IMPROVEMENTS IN STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to the Honorable Charles Algernon Parsons, of Connaught
Place, in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Charles Algernon Parsons
at the Office of the Commissioners of Patents on the 15th June 1877.
The Honorable CHARLES ALGERNON PARSONS, of Connaught Place, in the County
of Middlesex. "IMPROVEMEnts in Steam ENGINES."
This Invention relates to a novel arrangement of motive-power engine, whereby
the reciprocating motion of the pistons in the cylinders of the engine may be made
to produce a direct rotary motion.
i
Supposing a pair of working cylinders to be employed, these I mount on a
balanced frame, or they may form part of a balanced casting, which shall be capable
of rotating while the engine is in work. The casting is mounted on a hollow
trunnion, which has its bearings in a standard, and the working cylinders are set at
right angles to each other. The trunnion is made hollow to convey steam from the
steam supply pipe to the engine, and it is connected by suitable passages with the
valve chests of the cylinders. Surrounding this hollow trunnion is a fixed chamber,
which communicates with an exhaust pipe, and the exhaust passages of the cylinders
discharge into this chamber. Provision is made for securing a steam-tight joint.
between this chamber and the balanced casting constituting the engine proper.
The piston rods of the cylinders are made to embrace the crank pins of a double
crank shaft, which has its bearings in a second standard, and is intended directly.
or by means of a pulley or spur wheel fitted thereto to transmit the motion of the
engine to the machinery to be driven. This crank shaft is set out of line with the.
hollow trunnion to the extent on one quarter of the stroke of the piston, and the
throw of the cranks which connect with the piston rods will be equal to one-half
the stroke of the pistons.
For working the valves a stationary excentric is employed. This excentric is.
fitted to a slide, which allows of its being thrown to the right or left, thus reversing
Pris 77

page_text: its action. The concentric strap carries two radial arms, which are severally jointed
to an arm which by its rocking motion operates through suitable appliances the
slide valves of the cylinders.
When steam is admitted to the cylinders of the engine the piston rod will receive
a reciprocating motion, and by reason of their connection with the crank shaft they
will impart rotary motion thereto, the engine itself meanwhile following the axial
motion of the crank shaft.
By the peculiar connection of the engine with the crank shaft the latter will be
caused to make two rotations for every rotation of the engine, and thus a high
speed may be obtained with a comparatively easy working of the slide valves and
their connections.
When it is desired to construct a compound engine according to this Invention,
one cylinder only will exhaust into the fixed chamber, namely, that receiving the
supply of steam from the cylinder which is in direct communication with the steain
supply pipe.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Algernon Parsons in the Great Seal Patent Office on the 15th
December 1877.
"
The Honorable CHARLES ALGERNON PARSONS, of Connaught Place, in the County
of Middlesex. IMPROVEMENTS IN STEAM ENGINES."
"
This Invention relates to a novel arrangement of motive-power engine, whereby
the reciprocating motion of the pistons in the cylinders of the engine may be made
to produce a direct rotary motion.
In the accompanying Drawing,—
Fig. 1 shews in side elevation my Invention as applied to a compound engine
containing two pairs of high and low pressure cylinders set at right angles to each
other, and secured to a central hollow trunnion which serves to carry them.
Fig. 2 is an elevation of the engine at right angles to Fig. 1, the foremost cylinder
being removed in order to expose to view some of the details of construction hidden
by that cylinder.
Fig. 3 is a partial sectional elevation showing the arrangement for supplying the
steam to the cylinders from the hollow trunnion.
And Fig. 4 is a partial side elevation shewing the casting to which the cylinders
are attached, the two high-pressure cylinders only being represented in place.
:
A and B are a pair of high and low pressure cylinders, and A', B¹, are a second
pair of high and low pressure cylinders, all attached to a central casting C. In this
casting are two steam passages D, D¹, one of which is clearly shewn in section at
Fig. 3. These steain passages are in communication with a hollow trunnion E,
which constantly supplies steam to the valve chests of the cylinders A, A¹, which
are high-pressure cylinders. These cylinders communicate by means of steam
pipes F with their respective low-pressure cylinders B, B¹, and supply steam thereto
to be further expanded after the steam has acted upon the pistons of the cylinders
A; A³, respectively.
The trunnion E is mounted in suitable bearings, and it carries the engine con-
sisting of the four cylinders before mentioned with their piston and valve gear so as
'

page_text: to premit of the same rotating freely on its axis. The engine is enclosed in a steam-
tight case G, shewn in section in Figures 1 and 2, and into it the low-pressure
cylinders discharge their exhaust steam, whence it passes off by the pipe H to the
condenser.
The piston rods of the cylinders A, B, A¹, B¹, respectively are connected together,
as shewn best in Fig. 3, and in the detached view, Fig. 3ª, in order that they may each
embrace a crank of the crank shaft K. These piston rods are arranged in different
planes for this purpose, and the crank shaft is set out of line with the trunnion E a
distance of one-quarter of the stroke of the pistons of the cylinders to provide for
its rotation. L are the valve rods connected at their opposite ends with the valves
of the two opposite cylinders, thus ensuring the simultaneous action of both valves,
that the high-pressure cylinder may discharge its partially exhaust steam into its
low-pressure cylinder while steam is being admitted directly from the boiler to the
high-pressure cylinder. These valve rods L are each connected with a rock lever M
mounted on a fulcrum pin carried by a bracket piece N. The other end of this
rock lever is fitted with a slide which enters an annular groove in a stationary
excentric plate O. The centre of this groove is intermediate of the centres of the
trunnion E and the crank shaft K, and its action is to operate the slide valves as
the engine rotates with its trunnion E.
For reversing the motion of the engine the excentric plate O is mounted on
guides, which will allow of its being thrown over to the right or left by means of a
crank P, to which it is linked, and thereby reversing the action of the valves. It
will now be understood that on steam being supplied to the engine a reciprocating.
motion will be imparted to the pistons, which by reason of the connection of their
rods with the crank shaft, as explained, impart a continuous rotary motion to that
shaft, the speed of which will be double that of the axial motion of the engine.
When applying the Invention to engines having two high-pressure cylinders only,
as indicated in Fig. 4, it will be requisite to balance the casting by adding weight
in place of the low-pressure cylinders.
It will be understood that to ensure the smooth working of the engine the casting
C and the attachınents thereto must be properly balanced, and a broad bearing
must be provided for the trunnion E.
Having now set forth the nature of my Invention of "Improvements in Steam
Engines," and explained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent I claim, the
arrangement of engine above described, whereby a rotary motion is imparted to the
driving shaft directly from the reciprocating piston rods.
In witness whereof, I, the said Charles Algernon Parsons, have hereunto set
my hand and seal, the 14th day of December, in the year of our Lord One
thousand eight hundred and seventy-seven.
CUT IT ON
PUSAN
CHARLES A. FARSONS.
(L.S.)