Improvements in Pistons for Steam Engines and other Engines.
Year: 1885

page_text: Improvements in Pistons for Steam Engines and other Engines.
We JOHN TWEEDY of West Lodge, Walker, in the County of Northumberland,
Engineer, and JAMES PATTERSON Junior, of Hawthorn Street, in the City and
County of Newcastle-upon-Tyne, Engineer, do hereby declare the nature of said
invention for "IMPROVEMENTS IN PISTONS FOR STEAM ENGINES AND OTHER
5 ENGINES to be as follows:-
"
This invention has for its object the improvement of the pistons of steam and
other engines, and consists essentially in providing for the wear, i.e-wear in the
direction of the motion of the piston-with only one outer or working ring, instead
of obtaining such adjustment by fitting two outer or working packing rings as at
present, thus materially reducing the depth and the friction, or with the same
depth of piston obtaining a still further considerable reduction of friction.
In carrying out this invention we make the packing ring which bears against
the side of the cylinder, in one piece, and in one modification provide a flange on
its top or bottom inner edge as the case may be (for facility of description we will
assume this to be the bottom edge).
Into the inside of this outer or working ring we fit another ring almost equal in
depth to the depth of the outer ring, less the aforesaid flange; stiff springs of any
convenient form are placed between the flange of the outer ring and the edge of
the inner one; suitable recesses and provision being made to receive the springs.
The springs acting on the flange of the outer ring press it down on the flange of
the piston making the piston tight against the action of the steam on that side
while the reaction of the springs presses the inner ring against the "junk"-ring,
making the piston tight against the action of the steam on that side. To prevent
the passing of steam behind the rings, the inner ring is very carefully fitted to the
outer one and asbestos or other packing may be placed in proper recesses made to
receive it.
To secure tightness between the sides of the cylinder and the piston, the outer
or inner ring, or both, are made to exert a pressure on the cylinder sides either by
their own elasticity or by the action of spiral, coach or other suitable springs, or
תה

page_text: by the combined action of the rings and springs. Various modifications in the
Ininor details of the parts may be made, for example in another modification the
flange of the outer ring may be placed near the centre of the ring and two inner
rings may be fitted instead of one.
In another modification, when for any reason a thinner or shorter piston is not
required, the end wear of the working ring may be taken up by another ring
pressed against its top or bottom edge by springs the second ring being made tight
against the flanges of the junk ring or piston by being carefully fitted or by
asbestos or other packing in proper recesses made to receive it.

page_text: We JOHN TWEEDY of West Lodge Low Walker in the County of Northumberland,
Engineer, and JAMES PATTERSON Junior of 19 Hawthorn Street in the City and
County of Newcastle upon Tyne Engineer, do hereby declare the nature of the
said invention for "IMPROVEMENTS IN PISTONS FOR STEAM ENGINES AND OTHER
ENGINES" and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention has for its object the improvement of the pistons of steam and
other engines, and consists essentially in providing for the end wear-ie: wear in
the direction of the motion of the piston-with only one outer or working ring,
instead of obtaining such adjustment by fitting two outer or working packing rings
as at present, thus materially reducing the depth and the friction, or with the same
depth of piston obtaining a still further considerable reduction of friction.
In carrying out this invention we make the packing ring which bears
against the side of the cylinder in one piece, and in one modification provide a
flange on its top or bottom inner edge as the case may be; (for facility of description
we will assume this to be the bottom edge). Into the inside of this outer or
working ring we fit another ring, almost equal in depth to the depth of the outer
ring, less the aforesaid flange: stiff springs of any convenient form are placed
between the flange of the outer ring and the edge of the inner one; suitable
recesses and provision being made to receive the springs. The springs acting on
the flange of the outer ring press it down on the flange of the piston making the
piston tight against the action of the steam on that side, while the reaction of the
springs presses the inner ring against the junk ring making the piston tight against
the action of the steam on that side. To prevent the passing of steam behind the
rings, the inner ring is very carefully fitted to the outer one, and Asbestos or other
packing may be placed in proper recesses made to receive it.
To secure tightness between the sides of the cylinder and the piston, the outer
ring is made to exert a pressure on the cylinder sides either by its own elasticity
or by the elasticity of the inner ring or of both combined or by the action of spiral
coach, or other suitable springs, or by the combined.action of the rings and springs.
Various modifications in the minor details of the parts may be made, for example
in another modification the flange of the outer ring may be placed at, or near, the
centre of the ring and two inner rings may be fitted instead of one.
In another modification, when for any reason a thinner or shorter piston is not.
required, the end wear of the working ring may be taken up by another ring
pressed against its top or bottom edge by springs, the second ring being made
tight against the flanges of the "junk-ring" or piston by being carefully fitted or
by Asbestos or other packing in proper recesses made to receive it.

page_text: carefully fitted inside of it. Stiff springs 4. of any convenient form are placed
between the flange 2. and the ring 3. for the purpose of pressing the ring 1. against
one flange of the piston and the ring 3. against the other flange or "junk ring,"
preventing any leakage of steam into the space behind the rings.
Asbestos or other packing may be introduced between the outer and inner rings
as shown at 5. Figure 3. Pressure against the cylinder sides is obtained by the
elasticity of the rings themselves or by the action of a spiral spring 6. shown in
plan in Figure 2. or by coach springs 7 Figure 2. or by other suitable springs, or
by the combined action of rings and springs. Numerous other modifications in the
details of the packing made according to our invention may be used. Figure 4.
shews one such modification. In this Figure the flange 2 of the packing ring 1. is
placed some distance from the flanges of the piston and two inner rings 3 and 3¹
are carefully fitted into the inside of the ring 1. Springs introduced at 4 press the
inner rings against the flanges of the piston, and prevent the leakage of steam into
the space behind the rings. The outer packing ring is shown projecting beyond
the rim of piston a mode of fitting very convenient for piston-valves, giving free
access for steam to and from the ports.
In the modification shewn by Figures 5. and 6. the end adjustment is obtained
by the insertion of the rings 3. into the "junk ring" or piston flange; springs 4.
being placed in the bottom of the recess to force the ring 3. tightly against the
ring 1. and the ring 1. tightly against the piston flange or "junk ring." The
rings 3. are made with outward spring and are fitted steam tight on their outer
edge in recess, or may be fitted with Asbestos or other packing 5. In another
modification they may be made with inward spring and fitted steam tight on their
inner edge or may be fitted with Asbestos or other packing, or Asbestos or other
packing may be used without the metallic ring, and pressed by the springs 4. on to
the ring 1.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we say that we
are aware that it has long been customary to employ a broad packing ring, and
also that a broad flanged outer packing ring has been used in conjunction with
a second ring forced by a spring both radially and in the direction of the motion
of the piston, and we make no claim to such arrangement of parts when one spring
only is used. Neither do we make a general claim to a broad flanged packing ring
in conjunction with a loose inner ring except when the same are constructed, com-
bined, and arranged in such a manner as to provide, not only for giving the vertical
or end wise adjustment by means independent of those to produce the outward or
lateral pressure of the broad ring against the cylinder, but also to prevent
entry of steam behind the ring as above set forth, and we declare that what we
claim is
In steam or other pistons (including pistons acting as valves) the use of a single
outer working packing ring, in combination with means for providing for the wear
and adjustment of said ring in the direction of the motion of the piston such
means being independent of those whereby the ring is caused to press against the
cylinder substantially as described herein and shewn in the drawings hereunto
annexed.
W. LLOYD WISE,
Applicants' Agent.