IMPROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Edward Charles Fredcrick Otto
at the Office of the Commissioners of Patents, with his Petition, on
the 10th April 1875.
I, EDWARD CHARLES FREDERICK OTTO, of Camden Cottages, Camden
Town, in the County of Middlesex, Civil Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN STEAM ENGINES," to be
as follows:-
The Invention relates to means for the more efficient use of steam
expansively, and to means for controlling the motion of the engine so as
to secure uniformity of action without the necessity of employing a fly
wheel.
In carrying out my improvements I employ the common slide valve
with scarcely any lap inside the steam chest, and another one between
steam chest and boiler. Both valves being so arranged that when the
outer valve shuts off the steam between the boiler and steam chest, the
inner valve will just begin to open and allow the steam to expand in the
cylinder and steam chest, driving the piston to the other end of the
cylinder. The outer valve remains shut till the inner one begins to

page_text: shut-off the steam in the cylinder from that in the steam clicst, it will
then open and allow the steam to enter the steam chest to be ready for
entering the other end of the cylinder when the inner valve has shifted
to the other side. As in this case the power on the piston is constantly
decreasing and is at the end of the stroke nil. Recesses are formed in
the surfaces of the valve seats to receive steam and lubricating matter
to aid the easy working of the respective valves.
To ensure uniformity of action to the engine a toothed wheel on the
crank shaft drives another one of half the diameter of the first, provided
with a crank pin that will stand exactly at night angles to the principal
crank pin while at one of the dead points To this smaller crank pin I
apply a connecting rod and piston which is either acted upon in its
cylinder by steam or water from the boiler, or by springs, or by other
clastic body, air, or gases.
When the principal piston is at the dead point at the end of, say the
down stroke, and travelling from left to right, then the other crank pın
will be, say on the left-hand side in position to exert the greatest power
to turn the smaller crank, and with it the larger one over that dead
point till the smaller piston has arrived at the end of its upward stroke,
and with it its crank pin when it will have gradually relinquished its
power over the principal crank. By this time the larger crank pin will
have made one eighth of the whole circumference of its movement, and
the steam being fully on it will have arrived at the position for the
exercise of the full power of the engine.
In the further movement of the larger crank its power increases,
but at the same time the smaller piston begins to move down, at first
slowly, but with an increasing speed against the clastic power applied
under that piston, till the larger crank pin has arrived at one-fourth of its
rotation, when the smaller one will be exactly in the middle of its stroke
on the right hand side At this stage the power of the larger crank pin
begins to diminish the storing up of power in the smaller piston as the
crank of the last named is quickly losing the power of its leverage, and
is arriving at the dead point of the down stroke, while the larger crank
pin is at three-cighths of its circumference. This last position finishes
the storing up of power in the smaller piston, and all further movements
of both pistons are in concert with each other, that is to say, while the
larger crank pin moves up to the dead point and altogether relinquishes

page_text: its power there, the smaller crank pin will be increasing in power and
exert its greatest force when the other crank is at nil, thereby carrying
the larger crank over its dead point.
The smaller crank will diminish its power and will be at its dead point
when the larger one has arrived at five-eighths of the circumference, and
has full steam under its piston The last three-eighths of the movement
continue in the same manner till the large piston has made one up and
one down stroke, while the smaller one has made two up and two down
strokes without using any steam. An engine thus arranged will run
without fly wheel, and though it has only one cylinder the power
exercised will be a constant power at all positions of the rotation of the
crank pin.