m and n, the circumference of which may be packed
with felt, leather, or other suitable material. These pump buckets
are provided with circular or other flap valves fitting on grids and
distributed over their surfaces. The bucket m is connected by a rod
to the short arm of the beam m', and the bucket n is connected by
a double rod to the elbow lever n¹. The beam m is furnished with an
arm connected by coupling links o to the vertical arm of the elbow
lever n'. The beam m¹ and the elbow lever n¹ vibrate upon axes
supported in bearings by the beams p. A vibrating motion is given to
the beam m and through the coupling links o to the elbow lever n
by the steam cylinder q, the stroke being regulated by the crank and
shaft r. By this arrangement the pump buckets m and n are made to
approach and recede from each other alternately. The tunnel to be
ventilated is connected to the space under the cylinder 1, consequently
every upward stroke of each bucket extracts a portion of the vitiated air
from the tunnel, which quantity is determined by its area and length
of stroke, and delivers it into an upcast shaft as before described in
reference to Sheet 1. When the pumping engine is at rest the flap

page_text: valves in both buckets are propped open and, the waste heat from the
boiler will by rarefying the air in the upcast shaft partially ventilate
the tunnel as before described.
The mode of ventilating railway tunnels by the rarefaction of air
may be described without reference to Drawings, as it is very similar
to that generally adopted in ventilating coal mines. The furnace for
generating the heat is placed in a chamber at the foot of an upcast
shaft, and this chamber is connected by a cross drift or passage with
the tunnel.
Having thus stated the nature of my Invention, and described three
convenient modes of carrying the same into operation, I wish it to be
understood that I do not intend to limit myself to the details given,
as they may be varied according to the peculiar construction of the
tunnel to be ventilated and to the length and dimensions thereof, but
what I claim as my Invention is, ventilating railway tunnels by
exhausting the vitiated air therefrom and producing currents of fresh
air therein by fans or pumps, or by the rarefaction of air by heat as
described.
In witness whereof, I, the said John Ramsbottom, have. hereto
set my hand and scal, this Sixteenth day of September, One
thousand eight hundred and sixty-nine.