AN IMPROVED VALVE FOR STEAM AND GAS ENGINES
Year: 1853

page_text: PROVISIONAL SPECIFICATION left by Theodore Dwight Davis
at the Office of the Commissioners of Patents, with his Peti-
tion, on the 26th January 1853.
(Void by reason of notice to proceed not having been given within the
time prescribed by the Act.)
I, THEODORE DWIGHT DAVIS, of 16, Castle Street, Holborn, in the
County of Middlesex, Engineer, do hereby declare the nature of the
said Invention for "AN IMPROVED VALVE FOR STEAM AND GAS ENGINES"
to be as follows: -
A, A, A, A, is a metal cylinder with openings B, B, and B¹, B¹;
C, C, are heads secured to the ends of the cylinder by bolts; D, D',
are bearings and boxes secured to the heads by bolts; E, is a chamber
in communication with the boiler; F, is a shaft working in the
bearings D, D¹. Secured to the shaft is a cylinder or valve G, with
openings H, H, parallel to the axis, for the admission of steam or gas
from the chamber E, through the openings B¹, B, into the cylinder
G. I, I, are openings for the admission of steam or gas from the
valve into the passages K, K, communicating with the reciprocating
cylinder L; M, is a hollow space or chamber in the valve G, con-
necting alternately the openings B, B, with the central opening or
exhaust passage N, through which the steam passes after being used
into the condenser or smoke pipe or into the air; O, is a crank or arm
secured to the shaft F, which has a vibratory motion from the eccentric

page_text: given by the eccentric rod, which is attached to the wrist P. The vi-
brating motion of the valve brings in communication alternately the
openings H, H, in the valve with the openings B', B', in the outer cylin-
der, and at the same time bringing in communication one of the open-
ings I, in the valve with one of the openings or passages B, in the outer
cylinder, admitting the steam or gas to the cylinder L, and vice
versa. The inside of the outer cylinder A is bored true and smooth.
The outside of the valve or inner cylinder is turned to correspond with
the inside of the outer cylinder. The two surfaces are then ground
to a joint with emery or otherwise. The valve is made conical for the
purpose of being easily adjusted, which is done by set screws at the
ends of the shaft F. The outer cylinder is secured to the recipro-
cating cylinder by the bolts R, R; the shaft of the valve passes through
packing boxes in the heads of the cylinder. The advantages of this
valve over the slide valve are its simplicity, it doing away with the
rock shaft, valve rods, &c., thus saving a very great expense in the
construction, also equalizing or doing away with the pressure on the
valve, thereby saving a great amount of power required to work the
ordinary valve; its durability, it doing away with a great amount
of friction, and not being liable to wear and get out of order, also
admitting the steam quicker than the ordinary valve, &c. When
this valve is used for governing or regulating the motion of steam
or gas engines it is worked by a lever communicating with the re-
gulator. A portion of the shaft F, and the bearing D₁, may be dis-
pensed with, and the cylinder adjusted by a set screw passing through
the head C¹ to the shaft F. The openings for the admission and exit of
the steam or gas are transverse to the axis, and may be made of any
suitable form. The cylinders may be made either of iron or of a
compound of metals to secure a suitable expansion.