IMPROVEMENTS IN SCREW VALVES
Year: 1873

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery
Lane, in the County of Middlesex, Patent Agent, for the Invention
of "IMPROVEMENTS IN SCREW VALVES."-A communication from abroad
by Philip Corrigan, of the City, County, and State of New York,
United States of America.
Sealed the 31st October 1873, and dated the 11th September 1873.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 11th September 1873, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN SCREW VALVES," and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent

page_text: for the same, and have made solemn Declaration that it has been
communicated to me from abroad by Philip Corrigan, of the City,
County, and State of New York, United States of America.
NOW KNOW YE, that I, the said Alexander Melville Clark, do
hereby declare that the following Complete Specification, under my
hand and seal, fully describes and ascertains the nature of the said
Invention, and in what manner the same is to be performed, in and by
the following statement, reference being had to the Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that
is to say):-
This Invention has for its object to furnish an improved valve which
shall be so constructed that the valve plug may be conveniently ground
to its seat without detaching the valve from its connections.
The Invention consists in the nut made in sections and provided with
lugs having screw threads cut upon their outer surfaces in combination
with the screw of the valve stem, the cap nut, and the body of the valve,
as herein-after fully described.
I will describe the Invention as applied to a globe valve, but do not
wish to limit myself to that use, as it may be applied to various other
screw valves.
Figure 1 is a detail sectional view of the improved valve; Figure 2
is a detail view partly in section of the cap nut, valve stem, and sectional
nut; Figure 3 is a detail section taken through the line x, x, Figure 1.
Similar letters of reference indicate corresponding parts.
A represents the body of the valve, and a¹ is the partition in which is
formed the valve seat in which the plug B rests; C is the valve stem.
which passes out through the cap nut D, to the outer end of which is
attached a stuffing box E. The inner part of the nut D screws. into the
hole in the side of the body A. In the inner end of the nut D is formed
a tubular cavity larger than the screw c¹ formed upon the inner part of
the valve stem C; F is a tubular nut which is made in two halves or
sections. The sectional nut F is made with a smooth outer surface, and
with a screw thread upon its inner surface fitting into the screw c¹ of the
valve stem C. Upon the outer surface of the lugs f¹ are formed
screw threads corresponding with the screw threads cut upon the outer
surface of the inner end of the cap nut D, so that the sectional nut F

page_text: may be kept in place by the said screw threads. With this construction,
when the valve plug B requires to be ground into its seat the cap nut D
is screwed out and the valve stem C screwed back as far as it will go.
The valve stem C is then pushed forward carrying the scctional nut F
with it, which sections drop off. The cap nut D is then screwed back
into the screw hole of the body A. and serves as a guide for the valve
stem C, so that the plug B can be readily ground into its seat. The
cap nut D is then removed and the sectional nut F replaced and the
valve is ready for use.
Having described the nature of the Invention and the manner of per-
forming the same, I declare that what I clam as new and desire to secure
by Letters Patent is, the nut F made in sections and provided with
lugs f¹, having screw threads cut in their outer surfaces, in combination
with the screw c¹ of the valve stem C, the cap nut D, and the body of
the valve, substantially as herein shown and described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Eleventh day of September,
in the year of our Lord One thousand eight hundred and seventy-
three.
Witness,
HENRY W. DEWEY,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)