Improvements in and relating to Piston Rings.
Year: 1895

page_text: 1
Date of Application, 4th Mar., 1845
Complete Specification Left, 4th Jan., 1896-Accepted, 15th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in and relating to Piston Rings.
1, JAMES WEIR of Holm Foundry, Cathcart in the County of Renfrew
North Britain Engineer do hereby declare the nature of this invention to be as
follows:-
It comprises improvements in and relating to the rings of pistons, more
especially those of pumps working with the higher pressures of modern steam
engines, and some of these improvements are advantageously applicable to other
purposes.
One of my objects is to avoid the excessive wear which takes place in the
metallic piston packing of ordinary construction, and at the sanie time make a
packing which will adjust itself to the cylinder in which it has to work.
One modification of this invention relates to a piston, which has the body-flauge
and junk-ring of slightly less diameter than the interior of the cylinder.
Between the body-flange and junk-ring there are (two or more) rigid or uncut
rings, hereinafter referred to as flange-rings and on either side of these flange-
rings there are (one or more) cut or expansible rings, herein described as
packing rings.
The said flange-rings fit the interior of the cylinder as nearly as possible
without tightness but none of these rings are confined at their inner edges or
otherwise but are free to accommodate themselves to the cylinder independently
of any alight deviation of the piston body or piston rod from the true axis of the
cylinder.
The rings are thin annular plates. Their outer cylindrical edges being
comparatively narrow whilst the surfaces which are in contact with each other are
made as truly flat as possible. Perfectly flat surfaces being also formed on the
body-flauge and junk-ring of the piston and on those parts of the flange-rings
which are in contact therewith.
Measured radially the rings are broad as compared with their thickness or edge
dimensions: the precise proportions depend upon the diameter of the piston, the
working pressure and other circumstances.
The outer, contact surfaces, only of the rings require to form fluid-tight joints
with each other their inner parts being thinner according to the modification thus
far described.
These rings are made of brass, white-metal cast iron or other suitablo metal or
alloy. When a packing ring is shaped to overlap at the cut part in order to
prevent a radial opening being formed through it as the ring expands with wear the cut
or severance is formed by inserting a piece of thin metal or other suitable parting
material in the mould wherein the said ring is cast; or in the said mould the plaue
of the ring may be slightly twisted to put one side of the cut out of the plane of
the other, similarly to a sorew thread, the ring being flattened after fitting the
surfaces of the said cut.
It is of great importance that the rings should be turned or shaped very
accurately so that they may be fluid-tight, for which purpose it is desirable that
the turning of each ring should be effected at one operation. That is, without
having to remove from and reset the ring in the lathe after it has been partly
turned.

page_text: To effect this purpose a gripping apparatus has been devised' containing one
fast and one detachable disc. This apparatus is fixed in the lathe by screwing or
other means, and the ring to be turned is held between the two discs, by its inner
flat edge; the parts beyond the gripping discs being then turned and surfaced
without in any way straining the ring or removing it from the lathe until the
work.is completed.
In other modifications, the inner part of one or more of these rings is made
thicker so as to project on one or both sides thereof, the gripping discs being so
arranged as to take hold of the projecting parts.
In some cases the outer part of a ring, after being turned and surfaced, may be
detached, by a parting tool, from the inner part by which it has been held in the
gripping discs:
These improved packing rings are onpable of application to a single-acting or
bucket-and-plunger type of pump so that they may act as the bucket valve; the
bucket being made smaller and having a space between it and the packing and
flange rings, the bottom flange-ring forming the valve, the top ring the stopper,
and the bucket itself constituting the guard and seat.
Dated this Second day of March 1895.
J
I, JAMES WEIR of Holm Foundry, Cathcart in the County of Renfrew
North Britain Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described aud
Ascertained in and by the following statement :-
It comprises improvements in and relating to the rings of pistons, more
especially those of pumps working with the higher pressures of modern steam
engines, and some of these improvements are advantageously applicable to other
purposes.
One of my objects is to avoid the excessive wear which takes place in the
metallic piston packing of ordinary construction, and at the same time make a
packing which will adjust itself to the cylinder in which it has to work.
Certain particulars of the invention are detailed in the accompanying drawings
in which :-
Figure 1 is a view in section shewing one arrangement of metallic packing for a
piston in accordance with this invention.
Figure 2 is a view in section shewing another arrangement of metallic packing
rings for a piston in accordance with this invention.
Figures 3, 4, 5, 6 and 7 are views showing details of these improved pieton
rings.
Figure 8 is a view in section shewing an arrangement of metallic packing for a
piston of the "bucket-and-plunger" type, in accordance with this invention.
Figures 9, 10 and 11 are views in section shewing the gripping and other devices
for turning and surfacing these improved piston rings, and other details.
Similar letters of reference throughout the drawings indicate corresponding
parts.
One modification of this invention is shown in Figure 1 and relates to a piston
which has the body-flange A and junk-ring B of slightly less diameter than the
interior of the cylinder.
Between the body-flange A and junk-ring B thero are (two or more) rigid
or uncut rings C, Figs. 1 and 2 hereinafter referred to as fange-rings, and on

page_text: either side of these flange-rings C, there is or are (one or more) cut or expañsible
rings D herein described as packing.
The arrangement of metallic piston rings shewn in Fig. 1 consists of three rigid
or uncut rings C and two cut or expansible rings D inserted intermedially
between the uncut ones and held between, the body-flange A and junk-ring B.
This arrangement of the metallic piston rings is sometimes varied by the addition
of other and more numerous cut rings or of uncut ones or of both cut ones and
uncut ones.
The arrangement of metallic piston rings shown in Fig. 2 consists of two rigid
or uncut rings C'and' one cut or expansible ring D sandwiched between them
(similarly to those shown in Fig. 8) these three rings being designed for insertion
Between a body-flange A and junk-ring B corresponding with those shewn in
Fig. 1. This arrangement of the metallic piston rings is sometimes varied by the
insertion of one or more additional cut rings D placod intermedially between the
two uncut ones.
The said flange-rings C fit the anterior of the cylinder as nearly as possible
without tightness but none of these rings are confined at their inner edges cor
otherwise but are free to accommodate themselves to the cylinder independently
of any slight deviation of the piston body A, B, or piston rod from the true axis
of the cylinder.
The rings C, D are thin annular plates. Their outer cylindrical edges c³, ‹
being comparatively narrow whilst the surfaces &,, which are in contact with
each other are made as truly flat as possible. Perfectly flat surfaces being also
formed on the body-flange A and junk-ring B of the piston and on those parts
of the flange-rings C, which are in contact therewith.
Measured radially the cut rings D are broad on the surface as compared with
their thickness (or edge dimensions) the precise proportions depend upon the
diameter of the piston, the working pressure and other circumstances. The outer
contact surfaces c, d, only of the rings require to form fluid-tight joints, their
inner parts c, being thinner according to the modification thus far described
with reference to the drawings.
These rings C and D are made of brass, white metal, cast iron or other suitable
metal or alloy. When a packing ring D is shaped to overlap at d', d' of the cut
part, Figs. 3, 4 and 5 in order to prevent a radial opening being formed through
it as the ring expands (with wear) the cut or severance is formed by inserting a
piece of thin metal Fig. 3, or other suitable parting material in the mould
wherein the said ring D is cast: or, in the said mould the plane of the ring may be
slightly twisted to put one side of the cut out of the plane of the other side d'
Fig. 4 similarly to a screw thread, the ring being flattened after fitting the contact
surfaces of the said cut dª.
It is of great importance that the rings C, D, should be turned or shaped very
accurately so that they may be fluid-tight, for which purpose it is desirable that
the turning of each ring should be effected at one operation. That is, without
having to remove from and reset the ring in the lathe after it has been partly
turned.
To effect this purpose a gripping apparatus, Figs. 9 and 10 has been devised
containing one fast disc F and one detachable one G. This apparatus is fixed in
or to the lathe H by screwing or other means, and the ring C to be turned is held
between the two discs by its inner flat edge c¹ Fig. 9; the parts c³, o³, beyond the
gripping discs, are then turned and surfaced without in any way straining the
ring or removing it from the lathe until the work is completed.
In other modifications, the inner part of one or more of these rings is made thicker
( Fig. 10) so as to project on one or both sides, c³, thereof, the gripping
discs, F, G, being arranged to take hold of the projecting parts c¹ or o.
In some cases the outer part c², cof a ring C, after being turned and surfaced
is detached (see Fige. 10 and 11) by means of a parting tool J from the inner
purt or e, by which part it has been hold in the gripping discs.

page_text: Any such rings, whether of C or D type, are thus parted the tool L, Fig. 9 is
used for surfacing the two faces e or d simultaneously.
These improved rings C and D are capable of, and designed for, application to
a single-acting or "bucket-and-plunger "type of pump as shewn in Fig. 8, so that
they may act as the bucket valve; the bucket guard or body-ring A', and junk-
ring B', fitted upon the plunger E', are made smaller in diameter than the cylinder
and have a space K between them and the packing and flange-rings C and D ;
the bottom flange-ring C forms the valve, the top ring C is the stopper, and the
bucket A, B, itself constitutes the guard and seat.
The expansible piston ring shewn in Fig. 6 differs from those shewn in
Figs. 3, 4 and 5 only in the form of its cut or severance : Fig. 7 is an edge
elevation of the ring shewn in Fig. 4, after it has been flattened as before
described.
These arrangements of numerous cut and uncut thin metallic rings, arranged,
alternately or otherwise within the body of a piston, have been found to sustain
less injury, from wear and tear, than the ordinary metallic packing of such pistons,
and at the same time, to make a piston packing which will adjust itself to the
cylinder in which it has to work with remarkable precision.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what
I claim is :-
Firet. In a fluid-tight piston the combination therewith of the cut and uncut
rings D and C, all substantially as herein described with reference to Figure 1 of
the drawings or any mere modification thereof for the purposes specified.
Second. In a fluid-tight piston the combination therewith of the cut and uncut
rings D and C, all substantially as herein described with reference to Figure 2 of
the drawings or any mere modification theroof for the purposes specified.
Third. Tu a piston of the "bucket-and-plunger" type the combination therewith
of the cut and uncut rings, D and C, all substantially as herein described with
reference to Figure 8 of the drawings, or any mere modification thereof for the
purposes specified.
Fourth. The combination of parts described herein for turning and surfacing
the rings C and D, all substantially as herein described with reference to the
drawings for the purposes specified.
Dated this Thirtieth day of December 1895.