Improvements in Valve Gear for Fluid-pressure Engines.
Year: 1888

page_text: Date of Application, 6th Oct., 1888
Complete Specification Left, 26th June, 1889-Accepted, 27th July. 1889
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Fluid-pressure Engines.
We ARTHUR GEORGE MUMFORD, of the Culver Street, Iron works, Colchester,
in the County of Essex; Engineer, and JONAS DALBY, Foreman at 'the works aforesaid,
do hereby declare the nature of this invention to be as follows:-
Our invention relates to certain improvements in valve gear for fluid-pressure
engines and consists of a direct action supplemental valve controlling the steam moved
main slide valve.
In a suitable steam chest fixed to or forming part of the main cylinder is formed
a valve cylinder having a piston valve adapted to open and close the induction and
exhaust ports of the main steam cylinder in the well-known manner. Exterior to this
valve cylinder is a second cylinder of smaller diameter for the supplemental piston valve.
In this supplemental cylinder is fitted a long piston valve connected by a piston rod and
coupling. link, or equivalent device, to the main piston rod, or any other suitable
moving part of the engine, whereby the supplemental piston valve may receivera
reciprocating motion. This supplemental piston valve cylinder is connected with the
steam chamber or passage to the main piston valve so that steam is constantly
admitted to both ends of the piston. In the supplemental piston valve cylinder are
fixed five ports or passages, one a central one connected with the exhaust, and a pair
on either side thereof connected with the respective ends of the main piston valve
cylinder. One port or passage of each pair on either side of the centre one is so
arranged as to be put into communication with the central exhaust port by the
reciprocation of the supplemental piston valve, thus connecting the ends of the main
piston valve cylinder with the exhaust, and so forming exhaust ports for the main
valve cylinder. The other ports or passages are arranged to admit steam from the
supplement piston valve cylinder to the ends of the main valve cylinder, thus forming
induction ports for the main piston valve.
It will thus be seen that the main piston slide valve is moved by steam, the induction
and exhaust of which is controlled by the supplemental piston valve reciprocated
directly or indirectly from some moving part of the engine.
Although 'this valve gear is adapted for all types of fluid pressure engines it is more
particularly suited for direct pumping engines.
.
Dated this 6th day of Natobar 1000
ROBT. ED. PHILLIPS, M.I:M.E.,
Consulting Engineer and Patent Agent, 70, Chancery Lane, London, W.,
Agent for the Applicants.
COMPLETE SPECIFICATION.
"Improvements in Valve Gear for Fluid-pressure Engines.
We, ARTHUR. GEORGE MUMPORD, of the Culver: Street Iron Works, Colchester, in
the County of. Essex, Engineer, and JONAS DALBY, Foreman at the Works aforesaid,
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:-
-Our invention relates to improvements in valve gear for fluid-pressure engines, and
consists of a direct action supplemental valve controlling the steam'moved main slide
valve, the object being increased efficiency.
In a suitable: steam chest fixed to, or forming part, of the main cylinder,
is formed. a. valve.. cylinder having a. piston valve adapted to open and close the
гр

page_text: induction and exhaust ports of the main steam cylinder in the well known
manner.
Exterior to this valve cylinder is a second cylinder of smaller diameter for the
supplemental piston valve.
In this supplemental cylinder is fitted a long piston valve the piston rod of which
is connected by a coupling link, or its equivalent, and a rocking lever, to the main
piston rod, or to any other suitable moving part of the engine, whereby the supple-
mental piston valve may receive a positive reciprocating motion. This supplemental
piston valve cylinder is connected with the steam chamber, or passage to the main
piston valve, by a suitable port or passage so that it is in constant communication
therewith, and the supplemental piston valve is adapted to admit the steam con-
tinuously to both ends of the said piston. In the supplemental piston valve cylinder
are formed five ports or passages, one a central one connected with the exhaust, and
a pair on either side thereof connected with the respective ends of the main piston
valve cylinder. One port or passage of each pair on either side of the central one is
so arranged as to be put into communication with the central exhaust port by the
reciprocation of the supplemental piston valve, thus connecting the ends of the main
piston valve cylinder with the exhaust, and so forming exhaust ports for the main valvo
cylinder. The other pair of ports or passages are arranged to admit steam from the
supplemental piston valve cylinder to the ends of the main valve cylinder, thus
forming induction ports for the main piston valve.
It will thus be seen that the main piston slide valve is moved by steam, the
induction and exhaust of which is controlled by the supplemental piston valve
reciprocated directly or indirectly from some moving part of the engine.
In order that our invention may be perfectly understood we herewith append
drawings illustrating it, which we will particularly describe.
•
Figure 1. is a view in longitudinal sectional elevation of a steam cylinder fitted
with our improved valve gear, and Figure 2. is a view in transverse section on
line y. z. Figure 1.
Throughout these views similar parts are marked with like letters of reference.
The steam cylinder A is fitted with piston B, piston rod B¹, induction ports a and
exhaust port a' all of the usual construction On to the cylinder A is fixed a steam
chest C containing two cylinders D and E, the former is provided with a piston
valve D¹ of the usual type adapted to open and close the induction and exhaust ports a
and a¹. In the cylinder E is a supplemental piston E which is connected by a
coupling rod F and rocking lever F with the piston rod B', or with any other
reciprocating part of the engine, so that the piston valve E may receive a positive
motion. The cylinder E, of the supplemental piston valve E¹ is connected with the
steam chest C, or with the steam passage to the main piston valve cylinder, by the
port or passage e, and the valve El is so formed as to permit the steam to pass by
the said valve to both ends of the cylinder at all times. This is preferably done by
cutting a slot or its equivalent on the valve as illustrated. The valve is prevented
from rotating in its cylinder by means of the pin or stud c engaging with a slot or
featherway in the valve. In the centre of the supplemental valve cylinder E is an
exhaust port or passage c' leading into the main exhaust passage a². On each side of
the exhaust port or passage el are two ports or passages d and d connecting the ends of
the cylinder D with the cylinder E. The ports d, d, are arranged to admit steain
alternately to the ends of the cylinder D to operate the valve D', and the ports d' d'
are arranged to allow the exhaust steam from the ends of the cylinder D to pass to
the main exhaust a through the exhaust passage c' by means of a suitable recess e¹
in the valve E¹.
c¹
To supply steam to move the piston up to the main steam port, and to provide a
cushion for the main piston at the ends of its stroke, so as to give it a pause, or slow
motion, to allow the pump valves to close quietly when the engine is coupled
direct to a steam pump two steam ports as a³ are formed between the main
cylinder A and the piston valve cylinder D as illustrated. These ports have no

page_text: exhaust so that the steam therein on the return stroke of.the piston is compressed and
not exhausted thereby forming a cushion.
For convenience in construction the supplemental valve E may be made flat instead
of round.
.
The action of our improved valve gear is as follows;-Steam being admitted into
the steam chest passes into the hollow space between the heads of the main piston
valve D'. It also passes into the cylinder E and as either of the ports d' is uncovered
by the reciprocation of the valve E, steam is admitted to one end of the main piston
valve D, which is thereby moved to the other end of its cylinder, the steam in that
end passing away by the port d, recess e¹ in the valve E, and exhaust passage cl,
to the main exhaust a'. As the main piston valve moves to the end of its
cylinder, it opens the steam ports a a to the cylinder D, and exhaust port a¹
respectively, in the manner to produce the reciprocation of the main piston B, which
is cushioned at the ends of its stroke to give it a pause or slow motion, by steam
admitted by the ports a³, a³.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is ;-
A valve gear for steam or other fluid pressure engines, constructed, arranged, and
operating, substantially as and for the purpose set forth.
Dated this 26th day of June 1889
ROBT. ED. PHILLIPS, M.I.M.E.,
Consulting Engineer and Patent Agent, 70, Chancery Lane, London, W.C.,
Agent for the Applicants.