IMPROVEMENTS IN SINKING TUBES, CYLINDERS, OR CAISSONS FOR THE FOUNDATIONS OF PIERS, LIGHTHOUSES, QUAY WALLS, AND SIMILAR STRUCTURES, AND FOR THE SINKING OF MINE SHAFTS AND WELLS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Thomas Scott at the Office of
the Commissioners of Patents, with his Petition, on the 7th April
1866.
I, THOMAS SCOTT, of Inverkeithing, North Britain, Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SINKING TUBES,
CYLINDERS, OR CAISSONS FOR THE FOUNDATIONS OF PIERS, LIGHTHOUSES, QUAY WALLS,
AND SIMILAR STRUCTURES, AND FOR THE SINKING OF MINE SHAFTS AND WELLS," to
be as follows:-
This Invention relates to an improved system or mode of sinking tubes,
cylinders, or caissons in mud, quicksand, and other soft substances, whether
intended to form the foundations of piers, lighthouses, quay walls, or other like
structures, or required in the sinking of wells or mine shafts, and has for its
object the ensuring the perpendicular descent of such tubes, cylinders, or
caissons through soil of varying density, and the avoidance of the necessity
of using heavy weight for forcing them down.
In carrying out this Invention in practice it is proposed to unite or group
together a series of iron tubes, cylinders, or caissons, or one large cylinder or
other shaped chamber may be used, dividing it into two or more parts or com-
partments, which are rendered air tight excepting at the bottom or mouth,.
and are furnished at the top with removeable but tight-fitting lids or covers
bolted or otherwise secured thereon. These cylinders are forced into the soil
by atmospheric pressure, and are controlled in their descent by allowing more
or less air to enter therein, as required. For this purpose the covers are fitted
with the necessary cocks and connections for enabling air to be forced in or

page_text: extracted from any one or more of the cylinders, the cocks being what are
generally known as three-way cocks, or single-way cocks, or valves may be
substituted as circumstances may require, whereby air may be introduced into
any one or more of the cylinders when a vacuum is not required, whilst at the
same time the exhausting pumps may continue their action upon those
requiring the vacuum to be maintained. By reversing the pipe connections of
the pumps they are rendered capable of acting either as exhaust or forcing
pumps, as may be required, or separate pumps may be applied for this
purpose; this affords facility for checking the descent of, or even raising, one
or more of the cylinders or chambers of the group during the sinking opera-
tion, and by giving perfect control over the cylinders insures the sinking of
the entire group in a perpendicular manner, those cylinders which may meet
with greater resistance having the vacuum therein increased, whilst those
which may be passing through a more yielding soil are checked by introducing
air therein.
If preferred bydrostatic power may be employed for raising the cylinders,
or, if they be raised pneumatically or hydrostatically pistons may be intro-
duced inside for more effectually securing the air or water, by which the
pressure is brought to bear equally upon the lower strata inside the chambers
and at the top of the same. The cylinders may be built on shore, and are
provided with a water-tight but removeable compartment in order that they
may be floated by forcing air between the same and the floating medium, thus
raising it in the water to the required height, when launched to the required
place the compartments above referred to are then removed, and the
cylinders sink to the bottom. By exhausting the air from their interiors the
cylinders will be forced into the soil by the atmospheric pressure alone.
Should the soil or stratum be of uniform density the cylinders will descend
vertically, but should this not be the case (and it is in cases of this kind that
the Invention will be found particularly beneficial), and the soil be of
different density, one cylinder or side will tend to sink faster than another,
and the group will lose its perpendicular. To check this tendency it is
simply necessary to so adjust the cocks that air will be admitted into those
cylinders meeting with least resistance. If it be required to sink the cylinders
or caissons to a greater depth than at first contemplated the covers can be
removed and fresh lengths added to the tops of the cylinders, after which the
covers are to be replaced again, and the operation of sinking carried on as
before.
The same system or method is applicable to the sinking of a single cylinder,
if required, by detaching the cylinder after being sunk and left standing,

page_text: whilst the remainder are raised. It is preferred to make the bottom plates of
each cylinder of steel, and in some cases the sides of the cylinders may be
carried up some height above the air-tight covers in order to form a tank,
into which water may be pumped with a view to assisting the atmospheric
pressure by the weight of the water; or the cylinders may be still further
weighted by building inside them a circular wall or lining of concrete, the
gravity of which acts in conjunction with the atmospheric pressure.
It is obvious that the same system may be applied to the sinking of
cylinders with a view to the lining of mine shafts or wells sunk through
quicksand or other wet strata.