PROVEMENTS IN APPARATUS FOR ACTUATING THE VALVES OF STEAM OR WATER PRESSURE ENGINES
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Arthur Whalley at the Office of the
Commissioners of Patents on the 29th March 1878.
"IM-
ARTHUR WHALLEY, of Earlestown, in the County of Lancaster, Engineer.
PROVEMENTS IN APPARATUS FOR ACTUATING THE VALVES OF STEAM OR WATER
PRESSURE ENGINES."
This Invention is applicable to any class of engine whose motion is only recipro-
cating, and also to existing "Cornish" engines; and also relates to means of
adjusting the pause at each end of the stroke of a pumping engine to suit its
working to the flow of water in the pumps; the means employed being made to
regulate the admission of steam to suit every variation of its load, and in case of
the whole load being suddenly thrown off the valve is reversed, and steain admitted
to the opposite end of the cylinder, thus preventing the piston colliding with the
cylinder covers, and ensuring against accident.
In the arrangements hereafter described, my Invention is used in connection
with ordinary slide valves, but I do not confine myself to the use of this class of
valves, but in larger engines prefer to use double beat Cornish valves.
My arrangements are mainly as follows:-One arrangement for working the
slide valve of a horizontal engine is as follows:-On a frame carried by any
convenient part of the engine, I place a subsidiary steam cylinder, and a cataract
cylinder, the same piston rod being common to both pistons.
The cataract cylinder is provided with a port (governed by an adjustable plug)
for the passage of liquid from one end of the cylinder to the other.
The piston rod of the cataract and subsidiary pistons is jointed to the long arm
of a vertical double lever, the short arm of which is attached to the main slide
valve by means of a link. The fulcrum of this double lever is carried by the short
arm of a pair of vertical levers, the long arm of which extends downwards, and is
connected to the piston rod of the main cylinder by means of a link or other
arrangement. The fulcrum of this pair of levers is carried by a bracket attached to
the subsidiary and cataract cylinders.
The subsidiary cylinder is provided with a separate valve chest and slide valve,
which valve obtains its motion by means of tappets actuated by the levers attached
to the main piston rod.

page_text: The modus operandi is as follows:-As the main piston makes its stroke, the
long arm of the levers connected thereto is carried with it, the short arms above
moving in the opposite direction, in time with (but much more slowly than) the
main piston, and carrying with it the fulcrum of the double vertical levers attached
to the main slide rod, and to the subsidiary piston rod, thus moving the main
slide valve slowly in a direction opposite to that of the main piston, and cutting off
steam.
As the main piston approaches the end of its stroke, the slide valve of the
subsidiary cylinder is reversed (by the tappets actuated by the lever attached to
the main piston rod), thus admitting steam to one end thereof.
The subsidiary piston and the vertical double levers attached thereto are there-
fore propelled with a speed regulated by the resistance of the liquid in the cataract
cylinder to the piston thereof, which is on the samne rod. By the movement of
these levers the main slide valve is shifted, and steam admitted to the main
cylinder at the end which the main piston has reached, thus causing it to make its
return stroke.
It will be readily understood from the above description that the admission of
steain to the main pistons is effected by the subsidiary cylinder, whose speed is
governed by the cataract; thus naturally determining the speed of the engine,
while the cut-off or expansion is effected by the engine itself.
Another arrangement of the improved apparatus applicable to larger engines or
compound horizontal engines, where the high and low pressure cylinders are
situated one behind the other, with their axes in the same line, is as follows:-
Upon a frame or bracket carried by the engine bed or slide bars, I place a
subsidiary steam cylinder and cataract cylinder, the same piston rod being
common to both pistons.
The cataract cylinder is provided with a port, governed by an adjustable plug,
for the passage of liquid from one end of the cylinder to the other.
The piston rod of the cataract and subsidiary pistons is jointed to the long arm
of a horizontal lever, the short arm of the same lever being attached to the main :
slide rod by means of a link, and the fulcrum of this horizontal lever being carried
in a sliding block working on a horizontal slide bar, the block being actuated by
a connecting rod attached to an upright_short arm of a rocking shaft, from which
there is a long arm extending downwards, and connected to the main crosshead of
the engine to which the piston rod is attached.
The subsidiary cylinder is provided with a separate valve chest and slide valve,
which valve obtains its motion by means of tappets actuated by a lever on the
before-mentioned rocking shaft.
By this arrangement of the gear, the action is as follows:-The cross-head of
the main pistons, as they make their stroke in either direction, causes the long
arm of the lever working the rocking shaft to move in the same direction, the
short arm above coupled to the sliding block moving in an opposite direction, in
time with (but much more slowly than) the main piston, thus moving the horizontal
lever attached to the main slide valve, and to the subsidiary piston rod, and
causing the main slide to move slowly in an opposite direction to the piston.
As the main piston approaches the end of its stroke, the slide valve of the
subsidiary cylinder is reversed (by the tappets actunted by a lever on the rocking
shaft worked by the cross head) and steam is admitted to one end thereof; tho
subsidiary piston and the horizontal lever to which it is attached is therefore
propelled.
By the movement of the horizontal lover the main slide valve is shifted, so as to
admit steam to the main cylinders at the end which the main piston has reached,
thus causing it to make its return stroke.
When a greater degree of expansion is required, I use expansion valves thus:—
I make the main slide valve with ports, and work the expansion valves on the
back thereof, in the following manner:-I carry the rod of the expansion slides
through both ends of the valve chest, and to one end joint the long arm of a
4

page_text: vertical lever, which I pivot upon a centre carried by the main slide rod, the short
arın extending downwards being provided with a slot carrying a movable stud
attached to the connecting rod actuating the sliding block. By those means the
expansion valves are made to move for the admission of steam at the same time
and in unison with the main slide, but are put back with a greatly accelerated
speed, thus causing an early cut-off.
By altering the position of the stud in the slot, the expansion can be varied to
any grade.
In the arrangements above described, a pause will be caused at the end of each
stroke of the engine, equal in duration to the time required by the subsidiary
piston to move the main slide over its lap; but where it is necessary to have a
pause of longer duration, I make the valve chest of the subsidiary cylinder circular
at the ends, and form a small piston on each end of the slide valve, steam being
admitted to these pistons by means of a subsidiary slide valve, actuated by tappets
from the main engine, as before described. I then connect the rod of the main
slide valve of the subsidiary cylinder to the piston of a subsidiary cataract formed
on the back of the main cataract cylinder, and regulate the flow of the liquid by
means of a screw. It will thus be seen that when steam is admitted to the pistons
of the subsidiary slide valve, that valve must move with a speed regulated by the
subsidiary cataract, thus causing the slide valve of the main engine to open
sooner or later, and the main pistons to make a shorter or longer pause at each end
of their stroke.
Apparatus similar to that described above is applicable for working the slides of
engines actuated by water pressure and for regulating the pause at the end of each
stroke of such engines, as may be readily understood, the apparatus for working
the expansion valves being in such engines dispensed with.