IMPROVEMENTS IN IRON CAISSONS, AND IN APPARATUS TO BE USED IN SINKING THE SAME, AND IN SINKING CYLINDERS AND PIERS FOR MAKING FOUNDATIONS UNDER WATER
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by John Shaw at the Office of
the Commissioners of Patents, with his Petition, on the 20th April
1864.
I, JOHN SHAW, of No. 22, West Smithfield, London, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN IRON CAISSONS, AND IN APPARATUS TO BE USED IN SINKING THE
SAME, AND IN SINKING CYLINDERS AND PIERS FOR MAKING FOUNDATIONS UNDER
WATER," to be as follows:-
>
The object of my Invention is to facilitate the operations of sinking caissons,
cylinders, and piers, for making foundations under water, and to economise
labor in raising and discharging the soil or materials excavated, and at the
same time dispense with the use of pumps for drawing off the water.
The nature of my Invention consists in forming iron caissons with curved
sides and flat ends with flanges on the top and botton of all the upper caissons,
and flanges on the top only of all the bottom caissons. Projections are made
vertically and at right angles with the ends of the caisson's to fit into each
other and form a puddle box when put together, and the caissons are built
end to end, and raised in tiers, with water and air-tight joints bolted together,
to the length and height required.

page_text: A
The apparatus consists of a condenser or chamber mixed on the top of
caisson, cylinder, or pier to be sunk, and is made to receive air through
flexible tubes means of an air pump worked by a steam engine to a pressure
sufficient to force out the water from the bottom of the caisson, cylinder, or
pier, and thereby enable workmen to sink the same down to a solid foundation
without the aid of pumps. The condenser or chamber is made to overhang
the caisson on each side, and when made shorter than the length of the
caisson the part not covered by the condenser or chamber is covered by an ex-
tension of the bottom plate of the condenser at each end, and the whole is fitted
and bolted on the top of the caisson with an air-tight joint, an opening being
left in the centre of the bottom of the condenser, and a man-hole formed in
the top. A similar arrangement is made for sinking piers and cylinders, the
condenser being made one way to overhang the piers or cylinders to effect the
discharge of the soil through the hopper. The condenser or chamber is made
of sufficient capacity for men to work in, and is fitted inside with a hopper for
discharging the soil or material excavated, and a small cistern, the hopper
being placed on the part of the condenser. that overhangs the caisson, and a
windlass is fixed over the opening left in the centre of the condenser for raising
the soil or material from the caisson. The hopper is fitted with two valves,
one at the top and the other at the bottom, and is made to receive the materials
excavated, which are tipped into the top as they are raised by the windlass
from the bottom of the caisson. The upper valve is left open to receive the
materials, and the lower one kept shut; but when the hopper is discharged
the action of the valves is reversed, the top being closed and the lower one
opened; when the lower valve is opened the materials drop out, and are dis-
charged through a spout, when required, into a punt or barge beneath. The
small cistern is fixed near the hopper, and connected thereto by a short pipe
fitted with a stop-cock, and receives the water drained from the materials in
the hopper. When the material is discharged and the bottom valve shut, the
stop-cock is opened to let out the water from the cistern into the hopper until
the pressure becomes equal to the air in the condenser, so as to allow the
upper valve to be easily opened. On again filling the hopper with the
materials, the water is again forced into the cistern, and the cock closed before
the bottom valve is re-opened. A pipe is attached to the hopper and descends
down the caisson in order to blow the water out of the caisson when required,
the top valve of the hopper being closed and the lower one opened for the
discharge of the water. When the caisson is sunk down to a good foundation
and the bottom well puddled, the condenser is lifted off and placed over the

page_text: next caisson to be operated upon in a similar manner, and so on with the rest
in succession. The caissons can be extended to any length, and are returned
at right angles when a cross dam is required, projections being made on the
broad side of the caisson to receive the ends of the adjoining caisson, and form
the box to receive the puddle.