IMPROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the
County of Middlesex, Patent and Registration Agent, for the In-
vention of "IMPROVEMENTS IN STEAM ENGINES "-A communication
from abroad by Alfred Пoyois, of Clabecq, in the Kingdom of
Belgium. Civil Engineer
PROVISIONAL SPECIFICATION left by the said William Brookes at
the Office of the Commissioners of Patents, with his Petition, on
the 5th April 1875.
I, WILLIAM BROOKES, of 62, Chancery Lane, in the County of
Middlesex, Patent and Registration Agent, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN STEAM ENGINES,"
(communicated to me from abroad by Alfred Hoyois, of Clabecq, in
the Kingdom of Belgium, Civil Engineer), to be as follows:-
This Invention, as communicated to me, relates to that class of steam
engines in which the steam is admitted to and discharged from the
cylinder by separate valves. And it consists, firstly, in the improve-

page_text: ments hercin-after described in the construction and adaptation of the
annular disc valves described in the Specification of Letters Patent
granted to the said Alfred Hoyois, bearing date the 19th of July 1873,
No. 2490.
Instead of the said annular disc valves being made flat or slightly
conical, and resting directly upon their double valve scats, as described
in the said Specification, whereby considerable pressure of steam upon
the said valves has to be overcome in opening the steam passages or
ports, according to this part of the Invention the steam and exhaust
passages are opened and closed by annular valves of nearly rectangular
section, which valves fit on their respective valve seats by means of rims
projecting downwards from their lower surface and from near their
upper surface, one-side of which-upper-surface is-made-to overhang-the
said lower rim.
The object of the said improvement is to equilibrate the said valves
so that the steam be caused to press equally or nearly equally in all
directions on the said valves. The annular steam passages to be opened
and closed by the said valves are formed on one side of the said valves,
and the valve scats are made to correspond with the projecting rims or
the valves, one on the lower part of the said passage, and one above the
same. By this means the steam presses equally or nearly equally on
every part of the said valves; a groove or channel is also cut or formed
in the said valves above the lower rim or bearing of the same so as to
equilibrate the pressure of steam in that part The said annular
equilibrium valves work in annular chambers formed in the cylinder
covers.
This Invention relates, secondly, to improvements in the means of
distributing the steam in steam cylinders where the steam and exhaust
passages and the valves for the admission and exhaust of the steam are
in the cylinder covers.
According to this part of the Invention cach of the cylinder covers
is made in two parts bolted together, the upper part or lid when
removed giving access to the inner part of the cover. In each of the
said cylinder covers are formed two annular chambers, one for the
admission of the steam herein-after termed the steam chamber, and onc
for the exhaust, herein-after termed the exhaust chamber. In the outer
circular wall or partition round the steam chamber is formed a narrow

page_text: aperture or steam port extending all round the said chamber, and
passing through to the face of the cover where it opens into the
cylinder The exhaust chamber opens into the cylinder, and in its
outer wall or partition is an aperture or port extending all round the
said exhaust chamber, and opcumg into an annular passago formed
round the said chamber for the escape of the exhaust steam.
In the steam and exhaust chambers are annular pistons or slide
valves, by preference of rectangular section, which pistons are capable
of sliding up and down the outer walls of the said chambers so as to
cover and uncover the steam and exhaust ports respectively as required;
cach of the said annular pistons has let into its outer surface a metallic
annular ring which slides upon the chamber walls, being pressed up
against the said walls by the steam, which is mado to press upon the
back of the said rings, being admitted thereto through suitable apertures
or holes through the said pistons Each of the said pistous is suitably
guided in its chamber, and is so formed that the steam presses nearly
cqually on all sides.
The said annular pistons or valves are connected to rods which pass
through suitable stuffing boxes to the outside of the steam cylinder,
where they are attached to any suitable mechanism for imparting the
required motion to the said valves, and opening and closing at tho
proper times the steam and exhaust ports. Such mechanism is described
in the Specification of the said Letters Patent, dated the 13th of July
1873, No 2490, but it is preferred to use for the purpose the improved
valve gear herein-after described, which improvements constitute the
third part of this Invention
According to this part of the Invention the cam for actuating the
steam valves, which cam is affixed on the cam shaft actuated by the
driving shaft of the engine, is caused to act upon two iron rods or bars
placed in the axis of the steam cylinder. One of the said rods or bars
extending to the front of the cylinder, and the other to the back of the
same so as to give alternately motion to the two steam valves. Each
of the said rods or bars has formed or attached upon its outer end a
double or forked lever, the two arms of which lever extend downwards,
and by their lower ends are connected each to one of the rods of the
annular piston or valve in the steam chamber, which rods traverse the
said lever ends By means of the said bars or rods and forked levers

page_text: the steam cam acts directly upon the said valve rods and effects the
admission of steam to the steam cylinder as required, the return motion
of the said valves being facilitated by suitable springs in a spring box,
which springs act upon a piston on the end of each of the said bars or
rod. The exhaust cam which is affixed on the said cam shaft on one
side of the steam cam acts by means of suitable rollers or tappets upon
two cast-iron tubular slieves, each of which is traversed by one of the
bars or rods actuated by a steam cam. Upon the outer end of cach
of the said sheves is cast a forked lever, the two arms of which lever
extend downwards to the rods of the exhaust valve by which they are
traversed, the said rods being each connected to a piston in a spring box,
which piston is acted upon by a suitable spring to facilitate the return
motion of the exhaust valve. The rear end of cach of the said slicves
forms a sliding bracket or support projecting laterally on each side of
the said slieve, and being on a suitable slide disposed on or affixed to
the upper surface of the steam cylinder. The front ends of the said
slieves form similar shiding supports which bear upon and are capable
of sliding in slides cast upon the cylinder covers. The said slioves
receive the action of the exhaust cam and transmit it to the exhaust
valve rods so as to open and close the exhaust valves at the required
*time.
The bars or rods actuated by the steam cam are supported in a
similar manner to the slicves above described, being provided with
sliding supports bearing upon and capable of sliding motion in slides
attached to the upper surface of the steam cylinder and the cylinder
cover respectively.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Brookes in the Great Seal Patent Office
on the 5th October 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM 30
BROOKES, of 62, Chancery Lane, in the County of Middlesex, Patent
and Registration Agent, send greeting.

page_text: which valves fit on their respective valve seats by means of 11ms pro-
jecting downwards from their lower surface and from near their upper
surface, one side of which upper surface is made to overhang the said
lower rim.
The object of the said improvement is to equlibrate the said valves,
so that the steam be caused to press equally or nearly equally in all
directions on the said valves. The annular steam passages to be opened
and closed by the said valves are formed on one side of the said valves,
and the valve seats are made to correspond with the projecting rims or
the valves, one on the lower part of the said passage, and one above the
same. By this means the steam presses equally or nearly equally on
every part of the said valves; a groove or channel is also cut or formed
in the said valves above the lower rim or bearing of the same, so as to
equilibrate the pressure of the steam in that part. The said annular equi-
librium valves work in annular chambers formed in the cylinder
covers
This Invention relates, secondly, to improvements in the means of
distributing the steam in steam cylinders where the steam and exhaust
passages, and the valves for the admission and exhaust of the steam, are
in the cylinder covers
According to this part of the Invention each of the cylinder covers
is made in two parts bolted together, the upper part or lid when
removed giving access to the inner part of the cover. In cach of the
said cylinder covers are formed two annular chambers, one for the
admission of the steam, herein-after termed the steam chamber, and one
for the exhaust, hercin-after termed the exhaust chamber In the outer
circular wall or partition round the steam chamber is formed a narrow
aperture or steam port extending all round the said chamber and passing
through to the face of the cover where it opens into the cylinder. The
exhaust chamber opens into the cylinder, and in its outer wall or par-
tition is an aperture or port extending all round the said exhaust
chamber and opening into an annular passage formed round the said
chamber for the escape of the exhaust steam.
In the steam and exhaust chambers are annular pistons or slide valves
by preference of rectangular section, which pistons are capable of sliding
up and down the outer walls of the said chambers, so as to cover and
uncover the steam and exhaust ports respectively, as required. Each
of the said annular pistons has let into its outer surface a metallic

page_text: annular ring, which slides upon the chamber walls, being pressed up
against tho said walls by the steam, which is made to press upon the
back of the said rings, being admitted thereto through suitable apertures
or holes through the said pistons. Each of the said pistons is suitably
guided in its chamber, and is so formed that the steam presses nearly
equally on all sides.
The said annular pistons or valves are connected to rods which pass
through suitable stuffing boxes to the outside of the steam cylinder,
where they are attached to any suitable mechanism for imparting the
required motion to the said valves and opening and closing at the proper
times the steam and exhaust ports. Such mechanism is described in
the Specification of the said Letters Patent dated the 13th of July,
1873, No. 2400, but it is preferred to use for the purpose the improved
valve gear herein-after described, which improvements constitute the
third part of this Invention.
According to this part of the Invention the cam for actuating the
steam valves, which cam is affixed on the cam shaft actuated by the
driving shaft of the engine, is caused to act upon two iron rods or bars
placed in the axis of the steam cylinder. One of the said rods or bars
extending to the front of the cylinder, and the other to the back of the
same, so as to give alternately motion to the two steam valves; each of
the said rods or bars has formed or attached upon its outer end a
double or forked lever, the two arms of which lever extend downwards
and by their lower ends are connected cach to one of the rods of the
annular piston or valve in the steam chamber, which rods traverse the
said lever ends. By means of the said bars or rods and forked levers the
steam cam acts directly upon the said valve rods, and effects the
admission of steam to the steam cylinder as required, the return motion
of the said valves being facilitated by suitable springs in a spring box,
which springs act upon a piston on the end of each of the said bars or
rods; the exhaust cam, which is affixed on the said cam shaft on one
side of the steam cam acts by means of suitable rollers or tappets upon
two cast-iron tubular slieves, each of which is traversed by one of the
bars or rods actuated by the steam cam. Upon the outer end of each of
the said slieves is cast a forked lever, the two arms of which lever extend
downwards to the rods of the exhaust valve by which they are traversed,
the said rods being each connected to a piston in a spring box, which
piston is acted upon by a suitable spring to facilitate the return motion
'

page_text: Figure 1 represents in longitudinal section parts of a steam engine
constructed according to this Invention; Figure 2 is a horizontal view
of the same partly in section; Figure 3 is a transverse section of the
same; and Figure 4 is an end view of the same, partly in section.
Similar letters of reference refer to like parts in Figures 1, 2, 3, and 4,
wherever they occur. a is the steam cylinder; a¹, a¹, the cylinder
covers which are made of two parts forming together the steam
chambers a², a³, communicating with the steam passages a³, a³, and tho
exhaust chambers a", a*, communicating with the exhaust passages a³, a³;
a, a, are the annular steam ports which open into the steam
chambers a, a³; and a, a, are the annular exhaust ports opening
into the exhaust chambers a*, at; b, b, are the annular disc valves of
nearly rectangular section, and guided in the steam chambers a³, a², by
wings b², b. The said disc valves b, b, fit upon their valve seats by the
rims b¹, projecting from their lower ends, and the rims 6³ projecting from
their upper side, the valve seats being made to correspond with the
rims b¹ and b³ respectively, as shewn by Figure 1, where it is seen that
the steam in the steam chambers a², a², presses upon the annular
valves b, b, equally or nearly equally upon almost every part of them;

page_text: an inward groove or channel formed above the lower rim 6° affords a
surface for the pressure of the steam inside the port a³ to bear against;
c, c, c, c, are the equilibrated annular disc valves for opening and closing
the exhaust passages a³ as required. The construction of the exhaust
disc valves c, c, is similar to that of the steam disc valves b, b. The said
valves c, c, rest on their seats by means of a projecting rim c¹ on their
lower surface and another rim c³ projecting from their outer side c³ is a
series of apertures enabling the steam to pass readily from one side to
the other of the said valve.
Figure 5 represents in longitudinal section parts of a steam engine
constructed according to this Invention, and fitted with annular pistons
or slide valves for the admission and discharge of the steam, according to
the second part of the Invention; Figure 6 is a plan view partly in
section of Figure 5; Figure 7 is a transverse section of the same; and
Figure 8 is an end view of the same partly in section. a is the steam
cylinder; a¹, a¹, are the cylinder covers, in each of which covers are
formed two annular chambers a³, a³, for the admission and exhaust of
the steam respectively, a³ being the steam chamber in communication
with the steam passages a³, and a³ the exhaust chamber. In the outer
circular wall round the steam chamber a² is formed the aperture or
steam port a' extending round the steam chamber, and opening into the
steam cylinder a. The exhaust chamber a³ opens into the cylinder a,
and in its outer wall or partition a³ is an aperture or port a³ extending
round the said exhaust chamber a³, and opening into an annular
passage a' formed round the said chamber for the escape of the exhaust
stcam into the exhaust passages a³. In the steam and exhaust
chambers a³, a³, are annular pistons or slide valves b, of rectangular
section, capable of sliding up and down the walls of the said chambers,
so as to cover and uncover the steam and exhaust ports a², aº, respectively,
as required. Each of the said annular pistons 6 has let into its outer
surface a metallic annular ring 6¹ which slides upon the chamber walls,
being pressed up against the said walls by the steam, which is made to
press upon the back of the said rings, being admitted thereto by suitable
apertures 6º.
The annular pistons 6 represented in Figure 5, and the annular disc
valves b, c, represented in Figure 1, are each connected to two rods a, a,
and e, e, one on each side, which rods pass through suitable stuffing
boxes to the outside of the steam cylinder covers, where they are attached

page_text: to the actuating mechanismı hercin-after described, which constitutes the
third part of this Invention.
In Figures 1, 2, 3, 4, ♬ is a cam, giving the required motion to the
disc valve b The said cam f is mounted upon the cam shaft f¹, to
which rotatory motion is communicated from the driving shaft of the 5
engine by means of the bevilled wheels f", f³, and intermediary shaft f*.
The said steam cam is capable of sliding longitudinally upon the shaft f¹,
being actuated from the governor so as to move in either direction along
the said shaft f¹, according as the speed of the engine increases or
decreases. The said cam facts upon the rollers or tappets 9, 7, upon 1
one end of each of the rods g', g', which rods g¹, g³, are supported by the
brackets g², g², capable of sliding on the slides g³, g³, and by the
supporting arms 9', g', capable of motion on the slides g³, g³. Upon
the outer end of each of the rods g¹, g', is affixed the forked lever gº, gʻ,
the lower-ends of which-lever are connected one to each of the steam.]
disc valve rods d, d. h, h, are spring boxes, in which spiral springs give™
the valve rods d, e; is the exhaust cam affixed
on the cam shaft f¹. The said cam acts upon the rollers or tappets ², 2²,
upon the ends of the tubular sheves 2, 24, which are traversed by the
rods g¹, g¹, and are supported by the arms ³, 1, 2, 2, working on the
slides ',, respectively. Upon the outer ends of the slieves ² are
formed or affixed the forked levers ', ', the lower ends of which lovers
are connected to the rods e of the exhaust disc valves c.
the return motion to
It will be readily understood that the action of the steam cam fupon
the rollers or tappets will be transmitted through the rods g', g², and
forked levers gº, g, to the annular disc valves b, opening them as
required, whilst the return or closing motion is given to the said disc
valves by spiral springs in the boxes h. The action of the exhaust cam i
in like manner will be communicated to the exhaust disc valves c, the
return motion being given to the said valves by spiral springs in the
spring boxes h, h
The valve gear represented in Figures 5, 6, 7, and 8 for actuating the
annular pistons b is similar to that represented in Figures 1, 2, 3, 4,
and herein-before described, and the parts being marked with the same
letters of reference will be readily understood without further description.
In Figures 5 and 6 it will be seen that the return motion of the rods g¹
and steam piston valves is given by springs in the spring boxes h, h,

page_text: acting directly upon the ends of the said rods g', whilst the return
motion of the slieves and exhaust piston valves is given by tho
springs h¹, h¹.
Having now described the nature of the Invention, as communicated
to me, and means pursued in carrying the same into effect, I wish it to
bo understood that I do not confine myself to the precise details herein-
before described and illustrated in the accompanying Drawings, as the
same may be varied without departing from the nature of the Invention;
but I claim as the Invention of improvements in steam engines,—
Firstly. The equilibrated annular disc valves herein-before described
and illustrated in Figure 1 of the accompanying Drawings, and their
adaptation and arrangement in the cylinder covers, essentially as
described and represented.
Secondly. The annular piston valves hercin-before described and
illustrated in Figure 5 of the accompanying Drawings, and their
adaptation and arrangement in the cylinder covers, essentially as
described.
Thirdly. The combination and arrangement of parts for giving the
required motion to the annular disc valves or annular piston valves,
essentially as herein-before described and illustrated in the accompanying
Drawings.
In witness whereof, I, the said William Brookes, have hereunto
set my hand and scal, this Thirtieth day of September, in the
year of our Lord One thousand cight hundred and seventy-