Improvements in or applicable to Expansion Valves of Steam Engines.
Year: 1892

page_text: Date of Application, 31st Dec., 1892
Complete Specification Left, 30th Sept., 1893-Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in or applicable to Expansion Valves of Steam
Engines.
We THOMAS LEES, RALPH LEES and WILLIAM LEES Junior, all of Park
Foundry, Hollinwood, near Oldham, in the County of Lancaster, Engineers, do
hereby declare the nature of this invention to be as follows:-
Our said invention relates to improvements in the construction of expansion
valves for use in steam engines for the purpose of varying the quantity of steam
admitted to the cylinder at each stroke to correspond to the work or load on the
engine.
As applied to an engine in which the lifting or opening of a single valve controls
the quantity of steam for both ends of the cylinder we use two rocking shafts one
of which is operated by an excentric or other suitable means from the crank shaft.
On each of the said rocking shafts we mount a bell crank lever. The upper arms
of the bell crank lever are connected by a link so that both levers move
simultaneously but in opposite directions. On the lower horizontal arm of each
bell crank lever we pivot triggers also shaped as bell crank levers the lower arms
of which are so formed as to engage under lateral projections on the valve spindle
and to lift the spindle at each lift of either of the triggers. The upper parts of the
lateral projections on the valve spindle and the under surfaces of the triggers are
rounded so that in descending the triggers may easily pass over the lateral
projections of the valve spindle. The lift of the valve and the time it remains
open will depend on the length of time (hereinafter referred to as the dwell) during
which one or other of the triggers is acting on the under surface of the lateral
projections of the valve spindle. This dwell in turn depends on the amount of the
angular displacement of the triggers about their pivots and we may effect this
displacement in various ways. We preferably do so by means of wipers plates or
other suitable devices, connected either directly or indirectly with a governor.
this means the dwell will vary according to the varying speed of the engine.
By
A spring whose degree of compression may be regulated is provided for closing
the valve after each lift. To modify the shock due to the rapid closing of the
valve we connect the valve spindle with an air dash pot the piston of which is
provided with one or more longitudinal air passages, these are covered at the top
by a sliding or lifting plate.
When the valve spindle is being raised the piston of the dash pot is depressed
and the air contained therein passes freely through the said air passages by lifting
the sliding plate.
On the valve spindle falling the piston of the dash pot rises and drawing air
through a small orifice its free motion is impeded and thus the too rapid descent of
the valve spindle is checked. The relative position of the parts to each other may
be varied to suit special applications.
With slight modification our said invention is applicable to steam engines in
which separate expansion valves are used for each end of the cylinder. In this case
we invert the triggers and cause the acting points thereof to engage with the ends
of levers acting on the separate valves.
In any case instead of causing the triggers to engage directly on lateral
projections on the valve spindle as hereinbefore referred to when describing our
Baid invention as applied to a single valve we may cause them to act indirectly

page_text: on the valve spindle through suitable levers or other devices for transmitting
motion.
Dated this 29th day of December 1892.
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or applicable to Expansion Valves of Steam
Engines.
We THOMAS LEES, RALPH LEES, and WILLIAM LEES Junior all of Park
Foundry, Hollinwood near Oldham, 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 :-
Our said invention relates to improvements in the construction of expansion
valves for use in steam engines for the purpose of varying the quantity of steam
admitted to the cylinder at each stroke to correspond to the work or load on the
engine.
Figures 1, 2 and 3 of the accompanying drawings are respectively side elevation,
vertical section through x-y of Figure 1, and plan of our invention as applied to
an engine in which the lifting or opening of a single valve a controls the quantity
of steam for both ends of the cylinder. In this case we use two rocking shafts bb.
one of which is operated by the lever c from an excentric on the crank shaft or by
other well known means in such a way that the valve a is lifted twice during each,
revolution of the crank shaft so that steam may be admitted to each end of the
cylinder. On each of the said rocking shafts we mount. a bell crank lever d. The
upper arms of the bell crank lever are connected by a link e so that both levers
move simultaneously but in opposite directions. On the lower horizontal arm of
each bell crank lever we pivot triggers falso shaped as bell crank levers the lower
arms of which are so formed as to engage under lateral projections on the valve
spindle a¹ and to lift the spindle at each lift of either of the triggers. The upper
parts g of the lateral projections on the valve spindle and the under surfaces of the
triggers are rounded, so that in descending the triggers may easily pass over the
lateral projections g of the valve spindle a'. The lift of the valve and the time it
remains open will depend on the length of time (hereinafter referred to as the
dwell) during which one or other of the triggers is acting on the under surface of
the lateral projections g of the valve spindle a¹. This dwell in turn depends on the
amount of the angular displacement of the triggers f about their pivots and we
may effect this displacement in various ways, as for example by means of the
plate / capable of vertical adjustment by means of the lever h¹ on a rocking shaft h
operated by the governor in such a manner that as the speed of the engine increases
the plate is depressed and as the speed of the engine decreases the plate h.is.
raised.. Formed integral with the triggers fare projecting arms f¹ carrying anti-
friction bowls at their upper extremities where they are in contact with the plate h.
It will be evident that the lower the plate his depressed the more will the angular
movement of the triggers ƒ be restrained and the dwell will be correspondingly
decreased.
The weight of the triggers f is so disposed as to cause the lower. ends to
continually tend to approach each other and to engage with the projections 9.9 of
the valve spindle a².
A spring whose degree of compression may be regulated is provided. for closing
the valve after each lift. To modify the shock due to the rapid closing of the
valve we connect the valve spindle with an air dash pot the. piston of which is
provided' with one or more longitudinal air passages-k,-these are covered at the
top by a sliding or lifting plate k³.

page_text: When the valve spindle is being raised the piston k of the dash pot is depressed
and the air contained therein passes freely through the said air passages &¹ by lifting
the sliding plate k³.
On the valve spindle falling the piston of the dash pot rises and drawing air
through a small orifice & its free motion is impeded and thus the too rapid descent
of the valve spindle is checked. The relative position of the parts to each other
may be varied to suit special applications.
With slight modification our said invention is applicable to steam engines in
which separate expansion valves are used for each end of the cylinder, as shown in
Figures 4 and 5 and 6 which are respectively side elevation, section through x-y
of Figure 4, and plan. In this case we invert the triggers f¹ and cause the acting
points thereof to engage with the ends of levers 9³ acting on the separate valve
spindles a
The angular displacement of the triggers fis controlled by the position of the
plate which is determined by a lever * actuated by the governor as hereinbefore
described with reference to Figures 1 and 2. The rocking shafts &¹ carry the
levers d¹ (to which the triggers are hinged) are caused to oscillate simultaneously
in opposite directions by the levers connected by the link e. The springs and
dash pots are in this construction applied to each separate valve spindle.
In any case instead of causing the triggers to engage directly on lateral
projections on the valve spindle as hereinbefore referred to when describing our
said invention as applied to a single valve we may cause them to act indirectly on
the valve spindle through suitable levers or other devices for transmitting motion.
The links eel are provided with means for adjusting their length for the purpose of
setting the valves.
Figure 7 is an end elevation and Figure 8 an elevation partly in section of a
modification of our invention as applied to a valve at each end of the cylinder. In
these figures 6' is the rocking shaft actuated from the crank shaft in any convenient
manner. On the said rocking shaft are mounted opposite to each other levers d²
having simultaneous yet opposed motions. One of the levers actuates the
mechanism for one end of the cylinder while the other lever d' actuates the mechanism
at the other end of the cylinder. In Figure 8 for simplicity of description
the mechanism at one end of the cylinder only is shown. It is however to be
understood that the parts for each end of the cylinder are alike. Connected to the
lever is a link d by means of which an oscillating motion is imparted to the
link d to which the trigger fis hinged. The upper part of the trigger f* engages
with the lever g' for operating the valve spindle a as hereinbefore described. In this
construction the dwell is obtained by means of a prolongation f extending over a
wiper or anti-friction bowl mounted on a rocking shaft he operated directly from
the governor muff m.
In lieu of the opposed levers d of Figure 8 we may substitute excentrics having
their throw in opposite directions for the purpose of operating the wipers as will.be
well understood.
We are aware that it has already been proposed to use oscillating catches or
wipers engaging directly or indirectly with the valve spindle for the purpose of
opening and closing valves of steam engines and we do not broadly claim such.
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 :-
1. The combination of the oppositely oscillating rocking shafts b the link e the
bell crank levers d and the triggers hinged thereon and engaging directly with
suitable parts on the valve spindle substantially as and for the purpose herein before
described and shown in Figures 1, 2 and 3 of the accompanying drawings.
2. In combination with the steam admission valve of an engine a dash pot having
a piston with passages k' therein and a sliding cover plate k³ substantially as

page_text: and for the purpose set forth with reference to Figure 1 of the accompanying
drawings.
3. The combination of the oppositely oscillating rocking shafts & the link e¹ the
levers did the hinged triggers f' engaging with separate valve spindles by means
of the levers g substantially as and for the purpose hereinbefore described and
shown in Figures 4, 5 and 6 of the accompanying drawings.
4. The combination of the oppositely reciprocating links. d the hinged links d
the hinged triggers fengaging with separate valve spindles by means of the
levers substantially as and for the purpose hereinbefore described and shown in
Figures 7 and 8 of the accompanying drawings.
Dated this 29th day of September 1893.
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for the Applicants.