IMPROVEMENTS IN STEAM ENGINES
Year: 1886

page_text: I, WILHELM SCHMIDT of 48, Leonhardtstr. at Brunswick in the German Empire,
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN STEAM
ENGINES and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
These improvements consist in conducting the steam, coming from the steam boiler,
firstly under the slide-valve of the steam cylinder, and in admitting it from the space
under the slide-valve immediately into the cylinder in order there to generate power.
Boiler-steam has hitherto always been conducted over the slide-valve into the slide-box
and from the latter it was then admitted into the steam cylinder.
This new way of introducing the steam under the slide valve offers the advantage
that the steam coming from the boiler, which may be of a high pressure, does not
come in contact with the stuffing-box of the slide-box. When the steam comes directly
from the boiler and does not come in contact with the stuffing box, consequently steam
of a very high pressure and highly heated can be used. Hitherto it has been
impossible to use such steam on account of the packing of the stuffing-boxes, for the
steam had an injurious effect on them and destroyed them.
The using of steam of a high pressure is in particular advantageous because it
imparts a considerable amount of heat to the sides of the cylinder. These sides of the
cylinder are continually kept hot and therefore the cooled particles of steam cannot
condense on them. It is well known that the condensing of the steam in the cylinder
greatly diminishes the working power of the engine, which is avoided in this case by
The introduction of highly heated steam.
The method of introducing steam into the cylinder by conducting it firstly under
the slide valve is therefore of great advantage, and it is rendered still more so, by
combining this method of introducing the steam with an injector as may be seen in
the accompanying drawing, and this combination is claimed as patent. By means of
this combination described hereinafter it is not only possible to use steam of a very
high tension, but it is also possible to turn it to the best account by expansion, as will
he explained herein.
The drawing shows a cross-section of a steam-cylinder to which the above mentioned
combination is applied.

page_text: The arrangement and the working of this machine are the following:
M is the steam-cylinder in which two pistons L L are working, is the centre partition
of the cylinder. kk¹ppare 4 steam channels, leading into the cylinder. The slide
valve is composed of four parts m m'n n' which are moved in common by the valve
rod t. is an expansion slide valve of common construction and way of working.
is the steam inlet pipe leading to the room 0, which is situated under the slide-
valve mm. is an injector nozzle fed by the steam pipe r.
The pipe is in connection with a boiler of high pressure. The steam of high
While the steam is
pressure escapes through the nozzle and reaches pipe
escaping, the injector sucks up steam out of 7, which leads to the slide box S and
consequently steam is sucked up out of the latter. The steam that reaches 111 consists
therefore in a mixture composed of steam of high pressure from piper and of steam
coming from the slide-box S. The steam coming from S may, for instance, have a
pressure of G atm. and the steam of high pressure may be of 24 atm., then the steam
that enters the room O will have a pressure of about 16 atm.
This steam of 16 atm. pressure in room O passes through the slide-valve m¹ and
channel into the cylinder A'. As the slide valve m' moves to the left, the communi-
cation between 0 and A' shuts off when the cylinder-room is about half full, for the
the slide-valve m' covers the channel A. The steam then expands from 16 to 8 atm.
and when expanded the steam contained in room A enters the slide-box S with this
pressure of 8 atm.
The high pressure steam of 16 atın. contained in A' has meanwhile heated the sides
of the cylinder. During the back motion of the piston L' the slide-box S comes in con-
nection with the cylinder room B₁ and steam with a pressure of 8 atm. enters the
latter. In this room B¹ the steam can expand, provided there is a suitable motion of
the slide valve, from 8 atm. to 3 atm. There is no reason to apprehend a noxious
condensation of steam in this expansion, as the cylinder-sides are still highly heated.
This same effect is obtained on piston L, and the drawing shows the position in which
the steam of 8 atm. contained in room A enters the slide-box, and the steam comes
from the slide-box S through channel p into the room B.
The steam that enters room B B and which expands in the latter from 8 to 2 atm.
escapes after the expansion through channels p p into the pipes a¹ and can then
further be used for any desirable purpose.
It is ovident from what has just been said, that only a small portion of the steam,
that enters the slide-box S from the room A. A' is conducted back into the room B B¹
owing to the expansion in this room. The remainder of the steam is sucked up out of
the slide-box S through the pipe and by the injector and is compressed again by
the latter. In this compressed state it is reconducted to the room 0. One portion of
this steam is therefore always performing a circular motion, whereas the remainder,
which as regards quantity corresponds with the quantity of the high pressure steam
coming from the injector, is withdrawn from this circular motion by its escaping
through the pipes ¹.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :
The method of conducting the steam under the slide-valve after having previously
applied a steam-injector so that the steam operates in the cylinder before entering
the slide-box and so that the steam is sucked up in part out of the slide-box by the
steam-injector substantially as described.