Improvements in Slide-valves and Gear for Steam and other Fluid-pressure Engines.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Slide-valves and Gear for Steam and other
Fluid-pressure Engines.
I, EDMOND RAY of No. 10 Rue Cambon Paris, in the Republic of France, Civil
Engineer, 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 :---
My invention relates to a construction and means of working slide valves for
steam and other fluid pressure engines in such a manner as to give ample area
for admission and emission of the working fluid, to simplify the gear for varying
the expansion rendering at the same time the exhaust independent of variations of
the cut off, as I shall describe referring to the accompanying drawings.
Fig. 1 is a side view partly in section shewing slide valves and their working gear
according to my invention applied to the horizontal cylinder of a steam engine.
Fig. 2 is a longitudinal section of one of the parts of the admission slide valve
and the cylinder facing on which it works.
Fig. 3 is a longitudinal section of one of the parts of the exhaust slide valve
and the cylinder facing on which it works.
Fig. 4 is a section to an enlarged scale on the line Z Z of Fig. 1.
Although in what follows I speak of steam as the working fluid, it is to be
understood that my invention applies also to engines worked by compressed air or
other elastic fluid under pressure.
As shewn in Fig. 1, an eccentric on the crank shaft of the engine works a curved
link Lalong the slot of which the valve rods can be moved by connections from a
hand wheel W, or it might be a lever, for the purpose of starting, stopping, reversing
and varying the cut off in the well known manner. So far the gear is of a kind
known as Walschaert gear to which I make no claim. The rods is connected to a
rod K K working in guides and having an arm Vt projecting down from it and an
arm V projecting up from it. On the arm V is pivotted a lever PO the upper
end P of which is linked to the steam supply slide valve and the lower end O is
connected by a link to a bracket projecting down from the piston crosshead. The
exhaust slide valve, being directly connected to the lower end of the arm Vt moves
in correspondence with the guide rod K K as determined by the position of the
rods in the slot of the link. The steam slide being connected to the lever PO, has
its motion compounded of that derived from the rod rs and of the motion of the
piston. The main steam ports A A¹ open into the cylinder near its ends, and are
governed by connected short slide valves a a¹, of which the one a is shewn in Fig. 2.
It has within it a channel with three mouths b'b' band in the metal under the facing
there is a channel c, these channels and mouths being arranged so that when the
slide valve is moved for very early cut off, in which case the passage into A beyond
the end of the slide would be very small, there is so much additional passage given
that there is no throttling of the steam supply. The slide valve a being made level
on its back may have pressed on it by a spring a plate Z, which is kept from moving
lengthwise by having its edges lodged in grooves in the sides of the slide jacket, and
Price 6d l

page_text: which has through it a hole to communicate with the passage Y when the edge of
the slide is uncovering the port A.
The exhaust ports C C open from the cylinder at some distance from its ends,
and each is governed by a slide valve D D as shewn in Fig. 3. kept up towards
the cylinder facing by set screws n n³.
Owing to the position of the ports CC over which the pistoa passes, the period
of exhaust and the amount of compression for cushion are determined partly by
the piston and partly by the valve gear, and each of the slide valves D D₁
besides uncovering the port at its edge has through it a passage d giving additional
outlet for exhaust.
Exhaust would continue throughout the stroke but for the piston covering the
ports and thus producing cushion. This compression governed by the piston, acting
in conjunction with the difference in the movement of the admission and exhaust
valves, is a peculiarity of my invention which has the advantage of preventing very
premature opening of the exhaust ports and a great amount of compression, and
this without involving complex connections from the link to the slide valves, or any
handle or lever besides that employed for starting, stopping, reversing and varying
cut off.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described arrangement of admission and exhaust ports of the cylinder
and slide valves.
2. In combination with Walschaert slide valve gear, the guide rod K K, its arms V¹
and Vt, the lever PO and link h, substantially as and for the purpose herein set
forth.
Dated this 15th day of Novamban 1800
ABEL & IMRAY,
Agents for the Applicant.