Improvements in the Expansion Gear of Steam Engines.
Year: 1889

page_text: Date of Application, 27th Feb., 1889
Complete Specification Left, 18th Dec., 1889-Accepted, 18th Jan., 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by WILHELM RUDOLPH PROELL, Doctor of Philosophy,
of Dresden, in the German Empire.]
Improvements in the Expansion Gear of Steam Engines.
I HERMANN KÜHNE of 25-35 New Broad Street in the City of London Engineer
do hereby declare the nature of the said invention for IMPROVEMENTS IN THE
EXPANSION GEAR OF STEAM ENGINES to be as follows:-
My invention refers to that form of Expansion Gear where the admission of steam
is regulated by two slide valves one working on the back of the other the said
slide valves being actuated by eccentrics having different advance angles. The first
or main slide valve in my invention has the usual shape and also regulates the
exhaust of steam but it deviates from the usual shape in so far that the admission ports
at the outer face of the said slide valve have the shape of arcs.
The second slide valve or expansion plate has the shape of a circular disk the said
disk having the same radius as the said are shaped ports of the main slide.
The said circular expansion plate has on its back a round stud and is held in
position and is actuated in an oscillating manner by an arm or lever inside the steam
chest. The said arm or lever is pivotted on its other end on a shaft which shaft is :
carried in suitable bearings at one side of the steamchest and reaches through a stuffing
box to the outside of the said steamchest. Upon that part of the said shaft which
projects through the said stuffing box another arm or lever is fixed the other end of:
the said other arm or lever being connected with an expansion eccentric rod..
The notion of the said expansion eccentric rod will therefore actuate the said
circular expansion disk or slide in an oscillating manner and alternately cover
and open the arc shaped ports of the said main slide with similar effect as.
though the ports of the said slide were straight the expansion plate square.
and the expansion plate were moving in a straight path. The said stud on the back
of the circular expansion plate is turned to a round shape and projects into a fitting,
hole at the end of the said inner arm or lever. It is therefore evident that the said
circular expansion plate is free to turn on its pivot and as the friction on the outer:
are of its oscillating path will be greater than on the inner are the said circular;
expansion disk will be kept in continual rotary motion whereby it will grind itself,
automatically straight and tight together with the back face of the said main slide valve.
The said expansion disk may be actuated by a fixed or variable eccentric.
Dated London. 27th day of February 1889.
HERMANN KÜHNE
COMPLETE SPECIFICATION.
Improvements in the Expansion Gear of Steam Engines.
I, HERMANN KÜHNE of 25-35 New Broad Street in the City of London, Engineer
do hereby declare the nature of this Invention which has been communicated to me
from abroad by Wilhelm Rudolph Proell of Dresden in the Empire of Germany,
Engineer 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 expansion gear wherein the admission of:
steam is regulated by two slide valves one working on the back of the other, the said
slide valves being actuated by eccentrics having different advance angles. According
to this Invention, the first or main slide valve may be of the usual kind and may as
usual also regulate the exhaust of steam, but it differs from the usual shape in that
the admission ports at the outer face of the said slide valve are in the form of arcs.

page_text: The second slide valve or expansion plate is in the form of a circular plate or disc,
the said disc having the same radius as the said arc-shaped ports of the main slide.
The said circular expansion plate or disc is free to turn on a pivot or centre so that
the said circular expansion plate or disc as it is operated is free to have a movement
of rotation or partial rotation on the said pivot or centre, whereby it will grind itself
automatically straight and be kept true with the back face of the said main slide valve.
The said expansion disc may be actuated by a fixed or variable eccentric.
And in order that the said Invention may be fully understood, I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of Drawings, the same. letters of, reference indicating
corresponding parts in all the Figures.
Figure 1 illustrates the principle of this Invention, A, is the port face in the
Cylinder, B, is the slide valve, which is provided with the arc-shaped admission ports,
and C, is the aforesaid rotary disc expansion valve; capable of turning on the pivot
or centre c, Figure. 2 is a vertical section, Figure 3 a horizontal section, and
Figure 4a front view, with the cover removed, of the arrangement which I prefer.
Figures 5 and 6 are a front view, with the cover removed, and a horizontal section
of a modification wherein the expansion disc C is operated by movement in a right
line instead of in the arc of a circle as in Figures 2, 3 and 4. As in Figure 1 A is
the front face of the cylinder B the usual valve but with steam admission ports bb
having the arcs of circles of a radius equal to that of the disc C. Referring to
Figures. 2, 3 and 4 the round stud c, on the back of the expansion disc C is held
in position and is actuated in an oscillating manner or in the arc of a circle by an
arm or lever D'inside the steam chest the said slide being free to turn in the hole in the
said arm or lever D. which receives it. The said arm or lever is secured at its other end
on a shaft. E which shaft is carried in a suitable bearing at one side of the steam chest
and passes through a stuffing box g to the outside of the said steam chest. Upon
that part of the said shaft. which projects through the said stuffing box another arm or
lever H is fixed which latter arm or lever is connected with an expansion eccentric rod.
The motion of the said expansion eccentric rod will therefore actuate the said circular
expansion disc or slide C in an oscillating manner and alternately cover and open the
arc shaped admission ports 6 of the said main slide with an effect similar to that
which would be the case. if the ports of the said main slide were straight and the
expansion plate square and moving in a straight path.
In the arrangement Figures 5 and 6 I have shewn the expansion disc C as being
operated from the expansion eccentric in a right line its pivot c being received into
a hole in a boss carried in a rod I passing through a stuffing box and into a covering
cap as is the case with the main slide valve.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed I- declare that what I
claim. is.
First In expansion gear for steam engines the combination with a main valve
having in it are shaped admission ports of a circular plate or disc free to turn on its
centre and connected with an expansion eccentric. or equivalent device substantially as
herein before described.
Second The arrangement and combination of parts constituting, expansion gear of
steam engines substantially as hereinbefore. described and illustrated in Figures 2,
3 and 4 of the accompanying drawings.
Third--The arrangement and combination, of parts. constituting expansion gear for
steam engines substantially as hereinbefore described and illustrated in Figures 5
and 6-of the accompanying drawings.
Dated the 18th dor of The 100n