Improvements in Valves for Steam Engines.
Year: 1889

page_text: Date of Application, 22nd June, 1889
Complete Specification Left, 10th Feb., 1890-Accepted, 15th Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in Valves for Steam Engines.
We, DAVID CARMICHAEL, of Ward Foundry, Dundee, in the County of Forfar,
North Britain, Engineer, and ALEXANDER MACKIE, of the same place, Draughtsman,
do hereby declare the nature of this Invention to be as follows, that is to say :-
This Invention comprises further improvements in steam-engine valves of the
kind described in our complete patent Specifications No. 5834, and No. 8599, of
1889, these improvements being also applicable wholly or partly to various modifica-
tions of Corliss valves and valve gear.
In carrying out the present Invention three or more passages are formed through
and in connection with each admission valve and each exhaust valve, and the angular
movements for opening and closing the valves are proportionally diminished and the
wear and tear of the valves and valve gear lessened.
one
more
Each valve is made in the form of a hollow cylinder with ends, and with or
without one Gr more intermediate transverse diaphragms. According to
modification, six longitudinal ports, or twice as many as there are to be through
passages, are formed in the valve, each port being crossed by one or
strengthening bars or webs if required. The valve works in a cylindrical chamber
which it fits and which is formed in the cylinder end or gable; and between the valve
chamber and the cylinder there are formed three or more passages communicating
by ports with the chamber and uniting in a single passage communicating with the
cylinder. On the outer side of each valve chamber there are, similarly, three or
more ports in the cylinder end which may unite in a single passage by which the
steam has access to the valve in the case of an admission valve, or by which the steam
passes to the condenser in the case of an exhaust valve. When a valve is open its
ports communicate, half their number with the outer passages and the other half
with the inner passages, and when a valve is closed the parts of it between its ports
cover the ports of all the passages. The rocking shaft or spindle which works each
valve and which extends through the valve is made with cross bars at the ends to
act on the valve, the intermediate part being round so as to offer the least obstruction
to the passage of the steam.
The improved valves and their passages may be arranged as in ordinary Corliss
engines with the admission and exhaust valves on opposite sides of the cylinder;
they may however be very conveniently placed on the same side of the cylinder;
and the valve chambers and passages may be formed in the main cylinder casting or
in gables or end castings.
Dated this Twanty-first dose of Inno 1880
EDMUND HUNT,
Applicants' Agent.
COMPLETE SPECIFICATION.
Improvements in Valves for Steam Engines.
We, DAVID CARMICHAEL, of Ward Foundry, Dundee, in the County of Forfar,
North Britain, Engineer, and ALEXANDER MACKIE, of the same place, Draughtsman,
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, that is to say :-
This Invention comprises further improvements in steam-engine valves of the kind
described in our complete patent Specifications No. 5834 and No. 8599, of 1889,

page_text: these improvements being also applicable wholly or partly to various modifications of
Corliss valves and valve gear.
In carrying out the present Invention three or more passages are formed through
and in connection with each admission valve and each exhaust valve, and the angular
movements for opening and closing the valves are proportionately diminished and the
wear and tear of the valves and valve gear lessened.
On an accompanying sheet of explanatory drawings, figure, 1, is a longitudinal
section of a valve chamber the cylinder being in transverse section; and ägure, 2, is
a'section as at right angles to figure, 1, and as at the line, A-A.
Each valve is made in the form of a hollow cylinder, 3, with ends and with or
without one or more intermediate transverse diaphragms, 4. According to the
modification shown in the drawings six longitudinal ports, 5, 6, or twice as many as
there are to be through passages, are formed in the valve, 3, each port being crossed
by one or more strengthening bars or webs if required. The valve, 3, works in a
cylindrical chamber, 7, which it fits and which is formed in the cylinder end or
gable, 8, and between the valve chamber, 7, and the cylinder, 9, there are formed
three or more passages communicating by ports, 10, (which are crossed by
strengthening ribs, 11) with the chamber, 7, and uniting partly through a branch
passage, 12, in a single passage, 13, communicating with the cylinder, 9. On the
outer side of each valve chamber, 7, there are, similarly, three or more ports, 14, in
the cylinder end, 8, which may unite in a single passage by which the steam has
access to the valve, 3, in the case of an admission valve, or by which the steam
passes to the condenser in the case of an exhaust valve. When a valve, 3, is open its
ports, 5, 6, communicate, half their number with the outer passages and the other
half with the inner passages, and when a valve, 3, is closed the parts of it between
its ports, 5, 6, cover the ports, 10, and 14, of all the passages. The rocking shaft or
spindle, 15, which works each valve, 3, and which extends through the valve is made
with cross bars, 16, at the ends to act on the valve, 3, the intermediate part being
round so as to offer the least obstruction to the passage of the steam.
The improved valves, 3, and their passages may be arranged as in ordinary Corliss
engines with the admission and exhaust valves on opposite sides of the cylinder, 9,
they may however be very conveniently placed on the same side of the cylinder; and
the valve chambers, 7, and passages may be formed in the main cylinder casting or in
gables or end castings, 8.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
:
: The improved construction of Corliss valves for steam engines, each valve being
made of a form obtainable from a solid or hollow cylinder by forming three or more
passages or three or more pairs of ports through it, and the valve being arranged to
work in connection with ports and passages at both the inlet and egress sides of
the valve chamber, substantially as hereinbefore described and as shown in the
accompanying drawings.
Dated this Eighth day of February 1890.