AN IMPROVED PISTON PACKING
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by the said Jean Marie Trémaux
at the Office of the Commissioners of Patents, with his Petition, on
the 17th October 1872.
I, JEAN MARIE TRÉMAUX, of Algiers, do hereby declare the nature
of the said Invention for "AN IMPROVED PISTON PACKING," to be as
follows, that is to say :-
The object of this Invention is to obtain a good piston packing for
pumps, for engines, and other apparatus. This improved packing shewn
in the accompanying Drawing consists of a hollow ring of india-
rubber A, placed and pressed between the two piston plates. The
interior of the ring communicates with the chambers I made in the
piston. These chambers contain tongues or valves m serving to open or
close the orifices n, n', communicating at top or bottom. As the piston
rises or falls so the bottom or top is opened, and the steam entering the
ring swells it out in the direction of the upper or lower part and causes

page_text: it to lay against the surface of the cylinder. A packing for the piston
rod is shewn at B, constructed on the same principle; in this case the
tongues or valves are not required.
'
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jean Marie Trémaux in the Great Seal Patent
Office on the 17th April 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JEAN
MARIE TRÉMAUX, of Algiers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of October, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Jean Marie Trémaux, Her special
licence that I, the said Jean Marie Trémaux, my executors, adminis-
trators, and assigns, or such others as I, the said Jean Marie Trémaux,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED PISTON PACKING," upon the condition (amongst others) that I, the
said Jean Marie Trémaux, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent."
´NOW KNOW YE, that I, the said Jean Marie Trémaux, 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, reference being had to the Drawing hereto
annexed, and to the figures and letters marked thereon, that is to say :—
The object of this Invention is to obtain a good piston packing for
pumps, for engines, and other apparatus. This improved packing
consists of a hollow ring of india-rubber placed and pressed between the

page_text: two piston plates. The interior of the ring communicates with chambers
made in the piston. These chambers contain tongues or valves serving
to open or close orifices communicating at top or bottom. As the piston
rises or falls so the bottom or top is opened, and the steam entering the
ring swells it out in the direction of the upper or lower part and causes
it to lay against the surface of the cylinder. A packing for a piston rod
may be constructed on the same principle; in this case the tongues or
valves are not required.
Having now described the nature of my Invention, I will proceed to
more particularly describe the same and the manner of carrying the
same into effect, by reference to the accompanying Drawing.
Figure 1 is a half section of a single action piston or plunger shewing
the parts of which it is constructed; the packing a is formed of an
elastic material such as india-rubber, and if it be subjected to equal
pressures at b and c it will keep its normal position, shewn at a; but if
to the pressure c another pressure at c² be added by bringing together
the two discs d, d, of the piston, the packing in consequence of its
trapezoidal form, will assume the form shewn in dotted lines at a¹, and
will press against the cylinder and hermetically close the joint from the
effect of this initial pressure c¹ added to that of c, which latter is variable
but is always equal to that of b.
In Figure 2 the two discs are shewn fixed together, or the piston may
be constructed of a single disc provided in its neck with a packing a,
formed in segments, or of a material susceptible of expansion. I obtain
the initial pressure at c¹ by means of any suitable spring e or ƒ forming
a crown in the interior of the packing; the spring e may be made of
india-rubber or other suitable elastic material; the spring may also be
made of metal in segments or of a spiral or helical form.
Figures 3 and 4 shew a half plan and half horizontal section of a
piston.
Figure 5 is a half vertical section shewing the section of the packing
ring made of india-rubber or of an analogous material before its com-
pression by the bringing together of the two discs of the piston.
Figure 6 is a half vertical section shewing the shape the packing ring
is made to take by successive pressures, the amount of wear being
shewn by the dotted lines at a¹. The triangular form of the bottom of
the neck of the piston is given for the purpose of receiving any excess of

page_text: compression, the effect being to compensate for the wear by the
tendency which the part of the ring engaging into it has of recoiling
from the side of the cylinder, the compensation for the wear is therefore
partly automatic.
The bringing together of the discs is effected either by means of a
nut h, Figure 5, or by means of a key i entering wedge-wise into the
piston rod, as shewn in Figure 6.
Figure 7 shews another form of india-rubber packing ring, which
gives analogous results to the ring shewn in Figure 5.
The packing a, Figure 8, is much more simple in construction than
the two last herein-before described packings, but acts in a similar
manner against the cylinder.
The compression of the packing shewn in Figures 7 and 8 is effected
by means of nuts h, h. Figure 9 is a half plan, and Figure 10 half
horizontal section of a piston. Figures 11 and 12 are sections shewing
the valve j, j', in its two opposite positions. It is guided by a small
rod k, moving in the piston rod 9, and also by the lugs / sliding along
the uprights of the cap m, preventing any rotary motion which would
tend to cover the openings c. The packing is similar to that shewn in
Figure 2, with the expanding spring e; the effect of the action of this
spring is shewn in Figure 12; the light continuous pressure which it
exerts against the whole of the interior periphery of the packing keeps
the latter against the cylinder and automatically compensates for the
wear at a¹ in proportion as it takes place.
In pistons large enough to allow of being formed with a neck and the
means of necessary compression, all the different forms and constituent
parts of my improved packing can be applied.
My improved packing for double acting pistons differs only, from that
for single acting pistons herein-before described, in having openings in
the second disc, and valves for producing an equal pressure in the
required direction.
Figure 13 is a half plan, and Figure 15 a half vertical section of a
double acting piston; the packing a is similar to that shewn in Figure 1.
It is compressed by the partial bringing together of the discs so as
to make joint against the cylinder, this effect being produced by the
initial pressure c¹, the piston now acts by the recoil. The pressure b
towards this point is overcome by its equal pressure c, plus that of c¹,

page_text: which acts against the whole interior periphery of the packing, the valve
being pushed back by the pressure c against the opposite opening on the
admission of this pressure in the interior of the piston.
Figure 14 is a half horizontal section, and Figure 16 a half vertical
section of a piston, with a packing similar to that shewn in Figure 2.
The initial pressure c¹ is obtained by the expanding spring e; the worn
part of the packing is shewn by the dotted lines a². The valve n¹ is
shewn when the piston is in the position for sucking, and is kept there
during the action by the pressure c, which is added to that of c¹ in the
interior of the packing, and on the forcing action this valve takes the
position shewn in dotted lines at n¹, except there should be any inter-
ruption of the two pressures c and c¹ against the interior of the packing.
Figures 17 and 18 shew another method of introducing the pressure c
into the interior of the piston; the valve n is placed in the piston rod
and the small conduits o effect the transmission in the neck behind the
packing which receives the pressure c¹ of the helical spring f, forming
an expanding crown.
Figure 19 is a half vertical section of a piston constructed of a single
disc d'. The valve n is enclosed in its seat by the elbow pipe p; the
packing is that called a mixed packing, and consists of metal segments q,
and segments r of leather, india-rubber, or other suitable material;
they are pushed lightly against the cylinder by the expansion of the
helical spring crown f, which produces the initial pressure c¹, and they
hermetically close all the working joints.
Figure 20 is a half vertical section of a piston constructed of two
discs d, the valve n being placed between them. The packing consists
of metal segments q', trapezoidal in section, between which enters the
expanding belt e¹, pushed forward by a spiral spring f¹; the belt e¹
being formed of suitable material, in the centre of which the piston is
placed, forms all the working joints, and its wear against the cylinder
is connected by the sliding of the segments q¹.·
Figure 20 bis shews a packing of which the part in contact with the
cylinder is made entirely of metal, and is constructed of segments q", in
the interior of which is placed the spring crown e, Figure 2, or a crown
of a similar form, made extensible under the pressure of one of the
metallic springs herein-before described, or of its equivalent.

page_text: Figure 21 is a half horizontal section of the packing for a piston
plungers; and Figure 23 is a vertical section of same. The packing is
formed of a hollow ring a of india-rubber compressed by the stuffing-
box t, which communicates to it the initial pressure c¹; the pressure c
enters through holes corresponding to cavities made in the lower flange
of the neck, in which the ring is placed. Figures 22 and 24 are views
similar to Figures 21 and 23, and applicable to a piston rod or a piston
plunger. The packing a differs only from that shewn in Figure 1 in
having the interior stops removed, by which the action of the stuffing
box. t diminishes the interior diameter of this packing, and by its
elasticity it fits exactly against the rod; the packing is covered by a
washer which forms the joint between the stuffing box and its seating.
The pressure centers from the outer periphery of the packing through
cavities, as shewn in Figure 23.
Figure 25 represents a packing for a piston rod or plunger formed of a
ring of india-rubber, and having notches formed therein (as in Figure 28
at x); the entire surface of these notches on their outer circumference
is a little less than the difference between the interior and exterior
peripheries. This ring thus notched is kept against the piston 8 or rod g¹
by the action of the contracting belt e¹, which gives the initial pressure c¹,
and the pressure o is introduced through cavities, as in Figures 23
and 24.
•
Figure 26 represents a mixed packing constructed of metallic
segments q', having notches (x, Figure 28) together equal to the differ-
ence of the peripheries; a compressible belt e¹ forms the joint between
the segments and on their outer periphery. The whole is pressed against
the rod by a spiral spring which produces the initial pressure c¹, and the
pressure c is introduced as in the three herein-before described preceding
Figures.
Figure 27 is a half horizontal section, and Figure 29 a vertical section
of a piston rod or plunger. The alternate communication of the
pressures is effected by the conduits c, c, bored in the lugs on which
the valve n is placed, and the packing is similar to that shewn in
Figure 23.
Figures 28 and 30 shew similar views to Figures 27 and 29; the
packing is similar to that shewn in Figure 26, and the communication
of the pressures is effected through the washers c, c; in the space

page_text: between the two washers is placed the valve n', fixed at one end
in the middle of the chamber, the other end alternately closing the
conduits c, c.
Figure 30 his shews a packing of which the part in contact with the
piston rod or plunger is entirely made of metal, and is constructed
of segments with compensating notches for the wear, as shewn in
Figure 28. These segments are inserted in an elastic belt e¹, as shewn
at Figure 28, or in a compressible belt e" partially notched at discretion,
and surrounded by one of the springs herein-before described, or by any
other suitable spring.
Figures 31, 32, and 33, shew part sections of packing applicable to
pistons at present constructed, the only alteration required being the
substitution of these packings for those usually employed. This packing
is constructed of two washers of india-rubber or other suitable material,
in which are formed the conduits c, c; the two washers are fixed on
a metal ring v, which keeps them at the required distance apart; the
ring is provided with cavities in which are placed the valves n³, n¹, the lift
of which is regulated by the open space. In this space the packing
properly so called is placed. In Figure 31 the packing consists of
leather washers, and in Figure 32 of india-rubber rings, both being
formed with cross cut notches, and they are inserted in a contracting
belt made of india-rubber or other liguous compressible material, and
inserted in a spiral spring constructed so as to give the initial pressure
c', and keeps the packing in contact with the rod until it is entirely
worn out. The space remaining open in the stuffing box is filled by
a small cylinder entering it freely, and in which the rod can move
without friction.
In witness whereof I, the said Jean Marie Trémaux have hereto
set my hand and seal, this Fifteenth day of April, in the year
J. M. TRÉMAUX. (L.S.)