PROVEMENTS IN STEAM ENGINES AND BOILERS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Abraham Van Winkle at the Office of.
the Commissioners of Patents on the 15th January 1878.
ABRAHAM VAN WINKLE, of Queen Victoria Street, in the City of London.
PROVEMENTS IN STEAM ENGINES AND BOILERS."
"IM-
My Invention relates to that class of portable engines in which the cylinder and
crank shaft of the engine are attached directly to the boiler without framing of any
kind; and in carrying my said improvements into practice, I construct the boiler
in such a manner that the fly wheel shaft may be secured to the boiler across its
middle and very low down, thereby securing symmetry of design with the utmost
stability under rapid motion. The construction and arrangement of the distributing
valve and its gearing are also improved.
My improved boiler consists of upper and lower sections, cylindrical in plan and
united by two or more pipes or hollow columns secured between the said sections.
The lower section is also hollow, and is cast with a water space between two
metal surfaces at its top and around its whole circumference, the interior of the
water space forming a furnace chamber, in one side of which is an aperture for a
door, and provided at the bottom with a dumping grate of any desired pattern and
a pan to withdrawn ashes.
The grate and boiler both rest on an ash box base, constructed to support the
boiler and the pivots of the grate, and open at one side to remove the ashes.
In each of the said columns a flue or flues is inserted and secured to the top of
the said lower section and the crown of the furnace, perforating each in the manner
usual to flue boilers, and providing an outlet from the furnace for the gases generated
in it.
The water is carried in the boiler so as to fill the spaces about the furnaces, the
space between each of the flues and its surrounding column, and to stand part of
the way up in the said upper section.
The steam is taken from this latter section by a central opening on top into
a bell-shaped superheater, the base of which is expanded enough to extend over
the upper ends of the said flues and receive the heat in its passage to the chimney.
The said superheater is tapered upward at the top, conforming nearly to the
shape of a dome, fitted upon the top of the boiler, and confining the gases in contact
with the superheater until they pass out of the top into the chimney.

page_text: Steam for an engine is taken from the superheater by a pipe, and after passing
through a governor, enters a steam chest on the side of the engine cylinder, which
is bolted to the said upper section. The cylinder is inverted, the piston rod passing
out of the bottom, and being connected by a link to a crank and wheel shaft, which
is carried by bearings secured upon the top of the said lower section; whatever
number of columns are employed, the shaft passes through the space between them,
and has its fly wheel or driving pulley keyed upon the opposite end.
It has been found in practice that no inconvenience has resulted from the heat
passing from the water inside the said lower section to the said bearings, and the
extreme rigidity of the cylindrical section makes them quite true and firm in
position. This location of the crank shaft renders the whole structure very steady,
as the weight of the shaft and fly wheel are brought as low as they can be placed
without penetrating the furnace, thus enabling the engine to work quietly at a
great speed, being perfectly balanced on all sides.
I am aware that portable engines have been made with the shaft located low
down, but outside the shell of the boiler, and in other cases through the smoke box
on the top; but I consider my said arrangement preferable to the former in
carrying the crank shaft across the middle of the boiler, and to the latter in keeping
the weight and momentum of the moving parts at the lowest possible point above
the fire-box.
It is evident that another arrangement may be made to afford the same passage
low down across the boiler for the crank shaft of the engine. The boiler in this
case may be of the ordinary upright tubular kind, with a pipe inserted transversely
through its body just above the fire-box; or it may be of sections like those herein-
before described, and united by two semi-cylindrical or segmental shaped columns.
Inside these columns flues would pass, as before described.
According to my said improvements, I construct the said distributing valve of
the engine in the form of a cylindro-conical plug, which is encased in a steam chest
on the side of the cylinder, and rocked in its seat by a connecting rod, attached,
to a lever hinged at its lower end, and constructed to embrace an excentric behind
the main crank and disc.
The said hinged joint is connected to the plunger of a force pump, which serves
as a guide for the lower end of the said lever, and enables the excentric to work
the pump at the same time that it operates the said valve. This arrangement of
the excentric and its lever, moving in a straight line at one end and in an ellipse
at the point where it operates, the valve has a peculiar effect upon the motion of
the latter.
By the bend in the said lever above the excentric, this lever is brought in a
right line when the excentric is above the centre of the crank shaft, and when the
centre of the excentric moves from that position, it travels successively through the
other points, 45 degress apart in the circle of its revolution, and the point of con-
nection of the said lever and connecting rod describes an oval or ellipse. The
widest part of this ellipse bears such a proportion to the length of the aforesaid
connecting rod, that the hypothenuse of a triangle constructed on the following
points, that is to say, the centre of the said ellipse, the top of the said lever when
in a position to form a straight line as aforesaid, and the extreme right-hand point
of the said ellipse, is considerably longer than the direct line from the centre of the
said ellipse to the top of the said connecting rod. This arrangement has the effect
of shortening the said connecting rod when the excentric is at the respective
positions when the main crank is nearing its upper and lower centres, and a rapid
closing of the induction ports to the cylinder would act as a cut off, and secure the
greatest economy of steam possible with a single simple valve.
To promote this object still further, the said valve is made with considerable lap,
and with the aid of the peculiar valve motion herein described, the steam is cut
off shortly after half stroke, while with lap alone it is difficult to cut off earlier than
three quarters of the full stroke.
The said valve is of the common D valve pattern, but made in the form of a plug.

page_text: The said valve is. provided with cylindrical journal pins at each end, one of which
is extended outside of the said steam chest to receive a crank arm.
These pins
rotate in bushes screwed into the ends of the valve seat and fitted steam-tight
against the two ends of the valve. These bushes not only furnish bearings for the
valve journals, but serve to move it lengthwise in its seat when it wears loose on
its steam port joints, the taper form of the valve making it tight when it is moved
slightly toward the smaller end of the hole into which it is fitted.
The provision of these journal bearings takes almost all the wear off the port
surfaces, and the said bushes are prevented from working loose in 'their holes by
jamb nuts at the ends of the steam chest.
The cast iron boiler is perfectly safe and suitable for small powers, and much
cheaper than any other style, as the casting can be made in one piece, and requires
very little labor to finish it.
The engine is attached to the boiler, so as to run steadily at any desired speed,
the centre of gravity being kept as low as can be secured when the shaft of the
engine is attached solely to the boiler. The valve motion also secures a considerable
cut off for the steam, thus obtaining an unusually high degree of economy for a
portable engine.
The continuous motion of the pump is usual on all engines when the pump is
worked from the cross head, the supply of water being controlled by a suitable feed
cock on the suction pipe.
Gauge cocks are provided to regulate the height of water in the said upper section
of the boiler.
A safety valve and other appliances are also provided, and the whole arrangement
is such that the combined engine and boiler take the least possible space, exposing
no highly heated surface to radiation, and capable of being protected (below the
dome) either with a felt cover or some other non-conducting material. If no pump
is wanted on the engine an equivalent guide would be provided. All these
advantages can be secured in my said improved engine by the employment of an
upright tubular boiler with a transverse tube through the body for the shaft of
the engine; but the cost of such a boiler is much greater than the columnar boiler
described above, especially if the latter is cast all in one piece, which may be done
where small cost is a great object.
Three columns or any number may be used, as their size can be so designed that
the shaft will pass between them and the desired advantages secured.
When made of wrought iron, the columns can be screwed by right and left
threads into the two sections, or flanged and rivetted at the ends. Even if the
driving wheel is not placed at the side opposite the engine, it is a great advantage
to locate the weight of the shaft wheel and other parts at the middle of the boiler.
The driving of the pump by the same eccentric that works the valve is quite an
economic point in construction, as is also the arrangement of the valve with its
smaller end toward the boiler, so that its lever is inside the main link and crank
disc and has its connection behind the disc.
If outside the disc, a return crank would have to be used to drive the valve or
some indirect connection, thus preventing the casting together in one piece of the
crank disc, eccentric, and governor pulley.
The governor is so adjusted on the said steam chest, that the governor belt
clears all the parts of the valve motion as well as a rib, by which the cylinder is
secured to the boiler.