492
DOCK ENGINEERING.
Hydraulic Lift at London.
The following account of Clark’s hydraulic lift at the Victoria Docks,
London, is extracted from an article by Mr. G. B. Rennie in the Practical
Mechanic’s Journal Record of the Great Exhibition of 1862 :—
“ The life (fig. 483) consists of an excavated channel, of about 300 feet
long and about 60 feet broad, on each side of which 16 cast-iron columns,
5 feet in diameter, are sunk about 12 feet into the ground, 20 feet from
centre to centre. At the bottom of the column there is a hydraulic press or
lift. The diameter of the ram is 10 inches, with a travel of about 25 feet.
On the top of the piston or ram a wrought-iron crosshead is fitted, from
which iron links are suspended and connected with a cast-iron girder, one
on each side of the column, so that there are 16 coupled girders of about
60 feet length and 20 feet apart, each couple being suspended and lifted by
Elg. 483. —Hydraulic Lift.
two hydraulic rams or pumps. On the top of these girders a pontoon is
placed at the requisite length. These pontoons vary from 150 to 320 feet
in length, and are 59 feet broad. The smaller are placed on 8 sets of coupled
girders and the larger on the whole 16. They are made of sufficient depth
for stiffness and in order to give the required displacement, so that when
empty they have buoyancy enough to keep the vessel well out of the water.
The pistons or rams are worked by a pair of horizontal engines made by
Messrs. Easton & Amos. These engines are on the expansive condensing
principle, with one high-pressure cylinder of 23 inches diameter and 2 feet
stroke, and two expansive cylinders of 33^ inches diameter with the same
stroke. The steam expands from the small cylinder into the two larger
ones ; pressure of steam per square inch, 50 Ibs.; indicated horse-power, 120.
The engines work 12 hydraulic force pumps of 1'96 inches diameter and
2 feet stroke in three groups—viz., two groups of 3 and one of 6 pumps.