IMPROVEMENTS IN STEAM ENGINES, PART OF WHICH IS APPLICABLE TO STEAM PUMPS
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Henry Davey at the Office of
the Commissioners of Patents, with his Petition, on the 26th
. March 1868.
HENRY DAVEY, of 9, Victoria Chambers, in the City of West-
minster, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM ENGINES, PART OF WHICH IS APPLICABLE TO
STEAM PUMPS," to be as follows:-
This Invention consists, first, in an improved means by which the
admission and emission valves of steam engines are actuated, so that
the governor is made to vary the point in the stroke of the engine at
which the supply steam is cut off, with the varying resistances or work
which the engine has to overcome, or as it is termed, variable expansion
produced by means of the governor.
Secondly. In an improved means by which the piston of direct-acting
steam engines is controlled, so that the engine works smothly and is
peculiarly applicable to steam pumps or pumping engines.
And, thirdly. In means by which the steam valves of such engines
are actuated.

page_text: In carying out the first part of this Invention I employ separate
steam and exhaust valves; and in order that the steam valves may be
caused to close at varying points of the stroke of the engine by means
of the governor, I employ a moving cylinder with a piston in it, the
piston being attached to the steam valve or valves by means of a rod
or otherwise. The said cylinder, which may be driven by means of
an eccentric or any other convenient device, is filled with a suitable
liquid, and is provided with an opening leading from one end to the
other, the said opening being fitted with a plug, plugs, valve or valves.
As the said cylinder is moved by means of the engine to which it is
attached, the valves or plugs are caused to open the said communication
between the two ends of the said cylinder, and thus allow the oil or
other fluid to flow from one side of the piston to the other, thus releasing
the steam valve or valves, which may be made to close by means of
steam or a spring, or in any other convenient way. The said valves
or plugs are made to open by means of suitable connections coming
in contact with a triangle or wedge which is moved by means of the
governor, and as the position of the wedge or triangle is altered, so
the cut-off takes place sooner or later. The said cylinder may be fixed,
and the triangle which derives one motion from the governor may be
made to oscilate in a direction at right angles to. that motion, and thus
actuate the said plugs or valves. The mode of making the steam valves
steam closing is clearly defined on the Drawings.
In carying out the second part of this Invention I admit steam to
one side of the piston to produce the stroke in one direction, whilst the
other side of the said piston is open to the atmosphere or to the exhaust
pipe. Another piston,, herein-after called the water piston, connected
to the one above named, is submitted to the pressure of the steam in
the boiler constantly, but that pressure is transmitted through water,
the portion of the cylinder containing the water piston being in com-
munication with the boiler below the water level. During the steam
stroke of the engine the water contained in front of the water piston
is driven back towards or into the boiler, and during the return stroke
the water returns and steam is exhausted. The piston is controlled
by means of a plug or stopper, which can be made to contract the
opening through which the water enters to and leaves the water. piston.
In carrying out the third part of this Invention I make the piston
of direct-acting engines actuate the valves which give admission and

page_text: emission to the steam, in such a manner as is shown on the Drawings
hereinto annexed.
=
That my Invention may be clearly defined I have hereinto annexed
four Sheets of Drawings, the same letters of reference indicating corre
sponding parts throughout corresponding Figures.
Figures 1 and 2, Sheet 1, represent longitudinal sections of the valve
gear (not complete) for producing variable expansion by means of the
governor, according to my Invention. Figures 3 and 4 are transverse
sections, and Figure 5 an elivation (not complete) of an engine with
the said gear applied. A, B, are steam valves; D, the moving cylinder
containing oil or other liquid; H, a piston; I, a piston working in a
fixed cylinder containing a liquid; the last-named piston fits loosely
and allows the liquid to escape past it, the object of which is to check
the motion of the valves when closing; F is a crank handle of a plug
or valve; E is a triangle attached to the governor; G, G, are recesses
at the back of the valves A, B, in the valve casing; K is a space in
which steam is received from the boiler.
Figures 6 and 7, Sheet 2, are sections of a pumping steam engine,
with the improvement according to the second part of this Invention.
Figures 8 and 9, Sheet 3, are similar sections and part elevation of
a similar engine with a steam moved valve; H, I, are openings or ports;
K is a piston; E, the steam valve; M, the steam pipe; A, the water
piston; B, the pump piston; C, the steam piston; E, the steam valve;
F, a spring; G, the exhaust pipe; D, a plug.
Figures 10 and 11, Sheet 4, are sections and part elevation of an
engine on the same principle as the last named, and the same letters
of reference are used.
Having described the nature of my Invention, and the means by
which it may be carried into effect, I would in conclusion observe that
what I consider to be novel and original, and therefore claim,-
First. The employment of a cylinder or cylinders, containing a liquid
for producing variable cut-off in expansive working engines, in the
manner herein-before described.
Second. The employment of means by which the steam valves are
made steam closing, in a manner as herein-before described and.
illustrated.

page_text: Third. The combination of gear for producing variable cut off, as
herein-before described and illustrated.
Fourth. The controlling the pistons of direct-acting steam engines,
in the manner herein-before described.
Fifth. In the combination of parts of direct-acting pumping engines,
in the manner herein-before described and illustrated.