Improvements in Steam Actuated Dash-pot Mechanism for Use in connection with Engine Valve-gear.
Year: 1899

page_text: Date of Application, 6th Dec., 1899-Accepted, 6th Jan., 1900
Improvements in Steam Actuated Dash-pot Mechanism for Use in
connection with Engine Valve-gear.
We, RICHARD HENRY RICE and JOHN WARREN SARGENT, both of No. 521,
South Main Street, Providence, Rhode Island, United States of America, Mechani-
cal Engineers, 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 object of my invention is to provide improved means for the instant closing
of the steam valve upon its liberation by the action of a variable valve gear,
our invention being especially adapted for use in connection with the well
known Corliss" valve gear; and our invention consists in the improved com-
bination of a steam actuated plunger and a dash-pot with the valve and valve
bonnet, and in so piping the cylinder of the steam actuated plunger that the
water of condensation will collect in the said cylinder and tend to prevent leak-
age of steam therefrom.
In the accompanying drawings:
Fig. represents a side elevation of the valve bonnet, with the attached
cylinders of the steam-actuated plunger and the dash-pot, and showing the con-
nection between the piston-rod of the dash-pot, and the valve stem.
Fig. 2 represents a vertical section taken in the line A A, of Fig. 1.
Fig. 3 represents a side view of an engine cylinder, the valves of which are
provided with our improvement.
Fig. 4 is a detail view showing the slotted construction of the piston-rod, and
the sliding box carried thereby.
In the drawing, 10 represents the cylinder of a steam engine 11, 11, represents
the steam-valve caps or bonnets, and 12 12, the valve stems, which are made to
project outward beyond the bonnets in order to provide for the connection thereto
of a liberating valve-gear, which may be of any suitable construction. The
arm 13, is secured to the valve stem 12, and provided at its outer end with the
stud 14, upon which are placed the bearing boxes 15, 15, the said boxes being
held in the slot 16, which is formed in the piston rod 17, and adapted for the
limited sliding movement of the said boxes. The steam pressure cylinder 18,
is secured to a projecting horn 19, of the valve bonnet 11, and the air cushion
cylinder 20, is secured to the projecting horn 21, the axes of the said cylinders 18
and 20, being in line with each other. The piston rod 17, is provided at its
lower end with the plunger 22, which passes through the packing gland 23, of
the steam pressure cylinder, and at its upper end with the cushioning air
piston 24, which fits the bore of the cylinder 20. The face of the piston 24, is
provided with perforations 25, 25, which are covered by the leather flaps 26, 26,
the said perforations serving to allow the air in the cylinder to pass directly
from the under to the upper side of the piston at its downward movement, in-
stead of passing through the side ports 27, 28, and the vertical connecting
passage 29, through which the air is caused to pass upon the upward movement
of the piston. The port 28, is inclined upward at one end as shown in Fig. 2,

page_text: in order that the passage of the confined air through the said port will be
gradually checked, and its pressure above the piston 24, gradually increased,
until the piston passes upward beyond the extreme corner 30, of the port 28,
and thereafter, the confined air which forms the cushion above the piston 24,
will escape into the passage 29, through the annular valve opening 31, the
dimension of which may be regulated by turning the valve screw 32. As the
piston 24, moves upward in the cylinder 20, the air will flow from one side to
the other of the piston, through the ports 27 and 28, and the passage 29, and
upon its downward stroke, through the perforations 25, 25, of the piston, and
upon the release of the steam valve by the liberating valve gear, the valve will
be suddenly closed by the action of the steam upon the plunger 22, the momentum
of the connected parts being cushioned by the confined air in the cylinder 20.
The steam pipe 33, is connected with the steam pressure cylinder 18, by means
of the downwardly turned steam pipe 34, whereby the water of condensation will
be retained in the cylinder 18, and the leakage of steam therefrom prevented.
It is to be understood that any desired form of liberating valve gear may be
employed in connection with the steam actuated dash-pot mechanism herein
shown and described.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what
we claim is;-
1. In a valve-controlling dash-pot mechanism, the combination of the valve,
the attached arm for actuating the valve, and the valve bonnet with the steam
pressure cylinder and the air cushion cylinder attached to the valve bonnet,
the steam actuated plunger and piston rod, the cushioning air piston at the
opposite end of the piston rod, and means for connecting the piston rod and the
valve actuating arm.
2. In a valve controlling dash-pot mechanism, the combination of the valve,
the attached arm for actuating the valve, and the valve bonnet, with the steam
pressure cylinder and the air cushion cylinder attached to the valve bonnet,
the steam actuated plunger and piston rod, the cushioning air piston at the
opposite end of the piston rod, means for connecting the piston rod and the
valve actuating arm, and the downwardly directed steam pipe, whereby the water
of condensation will be retained in the steam pressure cylinder and serve to
prevent leakage of steam.
Dat is 5th ....
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.