Year: 1896

page_text: 1, JAMES AIREY, of No. 17 Bellerby Terrace, West Hartlepool, in the County
of Durhain, Marine Engineer, do hereby declare the nature of this invention to be
as follows:-
My invention has reference to improved means for preventing escape of fluid
between pistons, piston valves and the like and the walls or surfaces in contact with
which they are designed to travel practically fluid tight. According thereto the
piston or other body is provided with a ring of suitable flexible metal such as steel
which is fitted with segments or packing pieces of a metal that will at a given
temperature expand to a greater extent than the metal composing the ring, the
said segments or packing pieces being fitted to the outside edge or edges of the
ring in which there are recesses to receive the packing pieces which may be formed
with grooves, dovetails, or projections at their sides next to the ring, and which are
so fitted into the ring as to prevent their displacement, and in such wise that owing
to their greater expansion a practically fluid tight contact with the cylinder wall or
rubbing surface may be obtained with as little friction as possible.
If desirable the ring itself may be either cut at one place or divided into two or
more part rings. There may be two or more such rings as above referred to and
packing pieces may be applied to any one or more or to all of such rings as desired.
In some cases when a ring to which the packing segments or pieces are applied is
itself divided I arrange concentrically within it another ring or rings in compression
and so positioned as to overlap or break joint with the outer ring and with one
another so as to prevent the passage of fluid past the outer ring between the
abutting ends of its component parts to the piston or other body. The inner ring
or rings being of flexible material and in a state of compression will by lateral
extension keep the outer ring in close contact with the surface against which it is
designed to travel.
My packing rings may be kept in place by any suitable means such as ordinary
Junk rings.
When my invention is applied to pistons working more especially in high
pressure cylinders, an additional ring or rings of various well known types,
for instance such as the Ramsbottom rings, may be fitted into recesses cut in the
face of the outer ring as a further security against leakage and excessive
friction.

page_text: I, JAMES AIREY, of No. 17 Bellerby Terrace, West Hartlepool, in the County
of Durham, Marine Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
My invention has reference to improved means for preventing escape of fluid
between pistons, piston valves and the like and the walls or surfaces in contact with
which they are designed to travel practically fluid tight. According thereto the
piston or other body is provided with a ring of suitable flexible metal such as steel
which is fitted with segments or packing pieces of a metal that will at a given
temperature expand to a greater extent than the metal composing the ring, the said
segments or packing pieces being fitted to the outside edge or edges of the ring in
which there are recesses to receive the segments or packing pieces which may be
formed with grooves, dovetails, or projections at their sides next to the ring, and
which are so fitted into the ring as to prevent their lateral displacement, and in
suchwise that owing to their greater expausiou a practically fluid tight contact
with the cylinder wall or rubbing surface may be obtained with as little friction as
possible.
If desirable the ring itself may be either cut at one place or divided into
two or more part rings. There may be two or more such rings as above referred
to and segments or packing pieces may be applied to any one or more or to all of
such rings as desired.
Fig. 1 of the accompanying drawings shows my improved packing partly
in side elevation and partly in section applied to a piston which is shown in
dotted lines. Fig. 2 shows the packing in plan or top view parts thereof being
broken away.
In this example the piston 1 is provided with two rings 2, 2 of flexible metal
such as steel, that are separated by two other metal rings 3 and the outer edge of
each of which is recessed and fitted with a ring composed of segments or packing
pieces 4 of metal, such as brass or gun-metal, the co-efficient of expansion of which
is greater than that of the corresponding ring 2.
These segments or packing pieces 4 owing to their position and also to the
greater expansion of the brass or gun metal than the steel or even ordinary cast
iron rings 2, have the effect of practically preventing wear or cutting of the rings 2.
The segments or packing pieces are provided with projections 4 that fit into
corresponding recesses 2ª in the rings 2 so as to prevent lateral displacement of the
segments or packing pieces whilst permitting them to expand to a greater extent.
than the said rings when heated, in order to form a practically fluid tight joint with
the wall of cylinder in which the piston is to work as herein before stated. The
segments or packing pieces are kept in place endways on the one side by the flange
or rim 1 on the piston body and on the other side by a junk ring 5, against which
parts they may be respectively pressed by the action of coiled metal springs 6 of
oval cross section confined between the rings 3. In the example shown, each
ring 2 when being made, has a piece cut therefrom and theu compressed by a band
and turned to shape whilst in a state of compression so that when it is in position
for use it will bear with the requisite pressure against the wall of the cylinder.
The rings 3 are not cut. The rings 2 and segments or packing pieces 4 are so
relatively arranged that the lines of division therein break joint and they are kept
in such positions by suitable means such as pins 3, (Fig. 2) one of which is fitted
between each ring 2 and one of the corresponding segments or packing pieces 4.

page_text: 3b are pins between the adjacent ends of the springs 6. If desired each ring 2 may
be made in one piece with its adjacent ring 3 so as to form one wide ring.
In some cases when a ring to which the packing segments or pieces are applied
is itself divided, I arrange concentrically within it another ring or rings in
compression and so positioned as to overlap or break joint with the outer ring and
with one another so as to prevent the passage of fluid past the outer ring between
the abutting ends of its component parts to the piston or other body. The inner
ring or rings being of flexible material and in a state of compression will by lateral
extension, keep the outer ring in close contact with the surface against which it is
designed to travel.
Fig. 3 shows in longitudinal section, a packing thus constructed and suitable for
a piston valve, and Fig. 4 shows this packing in end elevation with parts thereof
broken away.
2, 2 are the metal rings carrying segments or packing pieces 4 of metal of the
kind hereinbefore mentioned and pressed apart by interposed springs 6, as in
Figs. 1 and 2. The rings 2 are divided as shown at 2b and are fitted internally
with another divided ring 7 that is in compression and so arranged that its line of
division 7 breaks joint with the joints 2 in the rings 2. This relative position of
the rings may be maintained by a pin 8 fixed to the ring 7 and entering a hole 9
formed between the adjacent surfaces of the rings 2 as shown in Fig. 3.
When my invention is applied to pistons working more especially in high
pressure cylinders, an additional ring or rings of various well known types, for
instance such as the Ramsbottom rings, may be fitted into recesses cut in the face of
the outer ring as shown at 10, 10 in Fig. 1, as a further security against leakage and
excessive friction.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Packing for pistons and the like wherein one or more rings of suitable flexible
metal such as steel is or are provided with segments or packing pieces of a metal
having a greater co-efficient of expansion than the metal composing the ring or
rings, the said segments or packing pieces being fitted in a recess or recesses to the
outside edge or edges of the ring or rings substantially as described and shown for
the purpose specified.
2. My improved packing suitable for pistons and the like constructed arranged
and operating substantially as herein before described with reference respectively
to and shown in Figs. 1 and 2, and in Figs. 3 and 4 of the drawings annexed.
Dated this 5th day of October 1896.
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.