Improvements in and in Connection with Metallic Packings for Pistons and other Analogous Working Parts of Fluid Pressure Engines or Apparatus.
Year: 1887

page_text: RESER
Date of Application, 22nd Oct., 1887
Complete Specification Left, 23rd July, 1888
Complete Specification Accepted, 21st Sept., 1888
Improvements in and in Connection with Metallic Packings for
Pistons and other Analogous Working Parts of Fluid Pressure
Engines or Apparatus.
I, THOMAS DOWNIE, of 33 Trinity Road, Bootle, in the County of Lancaster,
Engineer do hereby declare the nature of my said invention to be as follows :—
This Invention relates to what are known as metallic packings applicable for use in
steam and other fluid pressure engines or apparatus where fluids at different pressures
are employed, or exist on the opposite sides of a working part or on the opposite
sides of a stationary part through which a rod, or other like moving body works. For
example it relates to pistons and piston rod and other like packings of steam and
other fluid pressure engines, and it has for its object, amongst other things, to
construct such packings in such a manner that the friction upon the working parts, or
surfaces shall be less than that existing heretofore under equivalent applications or
conditions and at the same time shall secure the required tightness.
For facility of description I will first proceed to describe my Invention applied to a
piston say of a steam engine. It is known that to render two parts working upon one
another steam, or air tight, it is only necessary to provide a narrow bearing, or
touching surface so long as the contact between the two surfaces is complete. My
Invention is founded upon this fact and I construct pistons and analogous packings
with a narrow and preferably a single packing ring of split form, but having the ends
overlapping and I provide behind this ring another ring made up of two, or more
segments, which are pressed closely against the packing ring by a spring, or springs.
Both rings are supported above and below with the metal of the piston so as to
form tight joints therewith. The packing ring may be in segments like the rear ring
and it may also be made up of two layers, or thicknesses so as to facilitate construction
in providing the overlapping portions. In such a case I rivet, or otherwise connect
the two parts together. The joints of the two rings must be so disposed that they
"break joint or
:: bond
"with each other to prevent the fluid escaping past them.
This condition is maintained by fixing their relative positions with pins provided in
either one, or other, or both of the rings.

page_text: The springs employed to press the inner ring segments against the packing ring
may be disposed between certain projecting portions of the segments at certain
distances apart, or the same result may be obtained by employing a single
continuous spring. Or coach, or any equivalent springs may be employed for the
purpose.
"
I have above stated that the packing ring according to this Invention is narrow.
What is meant by this is that the ring employed may be of, or substantially of, a
depth, or thickness equivalent to those known as Ramsbotton's" rings, and which
vary in thickness and depth for different diameters of the bodies to which they
are, or may be applied. Approximately these known proportions I prefer to employ
and apply to rings according to this Invention. But by constructing, say a piston
according to this Invention in lieu of two, or more rings necessary when employing
Ramsbotton's rings, I render it possible to effect an equivalent, or superior result. by
the use of a single ring of the same size as one of the other rings and to diminish
the friction proportionately. In like manner the same effect can be equally applied
to the packing of piston and other rods; these requiring merely the inverse of the
piston arrangement.
I have described my Invention applied and constructed in certain ways, but 1
would have it understood that these applications and constructions may be varied, or
modified without departing from the nature of this Invention.
T
1001

page_text: COMPLETE SPECIFICATION.
Improvements in and in Connection with Metallic Packings for
Pistons and other Analogous Working Parts of Fluid Pressure
Engines or Apparatus.
I, THOMAS DOWNIE, of 33 Trinity Road Bootle, in the County of Lancaster,
Engineer, do hereby declare the nature of my said invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to what or known as metallic packings applicable for use in
steam and other fluid pressure engines or apparatus where fluids at different pressures
are employed, or exist on the opposite sides of a stationary part through which a rod
or other like moving body works. For example it relates to pistons and piston rods and
other like packings of steam and other fluid pressure engines, and it has for its object
amongst other things, to construct such packings in such a manner that the friction
upon the working parts, or surfaces shall be less than that existing heretofore under
equivalent applications or conditions, and at the same time shall secure the required
tightness.
For facility of description I will first proceed to describe my invention applied to a
piston, say of a steam engine. It is known that to render two parts working upon
one another steam, or air tight, it is only necessary to provide a narrow bearing or
touching surface, so long as the contact between the two surfaces is complete. My
invention is founded upon this fact and I construct pistons and analogous packings
with a narrow and preferably a single packing ring of split form, but having the ends
overlapping, and I provide behind this ring another ring, made up of two or more
segments, which are pressed closely against the packing ring by a spring or springs.
Both rings are supported above and below with the metal of the piston so as to form
tight joints therewith. The packing ring may be in segments like the rear ring and
it may also be made up of two layers or thicknesses so as to facilitate construction in
providing the overlapping portions. In such a case I rivet or otherwise connect the
two parts together. The joints of the two rings must be so disposed that they "“break
joint" or bond
with each other to prevent the fluid escaping past thein. This
condition is maintained by fixing their relative positions with pins provided in either
one, or other, or hoth of the rings.
The springs employed to press the inner ring segments against the packing ring
may be disposed between certain projecting portions of the segments at certain
distances apart, or the same result. may be obtained by employing a single
continuous spring. Or coach, or any equivalent springs may be employed for the
purpose.
I have above stated that the packing ring according to this invention is narrow.
What is meant by this is that the ring employed may be of, or substantially of a depth
or thickness equivalent to those known as "Ramsbottom's" rings, and which vary in
thickness and depth for different diameters of the bodies to which they are, or may be
applied. Approximately these known proportions I prefer to employ and apply to
rings according to this invention. In lieu of two or more rings necessary when

page_text: employing Ramsbottom's rings, I render it possible to effect an equivalent, or superior
result by the use of a single ring of the same size as one of the other rings and to
diminish the friction proportionately. In like manner the same effect can be equally
applied to the packing of piston and other rods; these requiring merely the inverse
of the piston arrangement.
I have described my invention applied and constructed in certain ways but I would
have it understood that these applications and constructions may be varied, or
modified without departing from the nature of this invention.
The drawings hereto annexed and forming a part of this specification serve to
illustrate the invention as above described. Two forms are shown and of these
Figures 1, 2 illustrate in sectional plan, and part sectional elevation, respectively, the
particular construction of piston and packing above generally described; whilst the
form illustrated in Figures 3 and 4 in sectional plan, and elevation is a modification
of that first named, in respect of the backing or means by which the rings are kopt
up to the surface traversed by them.
In the figures like or equivalent parts are marked with the same reference letters
and figures throughout.
With reference in the first instance to Figures 1 and 2 A designates the piston
formed in this instance of two parts a' a² and B is the packing ring composed of a
number of segments having overhanging ends c. Each segment is made up of two
parts connected together by screws or rivets e. Dis the rear or inner ring which is
composed of a plurality of separate segments & each having brackets d² near their
ends and E are springs which are placed between the brackets & in compression
and press the segments d' onto the inner surface of the packing rings B. The number
of segments of the inner ring D are so arranged in relation to the segments of the
ring B, that the space between the ends of the former segments lie between those of
the latter; by which means the steam is prevented from escaping from one side of the
piston to the other by way of the spaces between the segments d¹ and the rear
thereof.
The piston A and rings B and D are so fitted and adjusted that the rings may be
freely moved in the recess in which they work and are held without allowing steam
to pass above or below; a steadying pin or pins being provided for keeping the
segments of the two rings in their proper relative positions.
With reference to Figures 3 and 4 the modification of this example consists in
substituting for the ring D made of segments as set forth with reference to Figures 1
and 2, a number of plates ', fitting into the back surface of the jointed or overlapping
ends of the segments 6, and kept up to them by radially arranged springs, such springs
being either supported by a solid loose ring D as shown on the right hand half of the
Figures, or by the metal of the piston itself as shown in the left hand side of the
figures. In this example the plates d' are provided with a plain or flat surface, and
the inner surface of the segments is also made flat at that portion where the plates d'
bear upon them, to correspond thereto.
The examples shown in the drawings represent pistons of about 30 inches in diameter
and of about 7 inches deep the single packing ring B being about 14 inches deep
and 1 inches thick. I have found in practice that for pistons of say from 30 inches
in diameter to the largest size the above dimensions of packing ring are fully sufficient
to effect a practically perfect steam tight joint with the walls of the cylinder. And
I have also found that for smaller sizes of pistons than 30 inches the size of the
packing ring may be diminished proportionately, down to inch deep for a six inch
cylinder, or even smaller. The chief condition governing the size of the rings in
making them, being the nature and amount of work to be performed with relation to
the size of the piston; in all cases providing that they are made of sufficient depth
and thickness to prevent them becoming bent in work.
It will be observed that a great depth of piston, relatively to the depth of the
packing ring is provided; this is done in order to give it a large rubbing or wearing
surface, which shall take practically all the stresses imparted to it, and serve mainly
as a fairly fitting slide, the cylinder walls being its guide; whilst the packing ring

page_text: itself takes no stresses, performing solely the function of a moving steam tight joint.
By this construction a small pressure only is needed to press the packing ring out-
wards against the walls of the cylinder sufficiently to render the packing steam tight;
that is to prevent steam passing from one side of the piston to the other.
The packing ring herein given as an example of the preferred form of packing
according to my invention is of depth equal to about that of a Ramsbottom's ring used
for the size of such a piston 30 inches diameter, but as previously stated one ring only
is required according to my invention instead of a plurality as in the case of piston
packing of the Ramsbottom type.
It is evident that the packing described particularly with reference to the accom-
panying drawings is equally applicable to all forms of pistons and their engineering
equivalents operating under like or equivalent conditions; and I would state that
I do not intend to limit my Patent to the exact forms or construction herein set forth
as the packing herein described is capable of various modifications without departing
from the general nature of construction operation and effects herein embodied; also
various designs may be contrived to suit special cases, but in all, the essential feature
is the use of a packing so constructed and pressed up to the surface against which
it bears that a single ring split as described suffices to render the joint steam tight.
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
in respect of my herein described invention is :-
1. In a packing for pistons and other like or equivalent purposes, the combination
of a packing ring composed of a plurality of pieces or segments, a backing ring or
plates adapted to bear upon and cover the inner surface of the said pieces, and a
spring or springs arranged to keep the said backing or plates up to the packing ring:
substantially as set forth.
2. A packing ring for pistons and other like or equivalent purposes composed
essentially of a plurality of pieces or segments having overhanging ends, such ends
being arranged to overlap each other; substantially as set forth."
3. A piston provided with a large bearing surface and a packing ring of small
depth relatively to the depth of the piston bearing, surface said ring being of split or
divided form, and provided with a plate or plates at the point or points of division
thereof for preventing the escape of the working fluid, or fluid being operated upon,
past the ring at said point or points.
4. A packing ring for pistons and other like or equivalent purpose constructed of
segments of two rings, the segments of said rings being connected together by screws,
rivets, or equivalent means; substantially as set forth.
5. The piston and packing comprising the piston A, packing ring B, inner ring D
and springs E, said parts being arranged constructed and operating substantially as
set forth with reference to Figures 1 and 2 of the drawings.
6. The piston and packing comprising the piston A, packing ring B, inner plates D
and springs E said parts being arranged constructed and operating substantially as
set forth with reference to Figures 3 and 4 of the Drawings.
7. The piston and packing comprising the piston A, packing ring B, inner plates D,
springs E and ring D¹, substantially as set forth with reference to Figures 3 and 4 of
the Drawings.