Improvements in the Packings of Pistons or analogous Parts of Fluid Pressure Engines or Apparatus.
Year: 1895

page_text: Date of Application, 13th May, 1895
Complete Specification Left, 12th Feb., 1898-Accepted, 21st Mar, 1896
PROVISIONAL SPECIFICATION.
Improvements in the Packings of Pistons or analogous Parts of
Fluid Pressure Engines or Apparatus.
1, GEORGE RODGER of 3 Christchurch Road, Sheffield, in the County of
Yorkshire, Engineer, do hereby declare the nature of this invention to be as
tollows :-
The object of this invention has been to provide a ing, piston, or like packing,
by which the pressure acting upon the ring or ings, tending to press it of them
onto the surface or wall in connection with which it or they 18 or are used on work,
shall be relatively small to that which exists on ordinai y simple ring packings
commonly used.
Under this invention, piston packing ings are at their back or inner side, of
angular formation in crose section, say, of the form of an isosceles triangle, while
the groove or grooves in the piston or ng care are correspondingly formed.
By this, the pressure of steam in a cylinder, acting on the one side of the ring,
presses the other side onto the grooves, so that the ring at this side will make a
joint with the piston or cauer groove, and the steam can act only on the other
side. The effect of this is, that the pressure of the steam behind the ring, tending
to press it onto the cylinder wall, will not be equal to the pressure acting upon an
area equal to the whole face of the ring, but on an area equal only to one half
theroot.
One, two, o more rings may be used in a piston; and in one form of mounting
and carrying the rings in a piston, where a carrier 18 employed, such carrier will
be of angular form and section, with grooves carrying the rings in one part or
member, while the other part of member fits onto the body of the piston, and is
bolted or studded to it.
COMPLETE SPECIFICATION.
Improvements in the Packings of Pistons or analogous Parts of
Fluid Pressure Engines or Apparatus.
I, GEORGE RODGER of 3 Christchurch Road, Sheffield, in the County of
Yorkshire, Engineer, do hereby declare the nature of this invention and in what
mauner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
The object of this invention has been to provide a ring, piston, or like packing,
by which the pressure acting upon the ring or rings, tending to press it or them
onto the surface or wall in connection with which it or thoy is or are used or work,
shall be relatively small to that which exists on ordinary simple ring packinga
commonly used.

page_text: Under this invention, pistou packing ungs are at then back or inner side, of
augular formation in cross section, say, of the form of an isosceles triangle, while
the groove or grooves in the piston or ring carrier are correspondingly formed.
By this, the pressure of steam in a cylinder, acting on the one side of the ring,
presses the other side onto the grooves, so that the ring at this aide will make a
joint with the piston or carriei gioove, and the steam can act only on the other
side. The effect of this is, that the pressure of the steam behind the ring, tending
to press it onto the cylinder wall, will not be equal to the pressme acting upon the
area equal to the whole of the face of the ring, but on an area equal only to one
balf thereof.
One, two, or more ings may be used in a piston, and in one form the mngs are
mounted and carried in a carrier ring, such carrier being of rectangular form and
section, with grooves carrying the rings.
The drawings hereto annexed illustrate a piston packing according to my
invention, three modifications being shown. Figure 1 shews a piston partly in
ɛection in which the ungs are of triangular form, and Figure 2 is a detail shewing
this construction to a larger scale, while Figures 3 and 4 are sections shewing
modified forms of the ungs.
Refening in the first instance to Figmes 1 and 2, a are the piston rings, two of
which are used. is a carrier ring in which the rings a are held and work. r is a
Junk ing by which the ring is held in position d represents the body of the
piston, and e ropresents the cylinder wall. In action, the ring of the pair which
would be in operation, would be that nearest the face of the piston for the time
being acted upon by the steam or other fluid, and the pressure of the fluid acting
upon the ring tending to force it outwards onto the cylinder wall, would be upon
the outer surface or side, that is the side next the face of the piston acted upon by
the steam; whilst the opposite side would be pressed by the steam onto the body
of the piston or carte ing, with which it would make a tight joint. Therefore,
it will be seen, that as the total resultant pressure acting on the inclined surface
of the ring, tending to force the ring onto the cylinder wall, will be only half that
which would be exerted on a rectangula ng having the same depth of face, the
pressure on the back of the ring according to my invention, would be a great deal
less than in the case of an ordinary rectangular ring, and assuming that the mean
pressure tending to press the ring away from the cylinder wall, inwards into the
ring grooves, would be the mean of the pressure existing on the two sides of the
piston, the nett pressure pressing the ring outwards onto the cylinder wall, will be
reduced, and the resultaut friction and wear proportionately diminished In the
leverse stroke of the piston, obviously, the ring at the other side of the piston
comes into action, and with similar effects and results.
In the modification shewn in Figures 3 and 4, substantially the same effect n
that above described is obtained, that is to say, in each the surface of the ring furthest
from the face of the piston being acted upon by the pressure of fluid, is inclined,
as shewn, and the pressure of fluid on the opposite sido thereto, presses it onto the
surface or face of the groove in the piston body or carrier ring in which it lies, and
also onto the cylinder wall. In Figure 3 it will be seen that the back of the ring
and the outer surface are rectangular, so that the downward pressure of the steain
acting on the outer surface of the ring would be upon the horizontal surface, while
the pressure tending to press it outwards would be exerted on the back vertical
surface; and the depth of this is only half that of the ring.
Having now particularly described and ascertamed the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
olaim 18:-
1. The piston or like packing consisting of rings a having the surface furthest
from the side of the piston or the like, on which the pressure is acting, inclined
(such as shewn), and acting in connection with the piston or like body, or carrier
ring, substantially as and for the purposes described.

page_text: 2. The piston or like packings constructed and adapted to operate particularly
as set forth with reference to Figures 1 and 2; Figure 3; and Figure 4;
respectively, of the drawing.
Dated this 11th day of February 1896
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicant's Patent Agents.