IMPROVEMENTS IN PISTONS
Year: 1863

page_text: LETTERS PATENT to William Rowan, of the Firm of John Rowan and
Sons, of Belfast, in the County of Antrim, Engineers, for the Invention
of "IMPROVEMENTS IN PISTONS."
Sealed the 17th December 1868, and dated the 22nd June 1863.
PROVISIONAL SPECIFICATION left by the said William Rowan at the
Office of the Commissioners of Patents, with his Petition, on the 22nd
June 1863.
I, WILLIAM ROWAN, of the Firm of John Rowan and Sons, of Belfast, in
the County of Antrim, Engineers, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PISTONS," to be as follows:-
My improvements in pistons consist in keeping steam-tight the surfaces of
the top and bottom of the packing ring between the junk ring and lower part
of the piston, as well as the sides against the cylinder, by means of an expansion
ring, as hereafter described, cut into four, six, or eight segments, according to
the size of the piston, and placed behind the packing rings (of which there are
two);
the expansion ring is angled on the outside edges top and bottom, and
is fitted against corresponding angles on the internal side of packing rings,
the segments of the expansion ring being acted upon by springs of the usual
description at the back are pressed against the packing rings, which, being
separate, are, by virtue of the angles, pressed against the cylinder, the bottom
surface of the junk ring, and the upper surface of lower edge of piston as
above mentioned, thus rendering the whole steam-tight.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Rowan in the Great Seal Patent Office on the
22nd December 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RowAN, of the Firm of John Rowan and Sons, of Belfast, in the County of
Antrim, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of June, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Rowan, Her special licence that I, the said William Rowan,
my executors, administrators, and assigns, or such others as I, the said
William Rowan, 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
PISTONS," upon the condition (amongst others) that I, the said Williamı
Rowan, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, 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 I, the said William Rowan, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawings hereunto annexed,
that is to say:
My improvements in pistons consist in keeping steam-tight the surfaces of
the top and bottom of the packing ring between the junk ring and lower part
of the piston, as well as the sides against the cylinder, by means of an expan-
sion ring, as hereafter described, cut into four, six, or eight segments, according
to the size of the piston, and placed behind the packing rings (of which there
are two); the expansion ring is angled on the outside edges top and bottom,
and is fitted against corresponding angles on the internal side of packing rings,
the segments of the expansion ring being acted upon by springs of the usual
description at the back are pressed against the packing rings, which, being

page_text: separate, are, by virtue of the angles, pressed against the cylinder, the bottom
surface of the junk ring, and the upper surface of lower edge of piston as above
mentioned, thus rendering the whole steam-tight.
Figure 1 of the accompanying Drawings is a sectional elevation, and
Figure 2 is a plan, partly in section, of a piston constructed according to my
Invention.
A, A, are the packing rings; B is the expansion ring cut into segments, the
angled edges of these segments are shown in contact with the angles on the
inner faces of the packing rings; D, D, are the springs at the back of and
acting against the segments of the expansion ring B; E is the junk ring, and
F, F, are bolts for securing the junk ring to the piston G; H is a jib and cotter
for securing the piston to the piston rod K.
Figure 3 is a sectional elevation, and Figure 4 is a horizontal section of a
modification of my piston last described. In this case I dispense with the
springs at the back of the expansion ring, and instead of forming it in seg-
ments, I form it in one piece as a spring ring; the edges of this ring are angled
at top and bottom, and press against corresponding angular surfaces at the
back of the packing ring.
A, is the piston rod; B, B, are the packing rings; C is the spring ring;
D, D, bolts for junk rings.
In witness whereof, I, the said William Rowan, have hereunto set my
hand and seal, this Fifteenth day of December, One thousand eight
hundred and sixty-three.