Improvements in Corliss Valves for Steam Engines.
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
Improvements in Corliss Valves for Steam Engines.
We, JOHN HENRY HARGREAVES, and JOHN GEORGE HUDSON, both of
Soho Iron Works, Bolton, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention to be as follows, that is to say :-
Our said invention has for its object by a simple constructive improvement to
diminish the pressure acting on the back of a Corliss steam-engine valve, during
the movement of such valve.
The invention consists in forming one or more passages from the contact surface
of the lap (that is the part which uncovers the port to admit steam) into the
groove at the back of the valve. The valve is moved in the ordinary way by a
rocking bar or flattened spindle fitting more or less tightly in the groove at the back
of the valve; and it is with the space between the bottom of this bar and the
bottom of the groove that the passage or passages communicate.
When the valve
is moving to uncover the port, communication is made between the interior of the
port and the groove at the back of the valve as soon as the lap passage or passages
get on the port, and then the pressure on the back of the valve becomes
considerably reduced, and the further movement of the valve is more easily effected.
When the valve closes, as usual, by the action of a spring, such closing is rendered
more certain and accurate ás regards time, in consequence of the diminished pressure
on the valve, the full pressure only coming into action at the end of the closing
movement.
Dated this Ninth day of November 1894.
EDMUND HUNT,
Applicants' Agent.
COMPLETE SPECIFICATION.
Improvements in Corliss Valves for Steam Engines.
We, JOHN HENRY HARGREAVES, and JOHN GEORGE HUDSON, both of
Soho Iron Works, Bolton, in the County of Lancaster, 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, that
is to say:
Our said invention has for its object by a simple constructive improvement to
diminish the pressure acting on the back of a Corliss steam-engine valve during the
movement of such valve.
The invention consists principally in forming one or more passages from the
contact surface of the lap (that is the part which uncovers the port to admit
steam) into the groove at the back of the valve. The valve is moved in the
ordinary way by a rocking bar or flattened spindle fitting more or less tightly in
the groove at the back of the valve; and it is with the space between the bottom
of this bar and the bottom of the groove that the passage or passages communicate.
When the valve is moving to uncover the port communication is made between the
ID Ql

page_text: interior of the port and the groove at the back of the valve as soon as the lap
passage or passages get on the port and then the pressure on the back of the
valve becomes considerably reduced, and the further movement of the valve is more
easily effected.
And in order that our said invention and the manner of performing the same
may be properly understood we hereunto append a sheet of explanatory drawings,
to be hereinafter referred to, and showing valves as made according to our
invention.
Figure, 1, of the drawings is a longitudinal section, and Figure, 2, a cross section
of one modification.
Figures, 3 and 4, are cross sections at different points of a second modification.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
We form passages, A, (which may be either a series of small holes as in the first
modification or openings corresponding in length to the cylinder ports as in the
second modification) from the contact surface of the lap, B, into the groove, C, at
the back of the valve. In the second modification the sides of the passage, A, are
connected at intervals by bridge bars, the section in Figure, 3, being as taken
through a bridge bar and that in Figure, 4, as between two bars. The valve may
be in one piece as shown in Figures, 1 and 2, or in two pieces, D, and E, as shown
in Figures, 3 and 4. The valve is moved in the ordinary way by a rocking bar or
flattened spindle, G, fitting more or less tightly in the groove, C, at the back of
the valve. The sides of the valve are connected by rivets, H, (or it might be
bolts) which in the first modification are encircled by tubular distance pieces, J, to
prevent the sides of the valve from nipping the bar, G. It is with the space
between the bottom of the bar, G, and the bottom of the groove, C, that the
passages, A, communicate; and when the valve is moving to uncover the port, K,
communication is made between the interior of the port and the groove, C, at the
back of the valve as soon as the lap passages, A, get on the port, the pressure on
the back of the valve then becoming considerably reduced, and the further
movement of the valve being more easily effected. When the valve closes, as
usual, by the action of a spring, such closing is rendered more certain and accurate
as regards time in consequence of the diminished pressure on the valve, the full
pressure only coming into action at the end of the closing movement.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
In Corliss valves for steam engines, forming passages from the contact surface
of the lap into the groove at the back of the valve substantially as and for the
purposes hereinbefore described.
Dated this Sixth day of August 1895.
EDMUND HUNT,
Applicants' Agent.