IMPROVEMENTS IN EXPANSION VALVES FOR STEAM ENGINES
Year: 1853

page_text: LETTERS PATENT to Richard Archibald Brooman, of the firm of
Robertson, Brooman, and Company, of 166, Fleet Street, in the
City of London, Patent Agents, for the Invention of "IMPROVE-
SEBZEMA
Sealed the 20th May 1853, and dated the 2nd February 1853.
PROVISIONAL SPECIFICATION left by the said Richard Archibald
Brooman at the Office of the Commissioners of Patents, with his
Petition, on the 2nd February 1853.
I, RICHARD ARCHIBALD BROOMAN, of the firm of Robertson,
Brooman, and Company, of 166, Fleet Street, in the City of
London, Patent Agents, do hereby declare the nature of the
said Invention for. "IMPROVEMENTS IN EXPANSION VALVES FOR STEAM
ENGINES" to be as follows:-
This Invention is an Improvement in Expansion Valves for Steam
Engines, and is intended to effect the "cut off" by the drop of the
valve itself into its seat, and also to vary the measure of expansion
at pleasure, as circumstances may require. The kind of valve to
which this improvement is designed to be applied is the balance or

page_text: 66 poppet" valve.
Three different arrangements are described,
embracing, however, the same general principle, as follows.
ARRANGEMENT No. 1.
-
A, Figure 1, is the rock shaft.; B, the lifting rod, to which the
exhaust valve lifter is attached, as usually arranged and worked;
D, is the steam valve; E, the valve stem; F, is a piece-attached to
the valve stem, by means of which it rests on the toe G. This toe
G, has a fixed centre at H, on which it turns. On the lifting rod
B, is fastened the centre I; and on this latter is supported and turns
one end of the lever K. At the other end of K, at L, is the roller
M, which.is, supported on the extremity of the arm N. - This arm
N, is attached to the shaft O; and on the same shaft O is attached
the arm P, to which arm is given a reciprocating motion, coincident
with that of the piston, and taken from the side lever, or any other
part having the same motion, suitably reduced, as that of the piston.
On the lever K, is placed a moveable piece Q, the surface a, b, on
which it is moveable being a curve. A roller R, is attached to the
piece Q, and on it rests the toe G; the under surface of the toe is a
curve c, d, corresponding to the curve a, b, which forms the top of
the lever K. The parts being arranged as represented, and the
engine being supposed at that part of its motion when the crank has
just turned its centre, the parts will have their motions in the
directions indicated by arrows. It will be seen that by the upward
motion of the lifting rod, the end I of the lever K is raised, while
by the downward motion of the arm N, the other end of the lever
K is lowered, the roller M. moving over the surface n, o. But it
will also be perceived that the upward motion of the end I, is at its
greatest velocity at the beginning of the stroke, while the arm N;
which lowers the end L, has no motion at the immediate beginning
of the stroke. Hence by reason of their relative motions, the
lifting end will have the advantage, and the valve will therefore be
raised at the early part of the stroke; but as the motion of the
lifting end is rapidly diminishing, while that of the lower end is
encreasing, it therefore will soon happen that the lowering end will

page_text: lower the valve more rapidly than it is raised at the other end, and
thus the valve will be restored to its seat. The point of the stroke
at which the valve will be restored to its seat will depend on the
proportion of parts, and with suitable proportion of parts, on the
position of the moveable piece Q. If in the position represented in
the Drawing, the valve is restored at half stroke, then by moving
the piece toward the lifting end, the valve will be closed at a
later point, and by moving it towards the lowering end, the valve
will be closed at an earlier point. The piece Q is made to move on
a curved surface in order that the extent of the raising of the valve
may be kept within proper limits. If it were moved on a straight
line, the opening given to the valve would be too great when
cutting off short of half stroke, and too little when cutting off
Q
Figure 3, is a view of the front, exhibiting part of the two side.
pipes, viz. the steam pipe a, and the exhaust pipe a', with the valve cut-
off arrangement in elevation. Figure 4, is a side view of the same, as
it would appear with one of the side pipes removed. Figure 5, is a top
view, shewing one half of the upper steam chest. Figure 6, is a de-
tached view of one of the loose toes, with the regulating arms and
screws. The rock shaft is so arranged as to be in the same plane with
the valves, and in order to operate it in this position, the ends pass

page_text: directly through the centre of the side pipe, having their bearings
within them in long circular boxes, or rather cylinders cast in said
pipes; and because such boxes would diminish the capacity of the
side pipes to pass the steam, they are enlarged, as shewn in Figure
3, where is the axis of the rock shaft. To this rock shaft is
placed the exhaust valve; toes are permanently attached; and on it
also are placed the loose or secondary toes, by means of which the
steam valves are operated. Motion is given to raise the loose toes by
means of an arm permanently attached to the rock shaft, and to
lower them by means of an arm having its centre on the rock
shaft, and deriving its motion from any part on which the motion
commences with or slightly precedes the motion of the piston rod.
For the fuller explanation the following letters indicate the several
parts in operation. c, d, are the steam valves stems. e, f, are the
exhaust valve stems. b, is the rock shaft, placed in the same plane
as the plane of the valve stems. 01, 0¹¹, are the exhaust valve toes,
which, through the pieces i, k, operate the exhaust valves. p, p,
are the loose toes supported on the rock shaft. 0111, is an arm per-
manently attached to the rock shaft, at the end of which are the
rollers X, X¹.
The piece and arm being permanently attached to the rock
shaft, the rollers X, X', will of course have the same motion as the
rock shaft, having at the commencement of the up stroke a motion
as indicated by arrow 1; and at the commencement of the down
stroke, a motion in the direction indicated by arrow 2. 9, 9, are
pieces called "palls," connected with the ends of the loose toes by
pins on which they are free to turn. The lower ends of the palls
rest at the commencement of the motion against the rollers X, X', as
shewn, but the surface by which they rest against the rollers is an
inclined one, and, unless kept from sliding, the toe would not be
raised when motion was given to the arm in direction of arrow 1.
To provide the control of the palls, there is placed on the rock shaft
the arm 7. This arm carries, by means of the right and left screw,
the two rollers V,V₁, the arın itself being worked by a motion
coincident with or slightly preceding the motion of the piston. The

page_text: position of the rollers V,V, and the mutual adjustinent of the palls,.
is such that at the beginning of the stroke when the inclined head
of the palls rest against the roller X', the upper surface of the pall
will rest against the roller V; and as long as the roller V is in
contact with the upper surface of the pall, the pall must have the
saine motion as the arm. The upper surface of the palls is cir-
cular, the radius being such that when the pall is in its extreme
outward position, the centre of its circular surface is the centre of
the rock shaft. The parts described being adjusted as represented
in Figures 3, 4, 5, and put in motion, the arm carrying the roller
X will have a motion in the direction of the arrow 1; and the
arm r, carrying the roller V, will have a motion in the opposite
direction, as indicated by the arrow 2. It will be seen that the
roller X, will carry up the pall q', and lift the toe p¹, and thus raise
the steam valve resting on it, and continue to raise as long as the
collar V, keeps the end of the said pall against X'; but as soon as
the roller V, in its motion downwards ceases to be in contact with
the inner surface of the pall, the end of the pall q' will rise on the.
roller X', and will be held only by the roller V1; and as the motion"
of that roller is downward, the pall will be lowered with whatever
velocity the arm t may have, and thus shut the steam valve, not-
withstanding the roller X still continues to ascend. The point at
which the pall will be disengaged from the upward action to the
roller X will depend on position of the roller V. This adjustinent
of the two rollers V, VI, forms the adjustible feature of the cit off,
and is effected by placing each roller on an arm t, t, shewn sepa
rately at Figure 6, which is connected with the arm r, by the right
and left screw. By turning the screw s, s, in one direction, the arms
carrying the rollers V, V, will be separated, and by turning them
in the other direction, they will be brought toward each other,
which changes effect the disengagement of the pall from the roller
X, sooner or later, as may be, and that the drop of the valve is timed
to any particular part of the stroke: To provide the means of
working the engine by hand, there is placed on the rock shaft the
piece m, which is free to move round the rock shaft. On this piece

page_text: are short projecting toes 'n, n, n, n, one under each of the lifters of
the valve stems. The starting bar is inserted into the orifice in m;.
the piece m, when worked in one direction, will raise the steam and
exhaust valves for the up stroke, and when worked in the other
direction, will raise them for the down stroke.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Richard Archibald Brooman in the
Great Seal Patent Office on the 2nd August 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
RICHARD ARCHIBALD BROOMAN, of the firm of Robertson, Brooman,
& Co., of 166, Fleet Street, in the City of London, Patent Agents,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of February, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said Richard Archibald Brooman,
Her special licence that I, the said Richard Archibald Brooman, my
executors, administrators, and assigns, or such others as I, the said
Richard Archibald Brooman, 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 EX-
PANSION VALVES FOR STEAM ENGINES," communicated to me by a
foreigner resident abroad, upon the condition (amongst others) that
I, the said Richard Archibald Brooman, by an instrument in writing
under my hand and seal, 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

page_text: -
Figure I. A, is the rock shaft; B, the lifting rod to which the
exhaust valve lifter is attached, as usually arranged and worked;
D, is the steam valve; E, the valve stem; F, is a piece attached to
the valve stem, by means of which it rests on the toe G. This toc
G, has a fixed centre at H, on which it turns; on the lifting rod B
is fastened the centre I, and on this latter is supported and turns
one end of the lever K. At the other end of K, at L, is the roller"
M, which is supported on the extremity of the arm N. This arm N
is attached to the shaft O, and on the same shaft O is attached the
arm P, to which arm is given a reciprocating motion coincident with
that of the piston, and taken from the side lever, or any other part
having the same motion (suitably reduced) as that of the piston.
On the lever K is placed a moveable piece Q (the surface a, b, on
which it is moveable being a curve). A roller R, is attached to the
piece Q, and on it rests the toe G; the under surface of the toe is a"
curve c, d, corresponding to the curve a, b, which forms the top of-
the lever K. The parts being arranged as represented, and the
engine being supposed to be at that part of its motion when the

page_text: crank has just turned its centre, the parts will have their motions
in the directions indicated by the arrows.
It will be seen that by the upward motion of the lifting rod, the
end I, of the lever K, is raised, while by the downward motion of
the arm N, the other end of the lever K is lowered; the roller M,
moving over the surface n, o. But it will also be perceived that the
upward motion of the end I, is at its greatest velocity at the
beginning of the stroke, while the arm N, which lowers the end L,
has no motion at the immediate beginning of the stroke. Hence,
by reason of their relative motions, the lifting end will have the
advantage, and the valve will therefore be raised at the early part
of the stroke; but as the motion of the lifting end is rapidly
diminishing, while that of the lower end is increasing, it therefore
will soon happen that the lowering end will lower the valve more
rapidly than it is raised at the other end, and thus the valve will be
restored to its scat.
The point of the stroke at which the valve will be restored to its
seat will depend on the proportion of parts, and with suitable pro-
portion of parts on the position of the moveable piece Q. If in the
position represented in the Drawing, the valve is restored at half
stroke, then, by moving the piece Q toward the lifting end, the
valve will be closed at a later point, and by moving it toward the
lowering end the valve will be closed at an earlier point. The piece
Qis made to move on a curved surface, in order that the extent of
the raising of the valve may be kept within proper limits. If it
were moved in a straight line, the opening given to the valve would'
be too great when cutting off short of half stroke, and too little
when cutting off beyond half stroke.
ARRANGEMENT No. 2.
Figure II. The same letters of reference serve for this Figure as
for Figure I., with the exception of the part shewn in that Figure at
M. Here, instead of the end L of the lever K resting upon the

page_text: ARRANGEMENT No. 3.
Figure III. is a front view exhibiting part of the two side pipes,
viz., the steam pipe a, and the exhaust pipe a', with the valve cut
off arrangement in elevation. Figure IV. is a side view of the same
as it would appear with one of the side pipes removed. Figure V.
is a top view shewing one half of the upper steam chest. Figure VI.
is a detached view of one of the loose toes with the regulating arms
and screws. The rock shaft is so arranged as to lie in the same
plane with the valves; and in order to work it in this position, the
ends pass directly through the centre of the side pipes, having their
bearings within them in long circular boxes, or rather cylinders.
cast in said pipes; and because such boxes would diminish the
capacity of the side pipes to pass the steam, they are enlarged as
shewn in Figure III., where is the axis of the rock shaft. To
this rock shaft so placed, the exhaust valve toes are permanently
attached, and on it also are placed the loose or secondary toes, by
means of which the steam valves are worked. The motion requisite.
to raise the loose toes is given by means of an arm permanently
attached to the rock shaft, and that to lower them by means of an
arm having its centre on the rock shaft, and deriving its motion
from any part, the motion of which commences with or slightly
precedes that of the piston rod.
The nature of this arrangement will be better understood from
the following description of the several parts in operation:-c, d,
are the steam valve stems. e, f, are the exhaust valve stems.
b, is the rock shaft, placed in the same plane as the plane of
the valve stems. 01, 0¹¹, are the exhaust valve toes, which, through
the pieces i, k, operate the exhaust valves. p, p₁, are the loose
toes supported on the rock shaft. 0, is an arm permanently
end of which are the rollers
attached to the rock shaft, at the
X, X. The piece o¹, and arm being permanently attached to
the rock shaft, the rollers X, X', will of course have the same

page_text: Inotion as the rock shaft, having at the commencement of the up
stroke a motion as indicated by the arrow 1; and at the com-
mencement of the down stroke, a motion in the direction indicated
by the arrow 2. 7, 7', are pieces called "palls," connected with the
ends of the loose toes by pins, on which they are free to turn. The
lower ends of the palls rest at the commencement of their motion
against the rollers X, X', as shewn; but their surface which rests
against the rollers is an inclined one, and, unless kept from sliding,
the toe would not be raised when motion was given to the arm in
the direction of the arrow 1.
To provide for the control of the palls, there is placed on the rock
shaft the arm ?. This arm carries, by means of the right and left
screw, the two rollers. V, V₁; the arm itself being worked by a
notion coincident with or slightly preceding the motion of the
piston. The position of the rollers V, VI, and the mutual adjust-
ment of the palls, is such, that at the beginning of the stroke when
the inclined end of the pall rests against the roller X¹, the upper
surface of the pall will rest against the roller V; and as long as the
roller V is in contact with the upper surface of the pall, the pall
must have the same motion as the arm. The upper surface of the
palls is circular, the radius being such that when the pall is in its
extreme outward position, the centre of its circular surface is the
centre of the rock shaft.
The parts described being adjusted as represented in Figures
III. IV. V., and put in motion, the arm carrying the roller X¹ will
have a motion in the direction of the arrow 1; and the arm r,
carrying the roller V, will have a motion in the opposite direction,
as indicated by the arrow 2.
It will be seen that the roller X' will carry up the pall q', and lift
the toe p', and thus raise the steam valve resting on it, and continue
to raise it as long as the roller V. keeps the end of the said pall
against X; but as soon as the roller V₁, in its motion downward
ceases to be in contact with the inner surface of the pall, the end of
the pall q will rise on the roller X', and will be held only by the
roller V¹;
and as the motion of that roller is downward, the palla
-

page_text: will be lowered with whatever velocity the arm t. may have, and
thus shut the steam valve, notwithstanding the roller X, still
continues to ascend. The point at which the pall will be disengaged
from the upward action of the roller X will depend on the position
of the roller V. This adjustment of the two rollers. .V, V., forms:
the adjustable feature of the cut off, and is effected by placing each
roller on an arm t,.t. (shewn separately at Figure VI.), which is
connected with the arm
r, by the right and left screw. By turning
the screw s, s, in one direction, the arms carrying the rollers V, VI,
will be separated, and by turning them in the other direction they
will be brought toward each other, which changes effect the dis-
engagement of the pall from the roller X, sooner or later, as may bc,
and consequently.the drop of the valve, which can thus be timed.
to any particular part of the stroke.
To provide the means of working the engine by hand, there is
placed on the rock shaft the piece m, which is free to inove round
the rock shaft; on this piece are short projecting tocs n, n, n, n, one
under each of the lifters of the valve stems. The starting bar is
inserted into the orifice in m. The piece m, when worked in one
direction, will raise the steam and exhaust valves for the up stroke,
and when worked in the other direction will raise them for the
down stroke.
And having now described the nature of the said Invention, and
in what manner the same is to be performed, I declare that what I
claim is,
First, the method of operating expansion valves by means of two
motions derived from the engine itself, when one of said motions is
coincident or nearly so with that of the piston, while the other
motion is derived from an eccentric, having its greatest velocity at
the moment the piston is at its least velocity, as described.
Second, the combination of the loose toe G, with the adjustable
piece Q, lever K, arm N, and lift rod B, as described in Arrangement
No. 1, and the same combined with the short connecting rod M', as
described in Arrangement No. 2.
Third, the arrangement described as No. 3, that is to say, the

page_text: combination of the palls q, q', with the rock shaft arm o¹¹, and the
regulating arms t, t', and the loose toes p, as described.
Fourth, the manner of combining the rock shaft with the side
pipes, by forming boxes or bearings through the same, so that the
said rock shaft shall lie in the same plane with the stems of the
valves as described.
combination of the palls q, q', with the rock shaft arm o¹¹¹, and the
regulating arms t, t¹, and the loose toes p, as described.
Fourth, the manner of combining the rock shaft with the side
pipes, by forming boxes or bearings through the same, so that the
said rock shaft shall lie in the same plane with the stems of the
valves as described.
In witness whereof, I, the said Richard Archibald Brooman, have
hereunto set my hand and seal, this Second day of August,