Improvements in Steam and other Fluid Pressure Engines.
Year: 1892

page_text: Date of Application, 1st Dec., 1892
Complete Specification Left, 2nd Oct., 1893-Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Steam and other Fluid Pressure Engines.
I, ARTHUR FORBES SCOTT, M.I.M.E. of 27 Welbury Drive, Bradford, in the
County of York, Engineer, do hereby declare the nature of this invention to be as
follows:-
In Patents granted to me dated 1886 (No. 15858) and 1889 (No. 12258) !
described some engines in which a receiver or special clearance space at one side
of a piston is used to provide a constant thrust downwards or against the crank at
a high speed.
This invention relates to improvements and modifications in engines having such
receivers or their equivalents and it also relates to improvements in governing
these and other fluid pressure engines, and its object is to obtain economy and
silence in high speed engines, and to regulate the same, with few working parts.
These improvements are hereinafter described as applied to steam engines
having inverted vertical cylinders with downward thrust, though applicable to
other classes of fluid pressure engines. The letters h.p. and l.p. are used for high
pressure and low pressure respectively.
In one form of compound engine I place the cylinders side by side, the cranks
being opposite to one another and connected with the pistons by connecting rods,
crossheads, and piston rods passing through stuffing boxes, in the usual manner.
Between the cylinders is a valve worked off the shaft. Above the 1.p. piston and
permanently open to the top side thereof is a receiver, and this is also permanently
connected with the underside of the h.p. piston by means of a passage from which
a connection is made with the valve casing or seat. Above the h.p. cylinder is
another receiver from which a passage leads to the valve casing, and the latter is
also provided with ports leading to the top of the h.p. and the bottom of the
1.p. cylinders, and with inlet and exhaust ports. The whole is so arranged that
steam is admitted to and cut off from the top of the h.p. piston during its down-
stroke while during about the first half of the same period the two sides of the
1.p. piston are connected together, after which the steam above the same is
compressed and that below it expanded. During the next stroke the upper side of
the h.p. piston is connected with its under side, the 1.p. receiver, and also the
h.p. receiver, until about half stroke, after which it is connected with the last
mentioned only and it compresses the steam therein to a certain extent. Mean-
while the steam falls in pressure below the h.p. and above the 1.p. pistons, the
underside of the latter being connected with the exhaust during this stroke. In
a modification of this engine, the under side of the h.p. piston, instead of being
always open to the 1.p. receiver, is connected therewith during the whole of the
revolution except from about the middle of its downstroke until a point before
the end of the stroke, during which time it is connected with the under side of the
1.p. piston only. Either of these arrangements may be varied by making the
h.p. receiver permanently open to the top of the h.p. piston instead of connecting
it intermittently therewith by the valve.
The engines already described may be modified by abolishing the port con-
necting the under side of the h.p. piston with the 1.p. receiver etc., and by causing
a space below the h.p. piston to be filled with steam by the latter uncovering a
small port in the cylinder at the bottom of its stroke, so that the pressure below
the piston partly balances that above during its upstroke. Or the h.p. piston may
be directly connected with the crosshead without any stuffing box, the crosshead
being circular and of equal or different diameter to the piston, the space between

page_text: them being either closed to the steam or connected therewith during a certain
period of the stroke.
It will be seen that in the engines set forth above although there are only two
cylinders there is a triple expansion of the steam. When it is desired to have a
quadruple expansion with two cylinders I construct them in a similar manner with
cranks opposite and receivers open to the top of each piston, but I connect an
extra receiver (which may form a re-heater) with the valve casing. The steam
then passes during consecutive strokes or parts thereof to the top of the h.p. piston,
the bottom of the same, the extra receiver, the top of the 1.p. piston, the bottom
of the same, and lastly to the exhaust. There are thus four expansions of the
steam, one on each of the four sides of the two pistons. I sometimes place the
cranks not quite opposite, to assist the distribution of steam, in two crank
compound engines.
In my Patent Specification No. 12258 of 1889 I described a tandem compound
engine (Fig. 1) having the adjacent sides of the two pistons constantly open to
one another, the varying pressure in the inter-piston space or receiver controlling
the momentum of the pistons etc. and keeping the parts in constant thrust down-
wards. These improvements include modifications of engines so constructed, in
one form of which I employ a receiver or special clearance space open to the top
side of the h.p. piston. The valve I preferably make larger than usual and
arrange it so that the pressure thereon partly balances that on the pistons. On
the downstroke steam is admitted by the valve to the top of the h.p. piston, and
during the next stroke it passes thence to the bottom of the 1.p. piston and to the
inter-piston space until the piston at about half stroke covers a port admitting it
to this space, and shortly after which the valve closes the connection between the
top of the h.p. and the bottom of the 1.p. pistons, and for the rest of the upstroke
the steam in the two receiver spaces is compressed while that below the l.p. piston
expands and is exhausted next stroke. The port which is closed by the piston,
and through which steam passes to the inter-piston space, may be provided with a
valve or cock wherewith to regulate the running of the engine. I prefer to cut
off the connection with the inter-piston space by the piston closing the port in the
cylinder but it may be effected by the valve.' When economy is not the chief
object I abolish this port, and when so modified the steam from the top of the
h.p. piston passes to the bottom of the l.p. piston, the inter-piston space being
filled by leakage past the two pistons, and the pressure therein at half stroke tends
to assume a mean between the average pressures on the other sides of the pistons.
This leakage of steam into the inter-piston space may be supplemented if necessary
by a small cock taking steam from the bottom of the h.p. cylinder preferably, so
that the pressure between the pistons may be regulated by opening the cock more
or less and the pistons kept thereby in constant thrust downwards. This pressure
prevents knocking like that in the receiver Q, when the valve Y is closed, described
in reference to Fig. 4 in my Specification No. 12258 of 1889, but when the small
cock alluded to above is not in use or only slightly opened there is a net upward
pressure on the pistons at the beginning of the upstroke, thus aiding the crank to
overcome the inertia of the pistons, an advantage that was pointed out in the same
Specification p. 1. line 38. By modifying the valve etc. somewhat the inter-piston
space or receiver may be filled at a certain point in the stroke, in a similar
manner to that described in reference to the receiver O in Fig. 3 of the said
Specification.
In the engines described, those arranged so that the steam expands as
it leaves the h.p. cylinder may be provided with a receiver which is connected
with the h.p. cylinder during the upstroke only.
To prevent accumulation of water in these and other engines I sometimes turn
narrow grooves in the cylinders which are uncovered by the pistons at the extreme
end of the downstroke.
In engines constructed as shown in Fig. 1 of my Specification 12258 of 1889,
or in modifications thereof, I in some cases provide another receiver into which

page_text: the h.p. cylinder discharges and from which the steam passes to the inter-piston
space and then to the lower side of the 1.p. piston as before. Referring to the
same Specification, the cut off motions by the piston (Figs. 7 to 9) I now apply
to cylinders which have receivers connected thereto. Sometimes I use the port J
only, and the supply and discharge of the steam to and from the top of the piston
are cut off by the bottom and top edges respectively of that portion of the piston
which passes over the port. This piston cut-off may be applied to engines herein,
and those described with it in my Specifications may in some cases be used
without it.
My invention relates also to compound engines having receivers whereby the
pistons are kept in constant thrust downwards, in which one piston or an extension
thereof acts as a valve for the distribution of steam to the other. I place two
cylinders side by side, the h.p. piston working onto a crank or eccentric preferably
about 145° in advance of the l.p. crank. A piston rod passing through a stuffing
box connects the 1.p. piston with its crosshead below, and an extension of the
h.p. piston connects the latter directly with its circular crosshead which may be
of the same diameter as or smaller than the h.p. piston. Above each piston is
a receiver or special clearance space, and attached to the top of the pistons are
valve pistons, plungers, or other extensions, the whole arranged with ports so that
when the h.p. piston is at the top of its stroke, the end of a plunger or its
equivalent on the top of the 1.p. piston which is rising uncovers the inlet port, and
steam passes round a recessed or reduced part of the plunger through another
port connecting with a piston valve or other extension on the h.p. piston until
about mid stroke of the latter, when the port is closed by the descending piston
valve. When approaching the end of its stroke the h.p. piston uncovers a port
leading to the receiver above the 1.p. piston, and steam from the h.p. cylinder
passes thereto during part of the 1.p. downstroke, after which the steam remaining
in the h.p. cylinder is compressed into its receiver, the inlet port being closed by
the end of the plunger on the 1.p. piston until the h.p. piston gets to the top of
its stroke when the receiver takes steam again. Meanwhile the steam above the
1.p. piston has expanded to the bottom of the stroke thereof, and the lower part
of the h.p. piston or a part attached thereto has connected the two sides of the
1.p. piston, and during the upstroke of the latter the pressures thereon remain in
equilibrium until about half stroke when the connection is closed, after which the
steam above the piston is compressed in its receiver while that below the same
expands, and during the next stroke it is connected with the exhaust port by the
aforesaid lower part of the h.p. piston.
In some modifications of this engine I abolish the plunger on the top of the
1.p. piston and the ports connecting therewith. In the first of these modifications
steam is admitted to the h.p. cylinder by a port which is uncovered by the valve
attached to the h.p. piston at the top of its stroke only. In a second modification,
instead of this admission valve the h.p. cylinder and piston are extended upwards,
and the steam admitted to the receiver at top stroke only through ports in the
cylinder and piston, so that the interior of the top part of the piston forms part of
the receiver, and when the piston descends the upper part or extension keeps the
inlet port closed. In a third modification, very similar to the second, the steam
is admitted to the h.p. receiver by an additional port or holes in the cylinder
instead of through the piston, and is discharged into the port leading to the
1.p. receiver, either through the interior of the piston direct, or by an additional
port in the cylinder, the inlet port being closed by the piston during the
discharge.
These engines I have described, in which parts of the h.p. piston act as
distributing valves to the other piston, are further modified in the larger sizes
when it is desired to balance the pressure on the h.p. piston at the end of its
stroke. To effect this I make the lower or crosshead extension of the h.p. piston
of smaller diameter than the main h.p. piston, so that at the end of the stroke an

page_text: upward pressure equal to or greater than that above the large part may be
exerted on the difference in areas of the two parts. In the case of the original
arrangement, and the first and second modifications thereof, the port through
which the h.p. cylinder exhausts into the l.p. receiver has added to it a branch
port, or its equivalent, leading to the smaller or lower portion of the h.p. piston,
and through this branch port the steam passes from the upper to the under side
of the 1.p. piston, and the first mentioned port is closed by the lower edge of the
main piston as it approaches the bottom of its stroke, the steam below it being
compressed so as to balance the piston, or partly overcome its inertia, at the
beginning of the return stroke. If constructed according to the second modification,
steam may be admitted to and discharged from the interior of the h.p. piston
either through the small or large part of the same. To aid in balancing. the
h.p. piston in these engines I sometimes admit steam of the initial pressure below
the large part of the same at the bottom of its stroke. In the case of the third
modification above, I balance the h.p. piston by admitting the initial pressure
constantly between the large and small parts of the piston, except at the bottom
of the stroke when the pressure contained between the same may be somewhat
increased by compression after the inlet port is covered by the large part of the
piston.
It will be observed that in these two crank compound engines there is really a
triple expansion of the steam or three ranges of temperature, viz.-above the
b.p. piston, above the l.p. piston, and below the l.p. piston.
The improvements in the use of receivers which I have set forth serve the
double purpose of keeping the pistons in constant thrust downwards and reducing
the ranges of temperature in the cylinders. It is evident that the receivers I
have described in this and former Specifications may in some cases form part of
the cylinder ports or valve passages, which are then made larger than usual or
than necessary for the transit of the steam merely. To overcome the momentum
and inertia of a piston, I sometimes create a partial vacuum above the crosshead
by arranging it to close a port in descending so as to shut out the atmospheric
pressure from its top side.
A part of my invention relates to improved means of governing these and other
fluid pressure engines. On the top of the valve or piston which admits steam to
the cylinder I mount a governing valve and spring which are held down to the
distributing valve by a rod and disc, the latter fitting easily a bored chamber,
preferably in the governing valve, so arranged that when the engine attains a
certain speed the governing valve overcomes the spring and closes the admission
port more or less at the bottom of the valve's stroke, noise being prevented by
the cushioning action of the disc within the valve. The upper side of the governing
valve may have the same pressure on it as the underside, or it may be connected
with the inlet port so that the steam assists the closing action as soon as it begins.
The cushion chamber may either be filled by steam leaking past the rod or the
steam may pass through holes in the bottom which are covered by a loose thin
piece of material in the chamber. When such a governing valve is required to
work below the distributing valve, I construct it in a somewhat similar manner
but the cushioning space and disc may be annular.
I sometimes regulate the running of engines having receivers such as I have
described by closing or partly closing the port through which steam passes out of
the receiver, so as to increase the compression therein. This may be effected by
the governing valve above, or by a cock inserted in the said port and operated
by hand or ordinary governor, or the flow of steam both into and out of the
receiver may be controlled by an ordinary expansion gear specially arranged with
the distributing valve.
The engines described herein may exhaust into other cylinders or be worked in
conjunction with other engines or parts thereof of similar construction to those
described in this and my former Specifications, and they may be reversed by

page_text: movable eccentrics, additional valves or their equivalents and ports interchangeable
by cocks, or in other suitable ways.
Dated this 30th day of November 1892.
ARTHUR FORBES SCOTT.
COMPLETE SPECIFICATION.
Improvements in Steam and other Fluid Pressure Engines.
I ARTHUR FORBES SCOTT, M.I.M.E. of 27, Welbury Drive, Bradford, in the
County of York, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
In two Patents granted to me in the years 1886 and 1889 (respectively
numbered 15858 and 12258) I described some high speed engines in which a
receiver or special clearance space at one side of the piston is used to provide a
constant thrust downwards or against the crank.
This invention relates to improvements in engines having such receivers or their
equivalents and it also relates to improvements in governing these and other fluid
pressure engines, and its object is to obtain economy and silence in high speed
engines, and to regulate the same, with few working parts.
These improvements are hereinafter described as applied to steam engines having
inverted vertical cylinders with downward thrust, though applicable to other classes
of fluid pressure engines.
Throughout the Specification the abbreviations h.p. and 1.p. are used for high
pressure and low pressure respectively.
Reference is to be. had to the accompanying sheets of drawings forming a part of
this Specification in which as far as convenient similar letters of reference indicate
corresponding parts in each of the figures thus:
B is the h.p. cylinder, P the l.p. cylinder, C the h.p. piston, U the 1.p. piston,
Qthe h.p. receiver, O the I.p. receiver, F the valve, A the steam supply passage,
K the exhaust passage.
Figure 1, illustrates the application of my improvements to a compound engine
with pistons working on opposite cranks of the shaft H on which the fly-wheel L
is mounted. In the position shown the valve F connected by the rod I with the
eccentric G is rising and ring 1 admits steam from A through the port J to the top
of the h.p. piston C. The bottom side of the same is permanently connected with
the l.p. receiver O by ports J2 and R and the valve ring 2 is also connecting it with
the bottom of the 1.p. piston U by port T. The 1.p. piston is consequently in
equilibrium until a point in mid-stroke when rings 1 and 2 cut off the steam passing
to the top of the h.p. piston and bottom of the I.p. piston respectively after which
to the end of the stroke the steam above piston U is compressed in receiver O to a
certain extent, while the l.p. expansion takes place below the same, and at the same
time the h.p. steam expands above the piston C. During the next stroke the valve
having descended connects the top of the h.p. piston C with the bottom of the same,
with the receiver O, and with the receiver by ports J, J2, R, and Q' until about
mid-stroke after which it is connected by ports J and Q with receiver Q only
until near the end of the stroke, compressing the steam therein to about the pressure
above the h.p. piston when at bottom stroke. During this same stroke the steam
from the underside of the l.p. piston is exhausted through the port T to K. The
object of this arrangement of receivers and method of steam distribution is to enable
each piston during its up-stroke to be in equilibrium or balanced during the first
half of the stroke or thereabouts, with an increasing pressure downwards for the:
remainder of the stroke, so as to counteract the momentum of the pistons which, at
high speeds would otherwise cause knocking in the brasses or at the bearings. The.
arrangement also establishes three expansions and ranges of temperature, first,.
above the h.p. piston, second, above, the l.p. piston, and third, below the same.

page_text: In a modification, the underside of the h.p. piston instead of being always open
to the 1.p. receiver is connected therewith during both strokes except from about
the middle of the h.p. piston's down stroke until a point before the end of the
stroke, during which time it is connected with the under-side of the l.p. piston only.
This reduces the compression in the l.p. receiver which may be made smaller, it
also lessens the amount of expansion below the l.p. piston.
Either of these arrangements may be varied by making the h.p. receiver
permanently open to the top of the h.p. piston instead of intermittently connecting
it therewith by the valve. This has the effect of increasing the terminal pressure
in the h.p. cylinder, unless the cut-off is made so much earlier.
Figure 2, shows the second arrangement having the underside of the h.p. piston C
and the 1.p. receiver O connected with the valve liner by separate ports J2 and R,
and constructed with the h.p. receiver open to the h.p. piston C. In the position
shown the valve F is descending and ring 1 admits steam from the supply A through
ports to the receiver Q above the h.p. piston C, while steam from below the
latter is free to pass by ports J2, R, and T to both sides of the 1.p. piston U which
remains in equilibrium until mid-stroke when the hollow ring 2ª rising closes the
port R, causing the steam from below piston C to pass only to the underside of
piston U until a later point in the stroke when ring 3 closes the port T admitting it
thereto. During the next stroke steam above the piston C passes until midstroke
into the receiver O by ports J and R after which compression takes place in the
receiver Q, while during the same stroke the underside of piston U is connected
with the exhaust K, and the underside of piston C is open to receiver O by ports J
and R, the hollow ring 2 having risen above port R so as to connect the same the
whole stroke practically, at the end of which ring 2ª passes downwards over port R
into position shown.
Although I prefer the engines as already described they may be modified by
abolishing the port J2 connecting the under-side of the h.p. piston C with the
1.p. receiver O etc. and by causing a space below the h.p. piston to be filled with
steam by the latter uncovering a small port in the cylinder at the bottom of its
stroke, so that the pressure below the piston balances that above it at the bottom
of the stroke and to a large extent during its up-stroke. Or the h.p. piston may be
directly connected with the crosshead without any stuffing box, the crosshead being.
circular, and for small engines it may be conveniently made the same diameter as
the piston with the space between them closed to the steam, but if made smaller
than the piston the varying pressure between them will tend to balance the piston
when it arrives at the end of its stroke and begins to return, and the effect will be
somewhat similar if with the crosshead considerably smaller than the piston the
latter be arranged to uncover a port at the end of its stroke so as to admit steam
thereby to the space between them.
It will be seen that in the engines set forth above although there are only two
cylinders there is a triple expansion of the steam. When it is desired to have a
quadruple expansion with two cylinders I construct them in a similar mauner with
cranks opposite and receivers open to the top of each piston as illustrated in
Figure 3, in which a large extra receiver Q2 (which may form a re-heater for the
steam) is connected with the valve casing. In the position shown the valve Fis
descending and steam from the supply A passes through port J to the h.p. receiver Q,
while the underside of the h.p. piston C is connected with the receiver or re-heater Q³
by the port J, and the ports R and T are connected so that the 1.p. piston is in
equilibrium At mid-stroke ring 1 rising closes port J cutting off the steam to
receiver and ring 3 closes port T cutting off the steam from the l.p. receiver O
to the underside of the 1.p. piston U. During the next stroke, the valve having
risen, steam passes by ports J and J2 from the top to the bottom side of the
h.p. piston C putting it in equilibrium, while steam from the receiver Q2 enters
the I.p. receiver O by the port R, and the underside of the 1.p. piston U and port T
are connected with the exhaust K. At mid-stroke the communication between the
upper and under sides of piston C and between the receiver Q2 and receiver O is

page_text: cut off and at the end of the stroke the valve has descended to the position shown.
There are thus four expansions and ranges of temperatures of the steam, one on
each of the four sides of the two pistons.
In my Patent Specification No. 12258 of 1889 I described a tandem compound
engine (Figure 1) having the adjacent sides of the two pistons constantly open to
one another, the varying pressure in the inter-piston space or receiver controlling the
momentum of the pistons etc. and keeping the parts in constant thrust downwards.
These improvements include modifications of engines so constructed, in one form of
which, illustrated by Figure 4 herein, I employ a receiver or special clearance
space open to the top side of the h.p. piston C. The valve FI preferably make
larger than necessary and arrange it so that the pressure thereon partly balances
that on the pistons. On the down stroke steam passes from the supply A through
port J to the receiver Q above the h.p. piston C being admitted and cut off by
ring 1 of the valve F, and during the return stroke, ring 1 having risen above
port J, it is free to pass thence to the bottom of the 1.p. piston U by the port T and
to and from the inter-piston space by port S, until the piston at about half stroke
covers the port S, and shortly after which ring 1 descending over port J closes the
connection between the top of the h.p. and the bottom of the l.p. pistons, and for
the rest of the upstroke the steam in the two receiver spaces is compressed whilst
that below the l.p. piston U expands, and next stroke it passes through port T to
the exhaust K. An advantage of this arrangement is apparent in the simplicity
of the valve employed and on this account I prefer to cut off the connection with
the inter-piston space by the piston closing the port S, although the valve may be
arranged to cut off the same. The port S is shown fitted with a cock Z by partly
closing which the amount of compression and holding down power in the inter-piston
space may if desired be regulated.
For some purposes when it is not important to preserve the economy due to the
ranges of temperature in the two cylinders not overlapping, I abolish the port S
or close it with the cock Z and allow the inter-piston space to be filled by leakage
past the two pistons. This leakage may be supplemented if necessary by opening
more or less the small cock W (which the h.p. piston descends below at the end of
its stroke) so that the net upward pressure on the pistons at the beginning of the
up-stroke may accelerate the pistons but without the connecting rod lifting from
the crank when the normal speed is attained.
In a modified arrangement, illustrated by Figure 5, the inter-piston space or
receiver is filled at a certain point in the stroke (in a similar manner to that
described in reference to the receiver O in Figure 3 of my Specification No. 12258
of 1889) and the h.p. receiver Q is connected with the h.p. cylinder B during the
up-stroke only. In the position shown the pistons C and U are at the bottom of
their stroke, and the top side of the piston C is connected by the ports J, Q1
and T with the h.p. receiver Q and the bottom of the piston U. During the
up stroke when the piston U has arrived between the small ports S and S¹ the
valve F will have risen and descended again to about the position shown, so that
the two sides of the piston U are momentarily connected by the ports S and S'
and the recess in ring 2, the pressure in the inter-piston space being thereby
adjusted to that below the piston U, which as it rises closes port S while ring 2 closes
the lower end of port Q1 cutting off the flow of steam to the under side of piston U,
and later in the stroke ring 1 closes port J, cutting off the flow of steam from the
top of piston C into the receiver Q as soon as the pressure in the latter equals that
above piston C at bottom stroke. During the down stroke ring 1 admits steam
from the supply A through port J to the top of the h.p. piston C and cuts off the
same, while ring 3 allows steam from below piston U to pass by port T to the
exhaust K. The annular grooves y¹ y² which are uncovered by the pistons at
the extreme end of the stroke are provided to receive condensed water and drain
it below when the piston rises again. The speed of this engine should be such that
the net upward pressure on the pistons at bottom stroke does not exert any pull on
the crank but stores itself by imparting velocity to the piston.

page_text: In engines constructed as shown in Figure 1 of my Specification No. 12258 of
1889, or in modifications thereof, it will be seen that another receiver may be
provided into which the h.p. cylinder can discharge during the up-stroke, the steam
passing thence to the under piston space during part of the down stroke, and thence
to the lower side of the 1.p. piston during part of the up-stroke, as before the
object being to establish three ranges of temperature instead of two, the pistons
however will be not quite balanced at bottom stroke, which may be rectified to a
certain extent by creating a partial vacuum above the crosshead during the down
stroke as is effected by the grooves w shown in Figures 7 and 8 and described later.
Referring to my Specification No. 12258 of 1889 it is evident that the cut off
motions by the piston (Figures 7 to 9 of that Specification) may be applied to
cylinders which have receivers connected thereto. Figure 6, annexed hereto, shows
such an arrangement in which a novel feature consists in the use of the piece a of the
piston C for cutting off both the supply and discharge of the steam to and from the
receiver at the top of the piston C. To effect this the valve F is made with
sufficient travel so that ring 1 descends and rises again in time to close port J
somewhat before half stroke, while the lower edge of the piece a cuts off the steam
flowing from A through port J and to the receiver Q at an earlier point in the
stroke. During the up-stroke the steam passing from the receiver Q through
ports Jaud T to the underside of the piston C is cut off at half stroke by the top
edge of the piece a closing the port J. With a suitable size of receiver Qany
desired amount of expansion is obtained above the piston and a certain amount
below the same. If the lower and upper edges of the piece a be made slanting
circumferentially or inclined to the face of the piston the points of cut off may be
varied by rotating the top of the piston. It is evident that this piston cut-off may
be applied to engines herein, and that in cases where only a low rate of expansion
is desired the later cut-off by the valve will suffice.
My invention relates also to compound engines having receivers whereby the
pistons are kept in constant thrust downwards in which one piston or an extension
thereof acts as a valve for the distribution of steam to the other.
place two cylinders side by side, as shown in Figure 7 the h.p. piston C working
on to a crank preferably about 145° in advance of the 1.p. crank. The stroke of
the h.p. piston C may be conveniently made about three quarters that of the
1.p. piston U. A piston rod passing through a stuffing box connects the l.p. piston U
with its cross head below, and the extension F of the h.p. piston C connects the
latter directly with its circular cross head, which I prefer to make of smaller
diameter than the h.p. piston for the reason hereinafter given. Above each piston
is a receiver or special clearance space Q and O, and attached to the top of the
piston C is a valve piston N and to piston U a plunger or extension N', N³, the
whole arranged so that when the h.p. piston C is at the top of its stroke, as shown,
the end N³ of the plunger N¹ on the top of piston U which is rising uncovers the
supply port A, and steam passes round the reduced part N of the plunger N¹ and
through the port J (leading to the casing or cylinder in which the piston valve N
works) to the h.p. receiver Q. At about mid-stroke the port J is closed by
N descending (and by N' ascending) thus cutting off the supply to Q, and
towards the end of its stroke piston C uncovers port R leading to the
1.p. receiver O and steam from the h.p. cylinder passes thereto during part of the
1.p. downstroke, expanding as it goes, and after it is cut off by piston C rising over
port R the steam remaining in the h.p. cylinder above the piston C is compressed
during the up-stroke thereof into the receiver Q, the supply port A being closed
by the end part N of the l.p. plunger N₁ until the h.p. piston gets to the top of its
stroke, when the receiver takes steam again as before. Meanwhile the steam
above the l.p. piston U has expanded to the bottom of the stroke thereof, and
ring 1 of the extension F of the h.p. piston has risen above the port R and thus
connected the two sides of the 1.p. piston U by the ports R, R¹ and T, and during
the up-stroke of the latter the pressures thereon remain in equilibrium until about
half stroke when the connection is closed by ring 1 descending over port R', after

page_text: which the steam above the piston U is compressed in its receiver O while that
below the piston expands and during the next stroke ring 2 having descended it
passes through port T to the exhaust K.
By making the h.p. extension F and its rings 1 and 2 of smaller diameter than
the h.p. piston C I am able to balance the piston at the beginning of its up-stroke.
I proportion the parts so that as the piston descends over port R it entraps steam
below it before the maximum compression in the receiver O is reached, so that this
steam may be compressed below the piston to a suitable pressure for balancing the
same and be afterwards released when the piston C rises above the port R at about
the same pressure as that in the l.p. receiver O. The pressure below piston Cat
bottom stroke acting upwards on the difference in area of piston C and ring 1 of
the extension F may be made to equalize that acting downwards on C or it may be
somewhat greater than the same so as to assist in overcoming the inertia of the
piston. The inertia of the 1.p. piston U and pressure on the rod during the
stroke may be overcome to a certain extent by admitting air or vapour above the
crosshead by groove w at the top part of the stroke only and so creating a partial
vacuum above it as it descends. The flow of steam through port R¹ may be
regulated by partly closing the cock Z therein which tends to increase the com-
pression in the receiver O and indirectly that in the receiver Q.
up-
In some modifications of this engine I abolish the plunger on the top of
the l.p. piston and the ports connected therewith, and I admit the steam to the
h.p. receiver by the direct motion of the h.p. piston or an extension thereof at the
top of its stroke, the h.p. receiver being made of larger size.
In my Provisional Specification several of these modifications are described at
some length and I shall now describe two typical arrangements which are sufficiently
illustrated by Figures 7 and 8. I may say that I do not claim as a simple engine the
methods described of distributing the steam to or from the top of the h.p. piston
by its own direct motion, as I am aware that several similar simple engines have
been proposed many years ago, but the object and great advantage of my improvements
will be found in the combination with the l.p. piston of a h.p. piston which may be
balanced at the beginning of its up-stroke and having attached thereto an extension
arranged to act as a valve for the distribution of steam to or from the 1.p. piston,
whereby only the volume swept by the 1.p. piston and its passages are discharged
into the exhaust, so that the h.p. receiver may be made of considerable size
without undue waste of steam, which would not be so in the case of a simple engine
that connects its receiver with the exhaust at the end of a stroke.
One modification of Figure 7 may be described in reference to the same figure.
I abolish the l.p. plunger N' and the ports A and J and construct the steam supply
port as dotted at A², so that it is uncovered by the valve piston N attached to the
h.p. piston C when at the top part of its stroke. The steam in the h.p. receiver Q
which has been compressed to a certain extent during the up-stroke is thus raised
to the initial or boiler pressure and towards the end of the stroke the expanded
steam therein is admitted to the receiver O through the port R as before, and the
action is otherwise similar to what I have already described. The h.p. receiver Q
may if desired be made in compartments and fitted with a valve or valves whereby
the number of compartments in use may be altered so as to vary the amount of
expansion.
Another modification is shown in Figure 8. The steam supply A. is open to the
annular space between the h.p. piston C and ring 1 of the expansion F, and steam
enters the h.p. receiver Q at the top part of the stroke through the holes or ports J
in the cylinder B and also through the holes J2 in ring 1 which connect with
holes Jat the top of the piston, the hollow inside of which forms part of the
receiver Q. Towards the end of the stroke the expanded steam in receiver Q
passes out of the holes J' through port R to the 1.p. receiver O, afterwards passing
to the underside of the 1.p. piston U through ports R and T and thence to the
exhaust K in a similar manner to that described in reference to Figure 7. The
parts can be proportioned so that the constant pressure from A acting upwards in
B

page_text: the annular space below the h.p. piston may balance the lower pressure on the
greater area above at the beginning of the up-stroke. The pressure below the piston
may be increased somewhat at the end of the stroke by the piston descending below
the supply port A. If desired the engine may be governed or regulated by the valve
or cock Z in the port R thus controlling the flow of steam into and out of the
1.p. receiver O.
On a similar principle an engine with three cranks may be constructed, for
instance if the intermediate cylinder be in the middle with the cranks at about 120°,
the first and second pistons may be balanced in a similar manner to piston Cin
Figure 7 the extension F being connected to the second piston and controlling the
admission and exhaust to and from the underside of the third piston, while the
h.p. piston takes its own steam as described above or it may be supplied by a plunger
or valve on the third piston. There will thus be expansion of the steam above each
of the three pistons and below the third one in succession with a moderate range of
temperature in each of the four places, as against the three places of expansion in
the two cylinders of Figure 7.
The improvements in the use of receivers which I have set forth serve the double
purpose of keeping the pistons in constant thrust downwards and reducing or
sub-dividing the range of temperature in the cylinders. 'It is evident that the
receivers that I have described in this and former Specifications may in some cases
form part of the cylinder ports or valve passages, which are then made larger than
usual or than necessary for the transit of the steam merely.
In some cases, for distributing the steam or balancing the pistons, receivers such
as described herein may be arranged below the pistons and connected therewith
permanently or intermittently.
A part of my invention relates to improved means of governing these and other
fluid pressure engines.
Figure 9, shows my improved governor applied to a cylinder having a receiver at
one side of the piston to which steam is admitted and whence it passes to the other
side of the piston, similar to the cylinder in Figure 6 but preferably without the cut
off by the piston. In the position the valve is shown, the piston will be at top
stroke and the valve approaching the bottom of its stroke. On the top of the valve
or piston F which admits steam from the supply A through the port J to the
receiver end of the cylinder, I mount a governing valve Y and spring C which are
held down to the distributing valve F by a rod and disc L, the latter fitting easily
a bored chamber, formed in the distributing valve in this design, and so arranged
that when the engine attains a certain speed the governing valve Y overcomes the
spring C at the bottom stroke of valve F and closes more or less the ports or holes J³
which admit the steam from A to the cylinder port J, noise being deadened by the
cushioning action of the disc L within the valve.
The upper side of the governing valve Y may have the same pressure on it as the
underside as shown in Figure 9, or the holes through it may be abolished and it
may be arranged as shown in Figure 94, in which as soon as the valve Y descends
over ports A2 so as to reduce the pressure below the valve the pressure above
closes A² and cuts off the steam flowing from A through A, J, and J. It is
evident that with the distributing valve set to work in the opposite direction relative
to the piston the governing valve may be arranged below the valve ring instead of
as shown in the drawing.
In Figure 9 a second governing valve Y2 is shown which is provided when it is
desired to control the passage of the steam out of the h.p. receiver through the
port J in addition to the admission thereto. The valve is fitted with a spring C
and rod and disc L2 which latter for convenience works in the same cushion chamber
as the other disc L, and when the valve F approaches the top of its stroke steam
will be free to pass through ports J, J' and T to the underside of the piston, until
a certain speed is attained at which the spring C2 is overcome by the momentum of
the valve which then closes more or less the port J in a similar manner to the
top valve. These valves either throttle the steam flowing to the top or bottom of

page_text: the piston or cut it off earlier in the stroke, or do both partly, depending to a
certain extent on the angle of the eccentric or its equivalent. I generally employ the
top valve only, but as this tends to reduce the holding down pressure in the receiver,
for some purposes the lower valve may be added which tends to increase the
pressure in the receiver. The cushion chamber may be filled by leakage of steam.
past the rod and disc, or by a suitable hole or holes which may be fitted with a
valve or valves. By arranging the governing valves to work in a bored part
of the distributing valve their wear will be less than if working in the valve
liner.
Figure 10, shows a modified arrangement in which the bored part in which the
valve works forms also the cushion chamber. Steam from A passes through A², J³
and J to the cylinder until a certain speed is attained when the valve Y overcomes
the spring C and closes the ports A² more or less. The small hole b admits the full
pressure to the top of the valve Y when it has fallen a short distance and
simultaneously the pressure is admitted through holes 63, 63 to the bottom of Y,
which is balanced in the middle part of its travel but at the two ends thereof it
entraps the full pressure for cushioning.
Figure 11, shows this governor with a different arrangement of spring. The
governing valve Y works in a bored chamber within the valve F as before and is
securely attached or pivoted to the top ends of the curved, bow shaped or bent
springs C, of flat or other suitable section, the bottom ends of which are fastened
within the stem of the distributing valve. Annular cushion chambers L, L into
which the ends of the valve work assist the springs in bringing the valve to rest. In
the position shown the valve F is approaching the end of its stroke and at a
certain speed the momentum of Y compresses the curved spring C, and the steam
from A passing through the ports J³ and J to the cylinder is cut off or throttled by Y
descending. Towards the end of the governing valve's travel the springs C begin
to adapt themselves quietly at their lower ends to the curved ribs (or springs) C³, C³,
and the length of the springs in action being rapidly.shortened they are stiffened
thereby to strongly resist and limit the motion of the valve Y at the extreme end of
its stroke. On the other hand when the valve Y ascends towards its original
position its motion is shortly but gradually and quietly arrested by the curved
springs acting in tension, and its travel being thus limited it can be arranged so that
it cannot touch the end of the cushion chamber. By making the springs more
curved they may be arranged to work in tension when the valve is closing the ports
although I prefer the other method.
At moderate speeds or when the strain on the spring is not excessive I abolish
the annular cushion chamber L. Where space permits I may adapt this form of
spring to Figures 9, 9 and 10 instead of the spiral springs shown.
The governing valve may be attached by a rod Y' to an involute spring like C in
Figure 114 which is restrained by surfaces C³, C3, shaped so that the spring lays
itself by degrees thereon at each end of the valve's travel beginning at the outside
of the involute and is thereby proportionately stiffened.
Figure 12, shows the application of this governor to the slide valve F of a lower
speed double acting engine in which the cushion chambers may be dispensed with,
the governing valves Y and Y2 suitably weighted being attached to the curved or
bow shaped springs C and C2, these valves working in a bored chamber at the back
of the slide valve F which is shown approaching the bottom of its stroke and when
a certain speed is attained the valve Y descends and compressing C closes more or
less port J³ through which steam from the steam chest around F is passing to the
cylinder port J, thus throttling or cutting off earlier the supply thereto. In a
similar way the valve Y controls the admission of steam through the port J to the
port J at the other end of the cylinder. The springs C and C² bring the valves Y
and Y2 to rest by acting in tension at one end of their travel and in compression at
its other, the resistance of the springs in the latter case being increased by the
curved ribs or springs C³ and C as explained in reference to Figure 11. If two or

page_text: '
more springs are used those of one valve may be set across or between those of
the other.
A pair of springs may be arranged with their convex sides together at one end
and the other ends apart so that their resistance is increased when compressed
against one another. Or a combination of springs may be employed.
When the piston or an extension thereof controls the distribution of steam this
governor may in some cases be applied thereto.
The engines described herein may exhaust into other cylinders or be worked in
conjunction with other engines or parts thereof of similar construction to those
described in this and my former Specifications, and in some cases they may be
reversed by movable eccentrics, additional valves or their equivalents and ports
interchangeable by cocks, or in other suitable ways.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is :
1. A compound engine containing two receivers which are connected with the
top sides of the two pistons and a valve and ports arranged to admit steam to the
top of the h.p. piston or high pressure receiver and thence during the first half of
one stroke to the top side of the 1.p. piston or l.p. receiver, and during the first half
of the next stroke from the top to the bottom side of the 1.p. piston, each piston
compressing steam in its receiver during the latter half of its up-stroke,
substantially as herein shown and described and illustrated by Figures 1 and 2.
2. A compound engine containing two receivers which are connected with the
top sides of the two pistons, the 1.p. receiver being permanently open to the top side
of the 1.p. piston and the bottom side of the h.p. piston, and a valve and ports
arranged to admit steam to the top of the h.p. piston or h.p. receiver, and thence
during the first part of one stroke to the top side of the 1.p. piston or 1.p. receiver
and bottom side of the h.p. piston, and during the first part of the next stroke from
the top to the bottom side of the 1.p. piston each piston compressing steam in its
receiver during the latter part of its up-stroke, substantially as herein described
and illustrated by Figure 1.
3. A compound A. engine containing two receivers which are connected with the
top sides of the two pistons, the l.p. receiver being permanently open to the top side
of the 1.p. piston and connected with the bottom side of the h.p. piston during the
up-stroke and the first part of the down stroke thereof, and a valve and ports
arranged to admit steam to the top of the h.p. piston or h.p. receiver, and thence
during the first part of one stroke to the top side of the 1.p. piston or 1.p. receiver
and bottom side of the h.p. piston, and, during the first part of the next stroke,
from the top to the bottom side of the 1.p. piston, each piston compressing steam in
its receiver during the latter part of its up-stroke, substantially as described and
illustrated by Figure 2.
4. A compound engine containing a h.p. and a l.p. receiver and an intermediate
receiver or re-heater, and a valve and ports arranged to distribute the steam and
expand it successively on the four sides of the two pistons, substantially as described
and illustrated by Figure 3.
5. In a tandem engine containing two pistons with the space between them
forming a receiver which provides holding down power for the pistons, the
arrangement of the h.p. receiver Q and valve F with the ports J, S, T, and methods
of supplying the inter-piston space and regulating the distribution of steam,
substantially as described and illustrated by Figure 4.
6. In a tandem engine containing two pistons with the space between them
forming a receiver which provides holding down power for the pistons, the appli-
cation of the method of charging the inter-piston space by ports S S and recess x,
and the combination of the method of charging the inter-piston space, with the
valve F and receiver Q, substantially as herein shown and described in reference to
Figure 5.

page_text: 7. In a tandem engine containing two pistons with the space between them
forming a receiver which provided holding down power for the pistons, the appli-
cation thereto of another receiver into which the h.p. cylinder discharges during
one stroke and from which it passes to the inter-piston space next stroke and thence
below the l.p. piston, substantially as herein shown and described.
8. In an engine containing a piston having a receiver open to one side, the
particular arrangement of valve F with the piston piece a so that the latter may cut
off the steam passing both into and out of the receiver Q, substantially as described
and illustrated by Figure 6.
9. A compound engine containing two pistons the upper sides of which are open
to receivers and have attached thereto plungers, piston valves, or their equivalents,
the h.p. piston being attached to an extension thereof below it and the whole
arranged with ports so that the downward extension of the h.p. piston acts as a
valve for distributing the steam to and from the underside of the l.p. piston while
the valves on the pistons (or the h.p. piston alone) distribute the steam to the
h.p. receiver and the h.p. piston admits it thence to the 1.p. receiver, substantially
as described and illustrated by Figure 7.
10. A compound engine containing two pistons the upper sides of which are open
to receivers, the h.p. piston being attached to an extension thereof below it and
having its crank set in a certain relation to the l.p. crank, for instance at an angle
of 145° in advance thereof, and the whole arranged with ports so that the down-
ward extension of the h.p. piston acts a valve for distributing the steam to and from
the underside of the l.p. piston, while the h.p. piston or a part or extension thereof
distributes the steam to the h.p. receiver and thence to the 1.p. receiver, substan-
tially as herein shown and described in reference to Figures 7 and 8.
11. In a compound engine containing two pistons the upper sides of which are
open to receivers and in which an extension of the h.p. piston acts as a valve for
the distribution of steam to the 1.p. cylinder as described herein, the arrangemnts
for balancing the h.p. piston at the beginning of its up-stroke, substantially as
described in reference to Figures 7 and 8:
12. In an engine having a receiver which provides holding down power for the
piston, the arrangement herein of a groove w or its equivalent in the cross head
guide, substantially as herein shown and described and for the purpose specified.
13. In an engine having an inter-piston space or receiver which provides holding
down power for the pistons the application thereto of grooves y³, y² arranged as
shown in reference to Figures 4 and 5 substantially as herein shown and described
and for the purpose specified.
14. In an engine having a receiver which provides holding down power for the
pistons, regulating the passage of the steam from or to and from the receiver by
cocks Z (Figures 4, 7 and 8) or valve Y2 (Figure 9) substantially as herein shown
and described and for the purpose specified.
15. A governing valve arranged in conjunction with a reciprocating distributing
valve or its equivalent and a port or ports in such a manner that when a certain
speed is attained the momentum or inertia of the governing valve brings it into
action, substantially as herein shown and described.
16. A governing valve and suitable spring arranged in conjunction with a
distributing valve or its equivalent and ports in such a manner that when a certain
speed is attained the momentum or inertia of the governing valve brings it into
action, substantially as herein shown and described and illustrated in the
accompanying drawings.
17. A governing valve and spring and cushion chamber arranged in conjunction
with a distributing valve or its equivalent and ports in such a manner that when a
certain speed is attained the momentum or inertia of the governing valve brings the
parts into action, substantially as herein shown and described and illustrated in the
accompanying drawings.
18. A governing valve and spring and cushion chamber arranged in conjunction
with a distributing valve or its equivalent and ports in such a manner that when a

page_text: certain speed is attained the momentum or inertia of the governing valve
subsequently assisted by steam or fluid pressure brings the parts into action,
substantially as described and illustrated by Figure 9 of the accompanying
drawings.
Dated this 29th day of September 1893.
DRACUP & NOWELL,
Bradford, Agents.