Improvements in Direct-acting Duplex Engines.
Year: 1889

page_text: Date of Application, 18th Apr.. 1889
Specification Accepted, 18th May, 1889
[Communicated from abroad by HARLES CAMPBELL WORTHINGTON, OF
in the State of New York, United States of America, Engineer.]
Improvements in Direct-acting Duplex Engines.
I HENRY EDWARD NEWTON of the Office for Patents, 6 Breams Buildings, Chancery
Lane in the County of Middlesex Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This Invention relates to that class of engines known as "Direct-Acting Duplex
Engines," certain features of the invention being especially applicable to those engines
of this class having one or more compensating-cylinders and pistons for each side of
the engine, which act in opposition to the main piston or pistens during the first part
of the stroke and in conjunction therewith during the last part of the stoke, thus
permitting the steam to the main cylinder or cylinders to be cut off after the engine
has made part of its stroke. Examples of engines of this class are shown in. Letters
Patent No. 2342 of 1884; granted to C. C. Worthington and in Nos. 16858 of 1884;
15770 of 1885; and 6368 of 1886; heretofore granted to mo as communications from
the said C. C. Worthington.
The present invention includes certain improvements in the valve apparatus by
which the steam is admitted to and exhausted from the main cylinder or cylinders;
also certain improvements in the cut-off apparatus; also certain improvements in the
valve gear, by which the cut-off and the induction and exhaust-valves are operated,
and also in certain combinations of parts, all of which will be hereinafter explained
and particularly pointed out in the claims."
As a full understanding of the improvements constituting the invention can best be
given by an illustration and a somewhat detailed description of an engine embodying
the same, all further preliminary description will be omitted and a full description
given, reference being had to the accompanying drawings, in which-
Figure 1 is a plan view of a compound, direct-acting, duplex pumping-engine
embodying the invention.
Figure 2 illustrates a detail which will be hereinafter referred to.

page_text: Figure 3 is an end elevation of the engine, looking from the right of Figure 1.
Figure 4 is a side elevation of the engine.
Figure 5 is a side elevation of one half of the duplex engine, looking from between
the two engines, and showing particularly the valve gear for operating the induction
and exhaust valves.
In these Figures the two engines forming the duplex engine are both shown as at
the middle of their strokes, which position has been selected for the purpose of
illustration, although the engines will not assume this position in actual operation..
Figure 6 is an enlarged vertical-section of one of the main steam-cylinders and its
cut-off and induction and exhaust-valves.
Figure 7 is a cross-section taken on the line 7 of Figure 6.
Figure 8 is an enlarged section taken on the line 8 of Figure 7.
Figures 9, 10 and 11 are diagrams showing the valves in different positions.
Referring to said drawings it is to be understood that the steam end of this form of
compound duplex-engine consists of four steam cylinders, A, B and C, D, which are
arranged in pairs, the cylinders, A, C, being the high-pressure and the cylinders, B, D,
being the low-pressure cylinders of the respective sides of the engine. The steam is
admitted to the cylinders, A, C, through induction-pipes, 13, and after performing its
work in these cylinders is exhausted through exhaust-pipes, 10, and passes into
tanks, 12, from which it passes through induction-pipes, 14, (Figs. 4 and 5) to the
cylinders, B, D, and after acting at a reduced pressure in these cylinders it is
exhausted through exhaust-pipes, 15, and passes to a condenser or to the open air.
The water end of the engine or pump proper is composed of two water-
cylinders, E, F, having plungers which are connected directly with the piston-
rods, 16, 17 of the two sides of the engine. The two water-cylinders are provided
with the usual suction-chambers, a, which communicate with the suction-main, G, and
with force-chambers, b, which communicate with the force-main, H, in the usual
manner. The piston-rods, 16, 17 of the two sides of the engine are extended through
and beyond the water-cylinders and are connected to cross-heads, 18, (see Figure 3),
which slide in guides, 19, and are acted upon by the piston-rods of two pairs of
oscillating compensating-cylinders, c, having pistons which act in opposition to the
main piston-rods, 16, 17, during the first part of the stroke of the engines and in
conjunction therewith during the last part of the stroke. The arrangement of the
compensating-cylinders is substantially the same as shown in the letters patent, before
referred to, and need not therefore be herein further described. The compensating-
cylinders are supplied with a suitable motor fluid in any of the ways described in the
letters patent before referred to.
The induction and exhaust and cut-off valve apparatus for each of the four steam-
cylinders, A, B, C, D, are, as shown in the present case, exact duplicates, and a
description of the apparatus of one cylinder will therefore apply to all. It is to be
remarked, however, that in some cases the double ports, by means of which the steam
is confined so as to cushion the piston, may be omitted from two of the cylinders,
either the high or low-pressure, as may be preferred.
Each of the cylinders is provided at its opposite ends with indnction-ports, 9, and
exhaust-ports, 8 (Fig. 6). The exhaust-ports are located somewhat nearer the middle
of the cylinder than the induction-ports, as is common in this class of engines in order
to allow them to be covered by the piston as it approaches the end of its stroke in each
direction and thus confine a quantity of steam in the end of the cylinder to act as a
cushion or dash for the piston.
The induction and exhaust-ports at the opposite ends of the cylinder are controlled
by a pair of oscillating induction and exhaust-valves, f, g, which are located in cavities
formed in valve-chests, h, located at the opposite ends of the cylinder. The cavities
in the valve-chests in which the induction and exhaust-valves are located are provided
with exhaust-ports, 7, which communicate with the exhaust-pipes, 10 or 15, as the
case may be.
Located in the valve-chests, h, above the induction and exhaust-valves. g, f, are
cavities, 20, which communicate with the induction-pipes, 13 or 14, as the case may

page_text: be, and also with the cavities in which the induction and exhaust valves are located by
means of one or more ports, 6. The port or ports, 6, are controlled by oscillating
cut-off valves, k, m, located in the cavities, 20, of the valve-chests at the opposite ends
of the cylinder.
In order to secure the quick opening and closing of the port or ports, 6, which is
desirable to effect a quick cut-off, there will preferably be provided a plurality of
these ports, and the valves, k, m, will preferably be made of grid-iron form, as shown
in the present case.
The induction and exhaust-valves, f, g, are provided with cavities, 4, which are of
such extent that when the respective valves have reached the limit of their movement
in one direction, the ports, 7, 8, will be brought into communication and the exhaust
be fully open. The valves are also provided with cavities, 5, which are of such extent
that when the respective valves have reached the extent of their movement in the
reverse direction, the ports, 6, 9, will he brought into communication and the induction
be fully opened.
The working-faces, i, of the induction and exhaust-valves are of such extent and the
induction and exhaust-ports, 8, 9, are so positioned, and the valves, f, and g, are so
connected that they have no lap or lead; that is to say, the faces, i, are of such extent
that when the valves are in their central position they no more than cover both the
induction and exhaust-ports, 8, 9 at either end of the cylinder so that any movement
in either direction from this position will at once commence to open one or the other
of the ports, depending upon the direction in which the valves are moved. This is an
important feature in this class of engines, as by reason of this construction it becomes
impossible to stop the engine in such position that both the induction and exhaust-
ports will be absolutely closed and thus the valves are always in position to admit
steam to one end or the other of the cylinder and exhaust it from the opposite end so
It it were
as to start the engine whenever steam is admitted to the valve-chests.
otherwise that is to say, if the valves were constructed or connected so as to have
either lap or lead, the engine might be stopped in such position that it would require
some appreciable movement of the valves to open one or the other of the ports, and if
this were the case and the engine were stopped with the valves in such position, it
would be impossible, in this class of engines, to start the engine without bringing into
play some outside force or re-adjusting the parts.
The valve-chests, h, are cast separate from each other and from the cylinder so as
to be readily and separately removable, and the chests and valves for the opposite ends
of the cylinder are exact duplicates, which is a feature of importance as it secures
economy in the manufacture of the engine and facilitates the renewal of worn-out or
damaged parts. These valves and chests, are, however, as will be observed,
reversely arranged so that the two valves oscillate in the same direction at the same
time.
The making of the valve-chests in this manner and the locating of them at the ends
of the cylinder also secures another important advantage in that it permits the steam
jackets, n, (see Fig. 6), to extend entirely around the cylinders between the valve-
chests and thus secures more effective jacketing and reduces condensation.
For the purpose of operating the valves, f, g, each of the valves is provided with a
stem, 21, (see Figure 7), which passes through a stuffing-box in the side of the valve
chests and extends inward toward the opposite side of the duplex engine. Each of the
stems 21 is provided with a crank-arm, 22. The crank-arms of the valves of each
cylinder are connected by a link 23, and the crank-arms of the adjacent valves of the
two cylinders are connected by a similar link, 24, these links being so arranged that
all of the valves oscillate in the same direction at the same time, as shown in
Figure 5.
The valves of each side of the engine are operated from the opposite side of the
engine the same as is usual in duplex engines, and for this purpose the connections
are arranged as follows: The crank-arm 22 of the valve of each side of the engine
which is nearest the water cylinders is connected by a rod 25 with a stud 26 (see
Figure 2) projecting from a rock-arm 27 which is connected by a rod 28 with an

page_text: Rnd extending from the cross-head 18 of the opposite side of
the engine.
The cut-off valves, k, m, are provided with stems 30 (Fig. 7) which project
outward and are provided with crank-arms 31 which are connected to a pair of
T-shaped levers 32 (Figs. 1 and 4) which are connected to each other by a link, 33 and
operate the cut-off valves in substantially the same manner as described in the
Letters Patent No. 15,770 of 1885.
The cut-off valves for each side of the engine instead of being operated directly
from the piston-rod of that side of the engine, as shown in the Letters Patent before
referred to, are preferably operated through a rod, 34, which is connected to a rock-
arm 35 which in turn is connected by a rod 36 to an arm, 37 extending outward
from the cross-head 18 of that side of the engine (Figs. 1 and 4).
By reason of this form of valve gear the strain upon one side of the cross-head 18
of each side of the engine produced in operating the induction and exhaust valves of
the opposite side of the engine is nearly or quite balanced by the strain upon its
opposite side produced in operating the cut-off valves, and thus all tendency to
skew the cross-heads out of proper position by reason of unequal strain is obviated.
In engines of this class it frequently happens, owing to changes in speed or in
the effectiveness of the condenser, that the cushioning effect of the steam confined
in the end of the cylinder by the covering of the exhaust-port by the piston is not
as uniform as is desirable; that is to say, if the steam confined in the end of the
cylinder when the exhaust is covered by the piston is sufficient to produce the
necessary dash when the condenser is working at its maximum effectiveness, or the
engine is running at quick speed, the dash produced when the condenser is less
effective or the engine running at slower speed will be too great and the stroke of the
engine will consequently be shortened. To obviate this it is desirable to provide
means by which, under such conditions, a portion of the steam confined in the end of
the cylinder can be allowed to escape to compensate for these variations in the
condenser or speed of the engine, and to properly regulate the stroke.
For this purpose the induction and exhaust-ports 8, 9 are provided with branch
ports, 2, 3, (Figs. 7 and 8) which communicate with a small chamber 38 located at
the side of the valve-chest. The chamber 38 is provided with a valve 39 having a
threaded stem 40 by which it can be adjusted so as to entirely close the ports, 2, 3,
and thus cut off communication between the ports, 7, 8, or can be adjusted to open
the ports, 2, 3, to any desired extent and thus allow any desired portion of the steam
confined in the end of the cylinder after the exhaust port is closed by the piston
to pass through the induction port 9 and ports 2, 3 to the exhaust-port, 8, and thus
reduce the cushioning effect of the confined steam to any desired extent.
The operation of the engine thus organized is as follows:
In describing the operation of the engine it will be assumed that the pistons I of
the cylinders A, B, have just completed their stroke away from the water-cylinders
and have come to rest at the end of their stroke, as shown in Figures, 6, 9 and 10.
When the pistons I arrive in this position the valves f, g, will be in the position
shown in Figure 6. As the pistons of these cylinders arrive in this position they will,
through the piston-rod 16 and the connections which have been described, complete
the movement of the induction and exhaust-valves of the cylinders, C, D, to the same
position so as to start the pistons of those cylinders and cause them to make a stroke
in the same direction, and as the pistons of the cylinders C, D, make their stroke in
this direction they will, through the piston-rod 17 and the connections which have
been described, oscillate the valves f, g, of the cylinders A, B and as they arrive at or
near the middle of their stroke the valves f, g, of the cylinders A, B will arrive in
their mid position, as shown in Figure 9, in which position they will close, but not
more than close, the induction and exhaust-ports, 8, 9. But the valves f, g, being so
constructed and connected as to have no lap or lead, will as soon as they close the
exhaust-port at one end of the cylinder and the induction-port at the other end of the
cylinder, commence to open the induction-port at the first end of the cylinder and
the exhaust-port at the other end, and as the pistons of the cylinder C, D, complete

page_text: their stroke the valves f, g, will arrive in the position shown in Figure 10 so as to
completely open the induction ports 9 in front of the pistons I and the exhaust ports 8
behind them. The pistons I of the cylinders A, B, will then commence and make
their return stroke and as they arrive at the middle or about the middle of their stroke
they will, through the connections which have been described, operate the cut-off
valves, k, m, so as to close the ports 6, as shown in Figure 11, and cut off the further
admission of live steam in front of the piston and at the same time open the ports 6,
at the opposite end of the cylinder to permit the admission of live steam for the next
stroke, and so the operation will be repeated.
If at any time it is not desired to use the steam expansively all that is necessary is
to disconnect the rod 34 or 36 or disconnect the levers 32 from the cut-off
valves and turn the cut-off valves to such position as to leave the ports 6, permanently
open. The steam will then be admitted to the main steam cylinders during the entire
stroke of the pistons.
From this it will be seen that the construction which has been described is one by
which steam can be used expansively or not at pleasure without any material change
in the organization of the engine.
The improvements constituting the present invention are herein shown as applied to
a compound engine but it is to be understood that such an engine has been selected
merely for the purpose of illustration, as the improvements are equally applicable to
those engines which do not employ compound cylinders.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondeut I declare that what I clain is :-
:—
1. The combination with a steam-cylinder and piston, of separate induction and
exhaust-ports for each end of the cylinder, and two oscillating valves, (one for
controlling the induction and exhaust of the steam to and from each end of the
cylinder), said valves moving synchronously and being so timed and connected that
the opening of the exhaust-port at one end of the cylinder commences immediately
upon the closing of the exhaust-port at the other end of the cylinder, substantially as
described.
2. The combination with a steam-cylinder and piston, of separate induction and
exhaust-ports for each end of the cylinder, and two oscillating valves, (one for
controlling the induction and exhaust of the steam to and from each end of the ..
cylinder), said valves moving synchronously and being so timed and connected that
the opening of the induction-port at one end of the cylinder commences immediately
upon the closing of the induction-port at the other end of the cylinder, substantially
as described.
3. The combination with a steam cylinder and piston, of separate induction and
exhaust-ports for each end of the cylinder, and two oscillating valves, (one for
controlling the induction and exhaust of steam to and from each end of the cylinder),
said valves moving synchronously and being so timed and connected that the exhaust-
port for one end of the cylinder and the induction-port for the other end of the
cylinder are opened simultaneously, substantially as described.
4. The combination with the steam cylinders and pistons of a duplex engine, of an
oscillating valve, for controlling the induction and exhaust of the steam to and from each
end of the cylinders of the two sides of the engine, rods 23 connecting with two valves
of each cylinder so as to cause them to move synchronously and in the same direction
and without lost motion, and connections between one of the valves of each side
of the engine and the piston-rod of the other side of the engine, substantially as
described.
5. The combination with a steam cylinder and piston, of separate induction and
exhaust ports for each end of the cylinder, two oscillating valves, (one for controlling
the induction and exhaust port for each end of the cylinder), ports, 2, 3 located in the
valve-chests and connecting the induction and exhaust-ports, and adjustable valves 39
controlling sai ports, substantially as described.

page_text: 6. The combination with the main steam cylinders, pistons and piston-rods of a
duplex engine, of induction and exhaust-valves and cut-off valves, a cross-bead carried
by the piston-rod of each engine. a rod, 36, connected to one end of the cross-head of
each engine, to operate the cut-off of that engine and a rod, 28, connected to the other
end of the cross-head to operate the induction and exhaust of the other engine,
substantially as described.
7. The combination with a steam-cylinder and piston, of an induction and exhaust-
valve and a cut-off valve for each end of the cylinder, and connections for operating
the cut-off valves from one side of the cylinder and for operating the induction and
exhaust-valves from the other side of the cylinder, substantially as described.
8. The combination with a steam cylinder and piston, the cylinder being provided
with separate induction and exhaust-ports at each end, of two independent valve-chests, h,
located at the ends of the cylinder and detachably connected thereto, each chest
containing an oscillating valve for controlling the induction and exhaust of the steam
to and from that end of the cylinder, substantially as described.
Daten this Loth day of April 1
-
NEWTON & SON,
Agents for the Applicant.
NEWTON & SON,
- Agents for the Applicant.