IMPROVEMENTS IN ENGINES TO WORK WITH STEAM AND OTHER FLUIDS to be as follows
Year: 1884

page_text: I, PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey,
Engineer do hereby declare the nature of my invention for "IMPROVEMENTS IN
ENGINES TO WORK WITH STEAM AND OTHER FLUIDS to be as follows :-
'
.
"
These improvements apply especially to those engines in which the impulse is
given in one direction only. The return stroke being made by the crank. These
engines may be made either simple or compound, if compound, I arrange the
cylinders one above the other.
I mount the piston or pistons on a tubular piston rod, in the interior of which
I place a piston valve for regulating the admission and release of the steam. In
the sides of the tube I place suitable ports, some of which are covered and uncovered
by the piston valve..
In one arrangement one end of the tubular piston rod passes through the upper
end of the cylinder and it may be packed in any convenient way. Above the
cylinder is a cavity forming the steam chest. The other end of the tubular rod is
connected to the cross head and main connecting rod of the engine. I actuate the
piston valve by the rocking motion of the connecting rod..
Where a short stroke only is required I do this, by an arm at right angles to the
connecting rod, coupled by a link to the piston valve.
If a longer stroke for. the valve is required, levers may be used for increasing it.
I can cut off the steam at any desired point in the downward stroke of the
piston.
I make the piston valve in two parts with an annular cavity between. I place
this annular cavity in constant communication with the upper end of the cylinder
by means of a port through the tubular piston rod just above the piston..
There is another port at a higher point in the tubular rod-This port passes
through the end of the cylinder at some part of the stroke of the piston.
When the piston valve moving upwards reaches its mid position in the tubular
rod, the annular space overlaps the upper part and places the latter in communica-
tion with the space above the piston by way of the lower port, which, as already
stated is permanently connected with it.
I so adjust the piston valve that this overlapping takes place when the piston is
at or near the upper end of its cylinder and the upper port being then outside the

page_text: i
end of the cylinder the steam from the steam chest enters the cylinder and forces
the piston down.
When the piston has travelled so far that the upper port passes into the end of
the cylinder the steam supply is cut off and the piston moves for the remainder of
its stroke by the expansion of the steam above it.
The steam is used more or less expansively according to the point in the stroke
of the piston at which the upper port is closed by passing into the cylinder cover.
If the degree of expansion is determined before hand the upper port may be
placed in any desired position in the tubular rod..
If it be desired to vary the expansion while the engine is running, a sleeve free
to turn may be placed round the tubular rod where it issues from the cylinder.
The upper edge of this sleeve may be made inclined or spiral and by turning it
round so as to bring a higher or lower part of it opposite the port in the tubular
rod, the point in the stroke at. which that port is covered may be varied as desired.
In that part of the tubular rod which is below the piston. are other ports leading
direct to the lower end of the cylinder-These lower ports are covered and
uncovered by the lower part of the piston valve.
When the piston is at the lower end of its stroke the rocking action of the con-
necting rod causes the valve to uncover these ports and its annular cavity connects
the upper end of the cylinder with the lower,
The steam which forced the piston down is thus released, and in a simple-engine
the lower end of the cylinder may be connected to a condenser or to the atmo-
sphere.
In a compound, engine it may communicate with and form part of the receiver
and another larger cylinder may be placed below it, and the steam may by the
piston valve be admitted, cut off, and released from the piston of the larger cylinder
in the same manner as described for the first or smaller cylinder. The space below
the small piston constituting the steam chest for the larger one.
If the steam be admitted to the low pressure cylinder through the whole or
nearly the whole stroke of the piston, any receiver other than the lower end of the
high pressure cylinder may be dispensed with and the steam contained above the
high pressure piston may be merely transferred to the under side during the upstroke
and passed on to the low pressure cylinder during the next down stroke. In the
same way the underside of the low pressure piston nay be used as an intermediate
chamber between the low pressure cylinder proper in which the expansion takes
place and the condenser. Thus the steam after performing its work in the low
pressure cylinder during the downstroke is transferred into a separate chamber
before. being passed on to the condenser.
In this way I obtain a much smaller variation of temperature than is usual in
the best compound engines in either or both cylinders according as this system of
transferring the exhaust steam through an intermediate receptacle is applied to one
or both of them. I also gain much of the advantage of triple expansion without
its complication.
It is evident that the system may be still further extended and a triple expansion
engine be made by adding a third cylinder.
By suitably varying the diameter of the tubular piston rod the space above the
high pressure piston in a compound engine (or the piston of the single cylinder of
a simple engine) may be made smaller than that below it.
In the case of the simple engine the space below the piston is not.connected
permanently with the exhaust but only (by the action of the piston valve) during
the down stroke; expansive action taking place in the lower part of the cylinder
during the upstroke. The engine though having only one cylinder will then be a
compound engine, one end of the cylinder being the high pressure and the other
the low pressure.
•
And if the engine has two or more cylinders one above the other as before
described it is evident that upon this plan three or four successive expansions may
he obtained with only two cylinders.

page_text: It is evident that if two or more cylinders in line be employed the four spaces
above and below the pistons may be utilised in various ways as successive spaces
for either expanding or receiving the steam. Thus the space above the high pressure
piston may be either in constant communication with the boiler or may be the high
pressure cylinder.
The space below it may be either the high pressure cylinder, a transfer space as
before explained, or receiver.
The space above the low pressure piston may be either the working low pressure
space or the receiver.
The space below it may be either in constant communication with the exhaust,
the working low pressure cylinder or a transfer chamber between the low pressure
cylinder and the exhaust.
In high speed engines it is generally necessary to employ compression in order
to keep the connecting rods in constant thrust towards the end of the upward
stroke of the piston. The rocking motion of the connecting rod which gives a valve
action equivalent to that of an eccentric set at right angles to the crank, does not
permit of the use of much lap on the exhaust edge of the piston valve when used
by itself as a means of releasing the steam from the cylinder inasmuch as it opens
the exhaust late to the same extent as it closes it early.
I prefer therefore to combine in such cases the release of the steam by the piston
valve with the direct uncovering by the movement of the main piston, of a ring of
ports in the side of the cylinder itself just before the end of the downward stroko
of the piston. This annular exhaust is identical with that used by me for the
sane purpose in my three cylinder engine. In the case of a compound engine
this ring of exhaust ports from the high pressure cylinder will open into the
receiver.
As there are no outside passages, valves or other gear on the cylinders they may.
be entirely covered by a circular steam jacket or dome which can be readily.
removed, or the cylinders may be placed bodily in the dome or steam space of a
boiler. A chamber acting as a receiver in connection with the lower end of the
bigh pressure cylinder may be enclosed also in this jacket and the steam may in
this manner be reheated during its passage from the high pressure to the low
pressure cylinder. The surface of this receiver may be increased to any desired
extent by corrugating it or making it in the form of a coil or scries of tubes.
The high pressure cylinder (or the single cylinder of a simple engine) may be
made open to the steam chest at its upper end, and the lower side of the piston
may be used as the working cylinder.
In an engine constructed in this way the steam pressure in the steam chest forces
the piston down and it is more or less balanced on its upward stroke by the steam
admitted beneath it.
An effect similar to that of compression is obtained by working the steam
expansively in such an engine, the pressure above the piston being constant and
that below the piston becoming reduced as the piston moves upwards.
Any one of these engines may be made as a single engine actuating a single
crank with a heavy fly wheel, or engines may be made with two or more cranks
and sets of working parts where starting power or regular motion is required.
The above description applies especially to engines having vertical inverted
cylinders but the improvements would equally apply to horizontal or other engines
up-stroke" being read as "out stroke" and "down stroke" as "in-stroke."
Dated this 17th day of October 1884
:
CARPMAEL & Co.,
Agents for the Applicant.

page_text: i
I PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey Engineer
do hereby declare the nature of my invention for "IMPROVEMENTS IN ENGINES
TO WORK WITH STEAM AND OTHER FLUIDS" and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
These improvements apply. especially to those engines in which the impulse is
given in one direction only. The return stroke being made by the crank. These
engines may be made either simple or compound, if compound I arrange the
cylinders one above the other.
I mount the piston or pistons on a tubular piston rod, in the interior of which
I place a piston valve for regulating the admission and release of the steam. In
the sides of the tube. I place suitable ports, some of which are covered and
uncovered by the piston valve.
One arrangement is illustrated by Figure 1 of the annexed drawing.
This is a vertical section of a single cylinder engine provided with a fly wheel,
or three or other number of such engines may be arranged to work on to the same
main shaft in which case a fly wheel is not required.
Here before entering upon the description of this engine I would remark that
I do not claim broadly engines of this class for I am now aware although I was not
so at the time when I filed my provisional specification that I have been anticipated
in some of its features by a patent application No 11077 in the year 1884-what
I do claim in respect to such engines is herein after defined by my claiming clauses.
In Figure 1 a is the cylinder b the piston c is the tubular piston rod and d is the
piston valve working within the hollow rod. The upper end of the hollow rod c
works through packing rings e upon the top of the cylinder a. Above the cylinder
is a cavity f forming the steam .chest. The other end of the tubular rod c is
connected to the crosshead g and main connecting rod of the engine. I actuate
the piston valve by the rocking motion of the connecting rod.
Where a short stroke only is required I do this by an arın at right angles to the
connecting rod, coupled by a link to the piston valve.
If a longer stroke for the valve is required levers may be used for increasing it
às is represented in this figure or otherwise as hereinafter explained. is the arm
on the connecting rod and it is a lever carried by the hollow piston rod-they are
connected by a link and another link 3 connects the further end of the lever i¹
with the piston valve d.
I make the piston valve in two parts d' and d with an annular cavity d³
between. I place this annular cavity in constant communication with the upper
end of the cylinder by means of a port c¹ through the tubular piston rod just
above the piston b.

page_text: ▸
There is another port c' at a higher point in the tubular rod. This port passes
through the packing rings e closing the end of the cylinder at some part of the
stroke of the piston.
When the piston valve moving upwards reaches its mid position in the tubular
rod the annular space d³ commences to overlap the upper port c² and places the
latter in communication with the space above the piston b by way of the lower
ports c which as already stated is permanently connected with it.
I so adjust the piston valve that this overlapping takes place when the piston is
at or near the upper end of its cylinder and the upper port being then outside the
packing e at the end of the cylinder the steam from the steam chest enters the
cylinder and forces the piston down.
-
When the piston has travelled so far that the upper port passes into the end of
the cylinder the steam supply is cut off and the piston moves for the remainder of
its stroke by the expansion of the steam above it.
:
The steam is used more or less expansively according to the point in the stroke
of the piston at which the upper port is closed by passing into the cylinder cover.
In that part of the tubular rod.c which is below the piston b are other ports c³
leading direct to the lower end of the cylinder. These lower ports are covered and
uncovered by the lower part d of the piston valve.
When the piston is at the lower end of its stroke or immediately afterwards the
rocking action of the connecting rod causes the valve to uncover these ports and
its annular cavity d³ connects the upper end of the cylinder with the lower..
The steam which forced the piston down is thus released and in a simple engine
the lower end of the cylinder may be connected to a condenser or to the
atmosphere.
In high speed engines it is generally necessary to employ compression in order
to keep the connecting rods in constant thrust towards the end of the upward
stroke of the piston.. The rocking motion of the connecting rod which gives a
valve action equivalent to that of an eccentric set at right angles to the crank does
not permit of the use of much lap on the exhaust edge of the piston valve when
used by itself as a means of releasing the steam from the cylinder inasmuch as it
opens the exhaust late to the same extent as it closes it early.
I prefer therefore to combine in such cases the release of the steam by the piston
valve with the direct uncovering by the movement of the main piston b of a ring
of ports al in the side of the cylinder itself just before the end of the downward
stroke of the piston. This annular exhaust is identical with that used by me for
the same purpose in my three cylinder engines.
The piston rod c passes through the lower end of the cylinder a by a ring
packing which serves completely to shut off the cylinder from the crank
chamber below.
The crank chamber ? contains lubricating material (oil and water) into which the
crank dips and this chamber should be keep as cool as possible, whereas on the
other hand it is important that the cylinder should not be cooled. The extension
of the hollow piston rod to the cross head enables me much more effectually to
separate these parts than is possible when the connecting rod is directly jointed to
the piston.
Where the space in which the crank is contained is open it is even more
necessary to shut it off from the cylinder than where the crank is in a closed
chamber.
In the engine represented in this figure the crank chamber and the cylinder are
further separated by interposing an air buffer.
•
The hollow piston rod c is increased in size at its lower end at c* to contain the
crosshead the head of the connecting rod h and the gear iii and ³ within it,
it here fits the cylindrical buffer casing m. There are air ports m' in the side of
the casing the air in the casing is compressed during the up stroke,

page_text: F
.
The features in this engine to which I desire to direct particular attention and
to which my claims hereinafter set forth are more especially directed are:-
(1.) the method of actuating the valve by an arm on the connecting rod to
which a link is jointed giving motion (directly or indirectly) to the valve. The
valve motion thus obtained is smoother and works with less friction than a cam 5
projection on the connecting rod operating against a roller at the lower end of the
valve..
(2.) the convenient length of valve motion which I obtain by interposing
multiplying parts between the arm on the connecting rod and the link jointed to
the valve.
(3.) the effectual separation between the crank chamber and the cylinder. which
results from the use of the hollow piston rod coupling the piston with the
crosshead.
Figures 2, 3, 4, 5 and 6 show various modifications in the means for connecting
the arm upon the connecting rod with the valve.
Figure 2 shows the connection by a direct link and this is further illustrated by
Figure 2. The direct link connection is not usually to be preferred as the travel
thus communicated to the valve is short and the ports consequently have to be
inconveniently narrow.
Figure 3 shows the arm on the connecting rod in gear by means of teeth. with
an intermediate lever which is coupled by a link with the valve.
Figure 3 further illustrates this construction.
Figure 4 shows the arm on the connecting rod coupled by a link to the middle
of an intermediate lever which at one end has its fulcrum on the enlarged piston
rod and at the other end is connected by a second link with the valve.
Figure 4 further illustrates this construction.
*Figure 5 shows an arrangement differing from that shown in Figure 1 in that
the arm of the connecting rod is vertical at the ends of the stroke of the piston ;
the first link is then horizontal and the intermediate lever is bent.
Figure 5 further illustrates this construction.
Figure 6 shows an arrangement in which the part serving as the arm of the
connecting rod is vertically below the crosshead, the crosshead being divided and
the connecting rod forked to admit of it. It is an invertion of the arrangement
shown by Figure 5.
Figure 6 further illustrates the arrangement shown by Figure 6.
It will be observed that in these figures the arms and links are frequently double
for convenience of mechanical construction.
I would remark that when I speak of the arm on the connecting rod I. desire to
include arrangements where as in Figure 6 the link is jointed to a part upon the
connecting rod at a short distance from the crosshead and which part then serves
to operate the valve in the same way as the arın in the other arrangements.
If it be desired to vary the expansion while the engine is running a sleeve free
to turn may be placed round the tubular rod where it issues from the cylinder.
The upper edge of this sleeve may be made inclined or spiral and by turning it
round so as to bring a higher or lower part of it opposite the port in the tubular
rod the point in the stroke at which that port covered may be varied as
desired.
с
Figure 8 is a vertical section representing the upper part of an engine arranged
for a variable expansion but otherwise similar to Figure 1. The piston rod c here
has in it an inclined port cx .by which steam passes to the cylinder. It is
surrounded by the sleeve n and this can be turned round by means of a handle
applied to its square spindle n¹. The steam is cut off from the cylinder by the
descent of the port cx below the edge n³ of the sleeve and this takes place sooner
or later according to the position in which the sleeve is placed. The form of the
valve d* differs somewhat from that of the valve in Figure 1: to admit steam to
the cylinder it uncovers the port c¹ by descending below the upper edge of the port
#

page_text: to allow the steam to escape from the cylinder when it has done its work the valve
ascends and its lower edge rises above the lower edge of the port c¹.
Figure 9 shows an engine similar to Figure 1 except that the valve resembles
that shown in Figure 8 and operates entirely at the port c¹ falling below it to
admit steam, and rising above it for the exhaust. There is however an independent
exhaust by the piston uncovering the ports a¹.
This engine can be worked without any expansion in this case the side ports o²
(see Figure 1) are omitted as is the case in the figure and the tubular piston rod is
left open so that the fluid pressure may always pass when the valve is open such
an engine will operate efficiently when water under pressure is supplied to it.
I also according to my invention make compound engines with hollow piston
rods and with the valve within the rod and operated by the connecting rod.
.
In a compound engine the lower end of the cylinder into which the steam first
enters may communicate with and form part of a receiver and another larger
cylinder may be placed below it, and the steam may by the piston valve be admitted,
cut off and released from the piston of the larger cylinder in the same manner as
described for the first or smaller cylinder. The space below the small piston
constituting the steam chest for the larger one.
Figure 10 is a vertical section of a compound engine, it resembles in some of its
features the engines previously described and especially that shown by Figure 1
but an additional cylinder A. is added beneath the cylinder a.
The two pistons band B are on the same hollow piston rod c; and in this rod
the valves are contained. The steam delivered from the smaller cylinder a is
received into a chamber or receiver O, and from this chamber it is passed into the
cylinder A by the valve D¹ D* D³ which is similar to the valve d¹, d, d³, of
Figure 1, and also to the valve so lettered in the present figure. The valves are
rigidly connected and they move together.
As there are no outside passages valves or other gear on the cylinders they may
be entirely covered by a circular steam jacket or dome which can be readily
removed or the cylinders may be placed bodily in the dome or steam space of
a boiler.
A chamber acting as a receiver in connection with the lower end of the high
pressure cylinder may be enclosed also in this jacket and the steam may in this
manner be reheated during its passage from the high pressure to the low pressure
cylinder. The surface of this receiver may be increased to any desired extent by
corrugating it or making it in the form of a coil or series of tubes.
If the steam be admitted to the low pressure cylinder through the whole or
nearly the whole stroke of its piston, any receiver other than the lower end of the
bigh pressure cylinder may be dispensed with and the steam contained above
the high pressure piston may be merely transferred to the underside during the
upstroke and passed on to the low pressure cylinder during the next down stroke.
Figure 11 illustrates this arrangement. The steam passes from the steam chest f
at the top of the engine into the hollow piston rod by the port c³ during a con-
siderable portion of the down stroke and by the port c¹ the steam enters the
cylinder a and operates against the upper surface of the piston b. During the
upstroke the valve d. rising above the port c¹ allows the steam to pass from above
the piston b by the ports c¹ and c³, into the space beneath the piston b. Then on
the next down stroke this steam passes by the port c³, and the port C¹ into the
large cylinder A and it then operates against the upper side of the piston B. The
O steam escapes from the cylinder A during the upstroke as already described in
respect to the single cylinder engines.
By suitably varying the diameter of the tubular piston rod the space above the
high pressure piston in a compound engine (or above the piston of the single
cylinder of a simple engine) may be made smaller than that below it.
The engine though having only one cylinder will then be a compound engine,
one end of the cylinder being the high pressure and the other the low pressure.

page_text: •
:
:
And if the engine has two or more cylinders one above the other as before
described it is evident that upon this plan three or four successive expansions may
be obtained with only two cylinders.
Figure 12 represents a portion of an engine similar to Figure 11 but in this case
the cut off can be varied whilst the engine is at work by moving the sleeve n up
or down.
It is evident that the system may be still further extended and a triple expansion
engine be made by adding a third cylinder.
The steam may be transferred in a low pressure cylinder that is to say the
underside of the low pressure piston may be used as an intermediate chamber
between the low pressure cylinder proper in which the expansion takes place and
the condenser. Thus the steam after performing its work in the low pressure
cylinder during the down, stroke is transferred into a separate chamber before
being passed on to the condenser.
In this way I obtain a much smaller variation of temperature than is usual in
the best compound engines in either or both cylinders according as this. system
of transferring the exhaust steam through an intermediate receptacle is applied to
one or both of them. I also gain much of the advantage of triple expansion without
its complication.
Figure 13 illustrates the arrangement as applied to a single cylinder.
The engine is represented with the parts in the positions they occupy during the
effective stroke..
· Steam has entered by the ports c² and c¹ to the space. over the piston b and the
steam has been cut off by the descent of the port c² beneath the packing rings at e..
The expansion of the steam in the cylinder is maintaining the downward movement
of the piston. At the end of the downward stroke the upward movement of the
valve will permit the steam to pass from the upper side of the piston b to the
chamber O beneath it. Here the steam will be retained until the next. effective
stroke is about to commence.
2
The valve D will now descend below the port C regaining the position in which
it is represented in the figure, and the steam will then pass to the space P which is
permanently in connection with the outlet or with the condenser as the case may
be. By this arrangement the temperature in the cylinder a is better maintained
than it would be if the steam were allowed to pass direct from the upper side of
the piston into a chamber in permanent connection with the outlet or exhaust.
The high pressure cylinder (or the single cylinder of a simple engine) may be
made open to the steam chest at its upper end and the lower side of the piston
may be used as the working cylinder.
In an engine constructed in this way the steam pressure in the steam chest
forces the piston down and it is more or less balanced on its upward stroke by
the steam admitted beneath it. .
An effect similar to that of compression is obtained by working the steam
expansively in such an engine. The pressure above the piston being constant
and that below the piston becoming reduced as the piston moves upwards.
Figure 14 illustrates this part of my invention. a is an upper high pressure
cylinder and A a low pressure cylinder. bis the high pressure piston and B is
the low pressure piston. During the down stroke the full steam pressure in the
steam chest facts upon the piston 6 whilst at the same time steam from beneath
the piston passes by the ports c³, and C¹ to the upper side of the piston B.
b
During the up or return stroke steam passes from the steam chest f by the
port b which is then uncovered by the descent of the valve d and enters the
cylinder a beneath the piston. In the earlier part of the up stroke the piston b.
is thus nearly in equilibrium but later on the port 6x entering the bored part of
the cylinder ceases, expansion takes place and there is a preponderance of pressure
above the piston. During the upstroke also the steam above the low pressure

page_text: piston B passes by the ports C¹ and C³ to the under side and so to the outlet or to
an intermediate receiving chamber as the case may be.
At the end of the up stroke and during the succeeding down stroke the
cylinder A receives steam from the cylinder a as already described.
The upper side of the low pressure piston of a compound engine may in like.
manner be permanently open to its steam chest.
It is evident that if two or more cylinders in line be employed the four spaces
above and below the pistons may be utilized in various ways as successive spaces
for either expanding or receiving the steam. Thus the space above the high
pressure piston may be either in constant communication with the boiler, or, may
be the high pressure cylinder. The space below it may be either the high pressure
cylinder or a transfer space as before explained or a receiver. The space above the
low pressure piston may be either the working low pressure space or the receiver.
The space below it may be either in constant communication with the exhaust, the
working low pressure cylinder or a transfer chamber between the low pressure
cylinder and the exhaust.
Any one of these engines may be made as a single engine actuating a single
crank with a heavy fly wheel or engines may be made with two or more cranks
and sets of working parts where starting power or regular motion is required.
"
The above description applies especially to engines having vertical inverted
cylinders but the improvements would equally apply to horizontal or other engines
up stroke" being read as "out stroke" and "down stroke" as "in stroke."
These engines are all of the class commonly known as steam engines and it is
obvious that like other steam engines they are capable of being worked also by
means of air or other fluid under pressure; they are also capable of reversal that
is to say motive power may be applied to rotate them and they will then operate
to force air or other fluid into a receiver.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) An engine having a piston valve within the piston rod; a connecting rod
coupling the said piston rod or the piston with a crank, an arm (or equivalent
part) on the connecting rod and a link coupling the said arm (or part) with the
valve substantially as described.
(2.) An engine having a piston valve within the piston rod, a connecting rod
coupling the said piston rod or piston with a crank, an arm (or equivalent part) on
the connecting rod and intermediate multiplying parts coupling the said arm (or'
part) with the valve so that the travel of the valve is longer than that of the arm
substantially as described.
(3.) An engine having a hollow piston. rod and a piston valve within the rod
and a cylinder separated from the chamber or space containing the crank by a
partition through which the piston rod passes and which partition serves to isolate
the cylinder from the crank chamber or space substantially as described.
(4.) An engine having a hollow piston rod and a piston valve within the rod
and a sleeve surrounding the rod, the whole so arranged that by moving the sleeve
an inlet port in the hollow rod is covered sooner or later and the degree of expansion
thereby varied substantially as described.
(5.) An engine having a hollow piston rod with two (or more) pistons upon it
working in high and low pressure cylinders respectively and with valves within
the hollow rod substantially as described.
(6.) An engine having a hollow piston rod and piston valve within the hollow
piston rod, the whole so arranged that steam which bas operated against the piston
on one side is during the return stroke transferred to the other side into a closed
chamber where it is retained until the succeeding stroke when by the movement of
the valve it is permitted to pass away substantially as described.

page_text: (7.) An engine having a hollow piston rod and piston valve within the hollow
piston rod and a steam jacket or dome serving also, as the steam chest and
enclosing the working cylinder or cylinders substantially as described.
(8.) An engine having a cylinder and piston exposed on one side continuously
to the pressure and on the other side receiving the pressure intermittently; the
steam being admitted to this latter side of the piston by a piston valve within a
hollow piston rod substantially as described.
(9.) My improvements in steam engines substantially as described and represented
in the annexed drawings..