IMPROVEMENTS IN TUNNELS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Thomas Russell Crampton
at the Office of the Commissioners of Patents on the 11th May 1883.
THOMAS RUSSELL CRAMPTON of 4 Victoria Street in the City of Westminster.
"IMPROVEMENTS IN TUNNELS
"
This invention has for its object to facilitate the ventilation of long tunnels
especially railway tunnels in which considerable vitiation of air takes place from
the combustion of fuel in the motor engines working the trains.
For this purpose I form side by side three separate tunnels each of sufficient
dimensions to allow of a train passing along it.
About midway of the length of the tunnels I connect together all the tunnels by
large air passages so that air may pass freely from one to the other. About
midway between the centre of the tunnels and each of their ends I form a branch
tunnel either above or below the other tunnels and form openings from this branch
tunnel into each of the other tunnels. Each opening I provide with doors or
valves by which it may be closed. The branch tunnel I lead to any convenient
point at which a pumping engine or exhausting apparatus may be erected for
withdrawing air from it. If two of the tunnels are left open to this branch tunnel
and the third one shut off from it by closing the doors or valves vitiated air will be
drawn off from the two tunnels through the branch tunnel whilst fresh air will
enter the two tunnels partly through their open ends and partly at the centre
where it is in communication with the third tunnel so that fresh air will be drawn
along the third tunnel from the outer atmosphere and will pass into the two other
tunnels near their centre and be drawn off through the branch tunnels as above
explained the quantities of pure air being of sufficient quantity so as to dilute the
bad gases in the tunnel to the required extent.

page_text: By means of the doors or valves above mentioned any of the three tunnels can
be used as fresh air inlets whilst the others are used as outlets for the mixed impure
gas and air.
By this means all three tunnels will be efficiently ventilated whilst at the same
time the line of rails in any one tunnel can be repaired whilst the other tunnels
are used for the passage of trains and the tunnel in which repairs are going on
may be made the fresh air inlet tunnel so that the gangs of men working in such
tunnel may have perfectly fresh air to work in.
Or if a break down of a train occurs in any one tunnel that tunnel can at once
be converted into the fresh air inlet tunnel whilst the traffic is carried on through
the two other tunnels thereby avoiding delay in the traffic.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Russell Crampton in the Great Seal Patent Office on the
10th November 1883.
THOMAS RUSSELL CRAMPTON of 4 Victoria Street in the City of Westminster
'IMPROVEMENTS IN TUNNELS
رو
This invention has for its object to facilitate the ventilation of long tunnels
especially railway tunnels in which considerable vitiation of air takes place from
the combustion of fuel in the motor engines working the trains.
For this purpose I form side by side three separate tunnels each of sufficient
dimensions to allow of a train passing along it.
About
About midway of the length of the tunnels I connect together all the tunnels by
large air passages so that air may pass freely from one to the other.
midway between the centre of the tunnels and each of their ends I form a branch
tunnel either above or below the other tunnels and form openings from this branch
tunnel into each of the other tunnels. Each opening I provide with doors or
valves by which it may be closed. The branch tunnel I lead to any convenient
point at which a pumping engine or exhausting apparatus may be erected for
withdrawing air from it. If two of the tunnels are left open to this branch tunnel
and the third one shut off from it by closing the doors or valves, vitiated air will
be drawn off from the two tunnels through the branch tunnel whilst fresh air will
enter the two tunnels partly through their open ends and partly at the centre
where it is in communication with the third tunnel so that fresh air will be drawn
along the third tunnel from the outer atmosphere and will pass into the two other
tunnels near their centre and be drawn off through the branch tunnel as above
explained. The quantity of pure air being sufficient to dilute the bad gases or the
fumes to the required extent.
By means of the doors or valves above mentioned any of the three tunnels can be
used as fresh air inlets whilst the others are used as outlets for the mixed impure
gas and air.
'
By this means all three tunnels will be efficiently ventilated whilst at the
same time the line of rails in any one tunnel can be repaired whilst the other
tunnels are used for the passage of trains and the tunnel in which repairs are
going on may be made the fresh air inlet tunnel so that the gangs of men working
in such tunnel may have perfectly fresh air to work in.
Or if a breakdown of a train occurs in any one tunnel that tunnel can at once
be converted into the fresh air inlet tunnel whilst the traffic is carried on through
the two other tunnels thereby avoiding delay in the traffic.
In order that my said invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a vertical longitudinal section.
Figure 2 is a horizontal section showing in diagram tunnels arranged in
accordance with my invention.
Figure 3 shews to a larger scale a section upon the line A B in Figure 1.
Figure 4 shews a similar section upon the line C. D. in Figure 1.
The arrangements shewn by the Drawings are suitable for tunnels of great
length under conditions similar to those which would apply to tunnels sav thirt

page_text: A A A³ are three parallel tunnels each of dimensions suitable for receiving one
line of rails say about 17 feet in diameter.
The tunnels are connected together near the centre of their length in the manner
shewn by Figure 4 that is to say a free connection equal in area to one of the
tunnels is established for the passage of air at all times from one tunnel to another.
Two such connections may be made at a short distance apart, it is so represented
in Figures 1 and 2 the arrangements for the two halves being then entirely
independent but similar. Midway between these central connections and the place
where shafts can be made to the outer air, the tunnels are connected in the manner
shewn in Figure 2 with the auxiliary or branch tunnel B which is led in the most
convenient way to the surface.
The branch tunnel B shown in the Drawing is a drainage tunnel and its slope is
downwards to a point where a pumping shaft can be carried to the surface.
The tunnels A. A. and A³. intended for traffic when required incline upwards
from the junction with the branch tunnel B and they run out to the surface in a
convenient manner.
These portions of the tunnels are also connected with the surface by air shafts C¹.
C2 C3. as soon as it becomes practicable.
The ventilation of the tunnel is then effected as follows. An air exhauster or
pumping apparatus of any sort is erected at the top of the auxiliary or branch
tunnel B and air is constantly drawn from it.
In addition to this, means are provided by which air may be forced into the
three shafts C', C2, C³. If natural ventilation will suffice for the shore ends of the
traffic tunnels air may be forced only into the shaft connected with the tunnel
selected for the supply of air to the other tunnels but if otherwise air is forced into
all these shafts. The traffic tunnels are open at their ends and some of the air
forced into them escapes by the open ends. The tunnel selected and used for the
supply of air is closed by doors provided for the purpose, to prevent the escape of
air from its mouth. This tunnel will for the time being be out of use for traffic,
it may be a tunnel in which men are working repairing the way or a tunnel
which has been blocked by a break down; it will always be well supplied with
pure air.
The ventilation currents may then be traced as follows:-The suction at the
upper end of the branch or auxiliary tunnel B will induce currents of air from the
centre of the traffic tunnels where air is supplied to them by the tunnel which is
for the time devoted to this use. These currents will be joined by others descending
two of the shafts C. C2 or C³. in connection with the two traffic tunnels.
The shore ends of the traffic tunnels or the portions between the shafts and the
open ends will be ventilated by the portion of the air forced into the shafts at C
which finds its way out by the open mouths of these tunnels.
The tunnel which serves as the air inlet will of course in its main channel be
well ventilated by the pure air passing through it, the shore end of this tunnel
also, as there is no traffic through it, will be sufficiently ventilated, but if otherwise
the ventilation might be improved by partially opening the doors previously
referred to
This is a complete system of ventilation for tunnels of great length, it will not
always le necessary to carry it out in its entirety, in some cases pressure may be
entirely dispensed with and suction solely relied on or pressure may be used only
in connection with the tunnel supplying air to the centre of the traffic tunnels.
In some cases it may be desirable to permit some of the air from the tunnel
Femployed for the supply of fresh air to pass into the traffic tunnels before reaching
the centre.
This can always be done if thought desirable by establishing between the tunnels
at the points desired additional connections as in Figure 4 but provided-with valves
which can be opened and closed as may be required.
:-
The arrangements thus admit of variation, but what I claim is :-
First. The combination consisting of three tunnels each suited to a single line of

page_text: traffic and so connected that either can be employed to supply air near the centre
by a forced ventilation to the other two substantially as described.
Second. The combination consisting of three tunnels each suited to a single line
of traffic; such tunnels being connected together near the centre of their lengths
and connected by passages having valves, at an intermediate place with a branch
or auxiliarly tunnel from which air can be withdrawn; so that in operation an air
current passes by one tunnel to the centre of the other tunnels and in these, air
currents pass in opposite directions to the branch or auxiliary tunnel substantially
as described.
Third. The arrangement of three tunnels and apparatus in connection therewith
substantially as described and illustrated by the annexed Drawings.
In witness whereof I the said Thomas Russell Crampton have hereunto set my
hand and seal this ninth day of November in the year of our Lord One thousand
eight hundred and eighty three.
TR CRAMPTON
(L.S.)