Improvements in Automatic Expansion Valve Gear for Steam or other Fluid Pressure Engines.
Year: 1884

page_text: Improvements in Automatic Expansion Valve Gear for Steam or
other Fluid Pressure Engines.
I, LARS ENGEBRETSEN of Brinken's Gade 50 Christiania in the kingdom of
Norway, Manufacturer, do hereby declare the nature of my said invention for
"IMPROVEMENTS IN AUTOMATIC EXPANSION VALVE GEAR FOR STEAM OR OTHER
FLUID PRESSURE ENGINES" and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
This invention has for its object a construction of a valve gear for steam engines
which automatically cuts off the admission of steam whenever the regulator
indicates too high a speed of the engine, and which therefore causes even working
of the engine however variable the work to be performed thereby may be.
The means for attaining this object are briefly as follows:
At the back of an ordinary slide-valve with ports for steam admission the
expansion gear (valve or the like) for cutting off the stean supply is so placed that
it will follow the movements of the slide and is governed, namely opened and
closed, by a link or rod capable of rotation.
The said rotary link, or rod is moreover connected by various parts of machinery
(the special arrangement whereof is immaterial) with the inain shaft, or some other
shaft of the engine and with the regulator, in such a manner, that the link or rod
is slightly rotated on its longitudinal axis, thereby causing the steam ports to be
closed, whenever the regulator indicates that the engine is running at too high a
speed.
This connection between the link or bar the engine and the regulator is according
to the present invention, produced in a special manner. A V-shaped piece c (Fig. 5
see the accompanying drawing) is moved in the direction of the arrow 1 by the
regulator sleeve, whilst motion in the direction of arrow 2 perpendicular to the
former, is imparted to it from the engine. If the piece c is drawn towards the left
it has no effect upon the working of the engine which then is governed solely by
the main slide and works with that amount of steam-supply which is determined
by the slide. If however the regulator carries the piece c towards the right and
this piece by its movement in the direction of arrow 2 comes in contact with the
cam d¹, then the link or rod is rotated and the steam admission into the cylinder
is throttled. It will be seen that by reason of the V-shape of piece c the com-
mencement of the throttling or cut-off of the supply depends partly upon the

page_text: extent to which the regulator-balls separate, partly on the time, when the balls so
separate. In any case the sooner the steam is cut off the further piece c can
proceed in the direction 1.before touching the cam d¹.
The annexed drawings show how this invention may be applied to a horizontal
stationary engine and serve as an example for rendering the invention quite clear
and readily intelligible.
Fig. 1 a and b is a side elevation of the exterior valve gear and the back of the
slide without the slide box.
Fig. 2 a and b plan of the same parts with the slide valve and adjacent parts of
the cylinders in section on the centre of the slide valve.
Fig. 3 Transverse section of the slide on line A B Fig. 1, and
Fig. 4 is a transverse section through parts of the outside valve gear on line CD,
Fig. 1.
The operation of the valve gear is as follows:
As soon as the machine runs too fast the regulator sleeve rises and by means of
an elbow lever c² and rod c¹ pushes the piece c to the right between the guide-
cheeks of the block X. This block constitutes the one end (that at the right hand
side) of the two-armed lever b which by the link a receives a vertical oscillatory
motion from the eccentric.
Now as soon as by the said motion piece c meets the cam d', this will be pushed
forward (in Fig. 4 to the right) and slight rotation of the link or rod is effected by the
angle lever d having its bearings on a rigid hanger z, the rod e and arms fof carrier f¹
in which moves a square part of slide rod g. This rotation of the slide rod is by
sleeves and their arms & in its turn transferred to arms m of drop valves n fixed
by hinges s to ribs on the body of the slide-valve and this has for its effect that
these valves descend upon the back of the slide and close the ports p. The whole
is so arranged that the closing is almost instantaneous and is promoted by the steam
pressure.
The opening of the valves (that is to say the backward rotation of the slide link
or rod) takes place only when the ports in the cylinder are closed by the main
slide and it is effected by a cam i (shown by dotted lines in Figs. 1 and 2 and in
side view in Fig. 4) connected by a frame i¹ with the slide link, abutting against
a stud fixed upon the hanger z.
Now as the steam pressure is equal upon both sides of the drop-valves, but little
power will be required for this.
To prevent untimely closing of the drop valves, arms are provided on the
sleeves and these take under nose pieces y projecting from the drop-valves when
the latter are open.
To prevent accidental actions of the lever b upon the piece c
the connection between the regulator-rod and lever c² is placed as near as possible
to the centre of oscillation of lever b.
In the machine shown in the drawings the regulator is caused to rotate by a
circle of teeth on the fly-wheel.
:
From what has been stated and described it will be seen how the invention may
be applied to a horizontal engine for use on land.
To apply the invention to other constructions and forms of engines sundry not
unimportant modifications of the transmitting parts are obviously necessary, it
does not however seem to be necessary here to give detailed description and
drawings of such modifications, as any engineer will readily be able to arrange the
same for each special case and because the special construction of these parts is
not essential to the present invention.
As parts for transmitting motion the following may be referred to:
1. The connection between the slide link or rod capable of rotation and the
expansion valve.
2. The connection between said rod and the cam d¹.
3. The connection between the engine and the piece c.
4. The connection between this said piece and the regulator. On the other hand
it is of importance for the invention that the motion 2 in Fig. 5 shall be produced

page_text: by the sideways movement of the eccentric disc, as this movement occurs at such a
time and is of such nature as to be just what is required for the present object as
will be easily perceived if the movements of the expansion valve which are
produced thereby are analysed; it is however not essential that it should be
perpendicular to the slide link.
The said motion 2 Fig. 5 can however, as is obvious be produced by other means
than by the eccentric, of the inain slide also say by a second eccentric.
It is equally clear that the two motions 1 and 2 Fig. 5 need not necessarily take
just the directions shown in the drawings, thus they may for instance be inter-
changed without in the least altering the nature of the invention.
'Nevertheless the inventor is of opinion that the construction shown and described
will prove the most effective in practice.
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:-
In an automatic valve gear for marine and land engines with simple slide gear:
1. The employment of the V-shaped coupling piece c Fig. 5-which is moved
in the direction of its point (1 Fig. 5) by the regulator, and receives from the
engine an oscillating motion at right angles to the former for the purpose of
transmitting the power of the engine to the outer expansion gear in such a manner
that various degrees of expansion are attained by reason of the V-shape of the
piece according to whether the movement of the piece is greater or less, namely
whether it takes place earlier or later and so that the resistance to be overcome in.
this may be without effect upon the working of the expansion valves.
2. For producing the two motions of the piece c 1 and 2 Fig. 5 (either by means
of the eccentric of the main slide or of another eccentric in the same position) the
arrangement of link a and lever b in connection with rod c¹ and lever c² which is
so supported on lever b in such a manner.
3. In slide valves, the ports of which are controlled by expansion valves which
follow the slide movements, the regulation of these valves by the rotation of
the slide rod and consequent avoidance of specially attached guiding rods in the
valve box substantially as herein described and illustrated in the accompanying
drawings.
4. The employment of the construction above referred to of the expansion drop
valves capable of turning on hinges 8 and the connections above indicated
between the drop valves and the slide link by means of arms k so as to close the
drop valves by rotation of the rod and of the arms 7 for fixing the drop valves,
substantially as drawn and described.
5. The employment of the rod and lever connection def for rotating the slide
link, and of the cams h and i etcetera for turning same back for the purpose and
in the manner described and shown.