IMPROVEMENTS IN STEAM ENGINES.
Year: 1863

page_text: LETTERS PATENT to John Milner, of No. 7, Bridge Street, Westminster,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
STEAM ENGINES.
Sealed the 17th July 1863, and dated the 23rd January 1863.
PROVISIONAL SPECIFICATION left by the said John Milner at the
* Office of the Commissioners of Patents, with his Petition, on the
23rd January 1863.
1, JOHN MILNER, of No. 7, Bridge Street, Westminster, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN STEAM ENGINES," to be as follows:-
Where two cylinders, are in proximity to each other, I employ two slide
valves. so constructed and arranged that each shall not only admit and discharge
steam to and from its own cylinder, but shall also, by itself or its adjuncts, cut
off the steam entering into the other cylinder at such part of the stroke of each
piston as may be desired.
The above general principle of my Invention can be carried out in various
ways, but the arrangement I prefer is as follows:-Each slide valve is formed
with passages through it for the admission of steam to the cylinder, and has
two faces, one face towards the cylinder and the other face (in contradistinction
called the back) towards and in contact with a plate or passage piece. This
plate or passage piece has four ways or passages with their apertures at
the surfaces in .contact with the slide valves, the backs of which are adapted to
open and close the ports or openings of such passages, in the order and at the
intervals necessary to admit steam to: the cylinders and to cut it off to obtain
the required expansion
1.. J

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Milner in the Great Seal Patent Office on the
21st July 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MILNER, of No. 7, Bridge Street, Westminster, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of January, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, 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 " IM-
PROVEMENTS IN STEAM ENGINES," upon the condition (amongst others) that
I, the said John Milner, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly 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 :-
Where two cylinders are in proximity to each other, I employ two slide
valves so constructed and arranged that each shall not only admit and discharge
steam to and from its own cylinder, but shall also, by itself or its adjuncts, cut
off the steam entering into the other cylinder at such part of the stroke of
each piston as may be desired.
The above general principle of my Invention can be carried out in various
ways, but the arrangement I prefer is as follows:-Each slide valve is formed
with passages through it for the admission of steam to the cylinder, and has
two faces, one face towards the cylinder, and the other face (in contradistinc-
tion called the back) towards and in contact with a plate or passage piece.

page_text: This plate or passage piece has four ways or passages, with their apertures at
the surfaces in contact with the slide valves, the backs of which are adapted to
open and close the ports or openings of such passages, in the order and at the
intervals necessary to admit steam to the cylinders, and to cut it off to obtain
the required expansion.
Figures 1 to 8 on Sheet I. of the accompanying Drawings, are Diagrams
serving to illustrate the principle of action of my improved slide valves when
they are employed in combination with a passage piece. Each Figure shews
the same valves and passage piece, but in different positions for indicating
clearly the various functions which they have to perform at certain parts of the
stroke of the pistons to the steam cylinders.
A and B represent the steam cylinders, of which only the steam and exhaust
ports C, D, E, F, G, H, and a portion of the pistons A' and B' are shewn.
The two cylinders have one common valve box L, L, in which are the slide
valve I to the cylinder A, the slide valve J to the cylinder B, and between
these the passage piece K. Each slide valve has two working faces, the one
working against its cylinder, acting as an ordinary slide valve, whilst the
other, which I call the back, working against the passage piece K acts
as the expansion slide to the other cylinder, such action taking place in the
following manner :-The passages c, e, of the valve I, admit steam respectively
into the ports C, E, of the cylinder A, when, by the motion of the valve the
apertures of such passages are respectively brought over the apertures of the
passages cand e in the passage piece K, and over the ports C, E, and when,
at the same time, by the motion of the valve J, the aperturej in the same is
brought respectively over the other apertures of the passages c' and e¹, the
steam passing from the valve box into the interior of the valve J through the
opening in the side of the latter, when, by the further motion of the valve J,
the communication between the aperture j, and the passages c¹ and e¹ is cut off,
the further ingress of steam into the cylinder A is prevented, and expansion
takes place.
In a similar manner the passages f, h, of the valve J admit steam respec-
tively into the ports F, H, of the cylinder B, when, by the motion of the valve,
the apertures of such passages are respectively brought over the apertures of
the passages f¹, h', in the passage piece K and over the ports F, H, and when
at the same time the opposite apertures of the passages fi, hi, are by the
inotion of the valve I uncovered respectively by the laps f* and * of this valve.
When by the further motion of the valve I, the laps f and h² of the same are
made to cover the apertures of the passages f' and h', the ingress of steam into
the cylinder B is cut off, and expansion takes place.

page_text: The eight Diagrams here shewn serve to indicate the various positions of
the slide valves for fulfilling the above described functions during one revolu-
tion of the crank shaft, the two pistons being coupled together at right angles
and the slide valves arranged without lead, and for cutting off steam at one
quarter of the stroke.
In Figure 1 the piston A¹ of the cylinder A is exactly at end up stroke, and it
will be observed that the valve J is in such a position as to admit steam freely
into the passage c', whilst the valve I, in moving in the direction of the arrow,
is just opening both the port cand the other aperture of the passage c' so as
to admit steam at top of the piston A', as shewn by the arrows; at the same
time the port E is already in communication with the exhaust port D, through
the passage d of the slide valve I. In the cylinder B the port F is open to
the exhaust port G through the passage 9 of the slide valve J, and the steam
is cut off and is expanding behind the piston B', which is performing its up
stroke. The various arrows shew the direction in which the steam is passing
to and from the cylinders as also the direction of the motion of the pistons
and slide valves. In Figure 2 the piston A' has just arrived at one quarter
of the down stroke, when it will be observed that, by the motion of the
valve J, the steam has just been cut off from the top of the piston A¹ although
the passage c of the valve I is still full open to the port C; the port E is full
open to exhaust, and the steam is still expanding beneath the piston B', whilst
the port F is still open to exhaust. In Figure 3 the piston B', has just
arrived at end up stroke, and the valve J has moved into such a position that
it is just opening the port F and admitting steam on top of the piston B¹,
through the passages f, f'; the lap of the valve I, having already, in the
position shewn in Figure 2, quite uncovered the other aperture of the
passage f, and being now about to pass over it again in its upward motion;
at the same time the port H of the cylinder B is already open to exhaust; the
steam is expanding on top of the piston A', and the port E is still full open to
exhaust. In Figure 4 the piston B' has just arrived at one quarter of its down
stroke, and the lap f of the valve I has by its upward motion just closed the
passage f¹, and consequently cut off the steam, although the passage f of the
valve J is still full over the port F: at the same time the port H is full open
to exhaust, the steam is expanding on top of the piston A', and the port E is
still open to exhaust. At Figure 5 the piston A¹ has arrived at end down
stroke, and is just commencing its up stroke, the valve I having already by its
upward motion slightly opened the steam port E, so that the steam is passing
in through the opening ; of the valve J, the passage e¹ of the passage piece
and the passage e of the valve I; at the same time the port C is open to

page_text: exhaust, whilst in the cylinder B the steam is expanding on top of the
piston B', and is passing to the condenser or atmosphere beneath the same.
In Figure 6 the piston A' is just arriving at quarter stroke, and consequently
the valve J is just closing the passage f of the passage piece, thereby cutting
off the steam. Everything else is still in the same condition as described with
reference to Figure 5. In Figure 7 the piston B¹ is just past end down stroke
and steam is consequently just being admitted beneath the same through the
passage h of the valve J, and the passage h' of the passage piece K. The steam
is passing to the condenser or atmosphere from the top of both the pistons A¹
and B and is expanding beneath the piston A. In Figure 8, the piston B¹
is just arriving at quarter stroke, and the valve I is just about to cut off the
steam from beneath the same, by the lap h³, closing the lap 1, of the passage
piece. Everything else is in the same condition as at Figure 7. From the
above described diagrams the action of my improved slide valves will be readily
understood, and. I will now proceed to describe some of the various forms and
arrangements of the valves which I prefer to employ for carrying my Invention
into practice.
Figures 9 to 22, on Sheet II. of the accompanying Drawings shew one
arrangement. Figure 9 shews a transverse section on line X, X, Figure 10,
of a pair of steam cylinders A and B, with their pistons coupled at right angles
placed in close proximity to each other, with one common slide valve box L
between the two, in which are situated the slide valve I to the cylinder A, the
slide valve J to the cylinder B, and, between the two, the passage piece K, K',
which in this case is formed in two separate parts, each of a wedge shape, so as
always to form steam-tight meeting surfaces with the backs of the valves I and J.
Figure 10 shews a longitudinal section through the valve box and ports on
line Y, Y, Figure 9; Figure 11 shews a side view of the passage piece K
detached; Figure 12 shews an end view of the same; Figure 13. shews. a
sectional plan on line Z, Z, Figure 12, and Figure 14 shews a longitudinal
section on line W, W, Figure 12. Figures 15 to 18 shew respectively a
plan of the face of the slide valve J, a section through the same at V, V;
Figure 15, a plan of the back, and a side view of the same. Figures 19 to 22
shew respectively a plan of the back of the slide valve I, a section through
the same at U, U; Figure 19, a plan of the face, and a side view of the same.
Similar letters of reference indicate similar parts in all the Figures.
In this arrangement, as in the before-described Diagrams, the slide valves
and passage pieces are so arranged as to cut off steam at one quarter stroke, but
by advancing the excentrics, or by making use of the "link motion". the
"cut off" may be made to take place earlier.

page_text: The functions of the various passages of the slide valves and passage pieces
are precisely the same as those of the passages in the before described Diagrams;
and in order to obviate a repetition of their description similar letters of re-
ference indicate similar valves, passages, and ports in both cases.
The passage piece is only formed into two parts to enable the cylinders to
be placed nearer together than could be effected were it to consist of a single
wedge-shaped piece, and the two parts K, K', together act in just the same
manner as though they were one, each part having precisely similar passages
to those of the other, which correspond to two precisely similar sets of openings
on the backs of each of the slide valves. The only difference existing between
the two parts K, K', of the passage piece consists in the addition to the upper
part K, of a contrivance by which, if required, the slide valves may be made
to work without cut off or as ordinary slide valves, instead of cutting off at
quarter stroke. For this purpose a space k is formed on the top of the
passage piece, into which the steam is free to enter, and in the lower surface
of this space are formed openings c³, e³, f³, h³ (seen in Figures 13 and 14),
communicating respectively with the passages c¹, e', f¹, h. Upon this surface
rests a plate M having corresponding apertures to those c³, e³, f³, h³, and
capable of being placed in such positions by means of the rod N, that these
apertures are either open or closed. If the apertures are open steam enters
the passages c, e, f, h', continuously, and the slide valves act as any ordinary
slide valves. In this condition supposing the faces of the slide valves to be
suitably proportioned, and the link-motion employed, the usual variations in
the admission and release of the steam may be obtained. If the apertures
are closed the steam can only enter such passages when permitted to do so
by the particular positions of the slide valves, as explained with reference to
the before-described Diagrams, and the steam is cut off at quarter stroke.
It is evident that, if requisite, the just described arrangement may be applied
to both the parts of the passage piece. Spaces m, m', are also formed between
the outer surfaces of each part of the passage piece, and the valve box covers
enclosed by suitable steam-tight packing n, n, as shewn, and a communication
is established between these spaces and the condenser or atmosphere, by which
arrangement a certain portion of the outer surfaces of the passage pieces may
be relieved from pressure, which owing to their wedge shape might otherwise
be exerted too greatly upon the slide valves. The passage pieces K, K¹, are
held stationary endways by being fitted between chipping pieces on the valve box
covers, as shewn, or they may be held in any other suitable manner, for instance,
by means of adjustable set screws, provided they are not thereby prevented
from being pressed by the steam against the backs of the slide valves; O is

page_text: the steam pipe to the valve box, and P is the eduction pipe to the cylinder B.
The formation of the slide valves will be readily understood by referring to
the various detached views and sections of the same at Figures 15 to 22;
Figure 18 shews one of the two side openings j¹, in the valve J, through
which the steam passes from the valve box into the hollow portion of the slide
'valve, whence it passes through the openings j, into the cylinder A, in the
manner as herein-before described with reference to the Diagrams on Sheet I.
of the Drawings.
Figure 23, Sheet III. shews a transverse section through another pair
of cylinders with a different formation of the slide valves and passage piece.
Here the faces of the ports to the cylinders A, B, and consequently
also the slide valves I, J, form an angle with each other, and the
passage piece K consists of a single wedge-shaped piece, fitting against
the backs of the slide valves, which are parallel to the faces; the passage
piece is, as in the before-described arrangement, provided with a space
k, in which are openings communicating with the passage c¹, and with
the others not shewn, and capable of being closed by the plate M, as
before described so as to render the engines capable of working more or
less expansively. A space m above the passage piece is here also shewn
enclosed by suitable steam-tight packing n, and is put in communication
with the condenser or atmosphere so as to relieve the valves from too
great a pressure. As the general arrangement of the various passages
are the same in this as in the before-described arrangement, the construc-
tion of the valves and passage piece will be readily understood from the
transverse section shewn, which corresponds with the transverse section shewn
at Figure 9, the same letters of reference indicating the corresponding cylinders,
valves, passages, ports, steam and exhaust pipes, to those in the arrangement
there described, and this observation also applies to Figures 24 and 25.
Figure 24 shews a transverse section through an arrangement in which
the faces of the ports to the cylinders A and B are placed at an angle,
as in Figure 23, but in which the passage piece K is formed with
parallel faces whilst the slide valves 1 and J are formed of a wedge shape;
the passage piece is therefore in this case not provided with the arrangement
for taking off the pressure from the same, as it does not exert any pressure
against the slide valves.
Figure 25 shews an arrangement in which the faces of the ports to the
cylinders A and B are both in the same plane; the slide valves I and J are
consequently working side by side with the passage piece K lying upon
the backs of both of them, which are also in the same plane. The only

page_text: difference between this form of the passage piece and those previously
described consists in the two angular or parallel faces, as in the other arrange-
ments, being here brought round so as to lie in one and the same plane as
shewn, the various passages being as it were bent round for this purpose.
In order to facilitate the passage of the steam into the openings j¹, of the
slide valve J, the slide valve I is formed with a passage i, through the upper
part over the exhaust passage, as shewn in dotted lines, so that the steam
can pass through the same into the valve J, besides passing in from the
other spaces between the valves and the side of the valve box. A space m
is enclosed by the packing n over the top surface of the passage piece,
as before described with reference to other arrangements, in order to
relieve the slide valves of too much pressure. This arrangement may be
so modified that the backs of the slide valves are made to form an angle
with each other, the faces being still kept in one plane, as shewn, when
the passage piece would be similar in form to that shewn in Figure 28;
or the faces of the ports and also those of the slide valves may even
be made to form a raised angle with each other instead of a hollow oue,
as in Figures 23 and 24, and the faces of the passage piece made to
correspond with them, that is, to form a hollow angle with each other. It
will be evident that various other modifications in the form and arrange-
ment of the slide valves and passage piece may be employed besides those
herein-before described as these serve merely to indicate the arrangements
which I consider the best. Thus my improved slide valves might be
readily adapted to compound high and low pressure engines; if, for instance,
the passage piece K, Figure 1, were made to divide the valve box L
into two separate compartments, having no communication with each other,
excepting through the passages f¹, c, e, h, and the space in which the
valve I. works were to receive steam from the boiler, whilst the space in which
the valve J works, were to receive the steam from the cylinder B, through
the exhaust passage g, of the slide valve J (such space being of course made
of sufficient capacity for constituting a suitable reservoir), it will be seen that
high-pressure steam would enter the cylinder B through the passages f¹, h,
and would be cut off by the valve I as before described, whilst the steam, after
doing duty in the cylinder B, would enter the cylinder A through the valve J
and passages c¹, e', and would be cut off by the valve J.
Figures 26 and 27 shew an arrangement of my improved slide valves in which
they are made to admit the steam to and to cut it off from the respective
cylinders, without the intervention of a passage piece as in the previously
described arrangements.

page_text: The functions of the passages and laps are precisely the same as in the
previously described arrangements, and they are designated by the same letters
of reference as those previously employed. The valves are here also arranged
to cut off at one quarter stroke; they have a certain amount of lead as will
be seen from their position, the piston A being in Figure 26, at end up
stroke, whilst the port C is already somewhat open to steam through the valve J
and passage c, as shewn by the arrows.
In Figure 27 the piston A is at quarter down-stroke and the steam is
just cut off from the top of the same by the valve J, which has already opened
the port H to exhaust, and closed the port F. The faces and backs of the
valves may be made to work steam-tight by making them of a wedge shape,
as previously described, or by constructing the valve J in two parts, as shewn,
the back of the same fitting into the body and being pressed by the steam
against the back of the valve I whilst the face of the valve J is pressed against
the face of the steam ports.
It will be evident that this latter mode of making the valves work steam-
tight may be employed in the before-described arrangements where a passage
piece is made use of, in which case both the valves and passage piece would
be made with parallel faces instead of wedge-shaped.
Having now described the nature of my Invention, and the best means I am
acquainted with of performing the same, I wish it to be understood that what
I claim is, the construction of slide valves to two steam cylinders that are in
proximity to each other in which each slide valve not only admits and
discharges steam to and from its own cylinder, but also, either by itself or in
combination with one or more passage pieces, serves to cut off the steam
entering into the other cylinder.
In witness whereof, I, the John Milner, have hereunto set my hand
and seal, this Sixteenth day of July, in the year of our Lord One
thousand eight hundred and sixty-three.
Witness,
C. D. ABEL,
20, Southampton Buildings.
JNO. MILNER. (L.S.)