IMPROVEMENTS IN DIRECT-ACTING STEAM PUMPS AND IN STEAM ENGINES
Year: 1876

page_text: LETTERS PATENT to Thomas Parker, of Coalbrookdale, in the County of Salop,
Moulder, and Philip Alfred Weston, of Coalbrookdale aforesaid, Machinist, for
the Invention of "IMPROVEMENTS IN DIRECT-ACTING STEAM PUMPS AND IN
STEAM ENGINES.”
PROVISIONAL SPECIFICATION left by the said Thomas Parker and Philip
Alfred Weston at the Office of the Commissioners of Patents on the 20th June
1876.
THOMAS PARKER, of Coalbrookdale, in the County of Salop, Moulder, and PHILIP
ALFRED WESTON, of Coalbrookdale aforesaid, Machinist. "IMPROVEMENTS IN
DIRECT-ACTING STEAM PUMPS AND IN STEAM ENGINES."
Our Invention consists of the improvements herein-after described in direct-acting
steam pumps and in steam engines, the said improvements being in part improve-.
ments on an Invention for which Letters Patent were granted to us on the 23rd
day of October 1874, No. 3658.
We will describe our improvements as applied to a direct-acting horizontal steam
pump, but the said improvements are equally applicable to vertical or inclined
steam pumps and engines.
We dispense with the exhaust valves at the middle of the valve rod described
In the Specification of the Patent referred to, and we make at each end of a hollow
cylinder working in the valve chest a valve piston, the said hollow cylinder and
pistons moving together, the said hollow cylinder being so constructed that it opens
and closes the main steam and exhaust ports of the steam cylinder after the
manner of an ordinary slide valve. The area of the back or outer face of each
valve piston is greater than that of the inner face. Two passages or ports in
connection with the main steam port are open to the valve chest in which the
valve pistons respectively work, and a third passage in connection with the steam
cylinder also opens into the said valve chest at the part where the valve piston
works. A small port or passage is also made in each valve piston. The last-named
port or passage is brought opposite, at the proper time, the port or passage in
communication with the steam cylinder.
The action of the parts is.as follows:-When the main steam piston is making
its stroke, say from right to left, the valve pistons and slide valve are at the end
of their stroke in the same direction. Steam from the main steam port is open
Price 1021

page_text: to the valve chest at the right-hand end, which steam, acting on the greater area
of the valve piston at the said end of the chest, holds the slide valve in its advanced
position till the end of the stroke of the steam piston. As soon as the steam piston
passes the port or passage at the left-hand end of the steam cylinder in connection
with the steam chest steam passes through the said port or passage and also
through the small port or passage in the left-hand valve piston to the outer side
of the said valve piston. The pressures on the outer faces of the two valve pistons
being thus balanced, or in equilibrium, the steam acts upon the inner face of the
right-hand valve piston giving motion to the said piston and to the slide valve,
and thereby reversing the positions of the steam and exhaust ports. Steam now
acts on the left-hand valve piston and maintains the slide valve in its reversed
position, the right-hand valve piston being open to the exhaust, these positions being
maintained until the steam piston passes the port at the right-hand end of the.
steam cylinder, when the slide valve is again reversed, and so on.
From the foregoing description it will be understood that the starting motion of
the slide valve is due to the pressure of steam on the inner face of one of the
piston valves, the pressures on the outer faces of both piston valves being balanced.
On the slide valve crossing the ports the pressure on the inner face of the piston
valve is removed, the same face of the piston valve and also the outer face of the
same piston valve being open to the exhaust. The opposite faces of the piston
valve at the other end of the chest are now open to the steam, the outer face of
the last-named piston valve continuing the motion by its greater area over the
inner face of the said piston valve, and retaining the slide valve at full port until
its position is reversed.
Our Invention consists further of an auxiliary valve for ensuring the working of
the main slide valve, herein-before described, or an ordinary piston slide valve
where great certainty of motion is required. The said auxiliary valve works in a
case parallel to the main piston slide valve, and its ends are open to the ends of the
steam cylinder. Near each end of the auxiliary valve is a port which opens by a
passage to the end of the main valve, near which it is situated. The ports of the
auxiliary valve are also alternately opened to the exhaust by means of passages at
the bore and nearer the middle of the steam cylinder than those which supply steam
to the ends of the auxiliary valve, the two ports in the said auxiliary valve are
alternately opened to the steam in the steam cylinder.
At the commencement of each stroke of the steam piston the auxiliary valve
moves with the said piston passing to the end of its stroke in one direction. One
end of the main slide valve is thereby put in connection with the exhaust by means
of the port in the end of the auxiliary valve, and the port at the opposite end of
the auxiliary valve is open to the passage in the bore of the steam cylinder at the
same end.
On the steam piston passing the last-mentioned passage in the steam
cylinder steam is admitted by the passage to the port in the auxiliary valve and
from thence to the main valve, and the said main valve is carried over and the main
ports reversed. On the steam piston making its stroke in the opposite direction the
auxiliary valve is moved in the same direction, and that end of the main slide valve
which was previously open to the exhaust is now open to the steam cylinder and
the opposite end to the exhaust, and so on.
Instead of the port described at each end of the cylinder a ball valve in the steam
piston or a ball valve at each end of the cylinder may be used for the purpose
described.
For working the steam expansively we arrange an expansion valve moving
vertically in the valve chest, the said expansion valve working across the steam
pipe which admits steam to the valve chest, and opening and closing the said steam
pipe at the proper times. The said expansion valve has two acting areas, the
bottom and larger area being acted upon by steam from the steam cylinder to close
the valve and the other area being acted upon by the steam in the steam pipe to
push back or open the expansion valve. A loose piece is placed on the underside
of the expansion valve, which piece rides upon the steam employed to move the valve

page_text: and cuts off the escape of the steam, the said loose piece or small valve cushioning
the fall of the larger valve and also forming a cataract governor to give a pause to
the engine when at the end of the stroke, the length of which pauses may be
regulated by the orifice by which the steam is allowed to escape back, the said
orifice being opened or closed as desired.
For the purpose of varying the cut off of the steam at the required travel of the
steam piston we use the following arrangement of parts:-Immediately beneath the
expansion valve we place a horizontal tube capable of a partial rotation by means of
an index wheel external to the said tube.
The tube is, divided at or about its middle into two parts by means of a small
valve, and between the said valve and one end of the tube are two holes situated
at different distances from the middle of the tube, and between the said valve and
the other end of the tube are two similarly arranged holes. The pair of holes nearest
to and on opposite sides of the valve are in the same line, and the pair of holes most
distant from the valve are also in the same line with one another, but at a different
angle in the circumference of the tube from the first-named pair of holes. By turning
the tube through the required angle either pair of holes in it may be brought
opposite corresponding holes in the steam cylinder so that the steam may be cut off
at different positions of the stroke of the piston, according to the angle at which the
tube is turned. The steam entering one of the holes on one side of the valve in
the tube opens the said valve to a passage in connection with the expansion valve,
but closes the other half of the tube and prevents the passage of steam to the other
hole of the pair of holes in the closed half of the tube. The steam passing through
the valve operates upon the expansion valve and cuts off the steam, as before
described.
Two constructions of the valve inside the regulating tube may be used, one
construction being employed when cutting off before half stroke of the piston, and
another construction when cutting off after half stroke of the piston. The regulating
tube may be made capable of sliding in its casing as well as rotating.
In this modification the tube is open at each end to the steam cylinder, as the
steam is admitted it moves the tube endways, thereby dispensing with the middle
valve already described.
By moving the tube through the required angle, holes in its circumference are
brought opposite corresponding holes in the steam cylinder, and the steam may be
cut off at any required length of the piston's stroke.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Parker and Philip Alfred Weston in the Great Seal Patent
Office on the 18th December 1876.
THOMAS PARKER, of Coalbrookdale, in the County of Salop, Moulder, and PHILIP
"IMPROVEMENTS IN
ALFRED WESTON, of Coalbrookdale aforesaid, Machinist.
DIRECT-ACTING STEAM PUMPS AND IN STEAM ENGINES."
Our Invention consists of the improvements herein-after described in direct-
acting steam pumps and in steam engines, the said improvements being in part
improvements on an Invention for which Letters Patent wero granted to us on the
23rd day of October 1874, No. 3658.
We will describe our improvements as applied to a direct-acting horizontal steam
pump, but the said improvements are equally applicable to vertical or inclined steam
pumps and engines.
We dispense with the exhaust valves at the middle of the valve rod described
in the Specification of the Patent referred to, and we make at each end of a hollow
cylinder working in the valve chest a valve piston, the said hollow cylinder and
pistons moving together, the said hollow cylinder being so constructed that it
opens and closes the main steam and exhaust ports of the steam cylinder after the
manner of an ordinary slide valve. The area of the back or outer face of cacli
valve piston is greater than that of the inner face. Two passages or ports in con-

page_text: nection with the main steam port are open to the valve chest in which the valve
pistons respectively work, and a third passage in connection with the steam
cylinder also opens into the said valve chest at the part where the valve piston
works. A small port or passage is also made in each valve piston. The last-named
port or passage is brought opposite, at the proper time, the port or passage in com-
munication with the steam cylinder.
The action of the parts is as follows:-When the main steam piston is making
its stroke, say from right to left, the valve pistons and slide valve are at the end
of their stroke in the same direction. Steam from the main steam port is open to
the valve chest at the right-hand end, which steam, acting on the greater area
of the valve piston at the said end of the chest, holds the slide valve in its advanced
position till the end of the stroke of the steam piston. As soon as the steam
piston passes the port or passage at the left-hand end of the steam cylinder in
connection with the steam chest steam passes through the said port or passage and
also through the small port or passage in the left-hand valve piston to the outer
side of the said valve piston. The pressures on the outer faces of the two valve
pistons being thus balanced, or in fequilibrium, the steam acts upon the inner
face of the right-hand valve piston giving motion to the said piston and to the
slide valve, and thereby reversing the positions of the steam and exhaust ports.
Steam now acts on the left-hand valve piston and maintains the slide valve in
its reversed position, the right-hand valve piston being open to the exhaust, these
positions being maintained until the steam piston passes the port at the right-hand
end of the steam cylinder, when the slide valve is again reversed, and so on.
From the foregoing description it will be understood that the starting motion
of the slide valve is due to the pressure of steam on the inner face of one of the
piston valves, the pressure on the outer faces of both piston valves being balanced.
On the slide valve crossing the ports the pressure on the inner face of the piston
valve is removed, the same face of the piston valve and also the outer face of the
same piston valve being open to the exhaust. The opposite faces of the piston
valve at the other end of the chest are now open to the steam, the outer face of
the last-named piston valvo continuing the motion by its greater area over the
inner face of the said piston valve, and retaining the slide valve at full port until
its position is reversed.
•
Our Invention consists further of an auxiliary valve for insuring the working of
the main slide valve, herein-before described, or an ordinary piston slide valve
where great certainty of motion is required. The said auxiliary valve works in
a case parallel to the main piston slide valve, and its ends are open to the ends of
the steam cylinder. Near each end of the auxiliary valve, is a port which opens
by a passage to the end of the main valve, near which it is situated. The ports
of the auxiliary valve are also alternately opened to the exhaust. By means of
passages at the bore and nearer the middle of the steam cylinder than those which
supply steam to the ends of the auxiliary valve the two ports in the said auxiliary
valve are alternately open to the steam in the steam cylinder.
At the commencement of each stroke of the steam piston the auxiliary valve
moves to the end of its stroke in one direction. One end of the main slide valve is
thereby put in connection with the exhaust by means of the port in the end of
the auxiliary valve, and the port at the opposite end of the auxiliary valve is
open to the passage in the bore of the steam cylinder at the same end. On the
steam piston passing the last-mentioned passage in the steam cylinder steam is
admitted by the passage to the port in the auxiliary valve and from thence to the
main valve, and the said main valve is carried over and the main ports reversed.
The auxiliary valve is then reversed and that end of the main slide valve which
was previously open to the exhaust is now open to the steam cylinder and the
opposite end to the exhaust, and so on.
Instead of the port described at each end of the cylinder a ball valve in the
steam piston or a ball valve at each end of the cylinder may be used for the purpose
described.
For working the steam expansively we arrange an expansion valve moving verti-

page_text: cally in the valve chest, the said expansion valve working across the steampipe which
admits steam to the valve chest, and opening and closing the said steam pipe at the
proper times. The said expansion valve has two acting areas, the bottom and
larger area being acted upon by steam from the steam cylinder to close the valve,
and the other area being acted upon by the steam in the steam pipe to push back
or open the expansion valve. A loose piece is placed on the underside of the
expansion valve, which piece rides upon the steam employed to move the valve and
cut off the escape of the steam, the said loose piece or small valve cushioning the
fall of the larger valve and also forming a cataract governor to give a pause to the
engine when at the end of the stroke, the length of which pauses may be regulated
by the orifice by which the steam is allowed to escape back, the said orifice being
opened or closed as desired.
For the purpose of varying the cut off of the steam at the required travel of the
steam piston we use the following arrangement of parts:-Immediately beneath
the expansion valve we place a horizontal tube capable of a partial rotation by
means of an index wheel external to the said tube.
The tube is divided at or about its middle into two parts by means of a
small valve, and between the said valve and one end of the tube are two holes
(or more than two holes) situated at different distances from the middle of
the tube, and between the said valve and the other end of the tube are two
similarly arranged holes. The pair of holes nearest to and on opposite sides of
the valve is in the same line, and the pair of holes most distant from the valve
is also in the same line with one another, but at a different angle in the circumference
of the tube from the first-named pair of holes. By turning the tube through the
required angle either pair of holes in it may be brought opposite corresponding
holes in the steam cylinder, so that the steam may be cut off at different positions
of the stroke of the piston, according to the angle at which the tube is turned.
The steam entering one of the holes on one side of the valve in the tube opens
the said valve to a passage in connection with the expansion valve, but closes the
other half of the tube and prevents the passage of steam to the other hole of the
pair of holes in the closed half of the tube. The steam passing through the valve
operates upon the expansion valve and cuts off the steam, as before described.
Two constructions of the valve inside the regulating tube may be used, one
.construction being employed when cutting off before half stroke of the piston, and
another construction when cutting off after half stroke of the piston.
The regulating tube may be made capable of sliding in its casing as well as
rotating. In this modification the tube is open at each end to the steam cylinder.
As the steam is admitted it moves the tube endways, thereby dispensing with the
middle valve already described.
By moving the tube through the required angle holes in its circumference are
brought opposite corresponding holes in the steam cylinder, and the steam may be
cut off at any required length of the piston's stroke.
Having now explained the nature of our Invention we will proceed to describe
with reference to the accompanying Drawings the manner in which the same is
to be performed.
Figure 1 represents in side elevation, Figure 2 in longitudinal vertical section,
Figure 3 in horizontal section, and Figure 4 in transverse vertical section a direct
acting horizontal steam pump provided with valve mechanism constructed according
to our Invention; Figure 5 is a plan of the upper side of the seat of the valve chest.
The same letters of reference indicate the same parts in Figures 1, 2, 3, 4, and 5.
a is the valve chest; b is the steam cylinder, and c is the steam piston working
therein. Working in the valve chest a is a hollow cylinder, consisting of a valve
piston at each end, marked respectively d and e and a slide valve fat its middle,
the said valve pistons d and e and slide f moving together. The slide valve fat
the middle of the hollow cylinder opens and closes the main steam and exhaust
ports g, h, after the manner of an ordinary slide valve; q is the exhaust passage
By an examination of Figure 2 it will be seen that each valve piston has two areas

page_text: marked respectively d², d³, and e², e³, the areas of the outer faces d², e, of the said
valve pistons being greater than the areas of their inner faces d³, e³.
The use of the inner areas d³, es, of the valve pistons is herein-after pointed out.
Opening into each end of the valve chest a, in which the valve pistons d, e, re-
spectively work, are two small ports or passages. These ports or passages are
marked respectively g², h², and i, k; also opening into the ends of the valve chest a
are other larger ports or passages l, m, in connection with the steam cylinder b.
A small port or passage is also made in each valve piston d, e, the said ports or
passages being marked respectively n and p. These ports or passages n, p, are
brought opposite, at the proper times, the ports or passages l, m, in connection with
the steam cylinder b. The passages g² and i are always open to the main passages
g and h.
When the main steam piston c is making its stroke in the direction of the arrow,
Figure 2, that is from left to right, the valve pistons d and e and the slide valve fare
at the end of their stroke, in the same direction as represented in the said Figure 2,
where it will be seen that the exhaust is open to the area e³ of the valve piston e,
and that steam from the main port g is open to the two areas d², d³, of the valve
piston d, and by the steam acting on the larger area d² of the said valve piston d,
holds the slide valve fin its advanced. position till the end of the stroke of the
steam piston c. As soon as the steam piston c passes the port or passage 7 in
the steam cylinder b, in connection with the right-hand end of the valve chest a,
steam from the said cylinder b passes through the port or passage l, and also
through the small port or passage n in the valve piston e to the outer side or
area e of the valve piston e. When the main steam piston has arrived at the
position just indicated it will be seen that steam from the left-hand end of the
cylinder 6 passing through the port is pressing on the outer face or area d³, and
stean by the passage i is also pressing on the inner face or area of the valve
piston d, and that the steam passing through the ports 1, n, is pressing on the
outer face or area e² of the other valve piston e. The pressures on the outer
faces and e2 of the two valve pistons d, e, being thus balanced or in equilibrium
the steam pressing on the inner face d³ of the piston valve d gives motion to
the two piston valves d, e, and slide valve f in a direction contrary to that
indicated by the arrow in Figure 2, and thereby reverses the position of the
main steam and exhaust ports. Steam from the main port / now passes by the
small port and presses on the outer face or area e2 of the valve piston e, and
maintains the slide valve fin its reversed position, steam also passes by the small
port g to the inner area e³ of the valve piston e. The area d³ of the valve piston d
is at the same time opened to the exhaust through the passage i, and the area d³
to the exhaust through the passages m, p. These positions are maintained until
the steam piston c in its back stroke passes the port m in the steam cylinder b,
when the slide valve f is again reversed in the manner herein-before described.
From the description herein-before given, reference being had to Figure 2 of the
Drawing, it will be understood that the starting motion of the slide valve f is due
to the pressure of steam either on the inner face d³ or e³ of the valve pistons d or e,
the pressures on the outer faces d², e², being balanced. On the slide valve f crossing
the ports g, h, (assuming the parts to occupy the positions represented in Figure 2)
the pressure on the inner face ds by which the reversal of the valve was effected is
removed, the same face d³, and also the outer face d³ of the same valve piston d, being
open to the exhaust by the passages i, m, p. The opposite faces or areas e³, e³, of
the other valve piston e are now open to the steam by the passages h³, g, the
outer face e² of the valve piston e continuing the motion of the slide valve f by its
greater area over the inner face e³ of the said valve piston e, and retaining the
slide valve at full port until its position is reversed.
In starting the engine the slide valve f is moved by the arm r through the
axis and lever ³. The valve is prevented from turning by the adjustable screw rod 8.
Figure 6 represents in longitudinal vertical section, Figure 7 in horizontal
section, and Figure 8 in cross section, our improved auxiliary valve for working

page_text: the main valves of steam pumps and steam engines, or for ensuring the working
of slide valves constructed as herein-before described. The section Figure 7 is
taken on the line A, B, of Figure 8. The same letters of reference indicate the
same parts in Figures 6, 7, and 8.
d, e, f, is an ordinary cylindrical main slide valve, and b, b¹, b², b³, b', is the
auxiliary valve constructed as best seen in Figure 7, the said auxiliary valve
working in the case c, cs, es, parallel to the main valve. The ends c, c, of the
auxiliary valve case c are open to the ends of the main steam cylinder a by the ports
or passages g, h, and the said ends c², c³, are also open to the main steam or exhaust
ports i, h, by the small ports 1, m... The said ends c³, c³, of the anxiliary valve
case c, c², c³, are also open by the ports or passages p, q, to the ends of the steam
chest in which the main valve e, f, d, works. The middle part c of the auxiliary
valve case is open to the exhaust passage by the ports t, t¹.
By means of the passages or ports g, h, the ends of the auxiliary valve 6, 6³, are
alternately opened to the steam in the main steam cylinder, by means of the
passages l, m, the extreme ends of the auxiliary valve case behind the pistons 63, 64,
of the valve are alternately opened to the steam and exhaust, and by means of the
ports p, q, steam is supplied to one end of the main valve, and the opposite end put
in communication with the exhaust.
The action of the auxiliary valve is as follows:-At the commencement of each
stroke of the main piston the auxiliary valve passes to the end of its stroke in the
same direction by steam passing through either the port or m and acting on the
piston 64 or 6s of the auxiliary valve, as herein-after more particularly explained.
When the auxiliary valve has passed from left to right the parts occupy the respec-
tive positions shown in Figure 7, that is, the part of the valve behind the piston b
of the auxiliary valve is open to the exhaust through the passage and the part b
of the valve is open to the exhaust by the passage g in the cylinder, and the end e of
the main valve is also open to the exhaust through the passage p, the opposite
part of the valve behind the piston 63 of the auxiliary valve is open to the steam
from the port m and the opposite end.d of the main valve is open to the exhaust
through the port t and passage q, the port h opening into the main steam cylinder
being closed. As the main steam piston travelling from left to right passes the
open port g in connection with the steam cylinder the said port admits steam
to the part 6 of the auxiliary valve, which steam passes through the passage p and
nets upon the end e of the main valve and reverses the position of the said main
valve. After the reversal of the main valve e, f, d, steam from the port i passes
by the port to the back face or piston 6 of the auxiliary valve and reverses the
position of the said valve, the opposite end 6s of the said auxiliary valve being
put into communication with the exhaust through the passages m and k, the
passage being open to the cylinder. The passage g at the end 6 of the auxiliary
h
valve is closed and steam by the passage presses on the auxiliary valve and holds
it in its reversed position. The same action takes place when the steam piston
passes the port h in making its stroke in the opposite direction, that is, by the
reversal of the auxiliary valve the port h in connection with the steam cylinder is
opened ready on the steam piston passing the said port h to convey steam through
the passage q to the main slide valve for reversing the same. Thus it will be seen
that the auxiliary valve by its motion in the same direction, and at the same time
as the main piston provides for the reversal of the main valve when the main
piston has made the required travel by steam taken from the steam cylinder, tho
said reversal of the main valve causing the reversal of the auxiliary valve ready
for the reversal of the main valve on the next stroke of the main steam piston.
For the purpose of providing for the cushioning of the main valve on the said
valve being reversed we adopt the following parts:-In the partition between the
main and auxiliary valve cases are the two ports t, t¹, opening respectively by the
ports n, n, in the slide valve f of the main valve with the exhaust. On the main
valve and between the ports n, n¹, is a bar or block v for closing either the port t

page_text: or the port that the proper time, and on the middle of the auxiliary valve is a
piston b for opening either the port t or the port t¹ at the proper time.
The action is as follows:-By an examination of Figure 7 it will be seen that
the end d of the main valve is open to the main exhaust by the passages q, t, and n,
and that the passage t¹ is closed by the bar or block v. On the main valve d, e, f,
moving from right to left by the action of steam upon its piston e, the bar or
block on the said main valve closes the port t, and thereby cuts off communi-
cation between the exhaust steam behind the piston d of the main valve and the
port n. The piston d of the main valve is thereby cushioned as it advances by the
exhaust steam behind it.
On the reversal of the auxiliary valve the port t¹ is opened by the piston b¹ of
the said auxiliary valve moving from off it, and the said port is open to the
exhaust port n¹, the said port t¹ being closed by the block or bar v on the reversal
of the main valve for cushioning the end or piston e. The block or bar v may be
constructed to close the port t or t¹ at any required position of the stroke of the
main valve.
We do not limit ourselves to the kind of main slide valve represented, with
which our improved auxiliary valve is used, as the said auxiliary valve may be used
with other kinds of main slide valves.
Figure 9 represents in cross section a portion of a direct-acting steam pump
provided with an expansion valve constructed according to our Invention, and
Figure 10 is a plan and vertical section of the expansion valve.
a is the expansion valve moving vertically in the valve chest band working
across the steam pipe c which admits steam to the valve chest. The bottom of the
case in which the expansion valve works is open by the passage d to the steam
cylinder. By means of the expansion valve a the steam pipe c is opened and
closed at the proper times. The said expansion valve has two acting areas marked
respectively a² and a³. The bottom and larger area a² is acted upon by steam from
the steam cylinder to close the valve, and the area a³ is acted upon by the steam in
the steam pipe c to push back or open the expansion valve. The expansion valve is
hollow, and in the hollow part a loose piece or small valve e works, as represented in
Figure 10. The loose piece e rides upon the steam employed to open the expansion
valve a and cuts off the escape of steam, the said loose piece cushioning the fall of
the larger valve a, and also forming a cataract governor to give a pause to the
engine when at the end of the stroke, the length of the pauses being regulated by
the orifice by which the steam is allowed to escape back, the said orifice being
opened or closed as desired.
Instead of the small valve or loose piece e in the expansion valve a, a valve e³
opening upwards situated in the passage d may be employed for the same purpose.
When the steam piston has made the required travel in the steam cylinder for
the cut off the said piston passes the passage d in the steam cylinder, as herein-
after described, and steam entering the said passage acts upon the bottom or larger
arca a of the expansion valve and lifts the said valve and closes the steam pipe c.
After the slide valve has been reversed, and the pressure removed from the under
side of the expansion valve a, steam from the steam pipe c acts upon the small
area of the expansion valve and pushes it down in its case, and again opens the
steam pipe c.
+
The said expansion valve a, a, a, arranged in the steam passage c may be ope-
rated upon from the pump cylinder instead of from the steam cylinder, as before
described. In this case the passage d is put in communication with the pump
cylinder, and the valve a, a, a³, is so arranged with respect to the steam port or
passage c that the rising of the valve a opens the passage c, and the descent of the
said valve a closes the said passage c, the said valve acting in a reverse manner
to that described when in connection with the steam cylinder. The water pressure
from the pump cylinder acting on the piston or arca a² of the valve a raises the
said valve and opens the steam passage c, and the steam from the passage e acting
on the area a³ closes the valve a. By combining the expansion valve with the

page_text: pump cylinder the engine is controlled in accordance with the work to be done in
the pump, and the economical working of the engine effected. The cut off of the
expansion valve is regulated so as not to entirely cut off steam to the area a³..
Figure 11 represents in longitudinal vertical section our arrangement of parts
for varying the cut off of the steam at the required travel of the steam piston.
The said arrangement is also represented in cross section in Figure 9 in connection
with the expansion valve. Figure 12 represents a portion of Figure 11 drawn to
a larger scale, and Figures 13 and 14 are cross sections of the same drawn to a
larger scale, the section, Figure 13, being taken through the line A, B, of Figure 11,
and the section, Figure 14, being taken through the line C, D, of Figure 12.
arrangement represented in Figures 11, 12, 13, and 14 cuts off the steam after the
half stroke of the steam piston.
The
Immediately beneath the expansion valve, herein-before described, is a horizontal
tube g, h, capable of a partial rotation by means of the index wheel i external to
the said tube. The said tube is divided at about its middle into two parts, marked
respectively g, h, by the small valve k, by the motion of which valve either the
part g or the part h of the tube may be opened to the passage d in connection with
the expansion valve a. In the part g of the tube three holes at l, m, n, are made,
and in the steam cylinder and opposite the said holes l, m, n, passages l², m³, n²,
are made. In the other part h of the tube are similar holes p, q, r, and in the
steam cylinder are corresponding passages p², q², r². The holes n, r, in the tube
nearest to and on opposite sides of the valve k are in the same line; the holes m, y,
are in the same line, and the holes l, p, are in the same line. It will thus be seen
that each pair of holes l, p, m, q, and n, r, is at a different distance from the middle
of the tube, and that each pair of holes is situated at a different angle in the cir-
cumference of the tube from the other pairs of holes. By turning the tube g, h,
through the required angle either of the pairs of boles l, p, or m, q, or n, r, may be
brought opposite the corresponding passages 1, p2, or m², q², or n², 2, in the steain
cylinder, so that steam may be cut off at different positions of the stroke of the
piston, according to the angle at which the tube is turned. In Figure 11 the pair
of holes n, r, in the tube is represented brought opposite the passages n², r², in
the steam cylinder, the other passages l, m³, q, p³, being closed by the tube I, h.
When the steam piston, moving in the direction of the arrow, Figure 12, passes the
passage steam enters the part of the tube, and acting upon the piston of the
small valve presses it towards the part g of the tube. The part of the tube is
thereby closed, and the part g is opened to the passage d in connection with the
expansion valve a. On the steam piston passing the port n² steam enters the
part of the tube and passes through the open valve k to the passage d and acts
upon the expansion valve, and the latter cuts off steam from the valve chest, as
herein before described. On the steam piston making its return stroke steam from
the cylinder first passes through the port n² and moves the valve k, thereby closing
the part g of the tube, and opening the part h to the passage d, and steam after-
wards passes through the port and the open valve k to the passage d. The same
action takes place when the tube g, h, is turned so as to make either the pair of
holes m, q, or 1, p, in the tube coincide with the passages m³, q², or 12, p, in
the cylinder; the steam is thereby cut off at different positions of the stroke of the
piston.
For the purpose of cutting off the steam before the piston has travelled through
half its stroke we arrange the small valve in the tube in the manner illustrated in
Figures 15 and 16. The valve t is spherical and seats itself against one or other
of the seats t, 3, in the pipes u, v, in connection with the parts g, h, of the tube.
When the steam piston passes the port in the steam cylinder steam enters the
tube h through the said port and the hole r in the tube and presses the valve t to
the scat t, thereby closing the half g of the tube, and allowing steam to pass
through the open valve to the channel d in connection with the expansion valve.
When the steam piston on its return stroke passes the port n the valve is pressed
to the seat and the half h of the tube is closed and steam passes through the
open valve to the channel d.

page_text: The adjustment of the position. of the tube g, h, is effected by the index wheel i,
and is indicated by the fixed pointer w.
The regulating tube g, h, may be made capable of sliding in its casing as well as
rotating, as herein-before described, but we prefer the arrangement represented in
the Drawings.
-y
Having now described the nature of our Invention, and the manner in which
the same is to be performed, we wish it to be understood that we do not limit our-
selves to the precise details herein described and illustrated, as the same may be
varied without departing from the nature of our Invention; but we clain, as our In-
vention of "Improvements in Direct-acting Steam Pumps and in Steam Engines,"-
First. The improvements in constructing and actuating the slide valves of the
said pumps and engines herein-before described and illustrated in Figures 1, 2, 3,
4, and 5 of the accompanying Drawings, that is to say, constructing each of the
valve pistons or closed ends of the hollow cylindrical slide valve with two areas,
the area of the back or outer face of each valve piston being greater than that of
the inner face, and the arrangement of the ports or passages for putting at the
proper times the said areas of the valve pistons in communication with the steam
and exhaust; the reversal or carrying over of the slide valve after the outer areas
or faces of the valve pistons have been balanced by pressure of steam upon them
being due to the pressure of steam on the inner face or area of one of the said,
valve pistons, the inner face or area of the other valve piston being open to the
exhaust, substantially as described and illustrated.
Secondly. The construction and arrangement of the parts of the auxiliary valve
for working the slide valves of the said pumps and engines herein-before described
and illustrated in Figures 6, 7, and 8 of the accompanying Drawings, that is to
say, an auxiliary valve working parallel or otherwise to the main slide valve, the
said auxiliary valve and the case in which it works, and the ports or passages in
connection with it, and the ends of the main slide valve being constructed and
arranged as described, the said auxiliary valve by its motion simultaneously with
the motion of the steam piston providing for the reversal of the main slide valve
when the steam piston has made the required travel by steam taken from the steam
cylinder, the said reversal of the main valve being followed by the reversal of the
auxiliary valve ready for the reversal of the main valve on the next stroke of the
steam piston, substantially as described and illustrated; also the construction and
arrangement of parts described and illustrated in the said Figures 6, 7, and 8 for
cushioning the main valve on its reversal.
Thirdly. The arrangement or combination of the parts of the expansion valve for
cutting off the steam to the steam chest at the required travel of the steam piston
herein before described and illustrated in Figures 9 and 10 of the accompanying
Drawing; also the modification described in which the expansion valve is acted
upon by pressure from the pump cylinder, instead of from the steam cylinder.
Lastly. The construction and arrangements of parts herein-before described and
illustrated in Figures 9, 11, 12, 13, 14, 15, and 16 of the accompanying Drawings
for varying the cut off of the steam to the valve chest at the required travel of the
steam piston.
A..
In witness whereof, we, the said Thomas Parker and Philip Alfred Weston,
have hereunto set our hands and seals, this Ninth day of December, in the
Land One thousand eight hundred and seventy-six
Witness,
W. I. WIGGINS,
Coalbrookdale,
Shropshire.
THOMAS PARKER.
PHILIP ALFRED WESTON.
(L.S.)
(L.S.)