IMPROVEMENTS IN OR APPLICABLE TO SLIDE VALVES FOR ADMITTING THE FLOW OR PASSAGE OF STEAM, WATER, OR OTHER FLUIDS AND GASES WHEN PRESSED
Year: 1867

page_text: LETTERS PATENT to John Davenport, of Bradford, in the County of York,
Machine Maker, and John Kitson, of Bradford, aforesaid, Pattern Maker,
for the Invention of "IMPROVEMENTS IN OR APPLICABLE TO SLIDE VALVES
FOR ADMITTING THE FLOW OR PASSAGE OF STEAM, WATER, OR OTHER FLUIDS
AND GASES WHEN PRESSED."
Sealed the 8th February 1868, and dated the 10th August 1867.
PROVISIONAL SPECIFICATION left by the said John Davenport and
John Kitson at the Office of the Commissioners of Patents, with
their Petition, on the 10th August 1867.
We, JOHN DAVENPORT, of Bradford, in the County of York, Machine
Maker, and JOHN KITSON, of Bradford, aforesaid, Pattern Maker, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN OR APPLICABLE
TO SLIDE VALVES FOR ADMITTING THE FLOW OR PASSAGE OF STEAM, WATER, OR.
OTHER FLUIDS AND GASES WHEN PRESSED," to be as follows:-
This Invention relates chiefly to the slide valves of steam engines, but is
applicable to other purposes where slidė valves are employed for admitting or
allowing the passage at intervals of steam, water, or other fluids or gases
when under pressure, the object of it being to diminish friction, and it consists
in so constructing and arranging them as that an equal amount of pressure
will be applied to the face as to the back part of the valve, consequently it
will be in equilibrium-at-all-times-when in action, thus removing or preventing

page_text: friction on the sliding surfaces. For this purpose a frame is applied to the
back of the valve, which is kept in position by passing through an opening in
the ordinary cover of the valve box to about flush with its outer surface, and
a flexible plate is placed over the same which overlaps the cover, also an
additional cover is applied having recesses formed therein of equal areas to
the areas of the steam and exhaust ports, with communicating passages through
the same and the frame to the back of the valve where other recesses are
formed of equal areas, and passages are also formed through the valve so that
the steam, water, or other pressed media will exert equal pressure on all sides
of these parts, while the flexible plate allows for variations of expansion and
contraction of the metal.
In some cases we apply friction rollers betwixt the surfaces of the valve and
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Davenport and John Kitson in the Great Seal 1
Patent Office on the 10th February 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
DAVENPORT, of Bradford, in the County of York, Machine Maker, and JOHN
KITSON, of Bradford, aforesaid, -Pattern Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of August, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said John Davenport and John Kitson, Her special licence that we, the
said John Davenport and John Kitson, our executors; administrators,
and assigns, or such others as we, the said John Davenport and John
Kitson, our 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 OR
APPLICABLE TO SLIDE VALVES FOR ADMITTING THE FLOW OR PASSAGE OF STEAM, WATER,
OR OTHER FLUIDS AND GASES WHEN PRESSED," upon the condition (amongst others)
that we, the said John Davenport and John Kitson, our executors or adminis-
trators, by an instrument in writing under our, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said

page_text: Invention,, and in what manner the same was to be performed, and cause
he 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 we, the said John Davenport and John Kitson,
do hereby declare the nature of our said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement thereof and accompanying Sheet of Drawings (that
is to say):-
This Invention relates chiefly to the slide valves of steam engines, but is
applicable to other purposes where slide valves are employed for adinitting or
allowing the passage at intervals of steam, water, or other fluids or gases when
under pressure, the object of it being to diminish friction, and consists in so
constructing and arranging them as that an equal amount of pressure will be
applied to the face as to the back part of the valve, consequently it will be
in equilibrium at all times when in action, thus removing or preventing friction
on the sliding surfaces. For this purpose a frame or back plate is applied to
the back of the valve, which is kept in position by projections passing through
an opening or openings in the ordinary cover of the valve box to about flush
with its outer surface, and a flexible plate is placed over the same which
overlaps the projections, also an additional cover is applied having recesses
formed therein of greater areas than the areas of the steam and exhaust ports,
with communicating passages through the said projections of the back plate,
where other recesses are formed of equal areas to the areas of the steam and
exhaust ports, and passages are also formed through the valve so that the
steam, water, or other pressed media will exert equal pressure on all sides of
these parts, while the flexible plate allows for variations of expansion and
contraction of the metal.
In some cases we apply friction rollers betwixt the surface of the valve and
the back plate.
This Invention will be readily understood by reference to the accompanying
Sheet of Drawings.
DESCRIPTION OF THE DRAWINGS.
:
Fig. 1 is a longitudinal section of a portion of a steam engine cylinder with
the valve and valve box constructed and arranged according to this Invention,

page_text: on the back of the valve, the projections passing through openings: in the
cover D to about flush with the outer surface thereof; G is the flexible plate
overlapping the openings and the projections, and is placed betwixt the cover D
and another cover H, which being fixed thereon by screw bolts in the usual
manner secures the flexible plate in position, and hollow plugs or pins g secure
it to the projections; recesses h are formed in this cover H of greater areas
than the areas of the steam and exhaust ports of the cylinder, and passages e
are formed through the projections of the back plate E to the back of the
valve, where other recesses bare formed in the said back plate of equal areas
to the areas of the steam and exhaust ports. These passages are each open
for the admission of steam simultaneously with the corresponding steam and
exhaust ports of the cylinder.
Fig. is a plan of the valve; Fig. 4 is a top plan of the back plate;
Fig. 5 is the ordinary cover with its openings to receive the projections of the
back plate; Fig. 6 is the flexible. plate with the hollow plugs or pins g;
Fig. 7 is the underneath plan of the back plate shewing the recesses b- and
the passages e, the two outer ones. .being elongated to give a lead in the
admission of steam to the top of flexible plate; Fig. 8 is the underneath 'plan
of the top cover H shewing the recesses.h for steam; Fig. 9 is a longitudinal
section of a portion of a cylinder with valve, back plate, and covers similar to
Fig. 1, and Fig. 10 is a cross section of same slewing. the application of
friction rollers J placed betwixt the valve and the back plate; also shewing
a modification in the construction of the back plate; and Fig. 11 is a plan
of the cover shewing the opening K for the projection of the said back plate
to pass through
2
Having thus described the nature of the said Invention, and shewn the
manner in which the same is or may be performed or carried into practical
operation, we would observe in conclusion that we do not claim the whole of
the parts in the Drawings we have had occasion to refer to; but what we do
claim as our Invention is,―
:
Firstly. The projection or projections on the back plate for passing through
an opening or openings formed for them in the ordinary valve box cover, also
the passages therein for the passage of steam into recesses formed outside a
flexible plate applied thereto.
· Secondly. The flexible plate and mode of securing or fixing it in position on
the back plate.
Thirdly. The additional cover with its recesses for the reception of steam
upon the flexible plate.
;

page_text: Fourthly. The application of friction rollers betwixt the valve and back
olate.
In witness whereof, we, the said John Davenport and John Kitson, have
hereunto set our bands and seals, this Eighth day of February, One
thousand eight hundred and sixty-eight.
JOHN KITSON.
(L.S.)
Signed, sealed, and delivered by the
within-named John Davenport and
John Kitson, in the presence of
WM. TASKER,
Patent Agent,
Halifax & Bradford.