IMPROVEMENTS IN BALANCE SLIDE VALVES
Year: 1856

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street,,
in the City of London, Patent Agent, for the Invention of "IMPROVEMENTS
IN BALANCE SLIDE VALVES."-A communication.
Sealed the 29th August 1856, and dated the 19th March 1856.
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
19th March 1856..
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention.
for "IMPROVEMENTS IN BALANCE SLIDE VALVES," (communicated to me by a
foreigner residing abroad,) to be as follows:-
The Invention is based upon a peculiar application of the steam, whereby
the pressure of steam on one side is neutralized by an equivalent force of
pressure on the opposite side. In the theoretical operation of this valve, a.
perfect equilibrium is produced; but in practice, it is required that there shall
always be sufficient pressure upon the valve to keep it in its seat, which is
accomplished by this Invention. Inasmuch, also, as the surface under the
valve is much less than the upper, the pressure of the steam upon these must
be different in the proportion of the areas exposed in order to produce an
equality, and to accomplish this by steam taken from the same boiler con-
stitutes a material part of my Invention. In the operation, the steam is

page_text: admitted to the ports from the under side, the exhaust being also from that
side, consequently, were nothing interposed to prevent, the valve would be
forced up from its seat. To obviate this, steam pressure is applied to the
opposite surface, and sufficiently in excess to keep down the valve. This is
accomplished by self-regulating parts. I first proceed to describe the con-
struction of the valve.
Figure II. is a sectional view of a portion of the cylinder, its steam and
exhaust ports, together with, the valve and. the case enclosing.it, which latter,
although resembling the ordinary steam chest, is not strictly the same, as the
latter is formed within the valve itself. a, a', are the steam ports and channel
ways in the cylinder, and 6 the exhaust passage; c are steam ways, cast in the
metal of the cylinder, and running across the same outside of and parallel
with the two steam channels a, a¹; to these, on one side of the cylinder, is
attached the steam nozzle c¹, as in Figures I. and III., and they are also con-
nected to two others, which form the outlets, as shewn at d, Figures-I: and
III. The valve is of such shape as to cover-these-outlets, as well as the
regular steam ports a and a¹?
Figure IV. is a perspective view of the valve, exhibiting its under side... In
Figure I. a portion of its top is shewn; and Figures II. and III. shew longi-
tudinal and transverse sections.. The-parts.e.and el form a valve of the ordinary
construction, and this is enclosed by a cover f, sufficiently large to leave a
channel or space between...When the valve, therefore, is on its seat upon
the cylinder, in whatever position it may be, this cover part, will always
embrace the two steam ports a and a¹ at its end, as well as, the two channel
openings d, d, Figures I. and III., at the sides. The steam which passes
through the pipe c will therefore discharge by d'into the channel f¹ and will
thence pass into the cylinder by the ports a or a¹, according to the position of
the valve, and as represented in Figure II: The passage d'is always open
to f¹, because the motion of the valve is in a direction parallel therewith, and
thus the space becomes, in fact, the steam chest. The part g is a tube cast
in the valve, to admit the passage of a stem or rod, by which it receives it's
motion in the usual way. It is apparent, from what has been set forth, that
the valve would be-blown upward by the steami passing through d with a force
due to the pressure of the steam and the surface exposed to that pressure;
which is the area of the channel f; and it will therefore require a like force
applied to the top of the valve to keep it in place. This is accomplished by
the application of steam, and 'the valve therefore is enveloped in a steam-tight
case h of sufficient strength to withstand the pressure. It will be seen, that as
the area exposed by the outside of the valve is very much greater than the

page_text: area of the channel f¹, steam of less pressure will be required within the case
½ to overcome the power of that exerted in the channel, and the difference
will be as the respective ratios of ƒ and f¹. To apply and maintain the
steam in h at such relative pressure to that in f¹ as will ensure the full
balancing of the valve constitutes one of the important features of the present
Invention.
Figures V. and VI. are views of apparatus connected with the operation of
the valve. Figure V. shews the instrument for maintaining the proper
pressure of steam in h; and Figure VI. shews an apparatus for discharging the
water from the condensed steam in the case h. The manner in which these
are connected with the valve is shewn in Figure 1. The steam from the
boiler must
pass through the regulator, Figure V., in its way to the steam
case h, and the operation of the regulator is such as to allow only so much to
pass as will accomplish the balancing of the valve. In the Figure the steam
is represented as being taken out of the steam pipe c¹, leading to the engine,
as at i, Figure I.; after passing through the regulator it flows into h by the
pipe . The regulator is constructed as follows:-k, Figure V., is a cylinder,
fitted with a piston k', the rod of which passes downward through a stuffing
box into another chamber 1, where it terminates with a valve l', fitting into an
aperture leading to the chamber. Beneath the valve a pipe m continues
downward, some distance out of which two pipes lead, the upper one being the
pipe i, before named. Out of the chamber 7 the pipe i, forming practically á
continuation of i, leads, and connects with the steam case h, as in Figure I.
The other pipe m starts near the bottom, and turning. upward, intersects the
pipe ', and terminates at its other end in the cylinder k. Between i and m¹
is a valve n opening upward, as shewn. The apparatus, Figure VI., is con-
structed as follows:-o is a vessel water-tight, in the bottom of which is á
balanced valve o¹, to the stem of which valve is attached a float p; q is a
pipe leading from o to the steam case h, Figure I.; q¹ is a discharge pipe; and
" is a safety valve, of common construction. The operation will be as follows:
-The valve f is operated in the ordinary vibratory manner; steam entering
through c¹ flows on and enters the channel f', as before set forth; from this it
passes into the ports a or a', according to the position of the valve; the exhaust
through 6 being as usual, steam will also flow through the pipe i into m;
hére it escapes by raising the valve l, and thence passes into the steam case h
through ; but unless means were taken to prevent it, the pressure in h would
soon be equal to that inf; and of course, as before mentioned, as the outer
surface of the valve exposed to the pressure of the steam is much greater than
that on the under side, it would be forced down upon its seat, and would in

page_text: consequence require considerable power to move it. To balance the great
pressure of the direct steam beneath in f¹ much less is required in h. This is
obtained by shutting off the flow of steam through ¹ as soon as enough has
entered to accomplish the object; and this is effected by means of the piston
, Figure V., where it will be seen that a branch pipe m' leads a portion of
the steam off from ¹ into the cylinder k, and acting on the piston k', forces
down the valve l, and stops the further influx of steam through i. But unless
the area of the piston k' were greater than that of the valve l' no such effect
would take place; and this is precisely the condition of the two, for the areas of
the piston and valve are to each other as the respective areas of the
outside of the valve f and of the channel f¹, so that the low pressure of the
steam in, or what is the same, in the case h, is sufficiently powerful to force
down the valve against the greater pressure of the steam in i. The moment,
therefore; the steam in h gets below the requisite pressure to maintain the
valve in its seat, the equilibrium between and is destroyed and l¹ is raised,
whereby more steam enters. In practice, as the steam in h must be all the
time condensing, and therefore diminishing in volume, the valve will be
always raised just so high as to permit the requisite flow of steam to supply this
source of waste, and maintain the equilibrium of the valve.
I have described the piston and valve as having the same relative differ-
ence in area that the two steam surfaces of the main valve have. In theory
this would be correct, but in practice it will be well to have a slight pressure
upen the valve, in order to insure its fitting closely to its seat; the piston will
therefore be less proportionately in area to that of the valve l' than the pro-
portion the inner side of the slide valve bears to the outer, and thus a greater
pressure of steam will be required to force down the valve .than would be
required to balance the steam on the under side of the main valve; hence it
would be worked under a pressure proportioned to that difference, which
difference may be whatever in practice will be found most advantageous. The
use of the valve n is to permit the steam to flow back into i, in case from any
.cause there should be an excess of pressure in h, and by this flowing. back it
would be relieved. As the water from the condensed steam accumulates in h
it must be removed; this may be done by a cock attached to q, opened so far
as to allow of a slight continuous blow-off or otherwise by means of the appa-
ratus, Figure VI. As the water rises it flows by the pipe q into the chamber o,
and so soon as it has filled it sufficiently to raise the float p, the valve o' will be
lifted and the water discharged, as shewn, no steam escaping thereby.

page_text: 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 19th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of March, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, 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 BALANCE SLIDE VALVES," communicated to
me by a foreigner residing abroad, upon the condition (amongst others) that I,
the said Richard Archibald Brooman, 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 Richard Archibald Brooman, 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 Drawings annexed,
that is to say:-
This Invention is based on a peculiar application of steam, whereby the
pressure of steam on one side is neutralised by an equivalent force of pressure
on the opposite side. In the theoretical operation of a valve constructed
according to the present Invention a perfect equilibrium is produced, but in
practice it is required that there shall always be sufficient pressure upon the
valve to keep it in its seat, all which is readily accomplished by this Inven-
tion. Inasmuch also as the surface under the valve is much less than that
above it, the pressure of the steam upon these must be different in the proper-

page_text: tion of the areas exposed in order to produce an equality, and to accomplish
this by steam taken from the same boiler constitutes a material part of the
Invention. In the operation, the steam is admitted to the ports from the
under side, the exhaust being also from that side, consequently were nothing
interposed to prevent, the valve would be forced up from its seat. To obviate
this, steam pressure is applied to the opposite surface, and sufficiently in excess
to keep down the valve; this is accomplished by self-regulating parts operating
automatically.
I first proceed to describe the construction of the valve, and the manner in
which the steam passes for working the engine..
Figure 2 is a sectional view of a portion of the cylinder, its steam and
exhaust ports, together with the valve and the case enclosing it, which latter,
although resembling the ordinary steam chest, is not strictly the same, as the
latter is formed within the valve itself. a, a, are the steam ports and channel
ways in the cylinder; and b, the exhaust passage; c are steam ways, cast in the
metal of the cylinder; and running across the same outside of and parallel with
the two steam channels a, a'; to these, on one side of the cylinder, is attached
the steam nozzle c', as shewn in Figures 1 and 3, and they are also connected
to two others which form the outlets, as shewn at d, Figures 1 and 3. The
valve is of such shape as to cover these outlets, as well as the regular steam
ports a and a'.
S.
Figure 4 is a perspective view of the valve, exhibiting its under side.
In Figure 1 a portion of its top is shewn, and Figures 2 and 3 shew longi-
tudinal and transverse sections. The parts e and e¹ form a valve of the ordinary
construction, and this is enclosed by a cover f, sufficiently large to leave a
channel or space f¹ between. When the valve therefore is on its seat upon
the cylinder, in whatever position it may be, this cover part f, will always
embrace the two steam ports a and a¹ at its end, as well as the two channel
openings d, d, Figures 1 and 3, at the sides. The steam which passes through
the pipe c will therefore be discharged at d into the channel f¹, and will
thence pass into the cylinder by the ports a or a¹, according to the position of
the valve, as represented in Figure 2. The passage d is always open to f¹,
because the motion of the valve is in a direction parallel therewith, and thus
the space f¹ becomes, in fact, the steam chest. 9, is a tube, cast in the valve,
to admit of the passage of a stem or rod, by which it receives its motion in the
usual way.
I now proceed to describe the means for balancing the valve, and keeping it
down on its seat. It is apparent from what has been set forth that the valve
would be blown upward by the steam passing through d with a force due to

page_text: the pressure of the steam and the surface exposed to: that pressures which is the
area of the channel f...and it will therefore require a like: force applied to: the
top of the valve to keep it in place. This is accomplished by the application of
steam, and the valve. is therefore enveloped or...enclosed in; a steam tight.casech,
of sufficient strength, to withstand the pressure. It will be seent that as thetarea
exposed by the outside of the valve is very much greater than the area of the
channel f1, steam of, less. pressure, will be required: within the case th to over-
come the power of that exerted in the channel, and the difference will be as
the, respective ratios of fand f; for example, if the area of f¹beiten square
inches, and the area off one hundred square inches, then will .steam of ten
pounds; to the square inch in balance the force of steam of one hundred
pounds to the square inch, in ff. To apply fand maintain the steam' in h at
such relative pressure, to that in f as will insure the full rbalancing of "the
valve constitutes: one of the important features of the present: Invention.
Figures, 5, and 6 are views, of 'apparatus.connected with the operation of the
valve; Figure: 5 shews, the instrument for maintaining the proper pressure of
steam in.h, and Figure 6 shews an apparatus for discharging the water from
the condensed; steam in the case.h. The manner in which these are connected
with the valve.is.shewn in Figure 1. The steam from the boiler must pass
through the regulator, Figure 5, in its way to 'the steam case h, and the opera-
tion of the regulator is, such as to allow only so muchito pass as will'accomplish
the balancing of the valve. In this Figure the steam is represented as being
taken out of the steam pipe.c leading to the engine,ras ati, Figure 1, after
passing, through the regulator.it flows intosh by the pipe. The regulator is
constructed as follows:k, Figure i5,.is a cylinder, fitted with, a piston k, the
rod of which passes downward through a stuffing box into another chamber,
where it terminates with a valve fitting in an aperture. leading to the
chamber. Beneath the valve a pipe 'm continues downward some distance,
out of which two pipes lead, the upper one being the pipe i, before "named.
Out, of the chamber, leads the pipe 2, forming a continuation of i, and con-
necting with the steam.case h,.as:in Figure 1. The other pipe micomniences
from near the bottom, and, turning upward, intersects the pipe, and termi-
nates at its other end in the cylinder k. Between and mis ja valve 'n,
opening upward, as .shewn.
.
The apparatus shewn in Figure 6 is constructed as follows:-o is a water-
tight vessel, in the bottom of which is a balance ivalvero, to the stem of which
valve is attached a float p!; q is a pipe, leading from o to the steam case'h,
Figure 1; is a discharge pipe; and ris a safety valve, of the ordinary con-

page_text: struction.. The operation is as follows:The valve fis worked in the ordinary
vibratory manner; steam entering. through c¹ flows on into the channel f', as
before set forth,, whence. it passes into the ports a or a³, according to the
position. of the valve; the exhaust through 6 being of the usual description,
steam will, also flow. through the pipe i into m, whence it escapes by raising
the valve, and thence passes into the steam case h through ; unless means
were taken to prevent it, the pressure in the case h would soon be equal to
that in f¹, and as the outer surface of the valve exposed to the pressure of the
steam is, much greater than that on the under side, it would be forced down
upon its seat; and would in consequence require considerable power to move it.
To, balance, the great pressure of the direct steam beneath in f¹ much less is
required in h: This is obtained by shutting off the flow of steam through as
soon as enough has entered into. the case h to accomplish the object; and this
is effected by means, of the piston, k¹, Figure 5, where it will be seen that a
branch pipe m leads a portion of the steam off from ¹ into the cylinder k, and
acting on the piston k; forces down. the valve l, and stops the further influx of
steam through; but unless the area of the piston k¹ were greater than that of
the valve no such effect would take place;. and this is precisely the condition
of the two, for the areas of the piston k¹ and valve are to each other as the
respective areas of the outside of the valve.f and of the channel f¹, so that the
low pressure of the steam in , or what is the same thing, in the case h, is
sufficiently powerful to force down the valve against the greater pressure of
the steam in i. The moment therefore that the steam in h gets below the
requisite pressure to maintain the valve in its seat, the equilibrium between
and k¹ is destroyed,, and is raised, whereby more steam enters. In practice,
as the steam in h, must be all the time condensing, and therefore diminishing in
volume, the valve will be always raised just so high as to permit the requisite
flow of steam to supply this source of waste, and maintain the equilibrium of
the valve..
I have described the piston and valve as having the same relative
difference in area that the two steam surfaces of the main valve have. In
theory this would be correct, but in practice it will be well to have a slight
pressure upon the valve, in order to insure its fitting closely to its seat; the
piston will therefore be less proportionately in area to that of the valve
than the proportion the inner side of the slide valve bears to the outer, and
and thus a greater pressure of steam will be required to force down the valve
than would be required to balance the steam on the under side of the main
valve. Hence it would be worked under a pressure proportionate to that

page_text: difference, which difference may be whatever in practice will be found most
advantageous. The use of the valve n is to permit the steam to flow back
into i, in case from any cause there should be an excess of pressure in h, and
which would thus be relieved. As the water from the condensed steam
accumulates in h it must be removed. This may be done by a cock attached
to q, which is opened so far as to allow of a slight continuous blow-off or other-
wise by means of the apparatus shewn in Figure 6. As the water rises it
flows through the pipe q into the chamber o, and as soon as it has filled it
sufficiently to raise the float p, the valve o' will be lifted and the water
discharged, as shewn, no steam escaping thereby.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim the means for
maintaining the differential pressures on the two sides of the valve necessary
for balancing the same, that is to say, the combination of an apparatus
substantially as described under Figure 5, with the valve, as set forth.
In witness whereof, I, the said Richard Archibald Brooman, have
hereunto set my hand and seal, this Eighteenth day of September,
One thousand eight hundred and fifty-six.