IMPROVEMENTS IN TUN-
Year: 1873

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Sutton, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN TUN-
."-A communication from abroad by Dewitt Clinton
Haskin, of Vallejo, State of California, United States of America.
NELLING.
PROVISIONAL SPECIFICATION left by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition, on the 26th June 1873.
I, GEORGE TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TUNNELLING," to be as follows:-
The object of this Invention is to enable tunnels under waterways to
be constructed with facility. One of the greatest obstacles to such
engineering works is the irruption of water. The Invention is designed
to overcome this obstacle, and it consists of the method of prosecuting

page_text: the work in tunnels in a compressed atmosphere, or while the atmosphere
within the tunnel is maintained at a sufficient pressure to prevent the
entrance of water in whole or in part.
The Invention may be understood from the following description :-
In the case thus represented it is assumed that the work is commenced by
sinking a shaft at one side of the waterway, such shaft being of suitable
dimensions to permit the removal of the earth, and the lowering of
the materials required in the course of construction. The tunnel
commences at the lower end of this shaft. At the entrance of the tunnel
an air-tight ante-chamber is established, such chamber being constructed
by preference of cast iron, and having its ends sufficiently strong to with-
stand the greatest pressure which may be required in the prosecution
of the work. Each of these ends is provided with a doorway, and with
a door for closing the doorway, the doors by preference being arranged
to open towards the waterway, so that the unbalanced pressure within
the tunnel or within the ante-chamber tends to hold the doors firmly
closed.
An air pipe is provided to conduct air from a suitable air compressing
engine to the outer side of the ante-chamber at the nearer end of the
tunnel, and the portion of this air pipe within the ante-chamber is fitted
with a stop-cock, by means of which compressed air can be admitted
into or shut off from the ante-chamber. A stop-cock also is provided
for permitting the compressed air in the ante-chamber to escape.
The ante-chamber and its appurtenances having been provided and
put in place, and any vacant space around the periphery of the ante-
chamber having been solidly packed with clay, the work of tunnelling
is prosecuted by the usual means from the end of the ante-chamber
forwards under the waterway, and during such prosecution compressed
air is forced down through the air pipe into the tunnel, so that the work
is prosecuted in a compressed atmosphere, which by its outward pressure
tends to prevent the entrance of water.
When access has to be had to the tunnel the ante-chamber is entered
by its outer door, which is then closed. The escape cock is closed, and
the ingress cock is opened, so that the ante-chamber is filled with a
compressed atmosphere of the same pressure as that in the tunnel. The
inner door of the ante-chamber can then be opened to permit of the
passage of men or materials to and from the tunnel Men or materials

page_text: may be passed from the tunnel by a reversal of the above operations, the
inner door and the air ingress cock being closed, and the escape cock
being then opened to permit the compressed air to escape from the ante-
chamber until the pressure within it is reduced to that of the external
air; whereupon the outer door can be opened, and the men or materials*
may be passed from the ante-chamber outwards. If notwithstanding the
pressure in the tunnel some water should leak in it may be permitted to
escape through a pipe fitted with a stop-cock or valve, so that the escapo
may be controlled.
.)
It is proposed to lay down a track or tramway in the tunnel as the
work proceeds, so as to permit cars to be run through it with earth and.
other materials, and to arrange the track so that it may be temporarily.
shifted, as required, to permit the opening of the doors of the ante-.
chamber.
: .
The means of compressing air and for raising and lowering the
materials, as well as the appliances for working in the earth, and for
putting in place the masonry or other lining of the tunnel, are not
represented, as all of these may be of the usual description for such.
engineering works; and the Invention is not restricted to any peculiarity
of the said means and appliances, nor to any peculiar construction of the.
ante-chamber and its appurtenances.

page_text: "
and grant unto me, the said George Tomlinson Bousfield, Her special
license, that I, the said George Tomlinson Bousfield, my executors,
administrators, and assigns, or such others as I, the said George Tomlinson
Bousfield, 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
"IMPROVEMENTS IN TUNNELLING,' a communication to me from abroad'
by Dewitt Clinton Haskin, of Vallejo, State of California, United States
of America, upon the condition (amongst others) that I, the said George
Tomlinson Bousfield, 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 George Tomlinson Bousfield, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained a
in and by the following statement thereof, that is to say :--
J
The object of this Invention is to enable tunnels under water ways to
be constructed with facility. One of the greatest obstacles to such
engineering works is the irruption of water. The Invention is designed
to overcome this obstacle, and it consists of the method of prosecuting
the work in tunnels in a compressed atmosphere, or while the atmosphere
within the tunnel is maintained at a sufficient pressure to prevent the
entrance of water in whole or in part.
The Invention may be understood from the following description
taken in connection with the accompanying Drawing, which represents
a central vertical section of a tunnel partly completed:-In the case
thus represented it is assumed that the work is commenced by sinking a
shaft A at one side of the waterway B, such shaft being of suitable
dimensions to permit the removal of the earth and the lowering of the
materials required in the course of construction. The tunnel commences
at the lower end of this shaft. At the entrance of the tunnel an air-
tight ante-chamber C is established, such chamber being constructed by

page_text: preference of cast iron, and having its ends d, d', sufficiently strong to
withstand the greatest pressure which may be required in the prosecu-
tion of the work. Each of these ends is provided with a doorway, and
with a door e, e¹, for closing the doorway, the doors by preference being.
arranged to open towards the waterway B, so that the unbalanced pressure
within the tunnel or within, the ante-chamber tends to hold the doors
firmly closed.
An air pipe m is provided to conduct air from a suitable air com-
pressing engine to the outer side of the ante-chamber at the nearer end
of the tunnel, and the portion of this air pipe m within the ante-chamber
is fitted with a stop-cock s, by means of which compressed air can be
admitted into or shut off from the ante-chamber. A stop-cock & also is
provided for permitting the compressed air in the ante-chamber to
escape.
.
'
The ante-chamber and its appurtenances having been provided and
put in place, and any vacant space
around the periphery of the anté-
chamber having been solidly packed with clay, the work of tunnelling is
prosecuted by the usual means from the end of the ante-chamber forwards
under the waterway, and during such prosecution compressed air is
forced down through the air pipe m into the tunnel, so that the work is
prosecuted in a compressed atmosphere, which by its outward pressure
tends to prevent the entrance of water,
When access has to be had to the tunnel the ante-chamber C is entered
by its outer door e, which is then closed. The escape cock t is
closed, and the ingress cock s is opened, so that the ante-chamber C is
filled with a compressed atmosphere of the same pressure as that in the
tunnel. The inner door e¹ of the ante-chamber can then be opened to
permit of the passage of men or materials to and from the tunnel. Men
or materials may be passed from the tunnel by a reversal of the above
operations, the inner door e¹ and the air ingress cock 8 being closed, and
the escape cock t being then opened to permit the compressed air to escape
from the ante-chamber until the pressure within it is reduced to that of
the external air; whereupon the outer door e can be opened, and the
men or materials may be passed from the ante-chamber outwards. If
notwithstanding the pressure in the tunnel some water should leak in, it
may be permitted to escape through a pipe fitted with a stop-cock or
valve, so that the escape may be controlled.

page_text: It is proposed to lay down a track or tramway in the tunnel as the
work proceeds, so as to permit cars to be run through it with earth and
other materials, and to arrange the track so that it may be temporarily
shifted, as required, to permit the opening of the doors of the ante-
chamber.
The means of compressing air, and for raising and lowering the
materials, as well as the appliances for working in the carth and for
putting in place the masonry or other lining of the tunnel, are not
represented, as all of these may be of the usual description for such
engineering works; and the Invention is not restricted to any peculiarity
of the said means and appliances, nor to any peculiar construction of the
ante-chamber and its appurtenances.
When the necessity of excluding water from the work has ceased, the
ante-chamber and its appurtenances may be removed.
The Invention claimed is, the method of tunnelling by prosecuting
the tunnel work in a compressed atmosphere, substantially as before' set
forth.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Twenty-third day of Decem-
ber, in the year of our Lord One thousand eight hundred and
seventy-three.
:
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ATA
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