IMPROVEMENTS IN SLIDE VALVES, APPLICABLE TO STEAM AND OTHER MOTIVE POWER ENGINES
Year: 1857

page_text: LETTERS PATENT to Frederic Sarley Stott, of Bradford, in the County of
York, Engineer, for the Invention of "IMPROVEMENTS IN SLIDE VALVES,
APPLICABLE TO STEAM AND OTHER MOTIVE POWER ENGINES."
Scaled the 30th June 1857, and dated the 1st January 1857.
PROVISIONAL SPECIFICATION left by the said Frederic Sarley Stott
at the Office of the Commissioners of Patents, with his Petition, on the
1st January 1857.
I, FREDERIC SARLEY STOTT, of Bradford, in the County of York, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SLIDE VALVES, APPLICABLE TO STEAM AND OTHER MOTIVE POWER ENGINES," to be as
follows:-
The Invention relates to certain improvements in the ordinary slide valves of
steam and other motive power engines, whereby the pressure of such motive power
upon the back of the valve, heretofore producing very great friction on the
sliding surface thereof, is entirely removed; and also to a method. of construct-
ing slide valves so as to render them capable of being expanded and contracted,
whereby I am enabled to regulate the amount of "lap" or cover, or to adjust
the "cut off." And the improvements consist in the application of a metallic
ring or rings, plates or packings between the back of the valve and the lid or
cover of the steam case or "valve box," so fitted and secured and capable of
adjustment as to fill up the space, yet allowing the valve to slide freely, thus

page_text: preventing the steam or other motive power from pressing upon the back of
the valve, and thereby relieving it of the great frictional bearing on the sliding
surface. I also form or construct slide valves in two or more parts, which can
be set and secured on the valve spindle by nuts and screws in such manner
that I am enabled to regulate the "lap" or cover to the greatest nicety, thus
cutting off the admission of steam at any point of the stroke; and I
also propose to pass the exhaust steam through the back of the valve, and
thence through the aforesaid ring, plate or packing, and lid or cover, or I
reverse the action and admit the steam thereat.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederic Sarley Stott in the Great Seal Patent Office
on the 1st July 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
SARLEY STOTT, of Bradford, in the County of York, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent, bearing date the First day of January, in the year of our
Lord One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Frederic Sarley Stott, Her special licence that I, the said Frederic
Şarley Stott, my executors, administrators, and assigns, or such others as
I, the said Frederick Sarley Stott, 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 SLIDE VALVES, APPLICABLE TO STEAM AND OTHER MOTIVE
POWER ENGINES," upon the condition (amongst others) that I, the said Frederic
Sarley Stott, by an instrument in writing under my hand and seal, 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 Royal Letters Patent.
NOW KNOW YE, that I, the said Frederic Sarley Stott, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement (that is to say) :-

page_text: My Invention relates to certain improvements in the ordinary slide valves
of steam and other motive power engines, whereby the pressure of such motivo
power upon the back of the valve, heretofore producing very great friction on
the sliding surface, is entirely removed; and also to a method of constructing
5 slide valves so as to render them capable of being expanded and contracted,
whereby I am enabled to regulate the amount of "lap" or cover, or to adjust
the "cut off," which improvements consist in the application of a metallic ring
or rings, plates or packings between the back of the valve and the lid or
cover of the steam case or "valve box," so fitted and secured and capable of
adjustment as to fill up the space, yet allowing the valve to slide freely, thus
preventing the steam or other motive power from pressing upon the back of
the valve, and thereby relieving it of the great frictional bearing on the sliding
surface. I also form or construct slide valves in two or more parts, which can
be set and secured on the valve spindle by nuts and screws in such a manner
that I am enabled to regulate the "lap" or cover to the greatest nicety, thus
cutting off the admission of steam at any point of the stroke; and I also
propose to pass the exhaust steam through the back of the valve, and thence
through the aforesaid ring, plate or packing, and lid or cover, or I reverse the
action and admit the steam thereat.
:
The manner in which my said Invention is to be performed will be
clearly understood by reference to the accompanying Sheet of Drawings,
with the letters of reference thereon, wherein Figs. 1, 2, 3, 4, and 5 repre-
sent different views of one of my improved valves as arranged for an
ordinary steam engine, with vertical or horizontal cylinder, and equally
suited to either condensing or non-condensing. On referring to Figs. 1 and 5,
which are sections of the valve, it will be seen that the space or depth
between the back of the valve and the under side of the valve case lid is
entirely filled up with the metallic plate a, the under side of which is exactly
similar to the face upon which the slide valve works, and is planed perfectly
true. It is so fixed to the lid or cover of the valve case, that the under side
is perfectly parallel in its length with the face upon which the valve slides, as
shewn at Fig. 1, but not parallel in its cross section, see Fig. 5, thereby
requiring the slide valve to be made in the form of a wedge, which at once
admits of easy adjustment by the screws at b, b, and at the same time allows
it to slide perfectly easy between the two surfaces in the direction of its stroke.
Now, in this arrangement the steam is admitted at either of the pipes c, c, and
passing through the before-mentioned "plate," it has free access to each end
of the valve or top and bottom steam ports of the cylinder without excrting
any pressure upon the valve, whilst at the same time an equal pressure is

page_text: maintained on the back of the valve by the small openings at d, here repre-
sented as communicating with the exhaust or condenser, but the action can
be reversed if requisite. Fig. 3 is a view of the top side of the plate with
the steam (or exhaust) pipe c cast on it. The ring at e is turned perfectly
true, and a corresponding recess is bored out on the valve case lid, into which
it is fitted steam-tight, then adjusted in the position before described, and
secured there by four or more screws f, f. Fig. 4 is a section of the
said plate.
The second part of my Invention relates to the construction of "slide
valves" in two or more parts, so arranged that the length can be altered, and
the bearing or rubbing surfaces expanded or contracted, thereby altering the
amount of lap or cover, and so cutting the steam off sooner or later, as may
be required, more particularly shewn in Figs. 6, 7, 8, 9, 10, 11, 12, 18, and 14;
which represent simple forms or arrangements of the same, adapted to any kind
of engine. Figs. 7 and 14 are vertical sections through the valve and case..
These valves it will be seen are cylindrical, and arranged so as to admit the
Steam at the pipes a through the centre of the valve, and to exhaust round the
middle; but the action can be reversed without any alteration further than
simply admitting the steam where the exhaust is shewn. The valve case is
cylindrical and truly bored out, having the steam ports cast in; and divided in
their diameter into four or more divisions by vertical ribs, as seen in Figs. 12
and 13 at b, b. The valve has corresponding ribs cast upon it vertically,
see Figs. 8 and 10 at b, b, intended to keep the valve in its proper position,
altogether independent of the packings, which are formed of metallic rings, or
segments half lapped together in their depth, see Figs. 7 and 14, at c, c, so as
to expand or contract, according to the breadth of the face required, and kept
to a true bearing against the faces in contact with the upper and lower
surfaces of the body of the valve by springs or otherwise. The valve spindle
is passed through cross bars cast upon each portion of the valve, and secured
by nuts, which at once allow of the plates forming the upper and lower sur-
faces of the valve at d, d, being raised or lowered, and with them the rings,
before described. The surfaces at e, e, are turned and fitted steam-tight
together.
The small groove formed by the expansion of the rings, at Fig. 8, f, f.
serves to communicate between the front and back surface of the valve, thereby
preserving an exactly equal pressure upon the same.
In the valve here described the rings are shewn to be of the eccentric kind
(see Fig. 9), but others may be substituted. In some cases I employ a fat
valve similarly arranged, which slides between the face plate and the under

page_text: side of the valve case lid, adjusted as before described in Figs. 1, 2, and 5,
and exhausting or or taking steam down the centre of the valve at a, a, a,
as shewn more clearly at Fig. 15.
Having thus fully described the nature and particulars of my said Invention,
and the manner in which the same is to be performed, I desire it to be
distinctly understood that I do not confine myself to the precise details of con-
struction or arrangement of parts as herein set forth, and I am aware that it
has been proposed to employ plates with compensating recesses and adjusting
screws for the purposes herein named, but not in the same arrangement or
construction as here shewn; but what I claim, and believe to be new within
the realm, is,
Firstly, the application of metallic rings, plates, or packings between the
back of the valve and the lid or cover of the steam case or valve box to
relieve the back of the valve from the pressure of the steam or other power,
and the sliding surface from unnecessary friction.
And, secondly, the construction of slide valves in two or more parts, so as
to regulate the lap or cover to cut off the admission of steam at any point of
the stroke, with the necessary arrangement of appliances for working and
effecting the said improvements, as herein described, and illustrated in the
accompanying Sheet of Drawings.
In witness whereof, I, the said Frederic Sarley Stott, have hereunto
set my hand and seal, this Thirtieth day of June, in the year of our
Lord One thousand eight hundred and fifty-seven.
FREDERIC SARLEY STOTT. (L.S.)
Signed, sealed, and delivered by the
within-named Frederic Sarley Stott,
in the presence of
W TASKER, Patent Agent,
Halifax.