IMPROVEMENTS IN SLIDE VALVES
Year: 1864

page_text: LETTERS PATENT to Thomas Adams, Engineer, and George John Parson,
Gentleman; both of No. 5, Duke Street, Adelphi, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN SLIDE VALVES."
Sealed the 7th April 1865, and dated the 11th October 1864.
PROVISIONAL SPECIFICATION left by the said Thomas Adams and
George John Parson at the Office of the Commissioners of Patents,
with their Petition, on the 11th October 1864.
We, THOMAS ADAMS, Engineer, and GEORGE JOHN PARSON, Gentleman,
both of No. 5, Duke Street, Adelphi, in the County of Middlesex, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SLIDE VALVES,"
to be as follows:-
Our Invention has for its object the construction of slide valves in such a
manner that the pressure of steam or other fluid on the one side may be
diminished by the simultaneous pressure of fluid on the opposite side thereof.
For this purpose the two ends of the valve at which steam is admitted to the
cylinder are bevilled off so as to admit of the steam from the boiler pressing
on such ends in a direction opposite to that in the ports of the cylinder, and
thereby diminishing the resistance to the sliding of the valve, as required,
between the face plate of the valve box and the cylinder face. The steam

page_text: space thus formed at each end of the valve is or may be equal in area to the
steam port on the opposite side of the valve, and the steam in such spaces is
prevented from passing into the valve by means of a rectangular ring inserted
and fixed in the central part of the valve between the two bevilled ends
thereof. This ring is formed in parts, -with-two surfaces fitting-accurately the
face plate of the valve box and the inner side of the valve, against which
respectively it is pressed by springs or packing so as to make such parts steam
tight. The centre of the valve inside the. ring is open; and is pressed upon
equally on all sides by the exhaust steam, the pressure being also equal at
each end of the valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Adams and George John Parson in the Great Seal
Patent Office on the 11th April 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, THOMAS
ADAMS, Engineer, and GEORGE JOHN PARSON, Gentleman; both'. of No. 5,
Duke Street, Adelphi, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria; by Her Letters
Patent, bearing date the Eleventh day of October, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Thomas. Adams and George John Parson, Her, special license
that we, the said Thomas Adams and George Jolin Parson, our executors,
administrators, and assigns, or such others as we, the said Thomas Adams
and George John Parson, 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 SLIDE VALVES," upon the condition (amongst others) that
we, the said Thomas Adams and George John Parson, by an, instrument in
writing. under our hands and seals, or under the hand and seal of one of us,
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.

page_text: NOW KNOW YE, that we, the said Thomas Adams and George John
Parson, do hereby declare the nature of our said, Invention, and in what
manner, the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being had to the Drawings
hereunto annexed, and to the letters and figures marked thereon (that is.
to say):
.
1. Our Invention of "Improvenients in Slide Valves" has for its object the
construction of slide valves in such a manner that the pressure of steam or,
other fluid on the one side may be diminished by the simultaneous pressure of
fluid on the opposite side thereof. For this purpose the two ends of the valve.
at which steam is admitted to the cylinder are bevilled off or formed so as to
leave a small space for the admission of the steam from the boiler, which;
steam presses on such ends in a direction opposite to that in the ports of the
cylinder, thereby diminishing the resistance to the sliding of the valve," as
required,. between the face plate of the valve box and the cylinder face. The
steam space thus formed at each end of the valve is or may be equal in area.
to the steam port on the opposite side of the valve, and the steam in such
spaces is prevented from passing into the valve by means of a ring inserted.
and fixed in the central part of the valve between the two ends thereof. This
ring is formed in parts, with two surfaces fitting accurately the face plate of
the valve box and the inner side of the valve, against which respectively it is
pressed by springs or packing, or the ring itself is made to act as a spring, so,
as to make such parts, steam-tight. The centre of the valve, inside the rings
is open and is pressed, upon equally on all sides by the exhaust steam, the
pressure being also equal at each end of the valve. *
Having thus stated the nature of the said Invention, we will, proceed to
describe more particularly in what manner the same is to be performed, by
reference to the accompanying Drawings, in which are, represented various,
modifications of the form of the ring and mode of applying the same to slide
valves:

page_text: lap and with inside clearance: C is the valve which is caused to work close
to and on the back of the moveable cylinder face B. The valve C regulates
the passage of steam through the ports D, D, and the moveable cylinder
face B regulates the passage of- steam-through the ports E, E;. Fis the ring,
which, in the first instance, is cast larger than the space it is intended to
-occupy,-as-shewn-in-Fig. 10-with-two lugs f,f, cast on it; the piece required.
to produce the spring is cut out between the lugs, which are then drawn
together by a bolt, and the ring is chucked in a lathe by means of the lugs
9, 9, and then bored and turned to fit its place in the valve. . Fig. 11 is a
section of the ring; G. Fig. 1, is a space for the insertion of springs or other
elastic packing for pressing the ring against the face plate K of the valve.
box; H is the bridle forming the valve spindle. Figures 4 and 5 shew the
modes of forming the junction of the ends of-the-ring.
In Fig. 2 the corners a, a, exposed to the pressure of steam from 'the boiler
are equal in area to the ports D, D, in the moveable cylinder face B. This
moveable cylinder face may be worked by one or more excentrics or cams in.
the ordinary way, and any known form of expansion gear may be applied to
work the valve C, and by varying the linear advance of this valve any required:
degree of expansion between the limits of one and ninety-nine per cent. may
be obtained.
Figures 6, 7, 8, and 9 are sections shewing the valve C applied to the
ordinary cylinder face. Fig. 6 shews the ring F without, a joint. d is a recess,
for the reception of a ring of india-rubber or other elastic packing; c is a
flange on the ring F, on which the pressure of steam from the boiler acts, and
thereby keeps the ring against the face plate of the valve box and balances
the force due to the vacuum at G; Fig. 7 shews the ring F with a small
flange c to keep it in contact with the face plate of the valve box by the
pressure of steam from the boiler; Fig. 8 shews the ring F kept against the
face plate of the valve box by another metallic ring N constructed so as to
have a spring in itself and bevilled to any suitable angle; Fig. 9 shews the
ring F with a ring O inside of it, and fitted against its internal surface, with or
without bolts, in the same manner as the junk ring of- a piston. Fig. 12 is a
section of a double-ported slide valve, to which any of the foregoing modes of
constructing the ring may be adapted and applied: Fig. 13 is a plan of the
same. Fig. 14 is a section of a rectangular ring in four pieces, which may be
constructed according to either of the modes above described; Fig. 15 is a
plan of the same. In all cases the steam may be admitted from either the
outside or the inside of the valve, and vice versâ for the exhaust.

page_text: Having thus described the nature of the said Invention, and in what manner
the same is to be performed, we hereby declare that what we claim as of our
Invention is, the mode of constructing and applying the rings F, N, and O to
slide valves, as herein-before described.
In witness whereof, we, the said Thomas Adams and George John
Parson, have hereunto set our hands and seals, the Eleventh day of
April, in the year of our Lord One thousand eight hundred and
sixty-five.
Witness,
WILLIAM SPENCE,
8, Quality Court,
Chancery Lane.
THOMAS ADAMS.
(L.B.)
GEORGE JOHN PARSON. (L.S.)