IMPROVEMENTS IN COMPOUND STEAM ENGINES
Year: 1883

page_text: LETTERS PATENT to Justin Rice Wells, of the city of New York, in the
County and State of New York, United States of America, Engineer, for an
Invention of "IMPROVEMENTS IN COMPOUND STEAM ENGINES"
PROVISIONAL SPECIFICATION left by the said Justin Rice Wells at the
Office of the Commissioners of Patents on the 13th January 1883.
JUSTIN RICE WELLS, [of the City of New York, in the County and State of
New York, United States of America, Engineer,] "IMPROVEMENTS IN COMPOUND
STEAM ENGINES"
The improvements relate to the construction and arrangement of the principal
parts. I make a high-pressure and a low pressure cylinder in line with each other
and preferably closely united, with a stuffing box between, and conduct the steam
first through the high pressure cylinder and thence directly, or, preferably, through
a jacket surrounding the latter, to the low pressure cylinder, the whole constituting
a very compact compound engine.
The pistons move always in opposite directions. The high pressure piston
descends and the low pressure piston rises until they are close together. Then
they both move in the opposite directions until they are at the greatest distance
apart.
The two pistons have, preferably, equal strokes, but this is not absolutely
essential. The high pressure piston carries a single piston rod, which, when the
high pressure or small cylinder is arranged above the low-pressure or large
cylinder, passes through stuffing boxes in the latter and in the low pressure
piston and is connected through a suitable cross-head and connecting rod to a
single crank.
The low pressure piston has two piston rods, each of which has an independent
cross-head and a connecting rod taking hold of a separate crank on each side of the
ingle crank which connects to the high pressure piston. The latter crank is
diametrically opposite to the two cranks connected to the low pressure piston,
Pine R32

page_text: I use piston valves for admitting and discharging the steam from both cylinders,
each cylinder having but one valve which operates in principle in the same manner
as an ordinary slide-valve.
I arrange the valve chests and valve stems so that both valves are conveniently
worked by a single lever and their weights are balanced. I operate the lever to a
variable extent and adjust the amount of expansion in both cylinders by a single
movement.
If desired the high pressure cylinder may be arranged below the low-pressure
cylinder, the connections being made in substantially the same manner as above-
described, with the exception that the piston-rod of the high pressure cylinder will,
in this case, not pass through the low-pressure cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Justin Rice Wells in the Great Seal Patent Office on the
13th July 1883.
JUSTIN RICE WELLS, of Brooklyn, in the County of Kings, in the State of New
York, one of the United States of America, "IMPROVEMENTS IN COMPOUND
STEAM ENGINES,”
The improvements relate to the construction and arrangement of the principal
parts. I make a high-pressure and a low-pressure cylinder in line with each other,
and preferably closely united, with a stuffing-box between, and conduct the steam
first through the high pressure cylinder, and thence directly, or, if preferred, through
a jacket surrounding the latter, to the low pressure cylinder, the whole constituting
a very compact compound engine.
The pistons move always in opposite directions. The high pressure piston
descends, and the low pressure piston rises until they are near together. Then
they both move in the opposite directions until they are at the greatest distance
apart.
The two pistons have preferably equal strokes, but this is not absolutely
essential. The high pressure piston carries a single piston-rod, which, when the
high pressure or small cylinder is arranged above, or further from the crank-shaft
than the low pressure or large cylinder, passes through stuffing-boxes in the latter
and in the low pressure piston, and is connected through a suitable cross-head and
connecting-rod to a single crank.
The low pressure piston has two piston-rods, each of which has an independent
cross-head and a connecting-rod taking hold of a separate crank on each side of
the single crank which connects to the high pressure piston. The latter crank is
diametrically opposite to the two cranks connected to the low pressure piston.
I use piston-valves for admitting and discharging the steam from both cylinders,
each cylinder having but one valvo which operates in principle in the same manner
as an ordinary slide-valve.
I arrange the valve-chests and valve-stems so that both valves are conveniently
worked by a single lever, and their weights are balanced. I operate the lever to a
variable extent, and adjust the amount of expansion in both cylinders by a single
movement.
In carrying out the invention, I make a compound engine which is compact, and
may be conveniently portable, if desired. I balance the momentum and weight of
the pistons and other reciprocating parts. The compound action, by which I mean,
working the steam first in a sinall cylinder, and afterwards expanding it in a larger
cylinder, has been long approved. My invention successfully utilizes the advantages
thereof, with the parts balanced so as to allow very rapid working.
My arrangement of the cylinders, and mode of transmitting the power from the
respective pistons to the crank-shaft, allows all the strains either from steam-
pressure or momentum of moving parts to be balanced so that all the friction the
crank-shaft encounters in revolving in its bearings is that due to the force of
gravity. The bed-plate, columns, &c. are also largely relieved from strain, and the
vibration or throb caused by the sinking of one piston, piston-rod, and connecting-
rod is entirely obvinted by reason of the balance maintained by the simultaneously
and equally ascending of the other piston and connected parts. By reason of this
relief from strain, my engine can be constructed much lighter for the same power
than any other form of engine; and on account of balanced momentum of moving
parts, I can attain a much higher piston speed, thereby reducing the engine in size,
weight and cost, below any at present constructed.

page_text: .
I employ a link motion so arranged that a single link and actuating eccentrics
operate both valves. The shifting of the single link changes the action of the steam
in both cylinders equally under all conditions. The movement of the link to reverse,
reverses the action in both cylinders.
The following is a description of what I consider the best means of carrying out 5
the invention. The accompanying drawings form a part of this specification.
Figure 1 is an elevation viewed in the line of the shaft, which shows the novel
parts, with so much of the ordinary parts as is required to indicate their relations
thereto.
'
Fig. 1 is a perspective detail showing the relative positions of the cranks.
Fig. 2 is a plan, showing the two cylinders and the adjacent parts.
Fig. 3 is a vertical section on the central line in Fig. 2.
Fig. 4 is a vertical section on the line t, t, Fig. 2,
Similar letters of reference indicate corresponding parts in all the figuros.
A is the smaller and high-pressure cylinder, and A' is the steam-chest therefor.
B is the larger or low pressure cylinder, and B₁ is the steam-chest therefor. The
A single piston-
small piston traversing in the high pressure cylinder is marked a.
rod a¹, fixed in the center thereof, connects to a cross-head a², which by means of a
connecting rod a³ actuates one of the main cranks a', formed in or rigidly fixed to
the main shaft O.
The larger piston b in the low pressure cylinder has two piston-rods b¹, b', fixed
as near the rim as will allow for suitable packing. These two piston rods b'
connect by two cross-heads b³, b³, and two connecting rods b³, b³, with two main
cranks b, b, formed in or keyed to the main shaft O. The two cranks 64 are
parallel to each other, and are arranged on the shaft O on the opposite side from
the single crank a*.
C, is the frame; C¹, C', are the outer slides; C2, C², are the inner slides. These
slides guide the cross-heads. The slides C serve both for the central cross-head a³,
and for the two outer cross-heads b², 6².
D is a lever turning on a fixed axis d, and receiving a vibrating motion through
a pin D' by means to be presently described.
One end of the lever D actuates a piston valve a³, which controls the action of
the steam in the high pressure cylinder A, through a valve-stem aº, having a
link a', which receives a pin as fixed on the lever D.
The other end of the lever D actuates the piston valve bo, which controls the
action of the steam in the low-pressure cylinder B. It is actuated by a stem 6º,
having a link 67, which receives a pin is fixed in the lever D, and vibrating
therewith.
•
The steam discharged from the exhaust port in the steam-chest A' of the high
pressure cylinder A Hows through a pipe E, and serves as the live steam for the
low-pressure cylinder B. The spent steam from the low-pressure cylinder is
discharged through a pipe F into the atmosphere, or into a condenser, not
represented.
The shaft O carries two eccentrics O', which receive straps 0³, actuating eccentric
rods O connecting to a link P. This is the open Stevenson link, well known in
steain engineering, actuating the lover D by means of a link-block P¹, which fits
tightly and easily in the curved slot in the link, and embraces the pin D', so as
to communicate the motion of that portion of the link P to the pin 11, and con-
sequently to the lever D. The link P receives a liberal rocking motion, and a
slight bodily motion from the two eccentrics O', which are set nearly opposite to
cach other, and is controlled in position laterally by a link R¹ which connects to
a hand-lever R turning on a fixed center, r, and adjustable by any ordinary or
suitable means, so that it may cause the link P to work in all the positions
required in practice for going ahead with full steam, going backward with full
steam, or going in either direction with various degrees of expansion of the live
steam, and of compression of the exhaust.
The pistons and their connections should be of equal weight; that is to say, the
1

page_text: small piston a, and its single piston-rod a', with its cross-head and connections,:
should be made heavy, and the large piston b, its two piston-rods b², its two cross-
heads b, two connecting-rods 63, and two cranks b, should be made as light as
consistent. with strength, so that the parts will exactly balance each other, and the
pistons will stand indifferently in any position in which they may be placed.
When the engine is running rapidly, and the momentum of the parts becomes an
important element, instead of as in most engines tending to violently shake the
machine and its foundation, my engine will run with any required degree of speed,
without any tendency to shake at all. My engine will run successfully in any
position without being fastened to its foundation.
When the strokes of the two pistons are unequal, the weights should be
unequal in the inverse ratio, so that the gravity and momentum shall remain.
exactly balanced.
The valves a, b, should be of equal weight, and the
should be equi-distant from the centre d of the lever D.
balance each other.
actuating pins a³ and 68
The valves thus perfectly
The valves are actuated in equal times and to equal extents always in opposite
directions the one to the other. The motion is derived through the link P, and
the shifting thereof produces the usual effect of giving more or less movement to.
the valves. When there is a large movement, the steam follows far both in the
large and small cylinders, and does not cushion in either. When the link is shifted
to give less motion to the valves, the steam is cut off shorter, and the exhaust is
cushioned. My arrangement insures that the changes shall be equal in both
cylinders under all circumstances. Throwing the hand-lever R, and consequently
the link P from one extreme position to the other instantly reverses the action in
both cylinders.
If the valves be of different size and weight, the spaces between the ports should
be correspondingly modified, and the distance of the actuating pins from the
center & of the lever D may be arranged so that the moment of their inertia will
be equal, and the balance thus preserved.
Modifications may be made in the forms and proportions. I can use dishing
pistons instead of the plane ones shown. I can use flat, ordinary slides, with
Corresponding flat faces, instead of the piston-valves and small cylinders for them
to work in, which are shown. I can employ other means for connecting the
lever D to the valve-stems. I can locate the pin D¹ nearer the centre of the
lever D. I can work the link P at a point intermediate between the lever D and
the eccentrics, and employ a link from the lever D to the link-block P¹. In such
case, I shall make the curvature of the link the reverse of that shown, and shift
the block instead of tho link, such arrangement being what is known in locomotives
as "shifting block" as distinguished from the "shifting link" motion.
One modification to which I attach much importance is to put the large cylinder
below the small one, thus working the engine in the reversed position to that
shown. An objection to such arrangement is that the single piston-rod of the
small piston, would in such case have to pass through two stuffing-boxes, or
equivalent steam tight devices, one in the fixed partition between the small
cylinder and the large one, and another in the centre of the large piston, either of
which would be difficult of access for adjustment or re-packing.
I prefer the precise arrangement shown, for the reason, among others, that only
three stuffing-boxes are required for the three piston-rods, arranged so that any
leaks would instantly be discovered, and that each is easy of access for examination,
adjustment or re-packing.
I propose in ordinary cases to employ a sleeve or casing which shall cover that
portion of each of the two piston-rods b¹, b¹ where it runs close along the oxterior
of the small cylinder A.
The small cylinder may be made to embrace and protect the adjacent portions of
the two piston rods b¹, b₁, for a less distance instead of the whole distanco shown.
Or, all such embracing and protection may be omitted, it being of course understood

page_text: that those piston-rods are necessarily stiff enough to maintain themselves, and
that they are guided mainly or entirely by the cross-heads b², 62, running in the
substantial slides C³, C¹, C³, C'.
Parts of the invention may be used without the whole. I can realize some of
the advantages of the invention with other means of actuating the valves.
I claim as my invention :—
1 The small cylinder A and larger cylinder B arranged in line as shown, in
combination with the two pistons a, b, moving in opposite directions, and with the
three piston-rods, cross-heads, connecting-rods, and cranks, arranged for joint
operation, as and for the purposes herein specified.
2: The valves a, b, and lever D, in combination with each other, and suitable
actuating means, and with the small cylinder A and large cylinder B, and their
respective pistons and connections arranged in line, and adapted to serve as herein
specified.
3: The compound engine described, having the sunall cylinder A, and larger
cylinder B, arranged in line as shown, in combination with the eccentrics O',
eccentric rods O', link P, adjusting means R, R', and lever D, operating the two
valves a, b, so as to regulate and reverse the action in both cylinders by the
movement of a single member R, as and for the purposes herein specified.
In Witness whereof, I, the said Justin Rice Wells, have hereunto set my
hand and seal, the twenty-sixth day of April, One thousand eight hundred
end eighty-three
Witnesses:
JOHN MILLER WILSON
WILLIAM CLARK DEY.
JUSTIN RICE WELLS (L.9.)