A NEW CONDENSING STEAM ENGINE WITH VARIABLE EXPANSION GEAR ACTUATED DIRECT FROM THE GOVERNOR
Year: 1873

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth & Comp.,
m
Patent Agency, Frankfort % (Germany), for the Invention of "A
NEW CONDENSING STEAM ENGINE WITH VARIABLE EXPANSION GEAR ACTUATED
DIRECT FROM THE GOVERNOR."-A communication from Messrs. Scheller
& Berchtold, residing at Thalweil, near Zurich (Switzerland).
Sealed the 1st January 1874, and dated the 10th July 1873.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the
Office of the Commissioners of Patents, with his Petition, on the
10th July 1873.
I, FRANK WIRTH, of the Firm of Wirth & Comp., Patent Agency,
Frankfort % (Germany), do hereby declare the nature of the said.
Invention for "A NEW CONDENSING STEAM ENGINE WITH VARIABLE EXPANSION
Gear Actuated DIRECT FROM THE GOVERNOR," a communication to me from
Messrs. Scheller & Berchtold, persons resident at Thalweil, near Zurich
(Switzerland)," to be as follows:-

page_text: and require too large engine rooms, or if this be not the case are too
complicated in construction.
The object of this Invention is to reduce these evils considerably as
hereafter described.
The distribution of steam is according to this Invention executed in
a similar manner as first constructed by Corliss, viz., on 4 points of the
cylinder. The elements of distribution are however not rotary slide
valves as made by Corliss, but flat circular rotary discs. In these discs
there are sector shaped holes usually 8 to 12 in number, according to the
size of the engine. These valves have the advantage that the ad-
mittance of steam begins at once on a great length as attained by the
Corliss valves, but with the advantage of smaller loss by "clearance or
waste space. These rotary valves have also the advantage of less move-
ment as the angle of rotation is not more than 10°, which can be
reduced to 5° or larger engines. Because of this the necessary force
for the movement of the valves is reduced so that the proportion
of indicated and efficient horse power is brought nearer to the
numbe 1.
"
The 4 rotary slide valves are so arranged that the steam is pressing
them against their seats thus ensuring tightness. To get further
security in this respect they are pressed against their seats by small
springs outside of the cylinder. The vertical axles of the slide valves
carry each one horizontal moving lever which is actuated as follows:-
The steam is let in at the back and front on the top of the cylinder by
means of two of the before described rotary slide valves which are
turned by levers in connection with small steel rods, on each of which
there is a piston which moves in a small air cylinder. These two pistons
are operated by a lever in a reciprocating manner. To enable this lever
to operate always the same piston rod first, one of them is put
somewhat higher than the other, and one half of the regulating lever
is movable in a vertical direction' as a backward prolonged piece catches
into an up-and-down moving groove' on the governor shaft. The dis-
tributing lever is moved in that way that a double cam fastened on the
governor shaft is pushing against a piece that is moving on the former.
This piece which moves on the distributing lever receives its movement
by a vertical connection from the lever which is moved by the governor
sleeve,

page_text: When the pendulums of the governor rise the moving piece on the
distributing lever is pushed towards the outside, through which move-
ment the cam of the governor shaft leaves the moving piece earlier, and
the now relieved lever can be brought back to its original position,
which is done by the springs in the air cylinders.
The office of the air cylinders. is to, receive the springs and for the
purpose of softening the shock on shutting the slide valves. Through
this arrangement the admittance of steam can be changed by means
of the pendulum of the governor from 0 to 50% of the piston stroke.
The steam outlets are on the lowest part of the cylinder and pass
through discs worked by a grooved cam that is fixed on the governor
shaft. Rollers work in the groove; these rollers are on pins at the ends
of double ended levers, which are connected with the levers of the axles of
the rotary outlet slide valves. The governor shaft forms in this way
at the same time the reversing shaft and is worked by a horizontal shaft
from the crank shaft. In order to afford easy access to the different
parts of the cylinder the same is overhung and screwed endways to the
back of the bed plate. The guide surface of the crosshead is formed
in the bed plate, in which also are formed the condenser and air pump,
which latter is moved from a counter crank on the crank pin by lever
connections.
The aten
-

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of July, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frank Wirth, Her special licence
that I, the said Frank Wirth, my executors, administrators, and
assigns, or such others as I, the said Frank Wirth, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "A NEW CON-
DENSING STEAM ENGINE WITH VARIABLE EXPANSION GEAR ACTUATED DIRECT FROM
THE GOVERNOR," (a communication to me from Messrs. Scheller &
Berchtold, persons resident at Thalweil, near Zurich (Switzerland),
upon the condition (amongst others) that I, the said Frank Wirth,
my executors or administrators, by an instrument in writing, under my,
or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frank Wirth, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying
Drawings and to the letters of reference marked thereon, that is to
say:―
Condensing steam engines as heretofore made occupy much room,
requiring large engine rooms, or if this be not the case are complicated
in construction.
The objects of this Invention are to reduce these evils considerably and
to improve the mode of distributing steam and of regulating the
movement of the engine, all as herein-after described.
The first part of this Invention will be understood without any
Drawings, and consists in a new or improved arrangement or com-
bination of cylinder, bed plate, and condenser, and air pump. The steam

page_text: cylinder is overhung and screwed endways to the back of the bed plate
of the engine. The bed plate is formed in the shape of a box under
the cross head guide, and in this box shaped part are situated the
condenser and other air pump, which latter is worked from a counter
crank on the crank pin by connecting rod and lever.

page_text: further security they are pressed against their seats by means of small
springs situated outside the cylinder.
The vertical spindles E of the slide valves D carry each a lever L
which moves in a horizontal plane, and is actuated as follows:-The
steam is let in at the back and front on the top of the cylinder by the
movement of the rotary slide valves D by means of the levers L through
a small angle (5° to 10°). This rotation takes place by the turning of
the lever q, F, B, round the fulcrum F, the end B of the said lever with
its roller working in a groove or set-off in the cam A. The lever B, F,
9, consists of two parts, the one sliding on the other, but the sliding
part kept on it by means of the lever N connected to the governor as
shewn. The cam dise A is keyed on to the governor spindle G and turns
with it. The shape of the groove or set-off on the disc is such that the
lever B, F, q, through 180° is moved once to the left and the next
time to the right. The lever therefore at c, c¹, at the other end
presses against the piston rod W pushing the spring piston R to the
left.
When the point C arrives at the point S it leaves the rod W
which then with its piston R by the spring is forced back to its previous
position, the slide valve D being connected thereto, thus obtaining its
movement. Meanwhile the piece u, u', on the lever is come opposite
the piece d, d', and when the lever thereupon again is pushed the other
way by the cam the picce u, u¹, will press against the piece d, d', and
thereby push the piston rod W₁ and piston R¹ to the right, thus opening
the right-hand slide valve.
་
When the governor rises or falls the piece u, u¹, or c, c¹, is drawn
back and leaves the piece d, d¹, or c, c², carlier or later, and thus the
spring shuts the slide sooner or later. This movement always takes
place periodically so that the steam is let into the cylinder once in front
and once behind. It is consequently necessary that the governor should
make as many revolutions as the crank shaft.
His a cast-iron bracket bolted on to the upper part of the steam
cylinder C, it serves as a guide or bearing for the governor spindle G.
Fig. 4 is a plan section, and Fig. 5 a side elevation of the bracket H.
The lever N which is connected to the sliding sleeve on the governor
spindle G is shewn in plan at Fig. 6. Its connection at one end to the
sliding part F, q, is illustrated by Figs. 7 and 8, the latter being a cross
section through the fork end, connected to the said sliding part F, q.

page_text: Fig. 9 is a side elevation of the slide valve lever L; Fig. 10 is a
sectional view shewing the way the piston R is connected to the link M
which is jointed to the lever L; and Fig. 11 is a section through the
spring piston R, the cylinder for the same, and the piston rod W jointed
thereto. The exhaust takes place at the bottom of the cylinder and is
effected similarly by a disc fixed on the governor spindle and formed
with a cam shaped groove wherein the rollers on the ends of the double
armed levers work; these levers are connected to the levers on the
exhaust slide valve spindles. The governor spindle thus entirely actuates
the slide valves; it is driven from a horizontal spindle driven from the
crank shaft.
In witness whereof, I, the said Frank Wirth, have hereunto set
my hand and seal, this Seventh day of January, in the year
of our Lord One thousand eight hundred and seventy-four.
FRANK WIRTH. (L.S.)