Year: 1887

page_text: Date of Application, 8th June, 1887.
Specification Accepted, 8th July, 1887.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane in the
County of Middlesex Consulting Engineer and Patent Agent, 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 :-
This invention relates to improved valves and valve gear for steam engines whereby
a very sensitive automatic adjustment of the expansion by means of the governor
without any detrimental action on the latter is insured, while at the same time a very
sudden and precise cut off is effected in such manner that it is rendered possible
without difficulty to enable high pressure engines of present construction to work in
any desired manner according to the work to be performed, without detriment to the
action of the valve gear.
•
The accompanying drawing shews the improved valves and valve gear applied to a
horizontal engine. Fig. 1 shews a front view; Fig. 2 a cross section without the
steam cylinder and slide casing, & Fig. 3 shews a sectional plan of the whole arrange-
ment of the valves and valve gear on line ax Fig. 1.
Figs. 4, 5 and 6 shew a front view, cross section and sectional plan of a modification
of the arrangement. Figs. 7 and 7 shew a front and side view of the oscillating
slide.
The improved construction of valves and valve gear has for its main slide the usual
form of flat slide with through passages, on the back of which works an expansion
slide similar to that of the Meyer expansion gear; but it differs from this on the one
hand in peculiar arrangements whereby the cut-off is effected by the expansion slide
in a sudden manner, irrespective of the motion of the engine and the action of the
governor, which arrangement has not been carried out before; on the other hand it
differs in the use of a tapered cylindrical body or disc acted upon directly by the
governor, the surfaces of which disc are caused to act upon the expansion slide in
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page_text: such manner that the cut off is automatically adjusted so that according to the form
of taper of the said disc, the manner in which the engine works can be modified so as
to adapt itself to any special purpose, without detriment to the proper action of the
valve gear.
Within the valve chest B of the cylinder A is the main slide D, similar to an
ordinary D slide with through passages, and which receives its motion in the known
manner from an excentric on the crank shaft; d is the slide rod. On this slide works
the expansion slide E which is actuated in the following manner by the
governor
in
combination with the motion of the slide D for suddenly closing the steam passages.
The slide E has rack teeth e formed on its back into which gear the teeth of a sector F
whose spindle is carried in bearings f¹ffixed to the slide D. The sector F has
lateral projections f2f2 on which are formed straight flat surfaces lying in the
direction of the slides motion, and against these surfaces bear blades springs f³ ³ in
such manner that the sector F has a tendency to return to a position at right angles
to the slides motion, in which position the slide E closes the steam passages d¹ d³ of
the slide D.
The sector F is extended beyond its axis and terminates in an arm or lever f^ with
opposite inclines, which passes through a slot in the slide chest cover b into a box G
fixed steam tight on the latter. Within this box is a shaft ½ actuated by the governor,
and prevented from moving longitudinally by the bearing and adjustable ring r
which shaft carries a disc H having tapered or wedge shaped side faces.
This disc being tapered in the same direction on both sides as described, presents
gradually increasing and decreasing thickness of its periphery, and is situated in the
path of the lever as this moves to and fro with the slide, so that at each motion of
the slide and lever the latter comes in contact with the disc H which consequently
turns the sector on its axis and causes it to move the slide E so as to uncover either the
passage or d of the slide D and to keep it open until the lever in travelling
becomes freed from the disc H again, against the periphery of which it slides. The
springs then act upon the sector F and cause it suddenly to assume its normal
position again, in which the expansion slide E closes the steam passages, and thus
effects a sudden cut-off.
According to the variations in the speed of the governor, the shaft is turned
more or less so as to bring a wider or a narrower part of the periphery of the disc H
to act upon the lever of the sector, which is thus depressed for a longer or shorter
space of time, so that the cut-off and expansion is automatically and accurately
regulated by the governor.
Instead of making the expansion slide E flat, it may be formed as the segment of a
circle working on a correspondingly hollow curved face on the slide D, as shewn
at E Figs. 4 to 7" and formed with lateral guiding flanges; the arrangement of the
surfaces f2f2 for the springs f³ ³ as also of the tapered disc H is similar to that
above described, the sector F being however replaced by the slide E¹ itself, thus
avoiding the toothed gearing.
It will be evident that the above described invention may be used with other forms
of expansion slide or lift valves besides those shown with the exception of ball valves,
that is to say, any arrangement in which a reciprocating main, slide carries a flat or
cylindrical slide or lift valve the relative movement of which opens and closes the
steam passages of the main valve.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is :-
1. The construction of valve gear for steam engines wherein an expansion slide or
valve on the back of a main slide valve and moving to and fro therewith, is acted
upon by a tapered disc such as H, actuated by the governor in such manner that
according as a wider or narrower part of the disc's periphery is presented in the path
of the expansion slide or valve or of a device connected therewith, it is thereby
caused to act for a longer or shorter space of time upon the slide or valve so as to

page_text: open the steam passage of the main slide until the expansion slide or valve has moved
beyond the tapered disc, whereupon it is brought back by springs into the normal
position on which it closes the steam passage.
2. In valve gear operating as set forth in the preceding claim, the arrangement of
an expansion slide E, provided with. rack teeth e on the back of the main slide D
and actuated by means of a toothed segment F carried by the main slide and having
an arm or lever f* which is brought in contact with a tapered disc H actuated by the
governor so as to present a wider or narrower part of its periphery in the path of the
lever so that in depressing this, it causes the slide E to open the passage d'or d²
until the lever has passed away from the disc whereupon the slide is suddenly brought
back into its normal position closing the steam passages by the action of a spring
or springs, substantially as herein described with reference to Figs. 1, 2 and 3 of the
drawings.
3. In valve gear operating as set forth in the preceding claims, the use in lieu of
the slide E with rack teeth e and toothed sector F, of a segmental expansion slide E¹,
working between guides on a hollow curved face of the main slide, and operating,
substantially as herein described with reference to Figs. 4 to 7" of the drawings.
ABEL & IMRAY,
Agents for the Applicant.