IMPROVEMENTS IN ACTUATING THE VALVES OF ENGINES WORKED BY STEAM OR OTHER FLUID
Year: 1868

page_text: LETTERS PATENT to Andrew Betts Brown, of the Vauxhall Iron
Works, Wandsworth Road, in the County of Surrey, Engineer, for
the Invention of "IMPROVEMENTS IN ACTUATING THE VALVES OF ENGINES
WORKED BY STEAM OR OTHER FLUID."
Sealed the 14th July 1868, and dated the 21st January 1868.
PROVISIONAL SPECIFICATION left by the said Andrew Betts Brown
at the Office of the Commissioners of Patents, with his Petition,
on the 21st January 1868.
I, ANDREW BETTS BROWN, of the Vauxhall Iron Works, Wandsworth
Road, in the County of Surrey, Engineer, do hereby declare the nature
of my Invention for "IMPROVEMENTS IN ACTUATING THE VALVES OF ENGINES
WORKED BY STEAM OR OTHER FLUID," to be as follows:-.
This Invention has for its object improvements in actuating the
valves of engines worked by steam or other fluid, and relates to the
working of what are known as steam moved valves. The valve I
prefer to employ is a balance piston valve composed of two discs
fixed at a distance apart from one another on a hollow rod; these
discs work to and fro in a cylindrical seat bored to receive them, this.
seat being formed on the exterior of the cylinder of the engine, and
conveniently in one piece with it. In the interior of the cylindrical
seat three ports are formed, the central port being connected with
[Price 8d.

page_text: the steam supply and the two outer ports through suitable passages
with the two ends of the cylinder of the engine. When the valve is
at one or other end of its stroke one of the discs will close one end
of the cylindrical seat, whilst the other disc will shut off the com-
munication between the central steam port and the outer port at the
opposite end of the cylindrical seat, leaving this end of the seat and
consequently the outer port formed therein open to a chamber or
casing by which the seat is surrounded, and which is connected with
the exhaust. This casing is also conveniently cast in one piece with
the cylinder of the engine. The valve rod I connect at one of its
ends to a hollow piston or plunger working in a cylinder formed at
one end of the chamber which surrounds the valve seat. One end
of this cylinder is open to the chamber and consequently to the
exhaust, and the other is closed by a plate which also forms the end
cover of the cylinder of the engine. The plunger at its back endi
carries a piston which is of larger diameter and which works within
a corresponding enlargement at the rear end of the cylinder. Steam
is at all times admitted to this enlargement of the cylinder, so that
there shall at all times be a pressure of steam upon the outer ring
of the piston which projects beyond the plunger; this I effect by
admitting steam to the interior of the valve rod through holes formed
in it between the two discs which it carries and allowing the steam
to pass out to the enlarged portion of the cylinder through perforations
formed in the side of the hollow plunger at its rear end where it has
the piston connected to it, as above explained. The pressure of steam
thus acting against the outer ring of the piston will tend to press the
piston back against the back end of the cylinder and so hold the
valve over to that end of its stroke. From the back end of this
cylinder is a passage leading into the side of the cylinder of the engine
near its further end. There is also another passage leading from it
to the exhaust; this latter passage is fitted with a valve the stem of
which passes out through a stuffing box in the end cover and is acted
on by a spring which keeps the valve closed. Through the end cover
of the cylinder of the engine a tappet is passed; the outer end of
this tappet is jointed to one arm of a lever other arm of which
is connected to the valve stem above mentioned. In order that when
the piston of the engine at the end of its stroke comes against the
tappet the lever may be pressed back, and so caused to open the
valve.
the

page_text: By the above-described arrangement for working the valve if the
piston of the engine be moving away from the end cover through
which the tappet passes the side opening near the opposite end of the
cylinder will be open to the exhaust until the piston has passed beyond
the opening; steam from the cylinder of the engine will then at once
pass to the back end of the cylinder which is for working the valve,
and by pressing against the whole area of the back of the piston will
drive back the sliding valve to the opposite end of its stroke, so.
admitting steam on the opposite side of the piston of the engine to
that upon which it was previously acting. The opening in the side
of the cylinder will then for an instant be open to the exhaust until
the piston has moved back sufficiently to pass over the opening; this
would for an instant tend to shift the sliding valve; to prevent this
I at this time allow a small leak of steam to pass from the frout to
the back of the piston which works the sliding valve. When the piston
of the engine has again passed back over the opening in the side of
the cylinder this opening is again opened to steam, and the valve is
thereby held over until the piston of the engine at the end of its
stroke hits the tappet which passes through the end cover, and (by
pressing back the lever and valve connected to it) opens the back
end of the cylinder (which is for working the sliding valve) to the
exhaust; the pressure of steam which as before stated is constantly acting
against the piston of this cylinder will then drive it towards the cover of
the cylinder, and so shift the sliding valve of the engine, and the sliding
valve will remain in this position until the piston of the engine again
passes over the opening in the side of its cylinder, and this opening will
until then be open to the exhaust. In order to deaden the force with
which the valve is driven over from one end of its stroke to the other
the opposite end of the valve rod to that which has the piston and
plunger connected to it has a piston fixed upon it working somewhat
freely in a cylinder closed at both ends; the air in the cylinder thus
forms a cushion to ease the blow as the valve is moved in one or other
direction.
In place of a tappet being employed at one end of the cylinder of
the engine to open the rear end of the valve cylinder to the exhaust
as above described the stem of this valve may be attached to a piston
the
working in a small cylinder carried on the exterior of the cover;

page_text: end of this small cylinder which is towards the cover is connected by
a passage with the port passage leading to the cover end of the cylinder
of the engine, and the back end of the small cylinder is by a suitable
passage connected with an opening in the side of the cylinder of the
engine near the same end. By this arrangement when the piston of
the engine is moved towards the end cover and has passed over the
opening at this end of its cylinder steam will pass through the opening
to the back of the piston in the small cylinder, so driving forward
the piston and opening the valve; the sliding valve will then be shifted,
as in the arrangement first described. The small leak of steam from the
front to the back of the piston which works the sliding valve (and which
leak of steam is, as before explained, required at the time when this piston
is at the end of its stroke furthest from the cover) may be effected by a
grooved valve projecting out from the valve in the cylinder cover and
entering a cylindrical recess in the hollow piston and plunger. The inner
end of the recess is left open so that steam may escape through the
grooves of the valve when the piston and plunger are away from the
end cover, but when the piston is against the cover these grooves will be
closed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Andrew Betts Brown in the Great Seal Patent Office
on the 21st July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANDREW
BETTS BROWN, of the Vauxhall Iron Works, Wandsworth Road, in the
County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of January, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Andrew Betts Brown, Her special
licence that 1, the said Andrew Betts Brown, my executors, adminis-
trators, and assigns, or such others as I, the said Andrew Betts Brown,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during

page_text: the terin 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 ACTUATING THE VALVES OF ENGINES WORKED BY STEAM OR
OTHER FLUID," upon the condition (amongst others) that I, the said
Andrew Betts Brown, 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 Andrew Betts Brown 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, that is to say —
This Invention has for its object improvements in actuating the
valves of engines worked by steam or other fluid.
For this purpose I
actuate the sliding or reciprocating valve which governs the admission
of steam or fluid to the cylinder of the engine by connecting such
valve to a rod carrying two pistons or plungers of different diameters
and which work in corresponding cylinders. The pressure of steam or
other fluid by which the engine is worked is caused to act constantly
either upon the area of the smaller piston or upon the annular portiou
of the larger piston which projects beyond the smaller piston, and so
tends to move the valve over to one end of its stroke whenever it is
free to do so. When the valve is to be moved to the opposite end of
its stroke the steam or fluid is allowed to act on the whole area of the
The steam
larger piston, so as to overcome this constant pressure.
or fluid which is so to act on the whole area of the larger piston is
led from the cylinder of the engine through a port in its side and near
to one of its ends, steam is free to pass through this port as soon as
the piston of the engine having arrived at this end of its stroke has
passed beyond the port. When the slide valve has been thus shifted.
this port in the side of the cylinder would until the piston of the
engine has again passed over it be open to the exhaust, so that the
area of the larger piston above mentioned would momentarily be
released from pressure, and to prevent the valve being then again

page_text: shifted a small leak of steam is at this time allowed to pass into the
cylinder in which the larger piston works. As soon as the engine
piston has passed back again over the port in the side of the cylinder
the port
will be again open to steam, and so the reciprocating valve
of the engine will be held over until the engine piston has arrived at
the opposite end of its stroke; the chamber in which the larger piston
above mentioned works is then opened to the exhaust, so allowing the
constant pressure of steam which is acting on the smaller piston or
on the annular ring of the larger piston to again shift the reciprocating
valve of the engine. The opening of this chamber to the exhaust is
governed by a valve which may be caused to open by the piston of
the engine striking against a tappet or by connecting the stein of the
valve to a piston working in a small cylinder, as herein-after described.
Figure 1 of the Drawings hereunto annexed shows a longitudinal
section of an engine in which the admission of steam or fluid to the
cylinder is governed by a balance piston valve to which a to-and-fro
reciprocating motion is transmitted in the manner above described.
In this Figure a is the cylinder of the engine; b, the piston; c,
the balance piston valve composed of two discs c¹ on a hollow rod c;
these discs work to and fro in a cylindrical seat; in the interior of
this seat three ports d are formed, the central port being connected
with the steam or fluid supply, and the two outer ports through suitable
passages with the two ends of the cylinder of the engine. When the
valve is at one or other end of its stroke one of the discs will close
one end of the cylindrical seat, whilst the other disc will shut off the
communication between the central steam port and the outer port at
the opposite end of the cylindrical seat, leaving this end of the seat
and consequently the outer port formed therein open to a chamber
or casing e by which the valve seat is surrounded; this casing is con-
nected with the exhaust, and is conveniently cast in one piece with
the cylinder of the engine. At one end of the hollow piston rod c
is formed a hollow piston or plunger c³ which works in a cylinder f
formed at one end of the chamber e; the rear end of this cylinder
is closed by the end cover f¹ which is formed in one piece with the
end cover of the cylinder of the engine; the back end of the plunger
c² carried a piston c3 which is of larger diameter and which works
in a corresponding enlargement in the cylinder f. A constant supply
of steam or fluid is admitted to this enlarged part of the cylinder so

page_text: as to act against so much of the piston c³ as projects beyond the
piston c; this is effected by admitting steam or fluid to the hollow
piston rod through small holes c, and allowing the steam or fluid
to pass therefrom through other holes c³ formed through the hollow
piston c².
The pressure of steam or fluid thus acting against the
outer ring of the piston will tend to press the piston back against
the back end of the cylinder, and so hold the valve over to that end
of its stroke, as shown in the Drawing. Through the cover f¹ of the
cylinder is a passage f leading to the port a¹ in the side of the
cylinder near its further end. Through the cover f¹ is also another
passage leading to the exhaust; this passage is fitted with a valve g
carried by a rod g' which passes out through a stuffing box in the
end cover outside the cover, the rod is acted on by a spring g²
which holds the valve closed. h is a tappet passing through a stuffing
box in the end cover of the cylinder of the engine; the outer end of this
tappet is jointed to the lower end of the lever k; the upper arm of this
lever bears against the stem g¹ of the valve g so that when the piston of
the engine at the end of its stroke comes against the tappet the lever may
be pressed back and so caused to open the valve.
By the above-described arrangement if the piston be moving
away from the tappet the port a¹ near the opposite end of the
cylinder a will be open to the exhaust until the piston has passed
beyond the port; steam from the cylinder of the engine will then at
once pass through the port to the back of the piston c³, and acting
against the whole of its area will force the slide valve cover to the
opposite end of its stroke, the port a', as before explained, would then
momentarily be open to the exhaust, so tending to relieve the back
of the piston from pressure and to allow the valve c to be moved
back again. The small leak of steam which as before explained is (by
passing from the front to the back of the piston c³) to prevent the
back of the piston c³ from being thus suddenly released from pressure
takes place through a small groove or channel f* cut in the side of
the cylinder as shown. When the engine piston 6 has again passed
back over the port a' the steam or fluid will again pass through the
port and will so hold over the slide valve c. When the engine piston
b arrives at the end of its stroke it strikes against the tappet h and
opens the valve g, so opening the rear end of the cylinder f to the
exhaust the constant pressure of steam which is acting against the
portion of the piston c* which projects beyond the piston c' will then

page_text: move the pistons towards the end cover fl and so again shift the
valve c,
when the same operation will be repeated. In order to
deaden the force with which the valve c is driven over from one end
of its stroke to the other the opposite end of the valve rod to
that which carries the pistons c², ³, has attached to it a piston
working somewhat freely in a short cylinder which is closed at
both ends so that the air in the cylinder may form a cushion to
ease the blow as the valve c is moved in one or other direction. This
arrangement for deadening the force of the blow may however be dispensed
with.
Figure 2 of the Drawings shews a longitudinal section of an engine
similar to that shown in Figure 1, except that the valve g is opened
and closed by a small piston g³ in place of by the tappet h, and that
the small leak of steam is governed by a grooved valve g' projecting
out from the valve g. The parts of this engine, which correspond
with the parts of the engine shown at Figure 1, are marked by
corresponding letters of reference. In this arrangement the small
piston g works in a short cylinder m one end of which is by a
passage m open to the port passage leading to the end of the engine
cylinder a and the other end of the cylinder m, is by a passage m³
connected with a port a' in the side of the cylinder. In this
arrangement when the engine piston 6 is moving towards the cylinder
cover and has passed beyond the port a steam will pass through
the port to the back of the piston and will so open the valve g,
thus at once causing the slide valve c to be shifted as before described;
steam will then immediately pass through the passage m', whilst the
port a will be opened to the exhaust, and thus the valve g will be
closed. As soon as the engine piston b has passed back again over
the port a steam or fluid will be acting upon both sides of the
piston g³, and the valve g will be held closed by the pressure of
gteam
fluid acting upon
the top of the valve.
engine piston 6 has travelled back to the opposite end of the engine
cylinder and has passed over the port a steam will as before
described pass through this port and will act against the whole
area of the piston c, so shifting the slide valve c; the momentary
leak of steam which must then take place is effected through the
grooves in the side of the valve g'; this valve works as is shown in
a cylindrical recess c' in the hollow piston c³, a small hole is formed
through the end of this recess so that steam is constautly admitted
or
When the

page_text: to the recess from the hollow piston to which as before explained steam
or fluid is at all times admitted. When the engine piston has again passed
back over the port a steam will again pass through the port and hold
over the slide valve c. At this time both ends of the small cylinder m
will be open to the exhaust, and the valve g will be held closed by the
pressure of steam or fluid upon it, and the valve will be thus held closed
until the piston 6 has passed beyond the port a2, when the same operation
will be repeated.
Figures 3 and 4 on Sheet 2 of the Drawings show a plan view and
section of an engine in which an ordinary slide valve is employed
for governing the admission of steam to the two ends of the engine
cylinder, and which slide valve has motion transmitted to it in a
similar manner to that above described. The Drawings also show
the piston rod of the engine as forming the rod of a pump, the pump
cylinder and the engine cylinder being cast together on one bed plate.
The parts of the engine which are similar to those above described
are marked with corresponding letters of reference; in this case
however the valve chamber e being open to the steam or fluid
supply in place of to the exhaust, the constant pressure of steam or
fluid is caused to act against the piston 2 instead of against the portion
of the piston c³ which projects beyond the piston c, this portion of the
piston being in this arrangement open to the exhaust by openings or
communications into the passage W (see Figure 3); this passage W also
forms the channel by which the rear end of the cylinder f is connected
to the exhaust or outlet, the opening from the cylinder f to the
passage W being closed by the valve g', as in the arrangement shown at
Figure 2.
In all other respects the engine shown at Figures 3 and 4 is (with the
exception of variations in points of construction, the nature of which is
clearly shown by the Drawing) similar to the engine shown at Figure 2,
and acts in precisely the same manner, so that it is unnecessary to again
describe it. The ball U, shown in Figures 3 and 4, is used simply to open
the valve when it is liable to be slow in action, as in the case of the
cylinder being full of condensed water.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that what I
claim is,-

page_text: First. Actuating valves of engines worked by steam or other fluid by
connecting such valves to a rod carrying two pistons of different areas, the
steam or fluid being allowed constantly to act on the smaller area, whilst
the largest area is alternately acted on by steam and open to the outlet or
exhaust, the admission of steam to act on the larger area being effected
through a port leading from the cylinder of the engine near to one of its
ends, as herein described.
Second. I claim the employment of a momentary leak of steam to pre-
vent the sliding or reciprocating valve from being again at once shifted
back at the time when it has just been shifted by steam, having passed from
the cylinder of the engine to act on the larger area piston, and when if
there were not such leak the valve would be shifted by reason of the port
through which steam had previously passed from the cylinder being then
momentarily open to the exhaust.
Third. I claim governing the opening of the cylinder to the outlet
or exhaust by a valve g actuated by a tappet or small piston, as herein
described.
In witness whereof, I, the said Andrew Betts Brown, have here-
unto set my hand and seal, this Sixteenth day of July, in the
year of our Lord One thousand eight hundred and sixty-eight.
ANDREW BETTS BROWN. (L.S.)