IMPROVEMENTS IN STEAM-ENGINES
Year: 1882

page_text: LETTERS PATENT to Pardon Armington, of Lawrence, Essex County, State of
Massachusetts, United States of America for an Invention of "IMPROVEMENTS
IN STEAM-ENGINES
"
COMPLETE SPECIFICATION filed by the said Pardon Armington at the Office
of the Commissioners of Patents on the 16th August 1882.
PARDON ARMINGTON, of Lawrence, Essex County, State of Massachusetts, United
States of America, "IMPROVEMENTS IN STEAM-ENGINES
"
This invention has reference to improvements in the construction of that class of
Steam Engines in which the piston is moving at a high speed and the steam is
supplied automatically in such quantities as will develop a uniform speed under
variable resistance, so that machinery can be run at a fixed speed under all
variations of load that may be applied, within the power of the engine.-The
invention consists in the peculiar and novel construction of the valve, regulating
the supply of steam to the cylinder; by which construction a larger quantity of
steam is supplied to the piston at the end of each stroke, in less time than was
heretofore possible-The invention further consists in the peculiar and novel
construction of the Governor by which the valve-operating eccentrics are operated
upon directly by weights and springs operated by the centrifugal force generated
by the speed of the revolving crank-shaft, as will be more fully set forth herein-
after. The invention further consists in the peculiar and novel construction of the
crank, and the means for balancing the same which is fully described hereinafter.
Figure 1, is a top view of my improved steam engine.-Figure 2, is a side view of
the same. Figure 3, is a side view of the improved Governor, showing the eccentric
placed on the crank-shaft, controlled by the weights and springs. Figure 4, is an
end view of the Governor partly in section. Figure 5, represents the two excentrics
at the two extremes of their movement, one in solid, and one in broken lines.
Figure 6, is a longitudinal, sectional view of the steam cylinder, and the valve for
regulating the admission and emission of steam. Figure 7, is a sectional view of
the steam cylinder and the valve, taken through the centre of the cylinder at right
Dir

page_text: angles to the axis of the same. Figure 8, is a view partly in section, of the crank,
and Figure 9, is a side view of the crank, showing the balance-disc secured to the
crank-disc. Similar letters of reference indicate corresponding parts in all the
figures. In the drawings, A, is the engine cylinder, one end of which is secured to
the heavy frame A¹, on which the slides A*, for the cross-head, and the bearings A³,
for the crank-shaft are formed, so that a solid and firmn bearing, and a permanent
alignment of all the parts is secured. B, is the steam-chest in which the valve B',
regulates the admission of the steam. C, is the valve by which the steam supply
from the steam generator to the steam engine is connected or disconnected. D, is
the piston rod, E, is the connecting rod, M the crank-pin. G, G, are balance discs
secured to the crank disc to balance the weight of the crank-pin, the connecting-
rod and other parts affecting the centre of motion of the crank-shaft and parts
connected therewith. H, H, are the fly-wheels provided with broad rims to receive
belts for transmitting the power generated by the engine. I, is the excentric
connected through the rock-shaft I', and connecting rod I2, with the valve B', so as
to reciprocate the valve at each revolution of the crank-shaft.-Referring now to
the first part of my invention Figures 6, and 7, clearly show the construction of my
improved valve and its connection with the cylinder,the ports leading to each end
of the cylinder,-the steam supply and the steam exhaust. The steam is admitted
by the inlet B2, and it will therefore be observed that the valve B', is at all times
surrounded by the live steam. B³, B³, are the steam-ports leading to the ends of the
cylinder; these ports, extend in the shape of grooves around the valve cylinder.
B, B, are the exhaust-ports formed at each end of the valve-chest. The valve B¹, is
in its form cylindrical; the central portion b, is of less diameter than the two ends;
the central portion is tubular, and is, at each end provided with the bearing b', of
larger diameter than the central part b,-and with the end caps b³, also forming a
bearing against the walls of the valve cylinder; between the bearings b¹, and the
caps 62 openings, 63, are formed which are made as nearly as possible, annular,
around the whole valve; these openings communicate with the interior of the
central portion b, and form an open duct from one end of the valve to the other.
The valve is shown in Figure 6, in the position occupied when both the ports are
closed, and steam is neither admitted to, nor emitted from, the cylinder: the live
steam surrounds the valve and thus a uniform temperature is maintained in the
valve. When now the valve moves in either direction, the port B³, from which it
moves, will be at once placed in communication with the exhaust port B, and this
end of the cylinder will discharge its steam freely, while the port B³, on the other
end of the cylinder will be placed into communication with the openings b³, and by
them, through the central duct and the openings b³, at the other end of the valve,-
with the steam supply, and at the same time directly with the steam supply, as at
that time the annular bearing b¹, at one end has passed beyond the edge of the
port B³, and at the other end, beyond the edge of the valve case; steam is therefore
admitted to the port, both directly by the opening of the port to the steam supply,
and by the opening of the openings 63, at the exhaust end of the valve, and the
admission of steam through the same and through the centre of the valve, so that
steam will be admitted from both ends of the valve simultaneously. Considering
that the ports B³, extend around the valve, that therefore the length of the port
opening is three times the diameter of the valve, and that two such openings are
formed, it will be observed that a large quantity of steam will be admitted
instantaneously at the end of each stroke, and that consequently, the full pressure
will be at once exerted on the piston. The most essential difference between this
valve and other valves as heretofore constructed, consists in supplying. the steam
in the centre of the valve, and surrounding the valve at all times with live steam,
and in discharging the exhaust steam at the ends of the valve, thereby maintaining
a uniform temperature in all parts of the valve and the valve chest, not
heretofore secured by a valve having the capacity to supply the large quantity of
steam as quickly as is done by this valve. Referring now to the second part of
my invention as shown in Figures 3, 4, and 5,-K, is a wheel secured to the main
"
-

page_text: shaft of the engine, and preferably forming part of the fly-wheel H, placed on the
side of the engine where the excentric I, is located; it is provided with two
studs k, k, on which the balance-weights k¹, k¹, are pivoted; these weights are held
in their normal position by means of the spiral springs le², le², of such tension that
at the desired speed of the engine, the spiral springs 2, k², will counter balance the
centrifugal force of the weights k¹, k'.-I, is the main or valve-opening excentric; it
is mounted upon the secondary excentric, which is mounted upon the main shaft ;-
the secondary excentric being movable angularly about the main shaft, and the
valve-operating excentric being movable angularly about the secondary excentric
in such a manner, that as the weights approach their centre of rotation under the
action of their controlling springs, as the engine runs more slowly, the excentricities
of the two excentrics will be partially added together, or lie toward the same side
of the main shaft; but when the weights are most remote from their centre of the
revolution, as is caused by an increase in the speed of the engine, the excentricities
of the two excentrics will lie in opposite directions relative to the centre of move-
ment of each, the centre of the main or valve-operating excentric, lying between
the center of the main shaft and that of the secondary excentric thus diminishing
the throw of the main excentric to its minimum. By properly proportioning the
excentricity, and governing the movement of the two excentrics, the lead opening
of the valve is maintained constant. To ensure this, and secure the accurate
working of the two excentrics by properly connecting the same to the balance
weight, is the main object of this invention. The secondary excentric l, is provided
with two projections and is connected with both the weights ¹, k¹, by means of
the links,, and at points equi-distant from the pivots k, k, while the main or
valve-controlling excentric I, is connected with one of the weights k', near the end
of the weight furthest from the pivot, by the link -The excentrics are, by this
connection, moved more quickly and accurately;-the same are, therefore, more
şensitive to any variation of speed, and will regulate the steam supply more
perfectly, so as to maintain a fixed speed of the engine under any sudden variation
of load, than when the two weights are connected by a link, as has been heretofore
the case.
The third part of my invention is shown in Figures 8 and 9. The
object of this part of my invention is to bring the bearings of the main, or
crank-shaft as close as possible to the line of the strain, or the centre line of
the engine, and also balance the crank and the connecting rod as near the line
of the strain as possible, to prevent torsion. In carrying out this part of
my invention, I make the shaft with two parallel discs and the connecting pin,
all in a single casting, preferably of steel. I then turn the shaft, the pin and the
discs, to give them a true surface. I now place balancing discs of a larger diameter,
on the crank-pin discs, and secure them in place by shrinking or otherwise.
large discs are concentric with the main shaft, and have their weight properly
disposed to balance the momentum of the reciprocating parts when the engine is
running. By this arrangement the crank-pin is rigidly connected with the main
shaft, the crank and balancing discs run close to the connecting rod, and the
bearing of the main shaft is brought very close to the plane of action of the
actuating forces; the main shaft and its bearings being entirely relieved of all
strain and torsion. L, is the main shaft, N, N, are the crank-discs, M, is the crank-
pin, and G, G, are the balancing-dises. The casting consisting of the shaft L, the
discs N, N, and the crank-pin M, can be mounted in a lathe on the axis of the
shaft, which can be turned to give it a true surface. It can now be mounted
concentric, so as to turn the periphery of the discs N, N, and then mounted on the
axis of the pin M, when the same is also turned. The outer faces of the discs N, N,
may be partly turned at either of the three different mountings, but the two inner
faces must be turned or faced when mounted on the axis of the crank-pin. In
order to balance the weight of the discs N, N,-the crank-pin M, the pitman and
reciprocating parts of the engine relative to the main shaft, the balancing discs
G, G, consisting of a hub connected by a web, with the peripheral rim,-are secured
to the discs N, N. These balancing disks G, G, have a portion cast hollow, forming
These

page_text: a chamber in which lead or other suitable material is placed to properly balance
the unbalanced parts before mentioned, and these weights being placed between
the pitman and the bearings of the shaft on the crank-discs, and on a line with
the force exerted, relieve the shaft and bearings almost entirely from strain. The
whole construction presenting a pleasing and finished appearance. -Having thus
described my invention I claim as new and desire to secure by letters patent:
First: In a steam-engine, the combination with the engine cylinder, of a live steam
port, centrally located, and exhaust steam ports located toward each end of two
valve cylinders, and a piston valve extending into both the valve cylinders, having
annular openings near its ends, connected by a longitudinal passage through its
interior, arranged relatively to the said live steam port, exhaust ports and the
steam ports of the cylinder, so that the live steam surrounds the said valve, and is
delivered to the cylinder through the annular openings in the valve, and directly
from the live steam chamber, simultaneously, as described.-Second: The engine
cylinder, and the live, and exhaust steam ports therein, combined with the valve
cylinders provided with annular depressions or port openings entirely surrounding
the valve, and the piston valve having annular openings near its ends, connected by
a longitudinal passage through the middle portion, which is of smaller external
diameter than the bore of the valve cylinders, as, and for the purpose described.
Third The combination with the centrifugally-operating weights, of main and
secondary excentrics both actuated thereby, and both connected with the weights
by links, the former near the end of the weights, and the latter near the pivotal
connection, as described. Fourth: The combination with the crank-shaft of an
engine, of the excentrics 1, and I,-the weights k', ', the springs k³, k², and the
connecting links 1, 1, and 1, constructed to control a steam valve as, and for the
purpose described. Fifth: In an engine, the herein described crank-shaft, consisting
of crank-shaft, discs, and crank-pin, all formed in a single piece, combined with
independent balancing-discs, mounted upon the said crank-discs, as described.
Sixth The shaft, excentric cylindrical discs, and connecting crank-pin, all made
of a single piece of metal, combined with balancing discs, mounted upon the said
eccentric discs, and having their peripheries concentric with the main shaft, sub-
stantially as described, constructed to be mounted on the excentric disks, and
provided with a chamber or chambers to receive heavy material for balancing the
reciprocating parts, substantially as described.
In Witness Whereof, I, the said Pardon Armington have hereunto set my hand
and seal this Sixteenth day of June in the year of our Lord one thousand
eight hundred and eighty two.
('G'IT)
RATTXזזז מזמז
NTACTATU T
Signed in presence of:
JOSEPH A MILLER.