IMPROVEMENTS IN THE CONSTRUCTION OF EQUILIBRIUM SLIDE VALVES
Year: 1870

page_text: LETTERS PATENT to Francis Jackson, of Stainburn, near Workington,
in the County of Cumberland, for the Invention of "IMPROVEMENTS
IN THE CONSTRUCTION OF EQUILIBRIUM SLIDE VALVES."
Sealed the 9th June 1871, and dated the 22nd December 1870.
PROVISIONAL SPECIFICATION left by the said Francis Jackson at the
Office of the Commissioners of Patents, with his Petition, on the
22nd December 1870.
I, FRANCIS JACKSON, of Stainburn, near Workington, in the County
of Cumberland, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF EQUILIBRIUM SLIDE VALVES" to be as
follows:-
The objects of this Invention are, firstly, to diminish the friction and
consequent wear of the valves, and, secondly, to dispense with the
necessity for packing the valve spindles. The first I effect by taking
the pressure off the back of the valves in the manner herein-after
described, and the second by not carrying the valve spindle out through
the side of the valve box.

page_text: For example I take an ordinary slide valve, and outside the lid or
cap of the valve box, I bolt on a second lid or cap forming as it were
an additional shallow valve box. Inside this box works a shallow slide
valve or plate connected to the back of the ordinary slide valve by means
of a strong stud or neck in the centre so that the two move together,
a slot being cut through the lid or plate which divides the two valve
boxes to allow the stud or neck to work through, and the said shallow
valve or plate working steam tight on the said lid or plate, whilst the
ordinary slide valve works similarly on the usual facings, a loose ring
working inside the shallow valve to keep it tight and prevent steam from
passing into the second or shallow valve box. The action of the steam
under the shallow valve or plate keeps the slide valve in equilibrio, and
hence the friction and wear are reduced.
In order to dispense with packing round the valve spindle I connect
it to the end of the additional shallow valve or plate in the outer valve
box where there is no steam, and the movement of this valve or plate
causes the slide valve (which is connected to it) to move therewith. Or
instead of this method I fasten a stud to the inner side of the slide
valve, which stud projects into the exhaust port, and I attach the spindle
thereto, and carry it out through a tube passing along the upper steam
passage.
In some cases I use steam passages having double ports, that is, ports
on each side, and I employ two valves, one at each side having flanges
which meet over the top and thus take the pressure off the faces of the
valves. The facings are slightly taper, so that as the valves wear they
keep themselves always tight.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Francis Jackson in the Great Seal Patent Office on
the 21st June 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS 30
JACKSON, of Stainburn, near Workington, in the County of Cumberland,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of December, in the

page_text: year of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Francis Jackson, Her special license
that I, the said Francis Jackson, my executors, administrators, and
assigns, or such others as I, the said Francis Jackson, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE CONSTRUCTION OF EQUILIBRIUM SLIDE VALVES," upon the condition
(amongst others) that I, the said Francis Jackson, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Francis Jackson, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawings (that is to say):-
The objects of this Invention are, firstly, to diminish the friction and
consequent wear of the valves, and secondly, to dispense with the
necessity for packing the valve spindles. The first I effect by taking
the pressure off the back of the valves in the manner herein-after
described, and the second by not carrying the valve spindle out through
the side of the valve box.
For example, I take an ordinary slide valve, and outside the lid or
cap of the valve box I bolt on a second lid or cap, forming as it were
an additional shallow valve box. Inside this box works a shallow slide
valve or plate connected to the back of the ordinary slide valve by means
of a strong stud or neck in the centre, so that the two move together,
a slot being cut through the lid or plate which divides the two valve
boxes to allow the stud or neck to work through, and the said shallow
valve or plate working steam tight on the said lid or plate, whilst the
ordinary slide valve works similarly on the usual facings, a loose ring

page_text: working inside the shallow valve to keep it tight and prevent steam
from passing into the second or shallow valve box. The action of the
steam under the shallow valve or plate keeps the slide valve in
equilibrio, and hence the friction and wear are reduced.
In order to dispense with the packing round the valve spindle I
connect it to the end of the additional shallow valve or plate in the
outer valve box where there is no steam, and the movement of this valve
or plate causes the slide valve (which is connected to it) to move there-
with. Or instead of this method I fasten a stud to the inner side of the
slide valve, which stud projects into the exhaust port, and I attach the
spindle thereto and carry it out through a tube passing along the upper
steam passage.
In some cases I use steam passages having double ports, that is, ports
on each side, and I employ two valves one at each side, having flanges
which meet over the top, and thus take the pressure off the faces of
the valves. The facings are slightly taper, so that as the valves wear
they keep themselves always tight.
Such being the nature and object of my said Invention for "Im-
provements in the Construction of Equilibrium slide Valves," I will
now proceed to describe more in detail the manner in which the same is
to be or may be performed or carried into practical effect, and in order that
the same may be clearly understood, I have annexed hereunto a Sheet of
Drawings illustrative thereof, and have marked the same with figures
and letters of reference corresponding with those in the following
explanation thereof.
In the annexed Drawing Fig. 1 is a sectional view of the first
described arrangement. a, a, is the steam cylinder; b, b, the ordinary
valve box or steam chest, and c, c, the slide valve; d, d, is the additional
valve box inside which works the plate e, e, connected to the back of the
ordinary slide valve by the stud f,f, and working with it, a slot g, g,
being cut in the lid or cover of the ordinary valve box to allow the stud
to work through. The valve rod h, h, is connected to the plate e, e,
in the outer or additional valve box, where there is no steam and hence
the packing may be dispensed with; x, x, is the exhaust.
Fig. 2 shows a modification of the same, in which a shallow the
valve e, e, is substituted for the plate and is kept steam tight by means of

page_text: a loose ring i, i. The valve rod h, h, instead of being connected to the
plate or valve e, e, is fixed to a stud k projecting into the exhaust port x
and attached to the inner side of the slide valve c, c, being carried out
through a tube 1, 1, passing along the upper steam passage.
Fig. 3 is another modification of the same in which the steam is
introduced into the outer or additional valve box d, d, and passes to the
slide valve c, c, through a hollow neck f, f, which is substituted for the
stud. In this case the valve rod h, h, is connected to the valve c, c, as
there is no steam in the valve box b, b.
Fig. 4 is a further modification in which the exhaust steam is taken
from the box b, b, the ordinary exhaust passage of the slide valve being
in this instance converted into a steam passage and the exhaust is
taken through the slots x, x, in the flange of the valve. In this
arrangement there is only the exhaust steam to pack against.
Fig. 5 is a modification of Figs. 3 and 4 wherein the necessity for a
second valve box is dispensed with by the introduction of a packing
ring m, m, which is kept tight against the inside of the valve box cover
by the pressure of the steam.
Figs. 6 and 7 show the arrangement of steam passages with double
ports, that is to say, ports on each side, so as to admit steam on both
sides at once. In this case the steam passages n, n, project from the
face of the cylinder, and have two valves c, c, working one on each side,
and provided with flanges o, o, meeting in the centre over the top, so as
to take the pressure of the steam off the valve facings. The valves are
connected by means of necks p, p, (also meeting at the centre) to the
valve rod which is in the exhaust passage x, x, and passes out through
a tube q, q.
Fig. 8 shows the way in which I propose to adapt the first described
arrangement (see Fig. 1) to locomotive engines, the additional valve
box d, d, being attached to one slide valve and the plate e, e, connected
to the other, so that one plate serves for both valves.
Having now described the nature and object of my said Invention
together with the manner in which the same is to be or may be per-
formed or carried into practical effect, I wish it to be understood that I
claim as my Invention, the improvements in the construction of
equilibrium slide valves as above described and illustrated by the annexed

page_text: Drawings, or any mere modification or imitation thereof, constructed
and operating in substantially the same or a similar manner.
In witness whereof, I, the said Francis Jackson, have hereunto set
my hand and seal, this Nineteenth day of June, in the year of
our Lord One thousand eight hundred and seventy-one.