IMPROVEMENTS IN MEANS OR APPARATUS FOR REGULATING THE ADMISSION AND EMISSION OF STEAM TO AND FROM STEAM ENGINE CYLINDERS, AND FOR OTHER PURPOSES WHERE IT IS REQUIRED TO CONTROL THE FLOW OF FLUIDS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Mark Silvester at the Office of the
Commissioners of Patents on the 1st October 1880).
MARK SILVESTER, of Mayall Road, Brixton, in the County of Surrey, Engineer.
"IMPROVEMENTS IN MEANS OR APPARATUS FOR REGULATING THE ADMISSION AND
EMISSION OF STEAM TO AND FROM STEAM ENGINE CYLINDERS, AND FOR OTHER
PURPOSES WHERE IT IS REQUIRED TO CONTROL THE FLOW OF FLUIDS."
My Invention relates to slide valves for regulating or governing the admission
and emission or flow of steain and other fluids, and means for placing such valves
in equilibrium or obviating friction, whether arising from pressure of the Buid or
from the valve's own weight.
To this end the valve is constructed and arranged so as to expose to the fluid
pressure two or more surfaces or faces of equal area, each provided with ports for
the passage of fluid. The valve so arranged I guide, or support and guide, in the
valve box or case by and between guides or slides, one or more of which is or are
adjustable, and which, where the valve is square or polygonal in cross section, are
so arranged at the angles of the valve as to afford the lap necessary to prevent
leakage, but to allow of the fluid pressure acting equally on all the working sides
or faces of the valve, and, in the case of a horizontal valve, upon an increased area
at the under part sufficient to balance the weight of the valve. My Invention may
be carried out in various forms.
One arrangement suitable for a steam engine is as follows:-
The valve is rectangular in cross section, and at each of its four sides has ports,
which may be of the usual kind. This valve is placed in the valve box with its
sides diagonal to those of that box, upon adjustable guides or slides, which guides
or slides have ports communicating through a chamber in the valve, box with each
other and with each end of the cylinder, and with the exhaust in the usual way.
In the cover of the valve box are also fitted guides or slides, which fit also the
other surfaces of the slide valve not covered by the slides in the valve box. These
guides or slides have also ports communicating through an external chamber with
the corresponding ports in the valve box, and are held iu position in the valve box
cover by suitable tee headed bolts, which fit into suitable slots in the guides and
Price 1

page_text: pass through the valve box cover and are secured by nuts on the outside. A
steam-tight joint is thus made where the ports of the slide meet those of the
external chamber, and rigidity of the guides or slides is attained. To adjust
the valve or to take up any wear, the guides or slides in the valve box cover are
set down upon the slide valve by suitable set screws in the cover of the valve box,
the nuts of the tee headed bolts being first slightly eased. Upon the nuts of the
tee headed bolts being again tightened, the adjustable slides are rendered rigid and
the fluid pressure will be therefore equal upon each plane or side of the valve. To
balance the weight of the valve there is cut a groove in the angle and throughout
the length of the lower guides or slides of such area that the pressure of steam
acting there against the under part of the valve may be equal to its weight.
Valves of other cross sections, whether polygonal or circular, may be arranged
according to my Invention.
For expansive working valves on my plan may be provided with separate
extensions at each end, having bosses fitting fluid-tight in corresponding recesses in
the ends of the valve body. Through these ends is passed a stud or spindle with
right and left hand screw threads fitting corresponding threads in the ends or
extensions of the valve, so that by turning the stud or spindle the ends may be
moved nearer together or further apart according as the length of valve is to be
shortened or increased.