IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, PUMP-BUCKETS, AND VALVES
Year: 1879

page_text: LETTERS PATENT to Henry Christian Löbnitz, of Renfrew, in the County of
Renfrew, North Britain, for the Invention of "IMPROVEMENTS IN METALLIC
PACKINGS FOR PISTONS, PUMP-BUCKETS, AND VALVES."
PROVISIONAL SPECIFICATION left by the said Henry Christian Löbnitz
at the Office of the Commissioners of Patents on the 20th November 1879.
HENRY CHRISTIAN LÖBNITZ, of Renfrew, in the County of Renfrew, North
Britain. "IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, PUMP-BUCKETS,
AND VALVES."
This Invention has for its object the fitting of pistons, pump-buckets, and valves
with improved metallic packings which are simple and reliable, and specially
adapted to the conditions and peculiarities of each case. The improved packings
are applicable for motive-power engines or other apparatus in which steam or other
fluid under pressure is employed.
In carrying out the Invention in the case of a piston for a steam engine cylinder,
one, two, or more metallic rings are employed, each being cut through at one point
in the usual way and fitted with a tongue to prevent the passage of steam. Each
ring may be of the simplest possible section and of uniform thickness all round, or
it may be of any convenient section or of unequal thickness, but it must in all cases
be capable of yielding sufficiently to pressure applied to its inner side at numerous
points, the pressure being applied radially, and so as to tend to expand the ring
against the internal surface of the cylinder. The body of the piston is made with
numerous radial sockets, the outer ends of which are open to or covered by the ring
or rings, and when the junk ring or cover of the piston is removed the upper sides
of the sockets are open. Springs, which may be helical, or conic-volute, or cylindro-
conic, are placed in the sockets so that each has one end abutting against the end of
the socket nearest the centre of the piston, whilst the other end bears outwards
against the inside of the packing ring or rings. No adjusting screws are provided
in connection with the springs, so that if they are at the outset made suitable for
their intended action they cannot afterwards be made to act improperly by
unskilful adjustment. In preparing and determining the strengths and sizes of the
Price Gl

page_text: springs, the maximum steam pressure to be employed in the cylinder is considered,
and the ratio to this pressure of that which is to be applied to the surface of the
packing ring or rings is fixed on. Then the total pressure to be applied to the ring
or rings being calculated and divided by the number of springs, the quotient will
be the pressure to be applied by each spring, and such a size and strength of spring
is taken as on being subjected to that pressure by means of weights or otherwise
before being put into the piston socket will be compressed into a space equal in
axial length to the radial length of the socket. Such springs on being put in the
compressed state into the piston sockets will react against the packing ring with
the precise pressure required.
The improved packing is to be applied in precisely the same way to the pistons
or buckets of pumps, and also to so-called piston valves which are of a circular
form, and to valves of the "D" or other form having a piston-like action. The
packing is specially well adapted for valves of the kind referred to, as the pressure
on the ring or metallic packing strip can be predetermined with great nicety, so as
to secure sufficient tightness with the least possible excess of pressure for crossing
the ports with facility. The improved packing may be termed the reliable just-
pressure piston packing.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Christian Löbnitz in the Great Seal Patent Office on the
18th May 1880.
HENRY CHRISTIAN LÖBNITZ, of Renfrew, in the County of Renfrew, North
Britain. "IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, PUMP-BUCKETS,
AND VALVES."
My said Invention has for its object the fitting of pistons, pump-buckets, and
valves, with improved metallic packings, which are simple and reliable and specially
adapted to the conditions and peculiarities of each case. My improved packings
are applicable for motive-power engines or other apparatus in which steam or other
fluid under pressure is employed.
In carrying out my Invention in the case of a piston for a steam engine cylinder,
one, two, or more metallic rings are employed, each being cut through at one point
in the usual way and fitted with a tongue to prevent the passage of steam. Each
ring may be of the simplest possible section and of uniform thickness all round, or
it may be of any convenient section or of unequal thickness, but it must in all cases
be capable of yielding sufficiently to pressure applied to its inner side at numerous
points, the pressure being applied radially, and so as to tend to expand the ring
or rings against the internal surface of the cylinder. The body of the piston is
made with numerous radial sockets to receive springs, which may be helical, or
conic-volute, or cylindro-conic, and which are compressed so as whilst bearing
against the bottom of the sockets to press outwards against the inside of the
packing ring or rings. No adjusting screws are provided in connection with the
springs, so that if they are at the outset made suitable for their intended action,
they cannot afterwards be made to act improperly by unskilful adjustment.
In preparing and determining the strengths and sizes of the springs, the maximum
steam pressure to be employed in the cylinder is considered, and the ratio to this
pressure of that which is to be applied to the surface of the packing ring or rings is
fixed on, according to the judgment of the engineer, who is responsible for the
design of the engines. Then the total pressure to be applied being calculated for
the surface of the ring or rings at the determined proportion of the maximuin
pressure, and its amount being divided by the number of springs the quotient will
be the pressure to be applied by each spring; and such a size and strength of spring
is to be taken, as on being subjected to that pressure by means of weights or
otherwise before being put into the piston socket will be compressed into a space
equal in axial length to the radial length of the socket. Such springs on being put
in the compressed state into the piston sockets will react against the packing ring
or rings with the precise pressure required.
""
My improved packing, which may be termed the reliable just-pressure piston
packing, is to be applied in precisely the same way to the pistons or buckets of
pumps, and also to so-called piston valves which are of a circular form, and to
valves of the "D' or other form having a piston-like action. My packing is
specially well adapted for valves of the kind referred to, as the pressure on the ring
or metallic packing strip can be predetermined with great nicety, so as to secure
sufficient tightness with the least possible excess of pressure for crossing the ports
with facility.
And in order that my said Invention and the manner of performing the same
may be properly understood, I hereunto append a Sheet of explanatory Drawings
to be hereinafter referred to, and representing examples of my improved metallic
packings. In these Drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
Figures 1 and 2 on the accompanying Sheet of Drawings are a sectional plan
and a sectional elevation or edge view of a piston for a steam cylinder as fitted
with my improved metallic packing. In this example a single packing ring 21, of
simple section and uniform thickness all round is employed, being placed, as usual,

page_text: between a flange 22, formed on the piston body 23, and a flange 24, formed on a
junk ring 25, which is bolted to the piston body after the ring 21 and the springs 26
have been put in their places. The piston body 23 is made with numerous radial
sockets 27, the outer ends of which are open to or covered by the ring 21, and
when the junk ring 25 has been removed the upper sides of the sockets 27 are
open. The springs 26, which in Figures 1 and 2 are represented as helical springs,
are placed in the sockets 27, so that each has one end abutting against the inner
end of the socket, that is, the end nearest the centre of the piston, whilst the other
end of the spring bears outwards against the inside of the packing ring 21. The
packing ring 21 is, as usual, cut through at one part, and a tongue 28 is fitted at
the cut part to prevent the passage of steam. Figures 3, 4, 5, are enlarged sections,
Figure 3 being as taken through one of the springs 26, and the packing ring 21,
Figure 4, being as taken through a spring 26, and through the tongue 28, applied
at the cut part of the packing ring 21, and Figure 5 being as taken midway
between two springs. The tongue 28 is made with thin cylindrical extensions or
flanges at its inner side, such flanges being as broad as the packing ring 21, and
bearing on the insides of the ends of the ring, whilst the spring 26 bears on the
inside of the tongue 28.
Figures 6, 7, 8, are enlarged sections, showing the application of two packing
rings 21 in each case. The adjacent inner edges of these rings 21 are bevilled,
and an inner reversely bevilled ring 29 is fitted to the angular space thus formed.
The springs 26 bear outwards against this inner ring 29, and cause it to tend to
press the packing rings 21 both outwards and against the upper and lower piston
flanges 24, 22. Different forms of helical or conic-volute springs 26 are shown in
the several Figures 6, 7, 8.
Figures 9 and 10 are sectional views, as at right angles to each other, showing
the application of my improved metallic packing to a piston valve. The piston
valve is represented as covering the ports 30, which are made with oblique edges as
usual.
Having thus particularly described my said Invention and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is,―
1. The arranging or combining together of parts forming metallic packings for
pistons, pump-buckets, and valves, substantially in the improved manner herein-
before described.
2. The mode of pressing outwards the packing rings or strips of pistons, pump-
buckets, and valves, by helical, or conic-volute, or cylindro-conic springs acting
radially, such springs being suitably proportioned so as on being compressed and
placed in their sockets to exert the required pressure without adjustment by screws,
substantially as hereinbefore described.
3. The forming of sockets (27) in the piston body to receive the springs (26), the
parts being proportioned and arranged substantially as and for the purposes
herein before described.
In witness whereof, I, the said Henry Christian Löbnitz, have hereunto set
my hand and seal, this Seventh day of May, in the year of our Lord One
thousand eight hundred and eighty
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
•
HENRY C. LÖBNITZ. (LS.)