ATION, Slide Valve Gear for Steam and other Motive Power Engines.
Year: 1898

page_text: Date of Application, 8th Dec., 1898-Accepted, 21st Jan.,
1899
COMIUMIN DIUIFICATION,
Slide Valve Gear for Steam and other Motive Power Engines.
I, JOHANNES DAMLOS, of 30, Mühlendamm, Hamburg, in the Empire of Germany,
Merchant, do hereby declare the nature of this invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:―
The apparatus for distributing the steam to steam engines, for example, which
together form the valve gear, has hitherto been applied externally of the cylinder,
and various improvements have recently been made which render these parts very
complicated and consequently frequent repairs are necessary, the cost of the
engine is increased, and its maintenance is rendered more difficult.
This present invention relates to a slide valve which is situated in the interior
of the steam or other cylinder and is actuated directly by the piston.
In the accompanying drawings Figures 1 and 2 illustrate in horizontal section
a steam cylinder with a valve gear of this kind. Figure 3 is a section on the
line A B of Figure 1, and Figure 4 is a detail view.
cl
As may be seen from the drawing, the steam cylinder C is provided with the
inlet passages o a' and the exhaust passages 6 61. In the interior of the cylinder C
the slide valve S is arranged to slide steam-tight in a dovetail-shaped groove in the
wall of the cylinder (Figure 3). This slide-valve is provided with the ports
which correspond with the steam and exhaust passages. It is also furnished with
projections d d and is so shaped that it forms with mathematical accuracy a con-
tinuation of the cylindrical surface of the interior of the cylinder and therefore
fits steam-tight against the piston.
The slide-valve S, which allows the steam to pass alternately to each side of the
piston, is shewn in its extreme left-hand portion in Figure 1 and in Figure 2 in
its extreme right-hand position. In the position shown in Figure 1 the steam
enters through the passage a in the cylinder, and port c in the valve whilst the
exhaust passage b' is open. The piston K is now driven along the cylinder, and
when approaching the end of its stroke it comes against the projection d', causing
the slide-valve to be pushed along into the position shewn in Figure 2, closing the
passages a and b and opening the passages a¹ and b. The steam from the boiler
then forces the piston K back again, whilst the exhaust steam escapes by the
outlet into the open air or into the condenser, till the piston K again occupies
its first position as shown in Figure 1.
To avoid what is known as clearance space in the cylinder, both the cylinder
covers D and D₁ are recessed into the cylinders as shewn so that this space is
reduced as much as possible. It is obvious that by arranging the projections a
and d adjustably so that they can be pushed forward or backward, or by means
of a spring packing in the piston K for example, the supply of steam to the
cylinder may be cut off before the piston has completed its entire stroke, so that
for the remainder of the stroke the piston is driven to the end of its stroke by
the expansion of the steam and so a thorough utilization of the steam pressure is
effected.

page_text: In order to regulate the friction of the slide-valve in its guides and to prevent
any movement taking place during the stroke of the piston but before the latter
has reached its extreme position, a pressure device, such as shown in Figure 4,
may be employed consisting of the screw e, pressure plate f and spring 9.
Reversing of the engine can be effected by a suitable apparatus worked from the
outside of the cylinder, for example, by a rod, provided with a handle, passing
through a stuffing box in the cylinder-cover and attached to the slide-valve S.
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. Slide-valve gear for steam and other motive power engines which consists
of a slide-valve recessed into the wall of the cylinder, and moved directly by the
piston to open and close the inlet and outlet passages, substantially as described.
Second. In slide-valve gear of the kind referred to in the first claiming clause
hereof, a slide-valve S provided with projections d d and ports c e¹ and sliding
in a dovetail-shaped groove in the wall of the cylinder, the cylinder covers being
suitably dished or recessed to avoid clearance space at the ends of the cylinder,
substantially as described.
Dated this oth day of December 1090.
J. DAMLOS.
Per W. H. Beck,
Agent, 115, Cannon Street, London, E.C.