IMPROVEMENTS IN VALVES FOR MOTIVE POWER ENGINES, AND IN THE MECHANISM FOR WORKING AND REGULATING THE SAME."
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Friedrish Wilhelm Unterilp at the
Office of the Commissioners of Patents on the 20th October 1879.
FRIEDRISH WILHELM UNTERILP, of Düsseldorf, in the Empire of Germany.
"IMPROVEMENTS IN VALVES FOR MOTIVE POWER ENGINES, AND IN THE MECHANISM
FOR WORKING AND REGULATING THE SAME."
The objects of this Invention are, firstly, to avoid the waste of power resulting
from the excessive amount of steam space in and around the valves of motive
power engines, and secondly, to simplify the construction of the mechanism for
working such valves.
In carrying out the first object of my Invention I have constructed a new type
of valve which may have a single or a double seal, and is applicable both as an
admission valve, and as an exhaust or discharge valve.
The valve consists of a tube open throughout and made either with or without
flanges, and it works in a cylindrical opening provided with lateral steam passages,
which are closed or opened as the valve rises or falls.
The admission and exhaust valves have their seats in the same tubular casting
which forms a cylindrical lining to the valve chest, and on opposite sides of a
horizontal partition which divides the tube into two parts.
•
The admission valve consists of an open tube which is cast with radial arms
carrying a central boss to which the valve stem is fitted. This valve stem passes
up through a stuffing box in the cover of the valve chest, and it is slotted near its
outer end to receive the end of a rocking arm by which the valve is actuated, as
will be hereafter described.
This valve is furnised with packing rings, and it is constructed so as to close by
the pressure of the steam, which renders unnecessary the use of springs or weights
for that purpose. The diameter of the upper part of the valve is somewhat larger
than the lower part, the tubular seating being correspondingly bored out to receive
it. This enlarged diameter acts as an annular piston upon an air cushion formed
by an air space below it, which is in communication with the atmosphere through
a small hole made through the side wall of the tubular seating, into an annular
channel cored out of the casting of the cylinder and valve chest.
The tubular casting which is divided into two parts by a transverse partition, as
above mentioned is formed above this partition with radial openings for the passage
of the steam to the cylinder. These radial openings are somewhat contracted in

page_text: depth by means of a fillet standing up from the partition for the purpose to DU
presently explained.
As the valve falls towards its seat it strikes upon the air cushion at the same time
that the lower edge reaches the top edge of the projecting fillet, and thereby closes
the steam passages. This arrangement is made in order that the valve should not
fall with violence, but gently settle down on its seat. The exhaust valve which
may be either a single or a double seated valve differs from the ordinary double
seated valves, inasmuch as the steam issues only from between the lower edge of
the valve and the lower seat.
This lower seat is formed virtually in the walls of the tubular casting, the ring
which constitutes the seat being connected by radial arms with the underside of
the horizontal partition.
A flange projecting from the tubular casting at about a level with the partition
forms the upper seat for the valve, which valve has an internal lip at its upper
edge to overlap and rest upon the upper seat. The exhaust valve is carried by
radial arms from a central boss attached to a valve spindle, which projects down
through a stuffing box at the bottom of the valve chamber, and is slotted like the
stem of the upper valve and for a like purpose.
The boss of the valve carries an upward projecting stem which passes through a
central socket in the horizontal partition and acts as a piston, the top of the stem
being open to the action of the steam in the interior of the valve; thus the valve is
pressed by the steam onto its seat rendering the use of springs and weights
unnecessary.
It may be here remarked that the valves above described may be employed as
distributing valves or stop valves in water or other motors than steam motors.
When applying the valves to water motors, washers of leather may be used for the
packing.
A simple arrangement of levers suitable for working the valves when employed
in winding engines, and other mechanism requiring a reversing motion may consist
of two rocking levers mounted in bearings on the covers of their respective valve
chests, and connected respectively with the stems of the admission valves. These
levers by means of link rods are connected with bell crank levers keyed to short
rock shafts carried in bracket bearings from the bed-plate of the engine. These
rock shafts have lever arms connected to the stems of the exhaust valves. The bell
crank levers are coupled by a link rod, which rod being connected to the ordinary
link motion of the engine will transmit through the arrangement of levers just
described the requisite motions to the valves.
Another arrangement of mechanism by which I secure the full advantages
derivable from the use of my improved valves, and which has also for its end to
render the admission valve free to fall in order to regulate the cut-off or degree of
expansion consists as follows:-
A pinion is fitted loosely to the stem of the admission valve so as to be free to turn
thereon, and upon its extended hub is secured a snail shaped flange. This pinion
with its flange is connected by collars to the valve_spindle, so as to ensure their
rising and falling together.
A rock lever bears against the underside of the flange and serves to lift the
admission valve from its seat. This rock lever is pivotted to the vertical arm of a
bell crank lever, having its fulcrum in a bracket bearing carried by the cover of the
valve chest. The other arm of this bell crank lever is connected to the rod of an
excentric, which is keyed to a horizontal shaft having its bearings on the bed
plate. The outer end of the rock lever is connected by the rod to a second
excentric on the shaft.
As therefore rotary motion is imparted to this shaft from the crank shaft of the
engine, the lever will not merely rock on its fulcrum, but will be made to advance
towards the valve stem, lift the valve from its seat by pressing on the underside of
the flange, and then retire from contact with that flange so as to allow the valve to
fall. In order to modify the action of this rock lever and enable the valve to cut

page_text: off the steam at various points of the stroke of the engine, an axial motion is given
to the flange so as to present to the rock lever a longer or shorter radius of the
flange, and thereby to vary the length of action of the rock lever upon the valve
during one of the vibrations of the lever. This axial motion of the flange is
derived from a reciprocating rack bar, which receives its motion from the steam
engine governor in any convenient manner.
For operating the exhaust valve a third excentric is provided on the shaft.
A rod from this excentric is pivotted to a rock lever which has its fulcrum on a
bracket bearing carried by the bed plate, and is connected by an adjustable slotted
head with the stem of the exhaust valve.
Instead of having a snail flange to which an axial motion is imparted for modifying
the action of the rock lever on the valve, I may use a fixed disc and connect the
bell crank lever carrying the fulcrum of the rock lever with the governor of the
engine in such manner that the rock lever will be drawn out of contact with
the disc when the valve is required to cut off steam.