Improvements in Balanced Slide Valves.
Year: 1899

page_text: Date of Application, 23rd Dec., 1899-Accepted, 3rd Feb., 1900
Tokio, in the Empire of Japan, Engineer].
Improvements in Balanced Slide Valves.
I, WILLIAM EDWIN HEYS, of 70, Market Street, Manchester, in the County of
Lancaster, Chartered 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 certain improvements in the balanced slide valve
described in the Specification of Letters Patent No. 8186 dated the 13th day of
May A.D. 1891 granted to me for an invention communicated to me by my.
correspondent resident abroad.
In the slide valve, as at present constructed, the exhaust chamber is made as
large as practicable and open at the part further from the ports. A cover is
fitted within the exhaust chamber in such a manner that it can slide perpen-
dicularly to a limited extent within the exhaust chamber, packings being provided
to make a tight joint between the sliding cover and the walls of the exhaust
chamber. Outside the valve there is a fixed faced plate parallel with the working
face of the valve against which plate the cover slides when in its outer (or higher)
position. The top of the cover is recessed to as nearly as practicable the full area
of the valve. Atmospheric pressure can be admitted to this recess through a valve
externally controlled.
I will now describe the said invention as communicated to me by my corre-
spondent, with reference to the accompanying drawings in which:-Figure 1
represents a transverse section: Figure 2, a sectional plan; Figure 3, a longi-
tudinal section and Figure 4, a partial transverse section, drawn to a larger scale.
The working face of the valve A, may be rectangular in plan. It has formed
in its back part, a vertical annular wall B, in which there is fitted the cover C,
capable of limited vertical movement. The joint between the annular wall B.
and the side of the cover C can be made steam tight by means of any suitable
known means, such as ordinary steam piston packings. A convenient form of
packing which is more advantageous for the purpose of this invention, consists
in turning the lower part of the cover side to a smaller diameter outside, than
the upper part, and in fitting upon the bottom of the cover side a retaining
ring R, which may be kept in place by the set screws S. This arrangement permits
a stiff packing ring to be used without risk of its distortion by springing it into
place, and it also renders the removal of the ring when required, much more
easy. The retaining ring is temporarily removed when it is required to remove
or replace the packing ring P. That part of the back of the valve which is
included within the cover has openings Othrough it, which will admit the exhaust
steam into the cover. In the two parts, one on each side of the valve (Figures 2
and 4), where the bottom side of the cover and the retaining ring can come into
contact with the back of the valve, the resulting diminution of the area exposed to
the exhaust steam is prevented by the openings E E. Below the centre of the

page_text: cover, a recess may be formed in the back of the valve with a vertical cylindrical
projection therein surrounded by the spiral spring F, the upper end of which
abuts against the under side of the cover which is thus constantly forced into
contact with its seating K. Other equivalent springs may be employed.
As in the existing construction of the valve, there is an air inlet L, to the
back of the cover, the inlet being controlled by the valve M.
This improved valve operates and is operated in the same manner as described
in my former specification hereinbefore referred to.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated to
me by my correspondent resident abroad, I declare that what I claim is
1. In a balanced slide valve of the type set forth, the construction upon the
back of the valve of an annular vertical wall for the reception of a vertically
sliding cover fitting within the wall, and in the back of the valve, of openings
through which the exhaust steam can enter the cover which is continually forced
outwards against its seating by a spring or springs, substantially as hereinbefore
described and as illustrated by the accompanying drawings.
2. In a balanced slide valve of the type set forth, a circular cover constructed to
slide vertically and steam tight on the back of the valve, having its interior
exposed to the exhaust and being constantly forced in the direction of its seating
by a spring or springs, substantially as herein before described with reference to
the accompanying drawings.
3. In a balanced slide valve in the back of which there is a vertically sliding
circular cover, means for making a steam tight joint, consisting of the retaining
ring R, the screws S, and the packing P, substantially as herein before described
and as illustrated by the accompanying drawings.
Dated this 22nd day of December & D 1800.