IMPROVEMENTS IN DIRECT ACTING DUPLEX ENGINES
Year: 1884

page_text: I CHARLES CAMPBELL WORTHINGTON of the City of New York, County of
New York, State of New York United States of America, Manufacturer, do hereby
declare the nature of my invention for IMPROVEMENTS IN DIRECT ACTING DUPLEX
ENGINES and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
It is well known to those familiar with the science of steam engineering that to
secure the greatest economy in the use of steam it is necessary to allow it to expand
in the cylinder or cylinders of the engine. In using steam upon this principle,
however its propulsive force necessarily decreases towards the end of the stroke,
and this decrease, unless compensated for, results in a spasmodic operation of the
engine.
In locomotive and marine engines the momentum of the load is so great that no
trouble is experienced from this source, while in stationary crank engines this
difficulty has usually been overcome by the use of a heavy fly wheel. When a fly
wheel is employed, the parts are so proportioned that the power exerted by the
steam at the beginning of the stroke, is somewhat greater, and at the end of the
stroke somewhat less, than is required to overcome the load upon the engine,
the fly wheel acting to distribute and equalize the power along the whole stroke,
by storing up the excess at the beginning and giving it off at the end.
In the class of duplex pumping engines, however, to which the present invention
relates, no fly wheel is used, and the moving parts are of necessity so light as to
acquire but little momentum during the stroke. It is therefore necessary in order
to overcome the constant, or nearly constant, load upon the engine, to maintain a
uniform, or nearly uniform, pressure of steam upon the pistons, throughout the
entire stroke of the engine. This being the case it has been found impracticable in
such engines, as heretofore constructed, to utilize the expansive energy of the steam
any considerable extent, except by the use of compound cylinders.
to
It is the object of the present invention to provide means by which the steam
may be used expansively in the cylinders of a direct acting duplex pumping engine,
with an even distribution of power throughout the entire stroke, and without
necessarily using compound cylinders. To that end the invention consists in the
combination with a duplex pumping engine, provided with means whereby the
inlet and exhaust valve or valves of one side thereof is or are operated by the other
side, of means whereby power is stored up at one period and utilized at another
period of the stroke of each side of said engine, without preventing the variable

page_text: }
pause at the end of each stroke peculiar to this engine, substantially as hereinafter
described.
Also in the combination with the main cylinders and pistons forming the two
sides of a duplex pumping engine, provided with means by which each actuates the
inlet and exhaust valve or valves of the other of a compensating cylinder or
cylinders at each side of said engine, each provided with a piston and rod and
supplied with a suitable motor fluid, and acting in opposition to the main cylinders
and pistons to which they are connected, during the first part of the stroke of said
main pistons, and in conjunction therewith during the last part of their stroke.
Also in other combinations and arrangements of parts and details of construction
all of which will be hereinafter fully described and claimed.
In the accompanying drawings:
Figure 1, is a plan view, figure 2, a longitudinal vertical section, and figure 3, an
end elevation of a duplex pumping engine embodying the invention.
Figures 4 and 5 are views showing the position of the compensating cylinders at
the beginning and at the end of the stroke.
Figures 6 to 14 inclusive, are views illustrating different ways of applying the
invention.
Figure 15 is a sectional view of one of the compensating cylinders showing also a
cushioning apparatus.
Figure 16 is an elevation partly in section of an apparatus for regulating the
pressure of the fluid in the compensating cylinder or cylinders.
Figures 17 and 18 are sectional details of the cut off apparatus.
Referring particularly to figures 1 and 2 it is to be understood that the pumping
engine here shown has two steam cylinders 11, 12, and two water cylinders 13, 14,
and is provided with means whereby the piston rod of each side of the engine
operates the inlet and exhaust valves, or valves of the other, in substantially the
same manner as is set forth in United States Letters Patent No 24,838 granted to
Henry R. Worthington, July 19th, 1859. As here shown the cylinders 11 and 12
are arranged to operate in connection with a tank in substantially the same manner
as described in the United States Letters Patent N° 116,131, the steam being
received from the generator through the pipe 7, and after acting in the cylinder 12,
passing out through the pipe 8, to the tank, (not shown) from which it enters the
cylinder 11, through the pipe 9, where it acts at a reduced pressure, after: which it
is exhausted through the pipe 10, into the condenser or the open air.
Each of the said cylinders 11, 12, may, however, receive its steam directly from
the boiler, and exhaust it directly into the condenser or the open air, said cylinders
in such case, being of substantially the same size.
As shown in figures 1 and 2 of the drawings, the piston rods 15, 16, are arranged
in the usual manner to connect the steam pistons with the pistons or plungers of
the pumps, and are provided with the usual connections for operating the inlet and
outlet valves of the steam cylinders. The rods 15, 16, instead of terminating inside
the water-cylinders, pass through suitable stuffing boxes in the opposite ends of said
cylinders, and are each connected to the piston rods of a pair of oscillating cylinders 18,
which are arranged in any convenient position, and provided with connections for
receiving a supply of steam from the generator.
As herein shown these cylinders are provided with trunnions 19, having bearing
in a suitable framework 20, which is connected to the ends of the water cylinders
by suitable tie rods 21, and are supplied with steam through pipes 22, 23, commu-
nicating with ducts 24, in one of said trunnions, as shown in figure 15. They
may, however, be supported and supplied in any other manner which may be found
more convenient or desirable.
For the sake of clearness the operation of one side of the duplex pumping engine
will be first described.
Assuming the piston 25, of the cylinder 11, to be in position to commence its
stroke, and its cylinders 18, in the position shown in figure 4, the operation will
be as follows: The inlet valve of the cylinder 11, will at this point be in its opened

page_text: position, and steam will be admitted to the cylinder under sufficient pressure to
overcome not only the load upon the engine, but also the resistance offered by the
pressure of the steam against the pistons of the cylinders 18, the rods 26, of which
are at that time, as will be seen by reference to figure 4, in such position as to act
against the rod 15. As the piston 25, advances, the resistance offered by the
steam in the cylinders 18, will, owing to the constant change in the angle of the
rods 26, gradually decrease until the parts arrive at the position shown in figure 2;
at which time the rods 26, will act directly against each other and offer no resistance
to the rod 15. During the remainder of the stroke.the operation of the cylinders 18
is reversed. Instead of acting in opposition to, they act in conjunction with, the
piston 25, and add a constantly increasing power to the engine until the end of the
stroke is reached, at which time they will be in the position shown in figure 5.
At the end of the stroke the valve, 47, will be reversed so as to admit steam upon
the opposite side of the piston 25 and start it upon its return stroke. During the
return stroke the operation of the cylinders 18 will be reversed Starting from
the position shown in figure 5, the rods 26 will act in opposition to the rod 15,
during the first half of the stroke, and then in conjunction with said rod, until
they arrive at their original position as shown in figure 4.
From the foregoing it will be seen that during the first half of the stroke of this
side of the engine, only a part of its power is available for performing the work to
be done, the remainder being stored up in the cylinders 18, during the first half
but that during the last half of the stroke the whole power of the engine is
available for work, and in addition thereto the power stored up in the cylinders 18,
during the first half. This being the case it is apparent that if the steam in the
cylinder 11, is maintained at its initial pressure during the entire stroke, the
available power of the engine will be much greater at the end than at the beginning
of the stroke; and this fact makes it possible to use the steam expansively in the
cylinder 11, and yet obtain a practically uniform propulsive power throughout the
entire stroke.
The cylinder 11, is therefore provided with suitable cut-off apparatus, by which,
after the piston of said cylinder has advanced a certain distance, (say one-half or
somewhat more or less than one-half the stroke) the further ingress of steam is
arrested, the remainde of the stroke being accomplished by the expansive force of
the steam already in the cylinder, and the force exerted by the compensating
cylinders, the gradual decrease of power due to the expansion of the steam in the
one, being compensated for by the gradual increase of power in the other..
As the piston 25, arrives at the end of its stroke, its rod 15 will operate the
induction valve of the cylinder 12, so as to start the opposite side of the engine,
which side will then make a stroke, its compensating cylinders operating in the
manner just described. This stroke will in turn reverse the valve of the cylinder 11,
so as to admit steam upon the opposite side of its piston, and so the operation will
continue to be repeated. The valves of one side of the engine being operated by
the piston rod of the other side, as is described in said Letters Patent N° 24838,
the same results due to the pausing of the pistons at the end of the stroke is
attained as described therein.
One form of valve and cut-off mechanism is shown in the drawings in Figures 17
and 18 for the purpose of cutting off the steam at the proper point in the main
cylinders. In this form, 48 are the steam admission ducts which are provided
with bushings, the plugs 57 of which extend through the sides of the steam chests
and are provided with arms 56 which are connected by rods 55 with the valve
operating levers 54. The parts are so adjusted that as each piston of the main
cylinders arrives at the point where it is desired to cut off the further admission
of steam, the plug 57 will be turned so that the solid parts 58 will close the
ports 59. The parts 58 are made of such width that although the plug will continue
to turn during the remainder of the stroke, the ports 59 will not be uncovered..
As the piston commences its return stroke the movement of the plug 57 will be
reversed, so that at the end of the stroke, the ports 59 will be uncovered. The.

page_text: relative position of the parts, 58, of the plugs at the opposite sides of the cylinders
will of course be such, that when one set of ports, 59, are open; the other will be
closed at the beginning of any stroke.
The arms 56 are slotted as shewn in Figure 17, so that the point of attachment
of the rods 55, may be varied, thereby affording means for changing the point of
cut-off when desired, the rods 55 being jointed to permit this. The point of
attachment of the rods 55, to the levers 54 can also be adjusted if desired.
The cut-off apparatus just described is shown merely as an example, as it is
apparent that any known form of mechanism for this purpose may be employed,
if preferred.
By the employment of compensating cylinders, as just described, all the
advantages due to the use of steam expansively, are attained, and without the
employment of a fly-wheel or other heavy moving attachment, or the use of
compound cylinders.
In the present case the compensating cylinders are located at the ends of the
water cylinders simply for the sake of convenience in illustrating the application
of the invention. It will readily be understood that these cylinders may be located
at any other convenient point, to act either upon the piston rods or other moving
part of the engine. If found more convenient they may be located between the
steam and water cylinders, or the piston rods may extend through the opposite
ends of the steam cylinders, and connect with the rods 26, at that point.
It is manifest that the means by which the rods 26 of the compensating cylinders
are connected or made to act upon the moving part of the engine may be varied
greatly from that already described, without departing from the principle of the
invention.
In figures 6 to 14 inclusive several such modified forms of connecting devices
are illustrated.
In the construction shown in figure 6, the rods 26, instead of being connected
directly to the piston rods of the engine, are attached to crank pins projecting
from the faces of the segmental gears, 31, which gears engage with racks, 32, formed
upon the extending ends of the piston rods. It is apparent that the operation of
the compensating cylinders will be the same in this organisation as in that already
described.
Figure 7 illustrates a form of connection, by which the compensating cylinders
receive little or no oscillating movement. To effect this the rods 26, are connected
to the piston rods, by means of links 27, the point of juncture between said rods
and links being connected to the water cylinders or some other fixed part by
pivotted tie rods 28. It will readily be seen that the effect of this arrangement
is the same as of that already described, except that the compensating cylinders
remain practically stationary.
Figure 8 illustrates another form of connections effecting substantially the same
result. In this case the links 27 are omitted, and the pivotted tie rods 28, are
provided with rollers, 34, which ride upon the opposite inclined sides of cams 33,
secured to the piston rods of the engine. The rods 26, are also provided with
joints, 35, by which the compensating cylinders are permitted to remain perfectly
stationary. The operation of this construction is substantially the same as already
set forth. During the first half of the stroke the rods 26 act against the diverging
edges of the cams 33, and resist the advancement of the piston rods of the engine;
while during the last half of the stroke they act against the converging edges of
said cams and assist the advancement of said rods.
In the organisation shown in both figures 7 and 8, the rods 28, may if preferred,
be omitted and the ends of the rods 26, made to slide in bearings similar to that
shown in figure 12.
It is also apparent that instead of two, three or more of the compensating
cylinders may be employed, upon each side of the engine, or if preferred the
number may be reduced to one. In figure 9 one form of connections for the latter
purpose is shown. In this case each rod 26, is connected to the piston rod of the

page_text: engine, by a link 29, the joint between said link and the rod 26, being supported
by an oscillating arm 30. The link 29, and arm 30, may be dispensed with, the
rod 26, being connected directly to the piston rod and a stationary bearing
provided, upon which the joint can slide back and forth. The arrangement shown
is however, preferable, in that it produces less friction.
In figures 10 and 11 organisations are shown, in which the rod 26 instead of
acting directly upon the piston rod of the engine, acts upon a lever 36, attached to
said rod. In these figures also the compensating cylinder is shown as located
between the steam and water cylinders In figure 10, the lever 36, is of the first
order and of bell-crank form, while in Figure 11, it is of the second order. It is
apparent, however, that the form of the lever and its mode of attachment may be
greatly varied, and also that more than one compensating cylinder may be
connected to each piston rod, in this manner, if desired.
In figures 12, 13 and 14 organizations are shown in which both the compensating.
cylinder and its piston have a reciprocating motion. To effect this each piston rod of
the engine is provided with links, 27, one of which is attached to the piston rod 26,
while the other is attached to the ends of a pair of rods 37, secured to the end of the
compensating cylinder, in substantially the manner shown in figure 14; the opposite
end of said cylinder being provided with a tubular projection, 39, which extends
through a stuffing box and reciprocates in the end of the supply pipe 23. The
rods 26 and 37, may be provided with sliding bearings 38, which move in suitable
guide ways 40, as shown in figure 12; or they may be connected to the end of the
water cylinder, or other stationary part by pivotted tie rods 28, as shown in
figure 13. In these organisations during the first half of the stroke the compensating
cylinder will be raised while its piston will be lowered, thereby doubling the
resistance of said cylinder; and during the last half of the stroke the piston will
be raised, while the cylinder is lowered, thus permitting the pressure of the steam
in both directions to be exerted upon the piston rod of the engine.
Many other forms of connecting apparatus can readily be suggested by any
person familiar with the art, but those shown and described are deemed sufficient
to carry out the invention.
It will be observed that the steam is admitted upon only one side of the pistons
of the compensating cylinders, and that this admission is uninterrupted, it being
allowed to flow freely in and out of said cylinders as the pistons move back and
forth. It is found desirable, however, to provide means by which the pressure
in the compensating cylinders can be controlled, and also by which it can be
maintained in a uniform condition no matter what may be the pressure in the
boiler or other source from which it is obtained. To effect this the pipe 22, is
provided at some convenient point with a tank 41 (see figure 16) of such size that
the withdrawal of sufficient steam to fill the compensating cylinders will not
materially reduce the pressure of the steam therein. This tank is provided with a
small opening 42, communicating with an ordinary diaphragm regulator 43, the
lever, 44, of which controls an ordinary throttle valve, 45, located in the pipe 22,
between the tank and source of supply. The weight 46, being adjusted to the
proper position, the steam will flow into the tank until the desired pressure is
reached, when the diaphragm will rise and cause the lever to close the throttle and
stop the admission. When by reason of condensation and waste the pressure in
the tank falls below the desired point, the diaphragm will fall, thereby opening
the throttle and admitting steam, until the proper pressure is restored.
The regulating devices used in connection with the tank may be varied widely
from those shown and described without departing from this part of my invention.
Among other devices that may be employed is a piston in place of the diaphragm,
or any of the well known pressure regulating valves in place of the diaphragm
and throttle valves.
Although it will usually be found most desirable te employ steam as the
resisting inedium in the compensating cylinders, and to supply this from the main
generator through connections substantially as herein shown, yet this is not

page_text: necessary. Compressed air or other gas may be employed in these cylinders, and
it may be supplied in any convenient manner. Water or other liquid fluid may,
if preferred, be employed, it being introduced into the cylinders under a sufficient
head to supply the desired. pressure.
The compensating cylinders may be provided with draincocks, as 4, (see
figure 15) located at any convenient point upon the cylinders, by which any water
resulting from condensation can be withdrawn.
The ends of these cylinders through which the rods 26 pass may be provided
with stuffing boxes as shown, or with elongated metal sleeves, to form a tight
joint around the rods, and this end of the cylinder or cylinders may be utilized to
form a cushioning and governing apparatus for the engine.
To effect this the head of each cylinder will be provided with an orifice, as 5,
(see figure 15) of considerable size, controlled by an inwardly opening valve 2, and
a second orifice, as 3, controlled by a cock 6.
As the piston passes to the opposite end of the cylinder, the atmospheric air
will pass freely through the orifice 5, and fill the space behind the piston. As soon
as the piston commences to recede, the valve 2 will close, and the air in the
cylinder will be forced to pass out through the opening in the cock 6. By opening
the cock to the proper extent, the air may be permitted to escape sufficiently fast,
to not interfere with the piston, when the engine is running at its normal speed.
If, however, the speed of the engine is suddenly accelerated by reason of accident,
or any sudden change in the condition of running, the confined air in the cylinder
will act as a cushion and prevent damage.
.
The cock for controlling the escape of the air may be controlled automatically by
any convenient governing device. Instead of the device shown and described for
controlling the inlet and outlet of the air any other convenient devices may be
employed for this purpose.
The cock 6, can also be adjusted so as to act as a partial governor to the engine
by increasing the resistance as the speed increases and vice versa.
If found more
desirable in any case to use some other resisting medium instead of air it may be
done without departing from the principle of, or losing the advantages of, the
invention.
When it is desired to obtain a very high ratio of expansion, compound cylinders
may be employed, and these cylinders may be arranged to operate in connection
with a tank as herein shown, or in any of the other well known ways.
Although for convenience in describing and illustrating the invention it is herein
shown as applied to a duplex engine for pumping water, it is equally useful in
duplex engines designed for pumping and compressing air.
In the case of an ordinary direct acting engine, a fly wheel or any other con-
trivance for storing up and imparting energy through the momentum of moving
masses, would enable it to perform the same service and to obtain equally good
results as it could accomplish by the aid of the compensating cylinders. The
compensating cylinders would, however, alter the character of its motion somewhat,
in so far as the increased momentum of their added weight would embarrass and
interrupt it. The tendency of this weight would be to oppose the sudden and
harsh reciprocation of the stroke, inherent in this type of engine, and this would
be found straining to the machine, and a serious difficulty, especially at high
speeds. With such direct acting engines an important desideratum is that the
weight of the moving parts should be reduced to a minimum to enable this sudden
stopping and starting of the strokes to be effected with the least possible wrenching
and distortion of the machine.
In the case of the duplex pumping engine described, its one peculiar feature is
the variable.and adjustable pause which its valve motion permits at the end of
each stroke: The effect of this pause, when dealing with the pumping of fluids, is
well known in the art, to be of great practical value. The combination with such
an engine of a fly wheel, or any other contrivance known before this invention, in
which the momentum of moving masses is employed for the purpose of enabling

page_text: it to run under higher ratios of expansion and consequent economy, would rob it
entirely of this distinctive and valuable characteristic, because only a determinate
and instantaneous pause at the end of the stroke would then be possible. This
fact has hitherto prevented the highest rate of economy being attained by this type
of engine.
By combining with it the compensating cylinders as described a result, hereto-
fore considered impossible with it, is accomplished, viz:-Not only does it realize
as high ratios of expansion as are possible with any fly wheel type, but the variable
and adjustable pause at the end of the stroke is retained.
The duplex pumping engine thus becomes capable of attaining the highest
economic results without the quality of its motion being effected in the least, or its
well known smooth and quiet action sacrificed.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination with a duplex pumping engine provided with means whereby
the inlet and exhaust valve or valves of one side thereof is or are operated by the
other side, of means substantially as described whereby power is stored up at one
and utilized at another period of the stroke of each side of said engine, without
preventing the variable pause at the end of each stroke peculiar to this engine.
2. The combination with the main cylinders and pistons forming the two
sides of a duplex pumping engine provided with means whereby the inlet and
exhaust valve or valves of one side thereof is or are operated by the other side, of
a compensating cylinder or cylinders at each side of said engine each provided
with a piston and rod and supplied with a suitable motor fluid and acting in
opposition to the main cylinders and pistons to which they are connected, during
the first part of the stroke of said main pistons, and in conjunction therewith
during the last part of their stroke, substantially as described.
3. The combination with the main cylinders and pistons forming the two sides
of a duplex pumping engine, provided with means whereby the inlet and exhaust
valve or valves of one side thereof is or are operated by the other side, of a
compensating cylinder or cylinders at each side of said engine, each provided with
a piston and rod and supplied with a suitable motor fluid, and acting in opposition
to the main cylinders and pistons to which they are connected during the first part
of the stroke of said main pistons, and in conjunction therewith during the last
part of their stroke, and a cut off mechanism substantially as described.
4. The combination with a main cylinder and piston, of one or more compensating
cylinders and pistons, and means for regulating the pressure of the fluid admitted
to said compensating cylinder or cylinders substantially as described.
5. The combination with a main cylinder and piston, of one or more com-
pensating cylinders and pistons, a tank 4, means for regulating the pressure of the
fluid in said tank, and connections, substantially as described.
6. The combination with a cylinder 18, provided with a piston and means for
maintaining a constant pressure upon one side of said piston, of means for per-
mitting the ingress and egress of a fluid from the opposite side of said piston,
in such manner as to cushion said piston when it exceeds its normal speed,
substantially as described.
Dated this 90th day of Januar 1001