IMPROVE- MENTS IN PACKING RINGS FOR THE PISTONS OF STEAM ENGINES, AND IN THE IN THE WEARING SURFACES, OF SLIDE VALVES AND OTHER WEARING SURFACES
Year: 1872

page_text: LETTERS PATENT to Loftus Perkins, of Seaford Street, Gray's Inn
Road, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN PACKING RINGS FOR THE PISTONS OF STEAM ENGINES, AND IN THE
PROVISIONAL SPECIFICATION left by the said Loftus Perkins at the
Office of the Commissioners of Patents, with his Petition, on the
18th December 1872.
I, LOFTUS PERKINS, of Seaford Street, Gray's Inn Road, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PACKING RINGS FOR THE PISTONS OF STEAM ENGINES, AND IN
THE WEARING SURFACES, OF SLIDE VALVES AND OTHER WEARING SURFACES," to be
as follows:-
This Invention has for its object improvements in packing rings-for
the pistons of steam engines, and in the wearing surfaces of slide valves

page_text: •
The packing rings for pistons and the wearing surfaces of slide valves
should be harder than the surfaces of the cylinder or valve face against
which they slide, as the wear to which they are exposed is much greater.
On these surfaces the metal also of which such rings or wearing surfaces
are composed should be of such a nature that they are capable of being
polished in presence of steam, and without the use of oil, as it is on
many accounts desirable to avoid the use of oil for lubricating such
surfaces. Hitherto no metal possessing these properties has been used
for such purpose.
Now I have discovered that such a metal can be
obtained by a mixture of about 5 parts of tin to 16 of copper. If less
than about 2 or 3 parts of tin be used to 16 of copper the metal will
be too soft for the purpose, and if much more than five be used the metal
is so extremely brittle that it cannot be worked; if more than 6 parts be
used the metal at once becomes softer.
When packing rings for pistons or the wearing surfaces of slide valves
are made from a metal composed as above stated, of 5 parts of tin to
16 of copper, they are of so hard-a nature that after long use, even when
exposed to steam of extremely high pressures (300 lbs. to the square inch)
they are in no way marked by the surfaces against which they slide,
and though no oil be used for lubrication they become highly burnished.
Metal bearings may also be formed from metal made as above
described, and may be lubricated with water in place of oil.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Loftus Perkins in the Great Seal Patent Office on
the 17th June 1873..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOFTUS
PERKINS, of Seaford Street, Gray's Inn Road, in the County of Mid-
dlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of December, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Loftus Perkins, Her special license that I, the
said Loftus Perkins, my executors, administrators and, assigns, or such

page_text: others as I, the said Loftus Perkins, 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 PACKING RINGS FOR THE PISTONS OF
STEAM ENGINES, AND IN THE WEARING Surfaces of SLIDE Valves and OTHER WEARING
SURFACES," upon the condition (amongst others) that I, the said Loftus
Perkins, 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 calender months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Loftus Perkins, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :
This Invention has for its object improvements in packing rings for
the pistons of steam engines, and in the wearing surfaces of slide valves
and other wearing surfaces.
The packing rings for pistons and the wearing surfaces of slide valves
should be harder than the surfaces of the cylinder or valve face against
which they slide, as the wear to which they are exposed is much greater
on these surfaces. The metal also of which such rings or wearing sur-
faces are composed should be of such a nature that they are capable of
bcing polished in presence of steam, and without the use of oil, as it is
on many accounts desirable to avoid the use of oil for lubricating such
surfaces. Hitherto no metal possessing these properties has been used
for such purposes. Now I have discovered that such a metal can be
obtained by a mixture of about 5 parts of tin to 16 of copper. If less
than about 2 or 3 parts of tin be used to 16 of copper the metal will
be too soft for the purpose, and if much more than five be used the
metal is so extremely brittle that it cannot be worked; if more than
6 parts be used the metal at once becomes softer.
When packing rings for pistons or the wearing surfaces of slide valves
are made from a metal composed as above stated of 5 parts of tin to

page_text: 16 of copper, they are of so hard a nature that after long use, even when
exposed to steam of extremely high pressures (300 lbs. to the square
inch) they are in no way marked by the surfaces against which they
slide, and though no oil be used for lubrication they become highly
burnished.
Metal bearings may also be formed from metal made as above
described, and may be lubricated with water in place of oil.
"
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that I claim, the
construction of piston rings, and the wearing surfaces of slide valves and
bearings, and other such like wearing surfaces of a metal capable of
burnishing or polishing in presence of water or steam, without the use
of oil, and composed of copper and tin within the proportions herein-
before giv
In witness whereof, I, the said Loftus Perkins, have hereunto sot 1
my hand and seal, this Seventeenth day of June, in the year of
our Lord One thousand eight hundred and seventy-three.