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

page_text: LETTERS PATENT to Henry Davey, of 9, Victoria Chambers, in the
City of Westminster, Engineer, for the Invention of "IMPROVEMENTS
IN STEAM ENGINES, PART OF WHICH IS APPLICABLE TO STEAM PUMPS."
Sealed the 19th March 1869, and dated the 26th September 1868.
COMPLETE SPECIFICATION filed by the said Henry Davey at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 26th September 1868, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
DAVEY, of 9, Victoria Chambers, in the City of Westminster, Engineer,
send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
STEAM ENGINES, PART OF WHICH IS APPLICABLE TO STEAM PUMPS," and have
petitioned Her Majesty to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the true and first Inventor thereof,

page_text: that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and in
what manner the same is to be performed, in and by the following
statement:
:
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 points in the stroke of the engine at
which the supply stream is cut off with the varying resistances which
the engine has to overcome.
Secondly. In an improved means by which the piston of direct-acting
steam engines is controlled, so that the engine is made to work smoothly,
and is particularly applicable to steam pumps.
Thirdly. In means by which the steam valves of direct-acting pumping
engines are actuated.
In carrying out the first part of this Invention I employ the ordinary
D slide valve in conjunction with an expansion valve, or any other
convenient arrangement, such as separate steam and exhaust valves, and
in order that the admission valve or valves may be actuated so as to
produce a variable cut-off by means of the governor I employ a small
moving cylinder with a piston in it, the said piston being connected
to the admission valve or valves by means of a rod or otherwise. The
said cylinder, which may be actuated by means of an eccentric or any
other convenient device, is filled with a suitable liquid, and is provided
with an opening or passage leading from one end to the other, the said
opening being fitted with a plug or 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 made to open the said passage, and thereby allow
the oil or other liquid to flow from one side of the said piston to the
other, thus releasing the admission valve, which is made to close quickly
by means of a spring, or from being attached to a subsidiary piston
submitted to steam pressure, or by any other convenient device. The
said plugs or valves are caused to open by means of suitable connections
coming into contact with a wedge or triangle which is moved by means
of the governor, and as the position of the wedge or triangle is varied
so will the points at which the steam is cut off vary; or the said cylinder
may be fixed, and the said wedge or triangle be made to actuate the

page_text: said valves or plugs by having a motion given to it at right angles to
the motion which it derives from the goveror.
In carrying out the second part of this Invention I employ a piston
or pistons attached to the steam piston of direct-acting steam engines,
which first-named piston or pistons is during the working of the engine
constantly submitted to the pressure of the steam in the boiler, but
that pressure is transmitted through water, the cylinder, herein-after
called the water cylinder, or part of the cylinder containing the said
piston or pistons being connected with the boiler by means of a passage
or pipe below the water level. The above-named water cylinder is
provided with a passage leading to the boiler, or to a pipe attached to
the boiler, or the said passage is made to lead from one end of the said
cylinder to the other. During the working of the engine the water
contained in the water cylinder is made to pass alternately from one
side of the piston to the other through a passage or pipe, or, as in the
case of single-acting pumps, from the said cylinder into or towards the
boiler, and back again alternately. The passage or pipe through which
the water enters and leaves the water cylinder or through which it.
passes from one side of the piston to the other is provided with a plug
or valve, by means of which the flow of the water may be regulated,
and consequently the speed of the engine governed.
In carrying out the third part of this Invention I cause the admission
and emission valves or valve of steam engines to produce expansive
working of the steam, either variable or fixed, in the following manner:——
The main slide valve is connected by means of a lever and rods or
otherwise to a small steam piston contained in a small subsidiary
cylinder, the length of the said cylinder being sufficient to admit of
a movement of the said piston sufficient to produce the maximum
stroke of the valve to which the said piston is attached. At the back
of the main slide valve is placed an expansion valve, which is actuated
by means of any convenient arrangement of connections from the piston
of the engine. Attached to the expansion valve is provided a small
slide valve, which is made to admit steam to and exhaust steam from
the small subsidiary cylinder at the termination of each stroke of the
engine, so as to reverse or move the main slide valve.
That my Invention may be clearly defined, I have prepared two
Sheets of Drawings hereunto annexed, the same letters of reference
indicating corresponding parts throughout corresponding Figures.

page_text: Figs. 1 and 2, Sheet 1, represent longitudinal sections of the valve
gear for producing variable expansion by means of the governor ac-
cording to my Invention.
A and B are steam valves; D, the moving cylinder containing oil or
other liquid; H, a piston; I, a piston working in a fixed cylinder con-
taining a liquid, the last-named piston fits loosely, and allows the
liquid to escape past it, the object of which is to check the too sudden
closing of the valves; F is the crank handle of a plug or valve; E is a
triangle attached to the governor. As the triangle E is raised or lowered
the crank F comes into contact sooner or later with the triangle and
opens the plug or valve, and thus allowing the liquid to escape from
one of the ends of the cylinder to which the plug is attached the cut-
off takes place, the steam admission valve or valves being closed by
means of a small subsidiary steam piston, or otherwise. Figs. 3 and 4
are transverse sections of Figs. 1 and 2;. Figs. 5 and 6 are elevations of
the moving cylinder and the triangle; Fig. 7 is an elevation of an
engine with the said gear attached.
Figs. 8 and 9, Sheet 1, are longitudinal sections and part elevation of
a pumping engine according to the second part of this Invention.
Figs. 10, 11, 12, and 13, Sheet 2, are similar sections of similar engines,
and the same letters of reference are used to indicate corresponding
parts throughout corresponding Figures..
A is a piston submitted to the water pressure from the boiler; B is
the steam piston, and C the pump piston; D, the governing plug;
E, the suction valve of the pump; F, the delivery valve; G, an
air vessel.
Fig. 11, Sheet 2, shews a longitudinal section of the valve arrange-
ment according to the third part of this Invention. H is the main
slide valve; I, the expansion valve, and K a small valve at the back
of the expansion valve. At the completion of the up-stroke of the
piston B steam is admitted on the top of the small piston L, and thereby
caused to move the main slide valve, so as to give steam for the return
stroke of the piston B. During the travel of the expansion valve I
on the back of the main valve H the steam is cut off by means of the
valve I closing either of the steam ports M or N. The degree of
expansion may be varied by causing the lever O to move between
adjustable stops or guides.

page_text: Having described the nature of my Invention, and the manner in
which the same may be carried into effect, I would, in conclusion,
observe that what I consider to be novel and original, and therefore
claim as the original Inventor,-
First. The employment of a cylinder containing a liquid, in the
manner herein-before described, for the purpose of producing variable
cut-off in expansive working engines.
Second. The combination of gear for producing a variable cut-off in
expansive working engines, in the manner herein-before described.
Third. The controlling the pistons of direct-acting steam engines, in
the manner herein-before described.
Fourth. The combination of parts of direct-acting pumping engines,
in the manner herein-before described.
Fifth. The employment of means by which the admission and
emission valves of direct-acting engines are actuated, in a manner
herein-before described and illustrated.
In witness whereof, I, the said Henry Davey, have hereunto set
my hand and seal, this 26th day of September, in the year of
our Lord One thousand eight hundred and sixty-eight.
HENRI DAVEI. (U.S.)