A CERTAIN IMPROVEMENT IN METALLIC PISTONS
Year: 1859

page_text: LETTERS PATENT to William Garforth and James Garforth, both of
Dukinfield, in the County of Chester, Engineers, for the Invention of
"A CERTAIN IMPROVEMENT IN METALLIC PISTONS."
PROVISIONAL SPECIFICATION left by the said William Garforth and
James Garforth at the Office of the Commissioners of Patents, with
their Petition, on the 24th March 1859.
We, WILLIAM GARFORTH and JAMES GARFORTH, both of Dukinfield, in the
County of Chester, Engineers, do hereby declare the nature of the said.
Invention for "A CERTAIN IMPROVEMENT IN METALLIC PISTONS," to be as
follows:-
Our Invention is designed to obtain a sufficiently tight packing between the
piston and cylinder, to ensure its being steam-tight without the necessity
of exerting more pressure and causing moro friction between the piston and
cylinder than is absolutely required to effect a steam-tight packing. The
improvement in the piston for effecting the desired purpose consists in an outer
ring or rings of ordinary construction, which are to be expanded against the
cylinder by an internal Y ring made in sections, each of which sections being
provided with a small piston or pistons, one end of which acts upon the Vring,
and the other receives the direct pressure of steam which is supplied and

page_text: conveyed to an annular space in the interior of the piston by a steam pipe
which risos and descends through a stuffing-box in the cylinder cover, with the
action of the piston. In this arrangement it will be evident that by so applying
the action of steam to the expanding V piston ring the pressure of such steam,
and consequently the piston packing may be so regulated as to admit of a
pressure being exerted sufficient only to maintain the piston packing in steam-
tight contact with the interior of the cylinder.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Garforth and James Garforth, in the Great Seal
Patent Office on the 23rd September 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
GARFORTH and JAMES GARFORTH, both of Dukinfield, in the County of Chester,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of March, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said William Garforth and James Garforth, Her special
license that wo, the said William Garforth and James Garforth, our executors,
administrators, and assigns, or such others as we, the said William Garforth
and James Garforth, 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 "A
CERTAIN IMPROVEMENT IN METALLIC PISTONS," upon the condition (amongst
others) that we, the said William Garforth and James Garforth, or one
of us, 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.
NOW KNOW YE, that we, the said William Garforth and James
Garforth, do hereby declare the nature of our said Invention, and in what

page_text: manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, and accompanying Drawings, that
is to say:-
Our Invention is designed to obtain a sufficiently tight packing between the
piston and cylinder, to ensure its being steam-tight, without the necessity of
exerting more pressure, and causing more friction between the piston and
cylinder than is absolutely required to effect a steam-tight packing. The
improvement in the piston for effecting the desired purpose consists in an outer
ring or rings of ordinary construction, which are to-be expanded against the
cylinder by an internal V ring made in sections, each of which sections being
provided with a small piston or pistons, one end of which acts upon the V ring,
and the other receives the direct pressure of steam, which is supplied and
conveyed to an annular space in the interior of the piston by a steam pipe,
which rises and descends through a stuffing-box in the cylinder cover with the
action of the piston. In this arrangement it will be evident, that by so applying
the action of steam to the expanding V piston ring, the pressure of such steam,
and, consequently, the piston packing may be so regulated as to admit of a
pressure being exerted, sufficient only to maintain the piston packing in steam-
tight contact with the interior of the cylinder. In order that the Invention
may be better understood and explained in detail, we have hereunto attached
a Sheet of Drawing, made upon a scale of about two inches to a foot, and
having similar letters of reference marked upon the corresponding parts in
both Figures.
Fig. 1 is a vertical sectional view of a cylinder and piston, to which the
improved steam-tight packing is shewn applied, clearly illustrating the method
of applying the steam to the packing ring by means of the pistons and V
wedges. And Fig. 2 is a plan view of the piston, having the cover and upper
spring removed to shew the internal pistons, and their action upon the packing
rings. In Fig. 1, a, a, is the cylinder, and 6 the piston; c, c, being the
packing rings, and d the annular V wedges which force the packing rings into
contact with the interior of the cylinder, by means of the small horizontal
pistons e, e, against which the steam exerts pressure; the steam being supplied
to the annular cavity f, behind the small pistons e, e, by means of the pipe g,
which rises and falls with the piston 6 through the stuffing-box in the cylinder
cover, and receives the steam from the chamber h, which is supplied by the
steam pipe i. Thus it will readily be seen, that the pressure of the piston
packing against the cylinder may be regulated according to the amount and
pressure of steam supplied to the annular cavity or chamber f.

page_text: Having now described the nature of the said Invention, together with the
method of carrying the same into practical effect, we wish it to be distinctly
understood, that we claim effecting a steam-tight packing between pistons and
cylinders, by means of the direct pressure of steam upon or against the packing
rings, employed separate and distinct from the steam used in the cylinder, and
applied by means of tho mechanism herein-before described, set forth, and fully
illustrated in the Drawings attached, and constituting our improvements in
metallic pistons.
In witness whereof, we, tho said William Garforth and James Garforth,
have hereunto set our hands and seals, this Twentieth day of September,
in the year of our Lord One thousand eight hundred and fifty-nine.
WILLIAM GARFORTH. (L.S.)
JAMES GARFORTH.
(L.S.)