A NEW MODE OF AND APPARATUS FOR PRODUCING AND OBTAINING AN HYDRO- PNEUMATIC MOTIVE POWER
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by Bartolomeo Predavalle at the
Office of the Commissioners of Patents, with his Petition, on the 28th
October 1861.
I, BARTOLOMEO PREDAVALLE, of 143, Fleet Street, in the City of London,
Civil Engineer, do hereby declare the nature of the said Invention for
"A NEW MODE OF AND APPARATUS FOR PRODUCING AND OBTAINING AN HYDRO-
PNEUMATIC MOTIVE POWER," to be as follows:-
My Invention consists in an atmospheric pressure imparting its gravitation
on a column of liquid communicating alternately with a cylinder under the
piston, the rod of which fits air-tight into the upper part of the cylinder in
which the vacuum is produced.
DESCRIPTION OF THE APPARATUS.
In a cylinder shut up in both sides a piston is adjusted touching exactly the
upper part of the cylinder so as to displace all the air through the space
round to the rod which passes out of the cylinder, and it is constructed in a
manner to permit a stuffing box to be adapted on the upper exterior part of
the cylinder so as to maintain the moving rod air-tight. On the extremity of
the rod is applied a lever with a weight in order to press it down. A column
of liquid communicates at the bottom with the interior part of the said
cylinder so as to touch the lower part of the said piston; when by a contri-
vance in the machine a valve is shut up, cutting off the liquid communicating
with the interior of the cylinder and the column of liquid, and a stop-cock in

page_text: the extremity of the said cylinder is open. The weight on the lever being
placed at such a distance as to produce by its pressure a depression on the
piston, a vacuum between the piston and the upper part of the cylinder is
produced, and the water is compressed. This weight, by a contrivance in the
apparatus, must move a little on the lever in order to press more when the
valve is shut up and less when it is open, in order that the pressure of
the column of liquid be able to raise the piston. The consequence of such an
arrangement is, that the volume of the compressed water (which it is better
should be small) intercepted in the interior part of the cylinder pressed by
the piston, is compelled to rush out from the open stop-cock acting against
the adapted mechanical resistance to be overcome. Whatever may be the
mechanical means employed to overcome the resistance, it must be observed,
that they must be at such a level as to discharge the compressed water into
the reservoir of the column of liquid after having wasted its disposable force;
for instance, if the compressed water is acting in a cylinder against a piston,
it is better to put the cylinder horizontal, because if the column of water is
stationary, the compressed water must return to the reservoir to maintain the
same height of level, and if it is moving as in the sea, it must be discharged
above the level of it. When the effect is produced, and the compressed water
is gone the stop-cock is shut up, and the valve between the column of liquid
and the interior part of the cylinder is open, and the consequence will be, that
the piston pressed by the water will rise on the cylinder by the pressure of the
column of liquid in order to produce the same effect as before described.