IMPROVEMENTS IN COMPOUND STEAM ENGINES
Year: 1885

page_text: I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and C° Patent Agents,
Southampton Buildings in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN COMPOUND STEAM ENGINES" and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
This invention relates to steam engines, the first part relating more particularly
to the construction and arrangement of the initial or high pressure cylinder and
the expansion cylinder of a compound engine whereby when the pistons have made
about one third of their stroke the steam is cut off from the high pressure cylinder
and the steam therein admitted into the expansion cylinder whose piston has a
larger area than that of the high pressure cylinder, the effect being that the steam
will continue its pressure against the piston in the bigh pressure cylinder and
expand within and exert, at the same time, pressure against the piston in the
expansion cylinder, thus preserving a regularity of movement, the increased area in
the expansion cylinder counteracting the effect of the decrease in the pre-sure in
the initial cylinder.
The engine constructed according to the present invention is to be distinguished
from other engines having expansion cylinders, in that, heretofore, the piston in the
high pressure cylinder has been allowed to make a full stroke under boiler pressure
before the steam was turned into the expansion cylinder.
By means of this invention the consumption of fuel is reduced to a minimum
amount, and the pressure on the pistons does not vary materially throughout their
stroke. The invention also admits of the use of a cut off in a direct acting engine
without the employment of a ty wheel, and in a crank engine to cause a uniform
and unvarying pressure throughout the stroke.
In sheet 1 of the drawings I have illustrated the invention as embodied in a
direct acting compound engine in which the steam valves of one cylinder pump are
operated by the engine of the other adapted for operating a duplex pump, but it is.
not to be understood that I limit the invention to this use; its employment in
combination with the pump, however, is very advantageous.
Referring to sheet No 1.
Figure 1 is a side elevation of an engine embodying the invention.

page_text: Figure 2 is a central vertical longitudinal section through the high pressure and
expansion cylinders.
Figure 3 is a detached sectional view of one corner of the high pressure cylinder,
illustrating the first position of the inlet valve.
Figure 4 is a front end view of the engine and
Figure 5 is a top view of the high pressure cylinder of same.
and
A denotes the initial or high pressure cylinder B the expansion cylinder;
C the piston rod passing centrally through said cylinders and having secured upon
it, in the cylinder A, the piston D and in the cylinder B, the piston E.
G is a valve connected with the pipe H and extending from the upper front
portion to the lower rear portion of the high pressure cylinder, as shown. The
lower end of the pipe H leads to a valve chamber I containing the valve J, and the
upper end of said pipe leads to a chamber K containing a similar valve L;. both
chambers being cast with the cylinder. From the valve chamber I a port M leads
to the back end of the cylinder A, and from said chamber also extends the
passage N into the back end of the cylinder B. By means of the valve L, the
chamber K may be placed in communication with the front end of the cylinder A
or with the passage O leading along the upper side of the cylinder B into the front
end thereof. The two lower corners of the cylinder B contain steam chambers P, Q
respectively having valves R, S, and being connected by a passage T leading to the
exhaust V. At all times during the operation of the engine when one of the
chambers P, Qopens into the passage T the other chamber will be shut off
therefrom. The chamber P is connected with the back end of the cylinder B by
means of a port W, and the chamber Q is connected with the front end of said
cylinder by means of the port X, as indicated in Figure 2. The exhaust steam
from the expansion cylinder B passes into a receiver Y, and thence into the
chamber Z, whence it passes into the low pressure cylinder a.
The rods b afford a means whereby the engine may be conveniently bolted to a
duplex pump if desired.
The
The valves J, L are operated by the well known Corlis gear, designated by d, d;
and the valves R, S are operated by the plate e, rods f, and arms g, constituting the
well known wrist motion. The Corlis gear d and the devices used to actuate the
valves R, S, as well as the low pressure cylinder a, the receiver Y, the steam
chamber Z and the connecting devices, are all of well known construction in steam
engines and form no part of the present application. They are illustrated, however,
in connection with the cylinders A, B, for the purpose of conveying an accurate
idea of the invention when embodied in a compound, direct acting engine.
elements specified as old being thoroughly understood will be unnecessary to
describe them; except to point out their general operation when employed in
connection with this invention which is illustrated in Figure 2. When, in the
operation of the engine, the pistons D, E are to commence their stroke, the valve J
will be in the position illustrated in Figure 3 and steam will pass from the
chamber I through the port M into the back end of the cylinder A, and will move
the piston towards the front end of the cylinder. After the piston has made about
one-third of its stroke the valve J will be moved to the position shown in Figure 2,
thereby cutting off the steam in the chamber I and opening the passage N, the
effect being that a portion of the steam already in the cylinder A will pass into
the back end of the cylinder B, where it will expand against the piston E and (in
connection with the pressure in the back end of the cylinder A) will move the
pistons with unvarying force to the front end of their respective cylinders.
After the pistons D, E have completed their stroke towards the front end of the
cylinders A, B, the valve L will open so as to open the passage m, when steain
from the chamber K will pass into the cylinder A at the front side of the piston,
and will move the latter about one-third of its back stroke, at which time the
valve L will turn to the position illustrated in Figure 2, cutting off the steam in
the chamber K and permitting a portion of the steam in the cylinder A to flow
through the passage O to the front end of the cylinder B, where it will expand and
i

page_text: move the pistons to the completion of their back stroke, in the manner before
described when referring to the forward stroke of the pistons. When the pistons
are upon their forward stroke the valves R, S, are in the position illustrated in
Figure 2, the valve R preventing the expanding steam from entering the oxhaust V,
while the steam on the front side of the piston E is allowed to exhaust into the
chamber Q.
It will be observed that the steam is cut off from the high pressure cylinder
when the piston therein has made about one-third of its stroke, and that a portion
of the steam in the high pressure cylinder is then allowed to expand against an
increased area in the expansion cylinder, whereby the stroke of the pistons is
completed with unvarying regularity and force, the expansion of the steam against
an increased area at the point of cut off counteracting the decreased pressure in the
initial cylinder.
The invention is applicable to single direct acting engines as well as to compound
and crank engines, and not only obviates the necessity of using a fly wheel, but,
also, of employing large cylinders, thus saving expense in the construction of the
engine as well as reducing the consumption of fuel.
I have shown and described an engine so constructed that the two pistons move
simultaneously, and as they travel a certain distance before the steam is admitted
from the high pressure into the low pressure cylinder, a large space is left behind
the piston in the latter cylinder. This in some instances might be found objection-
able in that a portion of the pressure of the steam in the piston in the cylinder
last mentioned is wasted, owing to the large space in which it is expanded. When
such is the case I overcome this difficulty by so constructing and arranging the
different parts of the engine that while the piston in the high pressure cylinder
makes a certain predetermined portion of its stroke before the cut off of live steam
is effected, the piston in the low pressure cylinder is moved a very short distance in
comparison with that travelled by the piston in the high pressure cylinder, thus
leaving a small space for the steam to expand in, said space being regulated in
accordance with the pressure of the steam in the high pressure cylinder.
Referring to sheet No 2 of the drawings Figure 1 is a view in side elevation of
an engine, embodying my improvement, shown in connection with a direct acting
pump.
Figure 2 is a sectional view thereof.
Figure 3ª, is a top plan view of a portion of the high pressure cylinder and cross
head.
Figure 4ª is a detached view of one of the valves leading from the high into the
low. pressure cylinders at a different portion of the stroke.
A represents a high pressure cylinder of any suitable dimensions, and A' a low
pressure or expansion cylinder located in the rear of the former. In these cylinders
are placed the pistons B and B¹, the latter piston within the low pressure cylinder
being of larger area than that in the initial cylinder A. C is the piston rod
connected to the high pressure piston B; and C₁ C₁ are piston rods connected at
one end with the piston B' in the low pressure cylinder, and at their opposite ends
with the cross-head D; the rod C is continued through the cylinder A, and
connected to a piston D¹ within the cross-head. On the opposite side of the
piston D is secured the rod C³, which is connected to the pump and is in reality a
continuation of the piston rod C.
On the lower forward end of the high pressure cylinder: A is formed the valve
chamber E enclosing the valve F, said chamber being provided with a port G,
leading into the forward end of the cylinder A, and also with a port H leading
into the passage I, which extends along the under side of the said cylinder A and
leads into the forward end of the cylinder A¹. When the valve F is in such
position that the port G is open, the port H will also be open, as shown in Figure 2a
of the drawing, thereby allowing the steam to pass from the forward end of the
high pressure cylinder A through the passage I into the forward end of the low
pressure cylinder A¹.

page_text: .
+
A
'
On the upper rear end of the cylinder A is formed the chamber E¹ enclosing a
valve F similar to the valve F said chamber being provided with a port G¹ leading
into the rear end of the cylinder A, behind the piston B, and also with a port H¹
. leading into and connecting with one end of the passage I formed in the upper
portion of the low pressure cylinder A' and leading to the rear end thereof, behind
the piston B¹.
On the underside of the low pressure cylinder and at opposite ends thereof are
formed the valve chambers E and E³ enclosing the valves F and F³ the former of
.said chambers being provided with a port G' leading into the forward end of. the
low pressure cylinder A', and the latter chamber being provided with a port G³-
leading into the rear of the low pressure cylinder, and each of said chambers being
connected with the passage G leading into a condenser.
The valves F F F F are operated by the Corliss gear well known in the
I construction of engines and therefore forming no part of the present invention..
..It is illustrated however, in connection with my improved engine for the purpose
of conveying an accurate idea of the invention as embodied in a compound direct
acting engine. This gear being well known I have not deemed it necessary to
describe it, and only refer to it in the operation of the engine.
"
In the crossbead D is formed a port J communicating with each end of the
cylinder D and with valve chambers a, the latter communicating with the cylinder
by means of the ports 6 and with the port J by means of the ports c. To the ends
of the cross-head D are secured the outwardly extending lugs or bars d to which
aro pivoted the levers e. To the upper ends of these levers are secured the valve
rods having on their inner ends the valves g having their seats formed at the
ends of the ports b. To the lower ends of the levers e are secured the springs.h the
tendency of which is to keep the lower ends of the levers e out, and the valves g
on their seats, closing the ports b connecting the chambers a with the cylinder
formed in the crosshead. The opposite ends of the springs are connected with the
downwardly projecting ends of the cross-head. To one of the lower rods K
which connect the engine with the pump are secured the springs k which are so
placed that when the cross-head is moved in close proximity thereto, the lower end
of one of the levers e will strike the said spring causing the upper end of the lever
to move outwardly and force the valve g from its seat.
Having described the construction of the improved engine, I will now set forth
its mode of operation.
As shown in Figure 2ª of the drawings, steam is about to be admitted to the
cylinder A through the chamber E' and port G', which will move the piston B
from left to right. The valves at this period of the operation will be in the
positions as shown in Figure 2 the valve É being so turned that it will allow the
exhaust or expanded steam in the forward end of the high pressure cylinder to
pass through the ports G, H and passage I into the forward end of the low
pressure cylinder. The valve F is so turned that it will allow the exhaust or
expanded steam in the forward portion of the cylinder last aforesaid, with the
exhaust from the high pressure cylinder to pass out through the ports G and G
into the condenser, thereby securing the benefit of the vacuum on both pistons.
The valves F1 and FS will both be closed to prevent any steam from passing in
behind the piston B.
The
As before stated when live steam is first admitted through the chamber E¹ the
piston B will move from left to right, the low pressure piston remaining at rest.
This is accomplished by means of the cross-head D in the following manner
piston D' within the cross-head being secured to the high pressure piston rod C,
and the pump rod C and the low pressure piston to the rods C¹ secured to the
outer portion of the cross head, the said piston D' is free to travel in the cylinder
formed in the cross head, without moving the latter, which allows the piston B' to
remain at rest, until said piston D' has travelled the whole length of the cylinder D.
This cross head is filled with oil or other suitable liquid, which is forced through
the port J, until the piston D1 covers or closes the end thereof. If the circulation

page_text: of the liquid through the cross-head were entirely checked at this point, it would
move the cross-head with a sudden jerk; but this I have obviated by the use of
the smaller ports b, c and the valves g. After the piston D' has closed the port J
the
the liquid is forced through the port b, an opening formed in the valve
chamber a, and the port c into the port J and thence into the cylinder behind
the piston D¹. The opening in the valve g allows only a small circulation of the
liquid the resistance created by which, together with that created by the gradual
closing of the port J by the piston D¹, causes the cross-head, and the low pressure
piston secured thereto, to move with the piston D¹ when it has just reached the
end of the cylinder within the cross-head and before striking the end thereof.
After the piston and cross head have travelled a certain distance, regulated by
means of the valve gear, the valve F' assumes the position shown in Figure 4*,
cutting off the live steam from the boiler, and allowing the steam which is already
admitted to the high pressure cylinder, to pass through the port I' into the low
pressure cylinder, and expand behind the piston B' into the space formed by said
latter piston moving the distance, as before mentioned. The piston B being of
larger area than the piston in the high pressure cylinder, overcomes the loss of
pressure of the steam by its expansion into the low pressure cylinder, and prevents
any irregularity in the motion of the engine, (which would be the case were the
two pistons of equal area) the pressure of the steam admitted, being sufficient to
complete the stroke. The pressure exerted in the piston Bis transmitted through
the rods C and cross-head D to the pump rod C. The tendency of the cross-head,
is to slide back on the rods C and C but this is prevented by the piston D'
closing the port J and preventing any circulation of the liquid within the cylinder
in that way; and the valve g having the pressure of the liquid on its outer side,
that is on the side within the chamber a is forced down tightly on its seat, thereby
effectually preventing and stopping any return circulation of said liquid, and
consequently preventing the cross head from sliding.
When the pistons have completed their stroke, the valve F is so turned that live
steam is admitted through the pipe L, connecting the chambers E, E¹, to the
forward end of the high pressure cylinder, and the port H closed. At the same
time the valve F2 closes.
°
After the pistons have made a portion of their stroke, the valve F assumes its
original position, and allows the steam already admitted to expand through the
passage I into the forward end of the cylinder A', and exert its pressure on the
piston B¹ in order to finish the stroke.
It will now be seen that by the above construction the space behind the piston
in the low pressure cylinder, may be regulated, so that, if the pressure on the high
pressure piston is small, the space behind the piston in the low pressure cylinder
may be made correspondingly sinall.
By these means I obtain the full amount of pressure of, the steam, securing the
same result from this engine with half' the steam necessary with other engines in
which the steam is not admitted until the stroke is completed.
I would have it understood that I do not limit the application of my invention
to a direct acting engine, as it may be employed with engines of different con-
structions such as crank engines, simple engines, duplex engines etc, and engines
where the valves of one engine, are operated by the other engine; nor do I limit
myself to the exact parts shown and described, as many slight changes might be
made therein without departing from the nature of my invention.
Having now particularly described and ascertained the nature of the said
Invention and in what manuer the same is to be performed as communicated to
me by my foreign correspondent 1 declare that what I claim is
First. In a steam engine, the high-pressure cylinder containing a piston and
having chambers I, K, valves J, L, ports m, M, and passage N, combined with the
expansion cylinder containing a piston on the same rod with the piston in the

page_text: high pressure cylinder, and being provided with a passage O, valves R, S, and
ports W, X; substantially as and for the purpose described.
Second. The combination with a high pressure cylinder and a low pressure
cylinder of pistons working therein, valves for simultaneously cutting off the live
steam after the pistons have made a portion of their stroke, and admitting steam
directly or indirectly from the high into the low pressure cylinder, and means
substantially as described, for regulating the relative distances travelled by the
two pistons, before the cut-off, substantially as set forth.
Third. The combination with a high pressure cylinder and a low pressure
cylinder and pistons working therein, the piston in the latter cylinder having a
larger area than that in the former, of valves for cutting off the steam after the
pistons have made a portion of their stroke and allowing a part of the steam then
in the high pressure cylinder to expand against the piston of larger area in the
expansion cylinder, and means for regulating the relative distance travelled by the
pistons before the cut-off, substantially as set forth.
Fourth. The combination with a high pressure cylinder and a low pressure
cylinder and pistons working therein, of valves for simultaneously cutting off the
live steam after the two pistons have completed a portion of their stroke, and
admitting steam from the high pressure cylinder into the expansion cylinder; and
a compensating cross-lead, connected with said pistons for regulating the relative
distances travelled by the pistons, substantially as set forth.
Fifth. The combination with a high pressure cylinder and a low pressure
cylinder and pistons working therein, the piston in the latter cylinder having a
larger area than that in the former, of valves for simultaneously cutting off the
live steam after the pistons have made a portion of their stroke, and allowing the
steam in the high pressure cylinder to expand against the piston of larger area
in the low pressure cylinder, and a compensating cross-head connected with the
rods of the low pressure piston, for regulating the relative distances travelled
by the two pistons, substantially as set forth.
Sixth. The combination with a high pressure cylinder and a low pressure
cylinder, the former having ports leading from its front and rear ends to the front
and rear ends of the latter, of pistons working therein, a compensating cross-head
connected with said pistons, and valves for simultaneously cutting off the steam
from the high pressure cylinder after the pistons have completed a portion of their
stroke and allowing the steam therein to expand against the piston in the low
pressure cylinder, substantially as set forth.
Seventh. The combination with a high pressure cylinder and a low pressure
cylinder, the former having ports leading from its front and rear ends to the front
and rear ends of the latter, and said latter cylinder having a passage leading from
either end to the condenser, whereby the exhaust from the two ends of the low
pressure cylinder will commingle and pass into the condenser, of valves for
simultaneously cutting off the live steam at a certain portion of the stroke and
allowing the steam in the high pressure cylinder to expand against the piston of
larger area in the low pressure cylinder, and a compensating cross head connected
with the piston rods of the low pressure cylinder, substantially as set forth.
Duted this 0th day of Tuan 100F
HASELTINE, LAKE & Co.,
For the Applicant.