Year: 1887

page_text: Date of Application, 4th June, 1887
Complete Left, 3rd Mar., 1888
Complete Accepted, 13th Apr., 1888
We, ALFRED TOLHURST, of 77 New Road, Gravesend, in the County of Kent,
Solicitor, and HENRY SKINNER, of 43 Singlewell Road, Gravesend aforesaid, Engineer,
do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide improved means for relieving the back of
the slide valves of steam and other engines from the pressure of steam or fluid upon
them so as to reduce the enormous friction which there commonly now is between the
valve and the face against which it works.
For this purpose the back of the valve is as has before been proposed faced as well
as the front making a true surface on both sides of the slide valve. A plate with a
true surface is also made to rest against and cover over the back of the valve. This
plate we carry from the cover of the valve chest in such a manner that it can be moved
towards or away from the back of the valve. The back surface of the plate is some-
what inclined and between it and the cover of the valve chest is interposed another
corresponding wedge formed plate which can be moved endwise to move the first
mentioned plate up to the valve or allow of its being drawn back away from it. The
plate has pins projecting out from its back face and passing through slots in the wedge
and through holes in the valve chest cover-and nuts are screwed on to the outer ends
of the pins. A pin also projects from the back of the wedge through a slot in the
valve chest cover and by this pin the wedge can be moved endwise or other suitable
means might be provided for moving the wedge end wise. If these nuts are slackened
the plate can be set up to the back of the valve by moving the wedge endwise-
the nuts may then be tightened up so as to lock the plate rigidly to the valve chest
cover.
In place of the plate being set up to the valve by moving the wedge endwise by
hand it might be set up automatically by the pressure of steam upon the larger end
of the wedge. In this case I prefer that the moving wedge should be next to the valve
and move in a direction at right angles to that in which the valve travels. The wedge
may be prevented from moving crosswise with the valve by making it to work in a
recess in the wedge plate which in this case is fixed to the cover of the valve chest.
Pine Ri

page_text: When two slide valves are set to work back to back in the same valve chest I effect
the object of relieving the valves from the pressure of steam upon their back faces by
interposing between them two wedge formed plates one of which can be moved end-
wise and the other of which is restrained from moving endwise but can be moved
towards or away from the valve against which it bears.
The valves may be formed with the ordinary D recess in their face or if preferred
the recess may be cut entirely through the valve so that the valve may not be drawn
against its seat by vacuum.
CARPMAEL & Co.,
Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in Slide Valve Mechanism.
We, ALFRED TOLHURST of 77 New Road, Gravesend, in the County of Kent
Solicitor, and HENRY SKINNER, of 43 Singlewell Road, Gravesend aforesaid, 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:-
The object of this invention is to provide improved means for relieving the back of
the slide valves of steam and other Engines from the pressure of steam or fluid upon
them so as to reduce the enormous friction which there commonly now is between the
valve and the face against which it works.
For this purpose the back of the valve is as has before been proposed faced as well
as the front making a true surface on both sides of the slide valve-A plate with a
true surface is also made to rest against and cover over the back of the valve-This.
plate we carry from the cover of the valve chest in such a manner that it can be moved
towards or away from the back of the valve-The back surface of the plate is some-
what inclined and between it and the cover of the valve chest is interposed another
corresponding wedge formed plate which can be moved endwise to move the first
mentioned plate up to the valve or allow of its being drawn back away from it-The
plate has pins projecting out from its back face and passing through slots in the wedge
and through holes the valve chest cover-and nuts are screwed on to the outer ends
of the pins-A pin also projects from the back of the wedge through a slot in the
valve chest cover and by this pin the wedge can be moved endwise or other suitable
means might be provided for moving the wedge end wise-If these nuts are slackened
the plate can be set up to the back of the valve by moving the wedge endwise-the
nuts may then be tightened up so as to lock the plate rigidly to the valve chest
cover.
Figure 1 of the drawings hereunto annexed is a longitudinal section of slide valve
mechanism constructed in the above manner.
A is the moving portion of the valve-B is the valve rod by which it is traversed
to and fro in the ordinary manner-C is the plate held against the back of the valve
-D is the wedge interposed between the inclined back face of the plate C and the
valve chest cover-)
-D is a pin projecting from it through a slot in the valve chest
cover Care pins projecting from the plate through slots in the wedge D and holes.
in the valve chest cover-E are nuts screwed on to their ends-In most cases the
pins C and nuts E holding the plate C against the wedge will be sufficient to prevent
all endway movement of the plate but if necessary stops projecting from the valve
chest may be used to prevent endway movement.
In place of the plate being set up to the valve by moving the wedge end wise by
hand it might be set up automatically by the pressure of steam upon the larger end
of the wedge-In this case we prefer that the moving wedge should be next to the
valve and move in a direction at right angles to that in which the valve travels―

page_text: The wedge may be prevented from moving crosswise with the valve by making it to
work in a recess in the wedge plate which in this case is fixed to the cover of the
valve chest.
Figure 2 is a longitudinal section and
Figure 3 a transverse section of valve mechanism constructed in this manner.
A is the valve B the valve rod-D the moving wedge-C the plate which in this
case is fixed to the valve chest cover-The plate is formed with flanges which prevent
all movements of the wedge D in the direction of the traverse of the valve.
D¹ is a
rod projecting from the wedge D through the side of the valve chest. By means of
a nut screwed on to this rod outside the valve chest the wedge may be drawn and
held back away from the plate C whilst the valve chest cover is being bolted on. The
extent to which the wedge can be pressed against the back of the valve by the action
of the steam upon it may also be regulated by this nut or it may be regulated by an
adjustable stop against which the smaller end of the wedge is forced by the action of
the steam.
When two slide valves are set to work back to back in the same valve chest we
effect the object of relieving the valves from the pressure of steam upon their back
faces by interposing between them two wedge formed plates one of which can be
moved endwise and the other of which is restrained from moving endwise but can be
moved towards or away from the valve against which it bears.
Figure 4 is a longitudinal section of slide valve mechanism arranged in this manner.
A A are the two valves and C and D the wedge plates between them.
GG are stops
for preventing endway movement of the wedge C, and H is a screw by which the
wedge D can be moved backwards or forwards.
The valves may be formed as shown with the ordinary D recess in their face or if
preferred the recess may be cut entirely through the valve so that the valve may not
be drawn against its seat by vacuum.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
-
1. Slide valve mechanism constructed substantially as herein before described with a
plate at the back of the valve restrained from endway movement and pressed against
the valve by a wedge.
2. Slide valve mechanism with a plate at the back of the valve and pressed against
it by a wedge interposed between itself and the valve cover and with bolts for
locking the plate to the valve cover substantially as herein before described with
reference to Figure 1.
3. Slide valve mechanism constructed with the wedge moveable endwise in a
direction at right angles to the traverse of the valve substantially as hereinbefore
described with reference to Figures 2 and 3.
4. Slide valve mechanism constructed substantially as hereinbefore described with
reference to Figure 4.
ALE. TOLHURST,
H. SKINNER.