Improvements in Slide Valves for Steam and other Engines.
Year: 1894

page_text: Date of Application, 24th Jan., 1894
Complete Specification Left, 17th Oct., 1894-Accepted, 17th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Slide Valves for Steam and other Engines.
I, JAMES HARGREAVES of 28 Gathorne Terrace Leeds, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention has reference to improvements in slide valves, especially relating
to the slide valves of hauling & winding engines, which are reversed by hand,
but it may be used also for any steam or other fluid pressure engine, in which slide
valves are used for distributing the pressure.
The object of this invention is to relieve the said slide valves from the whole or
any portion of the friction caused by the pressure of steam, or other fluid, upon
the valve, & to obviate undue wear of the valves & cylinder faces.
For this purpose I construct the slide valve with a planed rectangular surface on
the back, equal in area to that portion of the valve which works against the
cylinder face.
The valve is not essentially different from the ordinary slide valve in the manner
of distributing the steam, & may be single or double ported, & the ports may be
arranged in any convenient manner, as in the case of the ordinary slide valve.
I construct the valve chest cover with a circular aperture, of any desired size,
passing through it & suitably strengthened by a beading, or flange, passing around
the aperture on the outer side of the valve chest cover; into this aperture I insert
a round, but loosely fitting, plug or ram of any suitable metal; the lower, or
inner, end only of this ram is developed into rectangular form, this lower end is
planed on the underneath surface & the plug or rain is brought into such a
position as to rest upon the planed surface on the back of the slide valve above
referred to.
The upper or outer end of this plug, or ram, is secured to the beading, or flange,
on the valve chest cover, above referred to, by means of an annular diaphragm
plate, the inner circumference of this diaphragm plate being firmly bolted to the
end of the ram, or plug, & its outer circumference being firmly bolted to the flange,
or beading, on the valve chest cover.
By this means the pressure of the steam, or other fluid, is excluded from that
portion of the slide valve which is covered by the rectangular end of the ram as
described.
In a modified form of my invention, the circular portion of the ram may be
made of small diameter, as compared with the aperture in the valve chest cover,
instead of being merely a loose fit, & if desirable it may be screwed or bolted to
the square portion, instead of being of a piece with it, & it may be secured to the
inner diameter of the annular diaphragm plate by means of adjustable screws or
nuts; in this arrangement two lugs, or strips, are cast on the inner side of the valve
chest cover, for the purpose of keeping my ram in position.
Dated this 22nd day of January 1894.

page_text: I, JAMES HARGREAVES, of Providence Works Cross Stamford Street, Leeds,
Mechanical 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, reference being had to the accompanying
drawings & to the letters' & 'figures marked thereon, that is to say :-
This invention has reference to improvements in slide valves, especially relating
to the slide valves of hauling & winding engines which are reversed by hand, but
it may be used also for any steam or other fluid pressure engine, in which slide
valves are used for distributing the pressure.
The object of this invention is to relieve the said slide valves from the whole or
any portion of the friction caused by the pressure of steam, or other fluid, upon the
valve, & to obviate undue wear of the valve & cylinder faces.
For this purpose I construct the slide valve with a planed rectangular surface on
the back, equal in area to that portion of the valve which works against the
cylinder face.
The valve is not essentially different from the ordinary slide valve in the manner
of distributing the steam, & may be single or double ported, & the ports may be
arranged in any convenient manner, as in the case of the ordinary slide valve.
I construct the valve chest cover with a circular aperture, of any desired size,
passing through it & suitably strengthened by a beading, or flange, passing around
the aperture on the outer side of the valve chest cover; into this aperture I insert
a round, but loosely fitting, plug or ram, of any suitable metal; the lower, or
inner, end of this ram is developed into rectangular form, this lower end is planed
on the underneath surface, & the plug, or ram, is brought into such a position as to
rest upon the planed surface on the back of the slide valve above referred to, the
upper, or outer, end of this plug, or ram, is secured to the beading, or flange, on
the valve chest cover, above referred to, by means of an annular diaphragm plate,
the inner circumference of this diaphragm plate being firmly bolted to the end
of the ram, or plug, & its outer circumference being firmly bolted to the flange, or
beading, on the valve chest cover.
And in order that my said invention, & the manner of carrying the same into
effect, may be properly understood, I have hereunto appended an explanatory sheet
of drawings, in which the same reference letters are used to indicate corresponding
parts in all the figures.
Fig. 1 is a side elevation, in section, of the steam chest, cover & valve.
Fig. 2 is a plan, showing an outside view of the steam chest & cover, fitted with
my improvements relative to the slide valve.
Fig. 3 is an end elevation, in section, of the steam chest, cover & valve.
Referring to these drawings:-
X is the steam chest, with the steam & exhaust ports Y & Z respectively.
A is the slide valve, having a planed, rectangular surface on the back, equal in
area to that portion of the valve which works against the cylinder face.
B is the ram, which is round, excepting at the lower end, where it is developed
into rectangular form & planed so as to rest truly upon the planed surface on the
back of the slide valve; the centre portion of the underneath side of this ram is
slightly hollowed, as shown at C, & the cavity thus formed is connected with the
open air (or with any drain, or exhaust pipe, according to circumstances) by
means of a tube which is shown at D; the object of such tube being to allow of
the escape of any steam which might accumulate between the back of the valve &
the underneath side of the ram.

page_text: This tube is attached, by means of adjustable nuts E, to a circular bonnet, or
cover, F, such cover serving to protect the parts of the arrangement from dirt &
from damage.
G is the steam chest cover, having a circular aperture as shown to receive the
ram B; the sides of this aperture are grooved, as shown at H, to admit of the
steam passing freely from the steam chest to the cavity shown at I.
The upper, or outer, end of the ram B is connected by means of an annular
diaphragm plate J to the flange, or beading, on the valve chest cover shown at K.
The action of my invention, as above described in detail, is as follows:-
The square surface of the ram B excludes the pressure of the steam from the back
of the slide valve A & so reduces the friction on the valve & cylinder faces; the
pressure of the steam acting upon the upper surface of the four corners of the
rectangular portion of the ram is partially, or wholly, counteracted as may be
desired by the steam pressing upon the underside of the diaphragm plate J in the
cavity formed at I as described.
In a modified form of my invention, the circular portion of the ram may be
made of small diameter, as compared with the aperture in the valve chest cover,
instead of being merely a loose fit, & if desirable it may be screwed or bolted to
the square portion, instead of being of a piece with it, & it may be secured to the
inner diameter of the annular diaphragm plate by means of adjustable screws or
nuts; in this arrangement two lugs, or strips, are cast on the inner side of the
valve chest cover, for the purpose of keeping my ram in position.
Having now particularly described & ascertained the nature of my said inven-
tion, & in what manner the same is to be performed, I declare that what I
claim is : :-
1. A slide valve having a planed rectangular surface on the back, working in
conjunction with a ram as described.
2. A ram of any suitable material, made in one or more parts, fitting loosely into
an aperture in the valve chest cover, such ram being secured to the valve chest
cover by means of an annular diaphragm plate, & so placed as to exclude the
pressure of the steam from the back of the slide valve.
3. A valve chest cover with a suitable aperture for receiving the ram, & the
necessary recesses for the admission of the steam to operate on the diaphragm plate
as described.
4. In conjunction with the ram a brass tube, or connecting pipe, to allow any
steam to escape which may accumulate between the slide valve & the underneath
side of the ram.
5. The construction or arrangement & combination of the parts herein described
& for the purpose specified.
Dated this Sixteenth day of October 1894.
JAMES HARGREAVES.