An Automatic Valve-motion for Steam-engines and the like.
Year: 1893

page_text: Date of Application, 23rd Nov., 1893—Accepted, 23rd Dec.,
1893
COMPLETE SPECIFICATION.
An Automatic Valve-motion for Steam-engines and the like.
1, WILHELM SCHMIDT, of Villa Henkel, Wilhelmshöhe near Cassel, in the
Province of Hesse-Nassau, German Empire, Civil Engineer 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 :-
This invention relates to a valve-motion which is actuated perfectly automatically
by the throttling action of the valve proper on the steam, and by the expansion of
the latter within the cylinder, as will be more fully described hereinafter.
I have shown one mode of construction of my new automatic valve-motion in
Fig. 1 of the accompanying drawing, in which a is the cylinder of a single-acting
steam-engine, b the piston of the same, c the inlet for the steam, and d the annular
outlet for the latter.
A valve e is arranged in front of the inlet-channel f of the cylinder; the spindle e¹
of said valve extends upwards into a casing g, and the head of the spindle is
provided within said casing with a plate h, being under the influence of spring i.
This spring tends to keep valve e constantly open, and the extent of the stroke of
the valve, together with the tension of the spring, may be altered by an adjustable
screw k arranged in the top of casing g, and acting on the head of spindle e¹. This
arrangement now works as follows:-
Supposing, the piston has reached the end of its back-stroke, and steam is
entering the cylinder through inlet c, through the small annular space between
valve e and its seat, and through the channel f, the steam will be throttled then
by valve e, in consequence of which a difference in pressure arises between the steam
above and below said valve; that is to say, the steam within the space a¹ of the
cylinder will be of a tension somewhat less than that of the steam within chamber c¹
above the valve. The piston now travels forward, and the steam, owing to the
increasing velocity of the piston from the end of its path to the middle part of the
same, flows into the cylinder with a correspondingly increasing velocity, so that
the excess of pressure above valve e becomes greater and greater, until, finally, said
excess has become as great as to be sufficient for overcoming the counter acting
tension of spring i; valve e, therefore, is instantly closed in this moment, which
occurs at the latest, when the piston has reached the middle part of its path or,
with other words, has reached its greatest velocity: the steam expands now
during the further movement of the piston and is exhausted finally through the
annular channel d. The valve, in every case, is closed already, before channel d is
opened.
The fore-stroke of the piston being finished, the direction of the latter changes,
as usual, and the remainder of the steam within the cylinder is compressed by the
back-stroke now following. As a matter of course, the degree of compression of
the remaining steam increases according to the diminution of the space behind the
piston, and said compression will at the end of the back-stroke of the piston be as
As soon
strong as to balance finally the pressure of the fresh steam on valve e.
now as the pressures exerted on both sides of valve e are like, the latter is opened
by spring, and the steam now works in exactly the same manner as above
described.
In case, the pressure of the compressed remainder of the steam below valve e
should not be as strong as necessary for balancing the pressure of the fresh steam
above said valve, an auxiliary inlet-organ for the fresh steam may be arranged, as
also shown in Fig. 1.
The said arrangement consists of the valve 1, normally closing a channel m in the
rear wall of the cylinder-casing. A projection fixed to valve l extends through

page_text: said channel a short distance into the space a¹, and the valve is pushed backwards
by the impact of the piston on said part l' as soon as the piston reaches the end of
its back stroke. The fresh steam is, then,, entering the cylinder through a
channel n communicating on one side with inlet c, and on the other side with
channel m, and the pressures above and below the valve e become, thus, instantly
alike, so that the latter opens with perfect security.
The stroke of valve e may be altered by screw k, as already mentioned, and I
may thus alter also the degree of filling, as the latter will be the greater, the
greater the stroke of said valve. This may be performed, however, also by means
of a regulator, as shown as an example in Figs. 2 & 3.
9,
The spindle e, when in its highest position, lies against an eccentric disk o
fixed to a shaft p. The latter may be turned from the regulator by rod and
crank-lever r, and is turned, as a matter of course, as soon as an alteration of the
velocity of the engine occurs. If, now, the engine moves too fast, the disk o is
turned by crank r, or by the regulator respectively, in such a direction, that the
stroke of spindle e', or of valve e respectively, is diminished, in consequence of
which also the degree of filling is decreased by the earlier closure of valve e.
This regulation, however, may occur also automatically by the greater velocity
of the steam, when the engine is moving too fast, and by the increased throttling
of the steam resulting from said velocity, so that the excess of pressure necessary
for closing the valve occurs correspondingly earlier. In the contrary case, i.c. if
the engines move too slow, the valve will be closed correspondingly later.
I may still add, that there is exerted on the regulator, none or scarcely any
resistance at all by the alteration of the contact between spindle el and disco, as
the latter generally is moved only when piston 6 has reached the middle part of
its path, i.e. has reached its greatest velocity, and as, therefore, valve e has been
closed already before disk o is turned.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a steam-engine or similar motor, an automatic valve-motion, characterized
by an inlet-organ constantly tending to be open, said inlet-organ being adapted to
be closed by an one-sided excess of pressure, for the purpose as described.
2. In a steam-engine or similar motor, an automatic valve-motion, characterized
by an inlet-organ constantly tending to be open, said inlet-organ being adapted to
be closed by an outer excess of pressure arising from throttling of the steam or
the like, for the purpose as described.
3. In a steam-engine or similar motor, an automatic valve-motion, characterized
by an inlet-organ constantly tending to be open, said inlet-organ being adapted
to be closed by an outer excess of pressure, arising from the throttling and
expansion of the steam or the like, for the purpose as described.
4. In a steam-engine or similar motor, an automatic valve-motion, characterized
by an inlet-organ constantly tending to be open, said inlet-organ being adapted to
be closed by an outer excess of pressure arising from the throttling action of said
inlet-organ on the steam or the like, and from the expansion of the latter within
the cylinder, for the purpose as described.
5. In a steam-engine or similar motor, an automatic valve-motion, characterized
by an inlet-organ e, a spring i tending to keep said inlet-organ constantly open,
the latter being adapted to be closed by an excess of pressure in chamber c¹ with
regard to the pressure in space a¹, substantially as described.
6. In a steam-engine or similar motor, an automatic valve-motion, characterised
by an inlet-organ e, a spring i tending to keep said inlet-organ constantly open,
the latter being adapted to be closed by an excess of pressure in chamber c¹ with
regard to the pressure in space a', the stroke of said inlet-organ being adjustable
or regulable, for the purpose as described.
7. In a steam-engine or similar motor, an automatic valve-motion, characterised

page_text: by an inlet-organ e, a spring tending to keep said inlet-organ constantly open, the
latter being adapted to be closed by an excess of pressure in chamber c with
regard to the pressure in space a¹, the stroke of said inlet-organ being adjustable
or regulable by hand or from the regulator, for the purpose as described.
8. In a steam-engine or similar motor, an automatic valve-motion, characterised
by an inlet-organ e, a spring i tending to keep said inlet-organ constantly open, the
latter being adapted to be closed by an excess of pressure in chamber c' with
regard to the pressure in space a', the stroke of said inlet-organ as well as the
tension of said spring being adjustable or regulable by hand or from the regulator,
for the purpose as described.
9. In a steam-engine or similar motor, an automatic valve-motion, characterised
by an inlet-organ e, a spring i teuding to keep said inlet-organ constantly open, the
latter being adapted to be closed by an excess of pressure in chamber c' with
regard to the pressure in space a¹, the stroke of said inlet-organ as well as the
tension of said spring being adjustable or regulable from hand by a screw k, or
from the regulator by an eccentric disk o, substantially as described and shown in
Figs. 1 and 2 of the drawing.
10. The combination with an automatic valve-motion as characterised by
Claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, of an auxiliary inlet-organ adapted to admit fresh
steam into the cylinder, for the purpose as described.
11. The combination with an automatic valve-motion as characterised by
Claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, of an auxiliary inlet-organ adapted to admit fresh
steam into the cylinder at or near the end of the path of the piston, for the
purpose as described.
12. The combination with an automatic valve-motion as characterised by
Claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, of an auxiliary inlet-organ adapted to be opened
by the piston at or near the end of the path of the latter, for the purpose as
described.
13. The combination with an automatic valve-motion as characterised by
Claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, of an auxiliary inlet-organ normally closing an
inlet-channel m, and having a projection ', said auxiliary inlet-organ being adapted
to be opened by the impact of the piston on said projection, and to admit fresh
steam into the cylinder, substantially as described and shown in Fig. 1 of the
drawing.
Dated this 23rd day of November 1893.
WILHELM SCHMIDT,
By Geo. Thos. Hyde,
4, Moorfields, Fore Street, London, E.C., Agent for the Applicant.