Improvements in Accumulators for Direct-acting Engines.
Year: 1891

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by CHARLES CAMPBELL WORTHINGTON, of
Irvington, in the County of Westchester and State of New York, United
States of America, Mechanical Engineer.]
Improvements in Accumulators for Direct-acting Engines.
I HENRY EDWARD NEWTON of the Office for Patents, 6 Bream's Buildings,
Chancery Lane in the County of Middlesex, Patent Agent, 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 :-
This invention relates generally to that class of engines which are provided with
one or more compensating or auxiliary cylinders and pistons, which are supplied
with a suitable motor fluid, and are arranged to act in opposition to the main piston
or pistons during the first part of the stroke of the engine, and in conjunction
therewith during the last part of the stroke, thereby permitting the admission of
the steam to the main cylinder or cylinders to be cut off before the stroke is
completed, without reducing the power of the engine at the end of the stroke.
Forms of such an engine are shown and described in Specifications of Letters
Patent No. 2342 of 1884 granted to Charles Campbell Worthington, & No. 15770
of 1885 and No. 6868 of 1886, granted to the present applicant.
The present invention relates more particularly, however, to an engine of this
general class in which an accumulator is employed for producing the required
pressure upon the piston or pistons of the compensating cylinder or cylinders.
One feature of the invention relates particularly to means for adjusting or
regulating the power of the accumulator to conform to the different running
conditions of the engine. Other features of the invention relate to means for
packing the piston of the accumulator, means for controlling the amount of liquid
interposed between the accumulator and the piston or pistons of the compensating
cylinder or cylinders, means for preventing damage to the engine in case the load
should be suddenly reduced or entirely taken off, and means for preventing damage
to the accumulator, in case, through leakage or otherwise, the 'plunger should
descend violently to the end of its stroke.
As a full understanding of the various improvements constituting the present
invention can only be given by a detailed description of the organization and
operation of an engine embodying the same, all further preliminary description
will be omitted, and a full description given, reference being had to the accom-
panying drawings, in which
Fig. 1 is a side elevation of a compound duplex pumping engine embodying the
present invention, the parts being shown in the position they will occupy when
the pistons of the main steam cylinders are at the ends of their strokes in opposite
directions.
"
Fig. 2 is a sectional elevation taken between the two engines forming the duplex
engine.
Fig. 3 is an end elevation of the engine looking from the right of Figs. 1
and 2.
Fig. 4 is an enlarged sectional elevation of the accumulator.
Fig. 5 is a view showing a continuation of the suction main not shown in Figs. 1
and 2; and
Figs. 6 and 7 are views illustrating modifications which will be hereinafter
explained.
Fig. 8 illustrates an addition that may be employed in connection with the
construction illustrated in Figs. 1 to 5.
Referring to said figures, it is to be understood that, as therein illustrated, the
[P1177

page_text: steam end of the engine, or what may be termed the engine proper, consists of
four steam cylinders A B and CD, which are arranged in pairs, and operate upon
the compound principle, the pair A B forming one side, and pair C D the other
side of the duplex engine.
The pistons of the cylinders A B are connected to the single piston rod 25, and
the pistons of the cylinders CD are connected to the single piston rod 26 in the
same manner. The cylinders A B and C D are provided with the usual steam
chests a banded, having ordinary slide valves, which are provided with balancing
pistons suspended from swinging rods hung in the trunks 75 in the well known
manner. The two valves for cach side of the engine are operated by the same
valve rod, and these rods 23, 24 are provided with the usual connections consisting
of links 22, rock shafts 76, having arins 21, 77, and links 78, by which the valves
of each side of the engine are operated by the other side, in the same manner as
described in the Specification of Letters Patent No. 15770 of 1885 before
referred to.
The steam is admitted to the steam chests a c, and after acting in the
cylinders A, C, is exhausted, and enters the cylinders B, D, where it acts at a
reduced pressure, and after acting in these cylindere, is exhausted into a condenser,
or to the open air. The steam connections are the same as described in the
Specification of Letters Patent last referred to.
The organization thus briefly outlined is common, and will readily understood by
those familiar with this class of engines.
The water end of the engine, or what may be termed the pump proper, consists
of two water cylinders E F, the plungers of which are connected directly to the
piston rods 25 26. The water cylinders are provided with the usual suction and
force chambers, the former communicating with the suction main 100, and the
latter with the force main 101. The force main is also provided with the usual air
chamber 102, placed in any convenient location to equalize the flow of the liquid
discharged from the pump.
The piston rods 25, 26, instead of terminating at the plungers of the water
cylinders, are extended, and pass through the opposite ends of said cylinders, and
are connected to the piston rods of two pairs of oscillating cylinders 40, 50, which
are arranged at the ends of the water cylinders, and are supported upon trunnions,
the same as described in Specification of Letters Patent No. 15770 of 1885. The
connections between the piston rods 25, 26 and the piston rods of the oscillating
cylinders, and the connections with the links 78, and also the connections through
which the motor fluid passes into and out of the oscillating cylinders 40, 50, are the
same as described in said Letters Patent, and need not therefore be herein
particularly referred to. It is to be remarked, however, that the oscillating
cylinders 40, 50, instead of being located at the ends of the water cylinders, may
be located between the steam and water cylinders, as shown with reference to the
Specification of Letters Patent No. 6368 of 1886; or they may be located at the
outer end of the steam cylinders, the piston rods being extended through the steam
cylinders, or, in fact the compensating cylinders may be located in any convenient
position. It is also to be remarked that one compensating cylinder may be employed
for each of the main piston rods, instead of two, and also that the piston or pistons
of the compensating cylinder or cylinders may be arranged to act on the main
piston rod in any of the ways shown in the Specification of Letters Patent before
referred to, or in any other suitable way.
By the employment of the compensating cylinders, it becomes possible to cut off
the admission of steam to the main cylinders before the end of the stroke, without
interfering with the proper operation of the engine, and each side of the engine is
therefore provided with a cut-off mechanism 87, by which the steam is cut off from
the main steam cylinders, when their pistons have arrived at the proper points in
their strokes, after which the stroke is completed by the expansive force of the
steam in the cylinders, aided by the power exerted by the pistons of the com-
pensating cylinders. These cut-off mechanisms are of the form shown with

page_text: reference to Specification of my prior Letters Patent No. 15770 of 1885, and need
not therefore be herein described in detail. It is to be remarked, however, that
any other form of cut-off mechanism may be used if preferred.
The motor fluid which acts upon the pistons of the compensating cylinders may,.
as set forth in Specifications of Letters Patent before referred to, be steam, air, or
other gas, or it may be a liquid, but it has been found most desirable that the fluid
which acts directly upon the pistons of the compensating cylinders should be a
liquid, which is in turn subjected to the pressure of a gas, such as air. It has also
been found that in order to develope the desired amount of power in the compen-
sating cylinders without making them of an inconveniently large size, it is desirable
to employ an accumulator, which is interposed between the compensating cylinders
and the source from which the pressure of their motor fluid is derived. The pipe 37,
therefore, through which the motor fluid passes to and from the compensating
cylinders, communicates with a pipe 79, which is in communication with the chamber
or cylinder 51 of an accumulator, which chamber together with the pipes 79, 37,
and the connections with the compensating cylinders, are filled with water, oil or
other liquid, which also fills the compensating cylinders behind their pistons. The
upper end of the cylinder 51 is provided with an opening through which passes
the smaller end of a differential plunger 52, the larger end 36 of which forms a
piston which works in a cylinder 53, which is located above the cylinder 51, and is
provided, at a point above the piston 36, with a pipe 54, which communicates with
the air chamber 102, and through which air from the chamber 102 passes, so as to
fill the cylinder 53 above the piston, and thus communicate its pressure to the
piston which forms the larger end of the plunger. The accumulator, as thus far
described, is substantially the same as shown with reference to my prior Letters
Patent No. 6368 of 1886. The air for operating upon the plunger of the
accumulator may, of course, be supplied from any other suitable source, as set forth
in the said prior Letters Patent.
The operation of the organization, as thus far described, will be readily understood
without extended description. Assuming the engine to be in operation, and the
normal pressure to exist in the force main 101, the pressure existing in the main
will, through the body of air which fills the chamber 102, pipe 54, and cylinder 53,
be communicated to the larger end of the plunger 52, and thence, through the
smaller end of the plunger and the liquid in the cylinder 51, and its connections to
the compensating cylinders, and thus impart a pressure to the pistons of the com-
pensating cylinders, which will be to the pressure in the main, as the larger end of
the plunger 52 is to its smaller end. As either side of the engine commences its
stroke in either direction, the liquid in the compensating cylinders will be forced
out of these cylinders and back into the cylinder 51, thereby raising the plunger 52
against the pressure in the main, and offering a gradually-decreasing resistance to
the engine, and this will continue until the engine arrives at the middle of its
stroke. During the last half of the stroke, the operation will be reversed. The
liquid will pass from the cylinder 51 back into the compensating cylinders, thereby
allowing the plunger 52 to descend, and thus the pressure in the main, multiplied
by the accumulator, will offer a gradually imcreasing assistance to the engine
during the last part of the stroke.
It sometimes happens, owing to a change in the character or amount of the work
which the engine is to perform, that it is desirable to cause the compensating
cylinders to develope a greater or less amount of power without changing the
relative sizes of the two ends of the plunger 52, or the pressure at the source from
which the pressure upon the larger end of the plunger is derived. It is also
frequently desirable to do this temporarily, to meet the requirements of the conditions
under which the engine may be operating at any particular time, and to meet all
conditions it is desirable to provide means by which the power developed by the
accumulator can be reduced below what is due to the pressure in the force main, as
well as raised above what is due to that pressure.
To meet the first of these requirements, the pipe 54 is provided with a branch 20,

page_text: which communicates with the cylinder 53 below the piston 36, and which has a
cock or valve 19, which can be operated, when desired, so as to allow more or less
air to pass from the pipe 54 to the cylinder 53 beneath the piston 36. By this
means a back pressure can readily be established beneath the piston 36, which will
oppose the direct pressure upon the opposite side of the piston, and thus decrease
the power developed by the accumulator, and by this means, and by properly
manipulating the cock or valve 19, the power developed by the accumulator can be
reduced to any desired extent, to meet any temporary or permanent condition under
which the engine may be required to operate. An ordinary automatic pressure
regulator may be applied to the cock or valve 19, so as to maintain a constant and
unvarying back pressure upon the piston 36. The pipe 20 will preferably be
provided, upon each side of the valve 19, with a pressure gauge 18, from which the
relative pressures above and below the piston 36 can be read.
Fig. 6 illustrates a slightly modified form of apparatus for accomplishing the
same result.
In this case, the opposing pressure, instead of being applied directly to the
piston 36, is applied to one or more supplemental pistons 29, which work in small
cylinders 31 at the sides of the cylinder 51, and are connected to the piston 36 by
rods 32. In this case also the air pressure is not exerted directly upon the pistons 29,
but is communicated to the pistons through a body of liquid contained in_a
chamber 33, which communicates with the cylinders 31, and with the pipe 20. In
this case also, the cock 19 is shown as provided with an ordinary pressure regulator 34,
which acts to control the cock, and maintain a uniform pressure in the chamber_33
and the cylinders 31. The operation of this form of apparatus is the same as that
first described. To meet the opposite requirement, that is to say, to raise the
power developed by the accumulator to a point above that which would be developed
by the unaided pressure in the force main, the cylinder 53 is provided with means
by which, when such an increase of power is required, a partial vacuum can be
created and maintained in the cylinder 53 beneath the piston 36. For this purpose
the cylinder is provided with a pipe 38, which communicates with the suction
main 100 at any suitable point, and this pipe is provided with a cock or valve 17,
by which it can be opened or closed. By this means, it is only necessary, when
the conditions under which the engine is to operate require that the power
developed by the accumulator should be increased, to open the valve 17. As soon
as this is done, the suction upon the main 100 will create a partial vacuum in the
cylinder 53 beneath the piston 36, and thus the suction pressure will act in con-
junction with the force or direct pressure, and increase the power developed in the
accumulator by the pressure in the force main. The quality of the vacuum thus
formed in the cylinder 53 will depend upon the suction in the main 100 at the point
of the connection of the pipe 38, and in order to vary this within reasonably wide
limits, the pipe 38 may be provided (see Figs. 5 and 8) with a number of branches 16,
communicating with the suction main at different heights, and each provided with
a cock or valve 9, by which they can he controlled, so as to effect the connection
between the pipe 38 and the main at any desired height.
It sometimes happens that the level of the water from which the pump draws its
supply, is subject to wide variations, thus bringing the suction main under vacuum
at times, and at other times under pressure, and thus varying the amount of work
to be performed by the engine. In such case, it may be desirable to also connect
the pipe 38 with a chamber or enlargement 41 of the suction main (see Fig. 8),
that will answer as both a vacuum chamber and air chamber. When the level of
the water supply is below the pump valves, this chamber 41 will be under partial
vacuum, and the power of the accumulator be correspondingly increased. When,
however, the water rises above the pump valves, or above the accumulator, this
chamber 41 will be under such pressure as is due to the height of the water above
it, and this will communicate a corresponding. back pressure to the piston 36 of the
accumulator, and reduce the power of the accumulator accordingly. When under
pressure, the chamber 41 should be supplied with air, and this may be done either

page_text: by connecting the chamber with the pipe 20 or 54, so that air can be admitted from
that source, or by any other suitable and convenient means.
In order to prevent the leakage of air past the piston 36, it is desirable to
supply a water packing 35 above said piston, and as it is further desirable that the
body of water thus carried above the piston should not be unnecessarily great, it is
important to provide means by which any surplus of water can readily be drawn
off. For this purpose, the piston is provided with a tube 42, which passes through
a stuffing box in the top of the cylinder, and is provided, at the proper height
above the piston 36, with an opening 2, and at its upper end with a cock or
valve 15.
N
By this means, whenever the body of water 35 rises above the opening 2, it is
only necessary, in order to withdraw such surplus water, to open the cock 15; the
pressure of air above the water will then at once force the water upward through
the tube 42, and this will continue until the surface of the water is below the
opening 2.
The proper amount of liquid in the cylinder 51, pipe 79, and connections, is
maintained in any suitable manner; as, for example, by a small pump operated by
the engine to force in a small amount of liquid to compensate for leakage.
In order to prevent an undue amount of liquid from being forced into the
cylinder 51 and its connections, which would raise the accumulator plunger to an
improper height, the lower end of the plunger is made hollow, and is provided, at
a suitable height, with a series of openings 3. So long as the liquid in the
cylinder 51 and its connections is not increased beyond about the proper volume,
the plunger 52 will remain in such position, that when it is raised, by the forcing of
the liquid, backward into the cylinder 51, by the action of the compensating.
pistons, its openings 3 will not be raised above the stuffing box in the upper end of
the cylinder. If, however, for any reason, an undue volume of liquid is forced into
the cylinder 51, and its connections, the plunger 52 will be raised to such an extent
that as it completes its up stroke, its openings 3 will be carried above the stuffing
box in the upper end of the cylinder 51, so as to communicate with the cylinder 53.
As soon as this takes place, the liquid from the cylinder 51 will pass through the
openings 3, and be discharged into the cylinder 53, thus removing the surplus.
liquid from the cylinder 51, and keeping the plunger 52 in its normal position.
The liquid thus forced out will escape through the pipe 38 into the suction main, or
may be drawn off in any suitable manner.
In operating engines of this class, it is desirable to provide means by which, in
case the load should suddenly be reduced, or entirely taken off, the engine, as by
the breaking of the force main, the engine will be prevented from running at a
violent speed. For this purpose, the connections between the accumulator cylinder
and the compensating cylinders, are so arranged, that the liquid is not permitted
to flow from the cylinder 51 to the compensating cylinders at a greater rate of
speed than is required when the engine is operating at its normal speed: This may
be effected in a variety of ways, two of which are illustrated in the present cusе.
As shown in Figures 1, 2, and 4, the pipe 79 is provided with a check valve 14,
which is arranged to permit the liquid to pass freely from the compensating
cylinders to the cylinder 51, but to prevent its passing in the opposite direction.
The pipe 79 is also provided with a branch or by-pass 27, which passes around the
valve 14, and is provided with a cock or valve 13, which can be adjusted so as to
allow the liquid to pass freely in either direction, but only at such a velocity as to
supply the compensating cylinders when the engine is operating at its normal speed.
By this means, the full power of the accumulator is exerted upon the pistons of the
compensating cylinders, so long as the engine does not move above its normal and
proper speed, but if, for any reason, the speed of the engine is suddenly accelerated,
the pressure upon the compensating cylinders 18 at once greatly reduced, or entirely
removed, because of the inability of the liquid to flow fast enough through the
valve 13, while the water passes freely back from the compensating cylinders to
the accumulator, through the check valve, as the engine is reversed.

page_text: In Figure 7, a modified arrangement of apparatus for accomplishing the same
result is illustrated. In this case, the by-pass 27 is omitted, and the valve 14 is
made to serve the double function of a by-pass and check valve. This valve is
arranged to permit the liquid to pass freely from the compensating cylinders to the
cylinder 51, but tends to close and shut off the communication when the flow of
the liquid is in the other direction. The amount of liquid that is permitted to pass
in this direction may be governed by means of the adjusting spindle 8, that bears
against the under side of the valve 14, and holds it off its seat so that the liquid
can'pass through it. The valve may be provided with a spring 7, which operates
to normally hold the valve against the spindle 8, but will yield to allow the liquid
to flow freely into the cylinder 51. This controls the speed of the engine precisely
as described in the case of the arrangement shown in Fig. 4.
In case of the breaking of the pipe 79, or of any of the connections with the
compensating cylinders, or of the blowing out of the cylinder packing, so as to
suddenly remove the fluid from beneath the accumulator plunger, the plunger will
immediately fall, and strike the bottom with great force, and would be liable, unless
means were provided for preventing it, to cause damage.
To prevent this, the cylinder 53 is provided with a diaphragm or partition 28,
located somewhat below the lowest point which the piston 36 reaches, when the
accumulator is operating in a proper manner, and provided with an opening 12,
somewhat larger than the plunger 52. Just below the piston 36, the plunger 52 is
provided with an enlargement forming a plunger 10, which is of just sufficient size
to fill the opening 12.
So long as the accumulator is operating properly, the plunger 10 remains above
the diaphragm 28, and the spaces above and below the diaphragm 28 are in free
communication; but if, for any reason, the plunger 2 should be suddenly lowered,
the plunger 10 will enter the opening 12, and thereby confine a body of air in
the chamber 44, formed between the diaphragm 28 and the piston 36, which air
will act as a cushion to prevent the plunger from coming into contact with any
metal, or from striking violently so as to cause damage.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The combination with an engine, and its main and compensating cylinders and
their pistons, of an accumulator cylinder through which pressure is transmitted to
the compensating cylinder or cylinders, connections with a source of pressure
whereby the accumulator derives its power from pressure exerted on one side of
its piston, connections with a source of adjustable pressure, whereby adjustable
pressure may be exerted upon the other side of said piston, and means for adjusting
said adjustable pressure to regulate the amount of power developed by said
accumulator, substantially as described.
2. The combination with an engine and its main and compensating cylinders and
their pistons, of an accumulator cylinder through which pressure is transmitted to
the compensating cylinder or cylinders, connections with a source of pressure
whereby the accumulator derives its power from pressure exerted on one side of
its piston, connectious with an elastic fluid pressure-supply, whereby pressure may
be exerted upon the other side of said piston, and means for adjusting said elastic
fluid pressure to regulate the amount of power developed by said accumulator,
substantially as described.
3. The combination with an engine and its main and compensating cylinders and
their pistons, of the accumulator cylinder 53 and piston 36, the pipe 54 forming
a connection between a source of pressure and one side of the accumulator piston,
the pipe 20 forming a communication between an elastic fluid pressure-supply and
the opposite side of said piston, and the cock or valve 19 for controlling the
pipe 20, substantially as described.
4. The combination with an accumulator deriving its power from pressure

page_text: exerted on one side of a piston, of connections with an elastic fluid pressure supply,
whereby pressure may be exerted on the other side of said piston, and means for
adjusting said elastic fluid pressure to regulate the amount of power developed by
said accumulator, substantially as described.
5. The combination with an accumulator deriving its power from pressure
exerted on one side of a piston, of a source of pressure independent of the source
from which the power is derived, and connections whereby pressure may be
exerted upon the other side of said piston, and means for adjusting the latter
pressure to regulate the amount of power developed by said accumulator,
substantially as described.
6. The combination with a pumping engine and its main and compensating
cylinders and their pistons, of the accumulator cylinder and piston, connections
for applying the working pressure to the accumulator piston, and connections with
the suction main for allowing the suction pressure to bo applied to said piston in
conjunction with the working pressure, substantially as described.
7. The combination with a pumping engine and its main and compensating
cylinders and their pistons, of the accumulator cylinder and piston, connections for
applying the working pressure to the accumulator piston, a pipe connecting with
the suction main for allowing the suction pressure to be applied to said piston in
conjunction with the working pressure, and a valve apparatus for controlling the
Buction pressure so applied, substantially as described.
8. The combination with a pumping engine and its main and compensating
cylinders and their pistons, of an accumulator having a power piston, one side of
which is acted upon by pressure from the force main of said engine, and the other
side by pressure from the suction main of said engine, substantially as described.
9. The combination with the accumulator and connections for applying the
direct or working pressure thereto, of the pipe 38 for allowing the suction pressure
in the force main to be applied to the accumulator in conjunction with the direct
pressure, said pipe being provided with branches connected to the suction main at
different points, substantially as described.
10. The combination with the accumulator and the connections for applying the
direct or working pressure thereto, of the pipe 38 communicating with the accu-
mulator and with à chamber connected to the suction main, substantially as
described.
11. The combination with the accumulator cylinder and piston, of the pipe 42
passing through the cylinder head, and provided with the opening 2 and cock 15,
substantially as described.
12. The combination with an engine and its main and compensating cylinders
and their pistons, of connections for supplying the motor fluid to said compensating
cylinder or cylinders, and a check valve controlling said connections, and arranged
to retard the flow of the fluid to said cylinder or cylinders, but to permit the fluid
to flow freely from said cylinder or cylinders, substantially as described.
13. The combination with an engine and its main and compensating cylinders
and their pistons, of connections for supplying the motor fluid to the compensating
cylinder or cylinders, and controlling devices on said connections, retarding the flow
of the motor fluid to said cylinder or cylinders, but permitting the fluid to flow
freely from said cylinder or cylinders, substantially as described.
Dated thin 14th dow of Ll., 1901
NEWTON & SON,
Agents for the Applicant.