AN EQUILIBRIUM SLIDE VALVE FOR STEAM AND OTHER ENGINES
Year: 1885

page_text: I, ADAM FERGUSON, of 10 Havelock Street, Temperance Town, Cardiff, in the
County of Glamorgan, Engineer; do hereby declare the nature of said invention
for AN EQUILIBRIUM SLIDE VALVE FOR STEAM AND OTHER ENGINES," to be as
follows:-
The improved equilibrium slide valve for steam and other engines which
constitutes this invention is provided with cavities or chambers formed at the
underside of the upper and lower flanges. The chambers are closed at the top
except at those points where occur orifices which are formed for the purpose of
admitting steam or other motive agent by which the engine is actuated.
There are preferably two cavities or chambers in each flange. The steam or
other motive agent has free access by the orifices aforesaid to the face plate of the
cylinder and hence the valve is maintained in a state of approximate equilibrium,
the motive agent acting both above and below it. Friction is consequently
lessened and tear and wear of the cylinder face plate and of the valve and valve
gear reduced.
Corrosion by steam of the face plate of the cylinder is obviated by a bridge piece
which intervenes between a pair of chambers and constitutes a rubbing surface.
The said bridge piece is pierced to permit the passage of the steam or other motive
agent from one chamber of a pair to the other.
The orifices whereby the motive agent is admitted to the cavities or chambers
may be furnished with nozzles extending downwards into their respective
chambers. By these nozzles the stean or other motive agent may be conducted
for discharge into the cavities or chambers.

page_text: An Equilibrium Sude valve for steam and other Engines.
I, ADAM FERGUSON, of 10, Havelock Street; Temperance Town, Cardiff, in the
County of Glamorgan, 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 an improved construction of equilibrium slide valve for
steam and other engines.
In order that the invention, and the means by which the same is to be carried
into effect may be thoroughly understood, I will proceed to describe the same in
detail, referring in so doing to the accompanying figures, which are to be taken as
part of this specification and read therewith, and in which like parts are throughout
marked with the same reference letter.
Fig. 1 is a plan of the outer face of the valve.
Fig. 2 is a plan of the inner face of the valve..
Fig. 3 is a longitudinal section taken through two nozzles.
Live steam is admitted to the outer face A of the valve in the usual way, and
passes through the nozzles a, a, or otlier suitable openings, into the cavities b, b,
formed in the respective flanges of the slide valve.
I find that nozzles such as are 'sliewn in the drawings yield the best results in
the way of furthering the object of my invention, inasmuch as they act as injectors
and deliver the live steam through the cavities upon the cylinder face with
sufficient force to produce a lifting motion under the valve, and so far diminish
the friction between the valve flanges and the cylinder face.
There are, preferably, two cavities in each flange, as shewn in Fig. 2, although
I do not confine myself to this number.
The steam or other motive fluid has, therefore, free access to the face-plate of
the cylinder, the valve being maintained in a condition of approximate equilibrium,
in consequence of both its faces being subject to the pressure of the fluid at the
same time. The practical result is, that there will be less friction between the
contacting surfaces, and correspondingly less wear and tear of the valve and
its seat.
A bridge piece intervenes between the two cavities b, b, of a pair. These
provide rubbing surfaces, and obviate corrosion by steam of the face plate of the
cylinder.
Each bridge piece is perforated to allow of the motive fluid passing from one
cavity to another of the same pair.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is,
The improvement in equilibrium slide valves, consisting of the combination of
nozzles, or equivalent openings, with the cavities in the flanges of the slide valve,
substantially as described with reference to the accompanying drawings.
Dated this 8th day of April 1886.
PHILLIPS & LEIGH,
Agents for the Applicant.