IMPROVEMENTS IN STEAM ENGINES
Year: 1853

page_text: LETTERS PATENT to John Milner, of Stratford, in the County of
Essex, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
ENGINES."
Sealed the 25th March 1854, and dated the 6th October 1853.
PROVISIONAL SPECIFICATION left by the said John Milner at
the Office of the Commissioners of Patents, with his Petition, on
the 6th October 1858.
I, JOHN MILNER, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM ENGINES" to be as follows:-
I employ two working cylinders with pistons and piston rods and
connecting rods constructed in the usual manner, and connected to two
cranks placed at right angles to each other on the same shaft, and I
prefer to make one of these cylinders of greater capacity than the
other. The cylinders are provided with valves worked by cams or
excentrics, and so arranged that steam may be admitted from a boiler
into the top of the first or smaller cylinder until the piston has made
half its stroke, and then shut off; a communication is then opened
between the top of the first cylinder and the top of the second one,
whose piston is then at the top of its stroke.
Both pistons will now

page_text: descend until the small one has reached the end of its stroke, when the
second piston will be at half stroke. The motion still continues, and
the first piston begins to return and reaches its half stroke when the
second piston has completed its stroke. The steam which was at first
contained in one half of the first cylinder will now have expanded so
as to fill the whole of the second cylinder and one half of the first
cylinder. The steam is now discharged into the condenser or into
the atmosphere. When the first piston reaches the end of its stroke
as above mentioned, the steam from the boiler is admitted to the bottom
of the first cylinder until its piston has made one half of its stroke; the
steam is then cut off, and the half cylinder full of steam is allowed to
expand into the bottom of the second cylinder, in the manner above
described. Thus the second cylinder is open to and receiving its steam
from the first cylinder during the whole of the stroke of the second
piston. For reversing the engine a passage or passages, and a valve or
valves, are arranged so as to connect the top of the first cylinder with
the bottom instead of with the top of the second cylinder, and vice
The relative dimensions of the two cylinders, and the point at
which the steam is cut off from the first cylinder, may be varied accord-
ing to the degree of expansion required. The position of the cylinder
may be vertical, horizontal, or inclined, and the angle of the cranks
may also be somewhat varied.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Milner in the Great Seal Patent Office on
the 5th April 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN MILNER, formerly of Stratford, in the County of Essex, but now
of Coleshill Street, Pimlico, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of October, in the year of
our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,

page_text: give and grant unto me, the said John Milner, Her special licence
that I, the said John Milner, my executors, administrators, and assigns,
or such others as I, the said John Milner, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN STEAM ENGINES,"
upon the condition (amongst others) that I, the said John Milner,
by an instrument in writing under my hand and scal, should particu-
larly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Milner, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying
Drawings, and to the figures and letters marked thereon, that is to say:
I employ two working cylinders with pistons and piston rods and
connecting rods constructed in the usual manner, and connected to two
cranks placed at right angles to each other on the same shaft, and I
prefer to make one of these cylinders of greater capacity than the
other. The cylinders are provided with valves worked by cams or
excentrics, and so arranged that steam may be admitted from a boiler
into the top of the first or smaller cylinder until the piston has made
half its stroke and then shut off; a communication is then opened
between the top of the first cylinder and the top of the second
one, whose piston is then at the top of its stroke. Both pistons
will now descend until the small one has reached the end of its
stroke, when the second piston will be at half stroke. The motion
still continues, and the first piston begins to return and reaches its
half stroke when the second piston has completed its stroke.
steam which was at first contained in one half of the first cylin-
der will now have expanded so as to fill the whole of the second
The steam is now dis-
cylinder and one half of the first cylinder.
The

page_text: charged into the condenser or into the atmosphere. When the first
piston reaches the end of its stroke, as above mentioned, the steam
from the boiler is admitted to the bottom of the first cylinder until its
piston has made one half of its stroke. The steam is then cut off, and
the half cylinder full of steam is allowed to expand into the bottom of
the second cylinder, in the manner above described. Thus the second
cylinder is open to and receiving its steam from the first cylinder during
the whole of the stroke of the second piston. For reversing the
engine a passage or passages, and a valve or valves, are arranged so as
to connect the top of the first cylinder with the bottom instead of with
the top of the second cylinder, and vice versa. The relative dimen-
sions of the two cylinders, and the point at which the steam is cut off
from the first cylinder, may be varied according to the degree of expan-
sion required. The position of the cylinder may be vertical, horizontal,
or inclined, and the angle of the cranks may also be somewhat varied.
Figure 1, Sheet I., of the accompanying Drawings, is a plan of a
steam engine with horizontal cylinders constructed according to my
Invention. This Figure will also serve to represent a similar engine
with vertical or inclined cylinders.
A, A', are the cylinders; B, B', are the piston rods; C, C³, are the
connecting rods attached to the cranks D, D', placed at right angles to
each other on the main shaft E; F, F, are the excentrics, and G, G',
their rods connected respectively to the valve rods H, H'; I, I', are
guides for the piston rods.
Figures 2, 3, 4, and 5, are longitudinal sections of the cylinders and
valves, shewing the arrangements for producing the required effects.
The same parts are indicated by the same letters as in Figure 1.
J, and J', are the pistons of the first and second cylinders respec-
tively. K, is a valve box which is supplied with steam from a boiler,
which is admitted by means of the slide valves L, M, into the first
cylinder. The eduction passage N, from the bottom valve L, com-
municates with the bottom of the second cylinder A', while the eduction
passage O, from the top valve M, communicates with the top of the
second cylinder. P, is a plain flat side valve working in a valve box
in communication with the bottom of the second cylinder A', and
opening and closing a passage Q, leading into the condenser or into the

page_text: atmosphere when tho engine is non-condensing. R, is a similar
slide valve working in a valve box communicating with the top of the
second cylinder A¹, and opening and closing a passage S, leading to the
condenser or to the atmosphere when the engine is non-condensing.
In Figure 2, the piston J of the first cylinder is at the bottom of
its stroke, and the piston J' of the second cylinder is consequently at
its half stroke or thereabouts. The valve L is rising in the direction
shewn by the arrow, and is just beginning to admit the steam from the
boiler under the piston J.
In Figure 3, the piston J has made about one half of its strokes,
and the piston J¹ is at the bottom of its stroke. The valve L, is now
descending, and having shut off the steam, is on the point of opening
the communication from the bottom of the first cylinder A, to the
bottom of the second cylinder A³.
In Figure 4, the piston J has arrived at the top of its stroke, and
the piston J is consequently at or near its half stroke. The com-
munication between the bottoms of the two cylinders is still full open.
The piston J now begins to descend until it reaches its half stroke or
thereabouts, when the piston J' has completed its upward stroke as
shewn in Figure 5. The steam which at first was contained in one
half or thereabouts of the first cylinder A, has now expanded, so as to fill
the half of the first cylinder A, and the whole of the second cylinder A².
The valve P, is now opened, and the steam escapes from both cylinders
to the condenser. Both pistons descend until the piston J, has reached
the bottom of its stroke as shewn in Figure 2, when the valve L
ascends, shutting off the communication with the second cylinder, and
admitting steam from the boiler into the bottom of the first cylinder as
before. The eduction valve P continues open until the piston J' has
reached the bottom of its stroke as shewn in Figure 8, when the steam
from the bottom of the first cylinder is again admitted as before.
The valves M and R, at the tops of the cylinders act in a similar
manner to the valves L and P, at the bottoms of the cylinders.
The steam is thus caused to expand in the proportion which the sum
of half the contents of the first cylinder, and the whole of the contents
of the second cylinder, bear to half the contents of the first cylinder.
In the Figures the cylinders are so proportioned, that the contents of

page_text: the second cylinder are about two and a half times the contents of the
first cylinder, so that the steam will thus be expanded to about six
times its original volume. The relative dimensions of the cylinders
may be varied to obtain different proportions of expansion. Thus, if
the cylinders be of equal contents, the steam will be expanded about
three times. The expansion may be increased by arranging the valves
to cut off the steam from the first cylinder before its piston has arrived
at the half stroke. The expansion may also be varied by somewhat
varying the angle of the two cranks, so as place them at rather more or
rather less than ninety degrees from each other. I, however, prefer to
fix the cranks at right angles to each other, and to cut off the steam
from the first cylinder and admit it into the second cylinder when the
piston of the first cylinder is at or close to the middle of its stroke, and
the piston of the second cylinder is at the end of its stroke. A similar
effect may be obtained by inclining the axes of the cylinders so as to
form an angle of ninety degrees with each other, and connecting both
pistons to the same crank. Various other arrangements may be
adopted, provided that in each case the one piston may be at the end
of its stroke when the other is at or near the middle of its stroke.
In the above description, I have described the engine as continually
moving in the same direction as is generally the case with stationary
engines, but in some cases, as, for example, in marine and locomotive
engines, it is required to have the power of reversing the engine so as
to drive it in either direction. For this purpose the excentrics F, F,
are made loose upon the shaft E, in Figure 1, and are driven by stops
fixed on the shaft in a manner which is commonly practised in marine
engines and well understood. When the motion of the shaft E is
reversed, the one set of stops leave the excentrics, which remain
stationary until the other stops come in contact with them, and carry
them round in the reverse direction. In addition, however, to this
motion of the excentrics, it is necessary to alter the course of the steam,
so that in lieu of its passing from the bottom of the first cylinder to the
bottom of the second cylinder, and from the top of the first to the top
of the second cylinder, it may be compelled to pass from the bottom of
the first to the top of the second cylinder, and from the top of the first
to the bottom of the second cylinder.

page_text: Figures 6, and 7, Sheet II., are sections of the cylinders and valves,
shewing also a reversing valve T, adapted for producing the aforesaid
change in the course of the steam. U, is the valve rod, which passes
through a stuffing box, as shewn also in Figure 1. The valve T, con-
sists of a tube having an enlargement or piston t, at each end, packed
to fit the valve box V, in which the valve is capable of sliding up and
down. The steam from the eduction passage N, at the bottom of the
first cylinder A, is conveyed by a pipe or passage (indicated by dotted
lines) to the bottom of the valve box V, and is thus put in communi-
cation with the interior of the valve T. The steam from the eduction
passage O from the top of the first cylinder is conveyed by another
pipe or passage (also indicated by dotted lines) into the space between
the valvo box V, and the exterior of the valve T. Two passages or
ports v, v', communicate from the valve box V, respectively with the
bottom and top of the second cylinder A'. When the valve T, is raised
into its highest position, as in Figure 6, the steam from the bottom of
the first cylinder passes to the bottom of the second cylinder, and the
steam from the top of the first cylinder passes to the top of the second
cylinder, and the effect is the same as herein-before described in
reference to Figures 2, 3, 4, and 5. When, however, the valve T is
made to descend into the position shewn in Figure 7, the course of
the steam is reversed, so that the steam from the bottom of the first
cylinder passes up through the tubular valve T, and enters the top
of the second cylinder, while the steam from the top of the first
cylinder descends between the tubular valve T, and the valve box V,
and enters the bottom of the second cylinder. The motion of the
valves L, M, P, R, is, at the same time, changed by the excentrics
shifting their positions on the shaft as already mentioned. It will
be seen, by examining the positions of the pistons and valves in
Figure 6, that steam is entering below the first piston and above
the second piston, and consequently the first is ascending, and the
second descending, as shewn by the arrows. In Figure 7, it will
be seen that steam is entering below both pistons, which are conse-
quently both ascending, as shewn by the arrows. The motion of the
crank shaft will thus be in the opposite direction in the one case to

page_text: what it is in the other case. By placing the valve T at an inter
mediate position or half stroke, the passages v, v', may both be closed,
and the engines thus stopped.
Having now described the nature of the Invention, and in what
manner the same is to be performed, I wish it to be understood that
I do not confine myself to the particular construction or arrangement
of valves shewn in the Drawings, as the same may be varied, and the
valves may be driven by cams or otherwise instead of by excentrics.
But what I claim is the constructing steam engines with two cylinders,
whose pistons are in connection with two cranks placed at right angles
to each other, or which are otherwise so arranged that when one piston
is at the end of its stroke the other piston may be at or near to the
middle of its stroke, such cylinders being provided with valves and
valve gear so arranged as that the first cylinder may be about half
filled with steam, and that a communication may then be opened
between that end of the first cylinder so filled with steam and the
second cylinder, such communication remaining open during or nearly
unto the end of the stroke of the second piston, and until the first
piston has made one half (or thereabouts) of its return stroke, when
the steam which has thus been expanded is discharged into the atmo-
sphere or into the condenser.
In witness whereof, I, the said John Milner, have hereunto set
my hand and seal, this Thirty-first day of March, in the year
of our Lord One thousand eight hundred and fifty-four.
Witness,
CHARLES COWPER,
20, Southampton Buildings,
Chancery Lane,
London.
JNO. MILNER. (L.S.)