Improved Apparatus for Relieving the Friction of Slide. Valves of Steam or other Engines.
Year: 1886

page_text: Date of Application, 15th Dec., 1886
Complete Left; 15th Sept., 1887
Complete Accepted, 25th Oct., 1887
Improved Apparatus for Relieving the Friction of Slide. Valves
of Steam or other Engines.
I JOSEPH CLULOW JACKSON of 253 Middleton Road Oldham in the County of
Lancaster Engineer do hereby declare the nature of this invention to be as follows:-
The object of this invention is to relieve the friction between the slide valve and
the cylinder facing, so that the slide valve will work as nearly as possible in
equilibrio.
To the back of the ordinary slide valve I fix or cast an additional plate of suitable
size which is planed on the upper face and brought to a true surface.
Bearing upon the surface of this plate is a hollow disc, which is screwed or other-
wise fixed to the end of a rod which passes out of the valve box through a gland or
stuffing box, and is jointed to a lever.
One end of this lever (near to the rod) works on a pin carried by a bracket which
is adjustable.
The other end of the lever is jointed to a rod attached to a piston which works in
a small cylinder, the lower end of which is open to the interior of the valve box.
Above the piston and between it and the cover of the small cylinder is a spiral
spring the action of which is to counteract the upward pressure of the steam in the
valve box.
From the inside of the hollow disc above mentioned is a passage to which is
connected a tube which passes out of the valve box through a steam tight gland and
is provided with a tap or valve opening to the atmosphere so as to admit air into the
hollow space between the disc and the surface of the additional plate on the back of
the valve; and to this air tube is connected a second tube in connection with the
space above the piston (before named) which encloses the spiral spring.

page_text: This spring will keep the hollow disc always pressing on the plate at the back of
the slide valve and thus keep the latter against its facing when the engine is not at
work or when there is a vacuum in the steam chest, but as soon as steam is admitted
this pressure is relieved by the action of the steam against the lower side of the
piston and the valve will then work as near in equilibrio as practicable.
The pressure may be increased or diminished by adjusting the bracket which forms
the fulcrum of the lever either nearer to or further from the rod which carries the
hollow disc.
Dated this 14th day of December 1886.

page_text: Improved Apparatus for Relieving the Friction of Slide Valves
of Steam or other Engines.
I JOSEPH CLULOW. JACKSON of 253 Middleton Road, Oldham in the County of
Lancaster, 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 relieve the friction between the slide valve and
the cylinder facing so that the slide valve works as nearly as possible in equilibrium.
My improved apparatus is shewn on the sheet of drawings appended hereunto;
figure 1 showing a longitudinal section of the cylinder steam chest and relieving
apparatus and figure 2 a cross section.
The slide valve a works on the cylinder facing b in the usual manner. To the
back of the ordinary slide valve I cast extensions a¹ a¹ as shewn on the drawing or
fix an additional plate of suitable size, and plane the upper face and bring it to a
true surface. Upon this surface I place a hollow or recessed plate or disc c which is
got up to a true surface on the underside. This plate c is prevented from moving
with the slide valve a by means of lugs c¹ cecast with the steamchest cover or
equivalent means, and is connected to links by means of lugs cast on the back of
said plate c and a pin e, and the links are connected to a lever f by the pin g. One
end of the lever works on a pin h fixed in a bracket i which can slide on a plate m
cast with the steamchest cover m). The lever is formed with an elongated slot hole
for the pin h, and the bracket i can be adjusted by means of the screw passing
through a stuffing box and formed with a square at the outer end for a screw key.
By this means the length of the shorter arm of the lever f can be varied. The other
end of the lever is jointed by links n to an eyebolt fixed in a piston o which works in
a small cylinder p the lower end of which is open to the interior of the steamchest,
and the upper end of which is in communication with the atmosphere through a
pipe t and cock u which is open when the relieving apparatus is in action. The
steam pressure on the piston o produces a lifting or outward force which is trans-
mitted by the lever and links d to plate c. By adjusting the pin h and bracket i
nearer or farther from the pin e from which the plate c is suspended this lifting or
outward force can be adjusted till it balances as nearly as practicable the steam
pressure on the back of said plate forcing it upon the back of the slide valve
a, and
thus relieves the slide valve of an equivalent pressure so that it will work as nearly
as practicable in equilibrium.
Instead of the lever ƒ being placed inside the steamehest as shewn on the drawings
and herein before described, it may be placed outside the same at the back of the
cover m¹. The plate c is in that case attached to a rod passing through a stuffing
box on the cover m¹ and the bracket i formed with a foot for bolting it to said
cover m² on the outside. The piston o is also attached to a rod passing through
stuffing box on the cover of the cylinder p and this rod connected to the lever.
By preference however I place the lever inside the steamchest as shewn on the
drawings.
a
Into the plate c I screw or otherwise fix a pipes passing through a stuffing box
on the cover m¹ and fitted with a cock s¹ through which the hollow space under the
plate c and between it and the valve facing af a¹ is put into communication with

page_text: the atmosphere while the relieving apparatus is working so as to keep the back of
the slide valve under plate e and the underside of the latter under atmospheric
pressure and free from steam pressure.
Above the position o and between it and the cover of cylinder p is placed a spiral
spring which answers several purposes. It firstly keeps the plate c tight upon the
back of valve a when the engine is standing and no steam is in the chest, so that
when steam is admitted there is no escape through pipe s. It also serves to push the
plate c up again to its working position on the back of valve a when the balance
after having been destroyed or put out of action by closing the cock s¹ is put into
action or restored again by opening said cock. The spring further holds the plate c
to the back of valve a when the balancing or relieving arrangement hereinbefore
described is applied to condensing engines. In that case the pipes t and s are
coupled to or placed into communication with the exhaust side of slide valve a or the
exhaust pipe between the cylinder and condenser. By this means the underside of
plate e the upper or outer side of piston o and the underside of slide valve a are all
working as nearly under one and the same vacuum or variations of vacuum as can
be attained, and the balance of steam pressures on the piston o and plate e is retained
under these variations. Should a vacuum be produced in the steamchest, the spring
is again useful for keeping the plate c up to its seat on the back of valve a, the
recess under plate c and the back of the piston being under the same variation or
under the same vacuum. The pipes can also be connected in the way before
described in cases where the back pressure in the engine is great or variable, which
will keep the parts balanced as nearly as possible under all variations of the back
pressure.
The top part of the cylinder p is connected by the pipes t and th with the steam-
chest, the cock u¹ being inserted into the latter. This arrangement is provided for
the purpose of putting the balancing or relieving apparatus into action again, should
the balance have been destroyed by closing the cock s¹. The cock u is closed and
cock opened when steam passes into the cylinder p' between the piston o and the
cover, so that the piston o is in equilibrium. The spring 9 then forces the plate c
upon its facing on the back of slidevalve a. The cocks and u are then opened and
cock u closed, by which the steam pressure under plate c and on the top of the
piston is let out and the balancing arrangement will then be acting again.
I do not confine myself to the details of the arrangement herein before described,
but these may be varied to suit different makes of steam engines and slide valves.
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.
Firstly, The general arrangement of an apparatus for relieving the friction of slide
valves of steam and other engines substantially as hereinbefore described and illus-
trated by the drawings.
Secondly, In apparatus for relieving the friction of slidevalves of steam and other
engines connecting the relieving plate to a lever having an adjustable fulcrum or
leverage and connected at its end to a piston under the same steam pressure as said
relieving plate, substantially as hereinbefore described.
Thirdly, In apparatus for relieving the friction of slide valves of steam and other
engines the use of a lever having an adjustable fulcrum or leverage and connected to
a relieving plate and a piston under the same steam pressure, substantially as herein-
before described.