IMPROVEMENTS IN COMPOUND ENGINES
Year: 1884

page_text: I HENRY EDWARD NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex, Civil Engineer do hereby declaré
the nature of the invention for "IMPROVEMENTS IN COMPOUND ENGINES," and in
what manner the same is to be perforined, to be particularly described and
ascertained in and by the following statement:-
This invention relates to that class of engines which consist of a cylinder into
which the steam is admitted direct from the generator, and a second cylinder of
larger size into which the steam passes from the exhaust, of the first cylinder, and
in which it acts expansively, and which are classed in the arts under the general
title of "Compound Engines."
The engines of this class possess many advantages and have gone into very
'extensive use particularly for pumping and other like purposes where it is desirable
that the piston rod of the engine should act directly upon the load. The especial
adaptation of this class of engines for such uses is due to the fact that by them the
economy due to the use of the stean expansively is secured, and at the same time
a practically uniform propulsive power is maintained throughout the entire stroke
of the engine without the aid of a fly wheel or other heavy moving part.
In order to secure the most economical results with an engine of this class, it is
desirable that the size of the engine should be so graduated, with relation to the
work to be performed, that when operating under its ordinary running conditions
the full power of the engine will be but little in excess of the resistance offered by
the constant load.
It frequently happens, however in running these engines that for various reasons
it is desirable that the engine should be able to temporarily perform an amount of
labor considerably in excess of that which it is ordinarily called upon to perform,
and consequently it is highly desirable that the engine should be capacitated to
meet these temporary demands, even though to do it the steam must be temporarily
used in an uneconomical manner.
It is the object of the present invention to provide means by which this result
is accomplished, and to that end the invention consists in a system of connections

page_text: by which the live steam may when desired be allowed to pass directly from the
supply pipe into the exhaust of the small cylinder or into the pipe leading therefrom
to the steam chest of the larger cylinder, so as to act upon the piston of said larger
cylinder at its initial or boiler pressure throughout its entire stroke, instead of
expansively, and at a reduced initial pressure. It will readily be seen that when
the stean is thus admitted to the larger cylinder at its initial or boiler pressure,
the pressure of the steam upon both sides of the piston of the smaller cylinder will
be equal so that said smaller piston will be constantly held in equilibrium and will
consequently perform no work, but it will also be observed that the relative areas
of the smaller and larger pistons are such that the increased pressure thus applied
to the larger piston will very much more than compensate for the loss of the smaller
piston, so that when the engine is operating in this manner it will develop a much
greater power than when operating in the ordinary manner, although to develop
this increased power it will sacrifice the economy due to the use of the steam
expansively.
In the accompanying drawings:
Fig: 1 is a plan view partially in section of an ordinary duplex compound engine
embodying the invention.
Fig: 2 is an end elevation partly in section of the same, looking from the left of
Fig: 1.
Fig: 3 is a similar view illustrating a modification to be hereinafter referred to.
Fig: 4 is a view similar to Fig: 1, showing the invention applied to an ordinary
duplex compound engine which is provided with a cross-exhaust.
Fig: 5 is a section taken upon the line x x of Fig: 4 one of the small cylinders
being shown in elevation.
Fig: 6 is a section taken upon the line y y of Fig: 5; and Figs: 7 and 8 illustrate
details which will be hereinafter referred to.
Referring to said drawings it is to be understood that the engine therein shown
consists of two cylinders 10. 11, which receive steam direct from the boiler and in
which the steam acts at its full pressure throughout the whole, or nearly the whole.
stroke of the piston, and two larger cylinders 12, 13 into, which the steam passes
from the exhaust of the first cylinders, and in which it acts expansively, after which
it is exhausted into a condenser or into the open air, the whole forming an ordinary
duplex compound engine. The cylinders 10, 11 are provided with the usual steam
chests 14, 15, into which the steam is admitted through the pipe 16 direct from the
boiler, and the cylinders 12,,13 are also provided with similar steam chests 17, 18,
which are connected by pipes 19, 20, with the exhaust ports of the first cylinders,
the exhaust ports of the last cylinders being provided with a pipe 21 leading to a
condenser or to the open air. The several cylinders are provided with induction and
exhaust ports 7, 8, 9 of the usual construction which are controlled by valves 6, of the
'common form, the rods 22, 23 of which are provided with the usual connections
by which the valves of each side of the engine are operated by the main piston
rod of the opposite side as in the well known Worthington Duplex Pumping
Engine.
Referring now particularly to Figs 1 and 2, it will be observed that the steam
chests 14, 15 are provided with openings 5, which communicate through pipes, 24,
with like openings 4 in the walls of the exhaust ports 9 of the cylinders 10, 11.
The pipes 24 are provided with ordinary throttle valves or cocks, 25, by which said
pipes can be opened or closed so as to establish or shut off communication between
the chests 14. 15 and the ports 9, as may be desired.
The operation of the engine thus organized is as follows:-If the engine is to
perform only the ordinary labor for which it is intended, the valves or cocks 25
will be closed so as to shut off communication through the pipes 24. The throttle
valve of the pipe 16 being then opened the steam will pass from the boiler to the
steam chests 14, 15, and will enter the cylinders 10 11, in which cylinders it will
cact at the full boiler pressure throughout the whole or nearly the whole stroke of
the pistons, after which, as the pistons in said cylinders commence their return

page_text: stroke, the steam already in the cylinders will pass through the pipes 19, 20 and
enter. the steam chests 17, 18 from which it will pass to the cylinders 12 13 where
it will act expansively upon the pistons of said cylinders so as to aid the steam
which is at the same admitted directly from the boiler to the corresponding sides
of the pistons of the cylinders 10, 11. And so the operation is repeated, the steam
which enters the cylinders 10, 11 at each stroke being exhausted into the steam
chests 17, 18 so as to act expansively in the cylinders 12, 13 at the next stroke.
After acting expansively in the cylinders 12, 13 the steam is exhausted through the
pipes 21 into a condenser or into the open air.
The connections by which the valves of each side of the engine are operated by
the movement of the other side, will of course be so adjusted as to properly time
the movements of the two sides with relation to each other.
The relative size of the cylinders 10, 11 and 12, 13 may be varied from that
shown in the drawings, the proportions there shown being only an approximation
of the true proportions for the purpose of illustrating the principle and and.
operation of the invention. These cylinders will however be so proportioned that
the steam acting upon the pistons of the two cylinders as just described, will exert
a substantially uniform propulsive power throughout the entire stroke of the engine,
and in order to secure the greatest economy in the use of the steam, the pistons of
the cylinders 12, 13 will be of at least two-and-one-half times the area of the
pistons of the cylinders 10, 11. From this it will be seen that if the steam is
allowed to enter the larger cylinders at its full or boiler pressure these cylinders
alone will develop a much greater power than all four of the cylinders will devolop
when acting in the regular way, as already described, although in doing it the
economy of using the steam expansively will be sacrificed.
Whenever therefore it becomes desirable for any reason to temporarily increase
the capacity of the engine, the throttle valves or cocks, 25, are opened so that the
steam will pass directly from the chests 14, 15 through the pipes 24 to the exhaust
ports, 9, of the cylinders 10, 11 and thence through the pipes 19, 20 to the steam
chests 17-18, thus causing the steam to be supplied at its full or boiler pressure
to both the cylinders 10, 11 and 12, 13. When this is done the pressure upon both
sides of the pistons of the cylinders 10, 11 will of course be the same, so that said
pistons will always be in equilibrium, and will consequently develop no power, but
the increased pressure upon the larger pistons of the cylinders. 12, 13 will very
much more than compensate for this, and thus have the effect of actually increasing
the power of the engine.
The arrangement of the pipes 24, and cocks or valves 25, may be varied
considerably from that shewn in Figs 1 and 2 without departing from the
invention. These pipes may, if preferred, be arranged as shown in Fig: 3 so as to
communicate directly with the pipes 19, 20 instead of communicating with these
pipes through the exhaust ports, 9.
Although the invention is herein shown as applied to a duplex engine, it will
readily be understood that it is not limited in its application to this class of
engines, as when embodied in the forms just described it may be applied with
equally good results to single compound engines.
In order to secure a steady and uniform action in a direct acting engine it is not
only necessary that each side of the engine should maintain a uniform propulsive
power throughout the entire stroke, but that the valve operating mechanism should
be so adjusted that just before the piston of each side of the engine completes or
complete its or their stroke in either direction, the valve mechanism will be
operated so as to start the piston or pistons of the opposite side of the engine upon
its or their stroke in the same direction.
Although, by means of compound cylinders arranged as just described, the
steam can be used expansively and yet cach side of the engine be caused to
develop a comparatively uniform propulsive power throughout its entire stroke,
yet it has been found in practice that, owing to condensation, loss by expansion
and other causes, even with cylinders so arranged, the power developed at the

page_text: 1,
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beginning of the stroke will be somewhat in excess of that developed at the end of
the stroke, thereby causing a more or less spasmodic action of the engine. To
correct this action these engines are frequently provided with what is known as a
"cross-exhaust" which consists as shown in Figs: 4, 5 and 6, of a pipe, as 26,
arranged to connect the exhaust ports of the two smaller cylinders of the opposite
sides of the engine. By reason of this connection it will be seen that the steam
exhausted from both the cylinders 10, 11 is allowed to circulate freely between the
steam chests 17, 18 of the expanding cylinders 12, 13. It will also be seen that, by
reason of the relative movements of the pistons and valves, of the two sides of the
engine as just described, as the pistons of each side of the engine are nearing the
end of their stroke and consequently losing power, the exhaust port of the smaller
cylinder of the opposite side will be opened so as to admit a fresh quantity of
steam into the pipes 19, 20, 26, and steam chests 17, 18, and thereby raise the
pressure in said pipes and chests and give an additional impulse to the pistons at
the end of their stroke.
When the engine is provided with a cross-exhaust; as just stated, this cross
exhaust may be also utilized as a means for admitting the live steam directly to
the expanding cylinders when it is desired to temporarily increase the power of the
engine. To effect this the steam pipe 16 is provided with a branch 24, which
communicates with the cross exhaust pipe 26 and thus affords means by which the
steam may when desired, be allowed to pass directly from the boiler to the exhaust
ports 9, of the cylinders 10, 11, and thence through the pipes 19, 20, to the steam
chests 17, 18 and the cylinders 12, 13. The branch pipe 24 is provided with an
ordinary throttle valve, 25, by which the communication between the pipes 16, 26
may be shut off when the engine is operating in the ordinary manner, and the
pipe 26 is provided with a valve 28 which may be constructed and arranged in
any suitable manner, as for example, as as shown in Figs: 7 and 8, which are
respectively a horizontal and vertical section of the valve shown in Figs: 5 and 6,
so as to close the cross exhaust when desired.
The operation of the engine when thus organized is the same, when running
under its ordinary working conditions, as has already been described in connection
with Figs 1 and 2, except as regards the cross-exhaust. When, however it
becomes desirable, for any reason to temporarily increase the capacity of the
engine, the valves 25, 28 will be opened so that the steam will pass directly from
the pipe 16 through the pipes 24, 26 to the exhaust ports 9, of the cylinders 10, 11,
and thence through the pipes 19, 20, to the steam chests 17, 18, thus causing the
steam to be supplied at its full or boiler pressure to both the cylinders 10 11 and
12 13. When this is done the pressure upon both sides of the pistons of the
cylinders 10 11 will of course be the same so that said pistons will always be in
equilibrium and will consequently develope no power, but the increased pressure
upon the larger pistons of the cylinders 12, 13 will very much more than com-
pensate for this and thus have the effect of actually increasing the power of the
engine.
When it.is no longer desired to have the engine develope this extra power, the
valve 25 will be closed thus shutting off the live steam from the pipe 26. If at
any time it is desired to stop the cross-exhaust it is only necessary to close the
valve 28.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The combination with two cylinders arranged to form a compound engine
and provided with a pipe for conducting the steam from the exhaust port of the
first cylinder to the steam chest of the second cylinder, of a pipe arranged to
establish communication between the main steam supply pipe and said conducting
pipe or the exhaust port of said first cylinder, and provided with a cock or valve,
as 25, substantially as described.

page_text: 2. The combination, with two cylinders arranged to form a compound, engine
and provided with a pipe for conducting the steam from the exhaust port of the
first cylinder, to the steam chest of the second cylinder, of a pipe arranged to
establish communication between the steam chest of the first cylinder and said
conducting pipe, and a cock or valve, 25, for closing said communication, sub-
stantially as described.
3. The combination, with two cylinders arranged to form a compound engine
and provided with a pipe for conducting the steam from the exhaust port of the
first cylinder to the steam chest of the second cylinder, of a pipe arranged to
establish communication between the steam-chest of the first cylinder and said
conducting pipe through the exhaust port of said first cylinder, and a cock or
valve 25 for closing said communication substantially as described.
4 The combination, with the two sides of a duplex compound engine and the
cross-exhaust thereof, of connections by which steam, can be admitted directly from
the boiler to said cross-exbaust substantially as described.
5. The combination with the pipe 16 leading from the boiler and the cross
exhaust pipe 26, of the pipe 24, connecting the two, and provided with a valve,
as 25, substantially as described.
6. The combination, with the pipe 16, leading from the boiler and the cross
exhaust pipe, 26, provided with a valve, as 28, of the pipe 24 connecting thic two
and provided with a valve as 25, substantially as described.
Dated this 16th day of December 1884.