Improvements in Piston Packings.
Year: 1894

page_text: Date of Application, 1st Feb., 1894
Complete Specification Left, 23rd Oct., 1894-Accepted, 1st Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Piston Packings.
I, EUGÈNE FRANÇOIS BOULET, of Montluçon, Allier, in the Republic of
France, Engineer, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to improvements in piston packings for fluids and
gases which are highly compressed, and particularly to packings of the kind in
which annular packing elements or pieces are arranged separately from each other
and in the intervening space or spaces the cylindrical surface which is to be
packed and made tight is in direct contact with the pressure fluid.
The packing is so arranged that each separate packing piece or element is
pressed against the cylindrical surface to be packed or made tight with a different
pressure from the adjacent elements, and, indeed, in such manner that the inner-
most element is submitted to the greatest pressure, the outermost to the least; and
furthermore the pressure-fluid in the intervening spaces is under a gradually
diminishing pressure from inwards to outwards, in succession, as the pressure in
each intervening space is maintained at a fixed amount by the aid of special
devices. Inasmuch as each packing-piece or element, on that side of it which is
directed to the inner end of the piston is in contact with a fluid of higher pressure
than that of the fluid in contact with its end that is directed towards the outer end
of the piston, such element needs only to be made tight against a pressure
representing the difference between those two fluid pressures.
former case,
This invention is applicable as well to so-called hydrostatic packings, such, for
instance, as leather packing, as to packing for glands and stuffing boxes. In the
the more highly compressed of the two pressure-fluids in contact with
the packing-piece or element is utilised for the purpose of pressing such element
against the surface to be packed and made tight, whence, on the assumption that
all the elements are of equal thickness, it follows that each outer element in
succession is pressed against the suface to be packed and made tight with a smaller
pressure than its neighbour on the inner side.
The hydrostatic packing-rings must be supported against each other, and this
can be done either by means of special annular pieces or by a corresponding shape
of the hydrostatic rings themselves. In this latter case the ring-shaped hydrostatic
packing bodies may be formed with annular projections substitutes for the special
annular pieces as well on the concave side that is to say towards the next preceding
element, as on the convex side, i.e. towards the next following.
In order to make the hydrostatic packing rings (which for high pressures are
best formed in metal) equally tight for very low pressures, the concave surface of
each packing ring may be lined or covered with elastic material, projecting slightly
beyond the edge of the metal ring so as to lie against the cylindrical surface to be
packed or made tight. These internal elastic coverings of the metal packing rings
or elements are well adapted to be secured between the metallic element itself
and the supporting ring which may or not be firmly secured to the said metallic
piece.
In the second case, riz. with packings for glands and stuffing boxes the varying
amount of the pressure per square unit of surface to which the cylindrical surface
to be packed and made tight is subjected by each packing piece or element is
produced by the elastic packing rings, which are subjected to the same pressure

page_text: throughout the stuffing box, having gradually decreasing external diameters from
inwards i.e. from the inner end of the piston or piston rod outwards, i.e. towards
the outer end of the piston or piston rod. In this manner the pressure which is
produced by pressing down the gland, acts upon annular plane surfaces of elastic
packing rings of varying areas, and thus brings to bear in each a variable relative
pressure per square unit of surface. At the same time the hollow annular space
within the stuffing box becomes larger in proportion to the contraction in the
external diameter of the successive packing-rings or elements, by steps, as it were.
The step by step decrease in the fluid pressure in the intervening spaces between
the packing-rings or elements can be effected and maintained in various ways,
as e.g. by means of valves.
One such arrangement, which the inventor preferably adopts, consists in connecting
each intervening space with the one that precedes it as well as with the one that
follows it, and also similarly the innermost one with the inside of the cylinder and
the outermost one with the open air or the low pressure accumulator by a capillary
canal of very great length. In this manner a very small quantity of the fluid escapes
from the cylinder through the packing rings or elements into the open air or the low
pressure accumulator passing from one intervening space to the next with a
considerable diminution of pressure, owing to the great amount of friction developed
in passing through the capillary canal.
For instance, this may be so carried out that, of two adjacent intervening spaces,
the one with the higher pressure is connected with the wide end, the other which
has the lower pressure, with the narrow end of a conical boring wherein is fitted a
conical valve-like plug, in the conical surface of which is cut a spiral groove of
minute sectional area, renning from one end to the other. These conical borings
are very well adapted to use with stuffing boxes, in the cylinder or gland, with
hydrostatic packing rings, preferably in the element itself.
For the hydrostatic packing elements also there is yet another arrangement to
be recommended, wherein the supporting ring (which may be cast in one piece
with the metal bucket-shaped piece, or separate therefrom) is made in two pieces,
one inside and one outside, of which the one carries the capillary helical groove
running round the inner surface of contact between the two parts. With this
arrangement, the length of the capillary canal can be made extraordinarily great.
The employment of cone-shaped plugs, as above described, has this advantage,
that they act as valves, whenever, for the purpose of filling the intervening spaces
and if required the cylinder, fluid is introduced, from outwards to inwards, through
the entire series of conical borings. A similar advantage may also be obtained
with the divided supporting rings, with spiral groove running round one of the
dividing surfaces, by making the said surfaces conical so as to enable the one or
the other of the divided parts to be lifted in the same manner as the conical plugs.
The same effect may be obtained by a third arrangement, in which a bi-conical
annular piece is fitted within the upper part of the undivided ring.
Dated this 1st day of February 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
improvements in Piston Packings.
I, EUGENE FRANÇOIS BOULET of Montluçon, Allier, in the Republic of
France, 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 :-
The present invention relates to improvements iu piston packings for fluids and
I, EUGENE FRANÇOIS BOULET of Montluçon, Allier, in the Republic of
France, 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 5
in and by the following statement :-
The present invention relates to improvements iu piston packings for fluids and

page_text: gases which are highly compressed, and particularly to packings of the kind in
which annular packing elements or pieces are arranged separately from each other
and in the intervening space or spaces the cylindrical surface which is to be packed
and made tight is in direct contact with the pressure fluid.
The packing is so arranged that each separate packing piece or element is
pressed against the cylindrical surface to be packed or made tight with a different
pressure from the adjacent elements, and, indeed, in such manner that the innermost
element is submitted to the greatest pressure, the outermost to the least; and
furthermore the pressure-fluid in the intervening spaces is under a gradually
diminishing pressure from inwards to outwards, in succession, as the pressure in
each intervening space is maintained at a fixed amount by the aid of special
devices. Inasmuch as each packing piece or element, on that side of it which is
directed to the inner end of the piston is in contact with a fluid of higher
pressure than that of the fluid in contact with its end that is directed towards the
outer end of the piston, such element needs only to be made tight against a pressure
representing the difference between those two fluid pressures.
This invention is applicable as well to so-called hydrostatic packings, such for
instance as leather packing, as to packing for glands and stuffing boxes. In the
former case the more highly compressed of the two pressure-fluids in contact with
the packing piece or element is utilised for the purpose of pressing such element
against the surface to be packed and made tight, whence on the assumption that
all the elements are of equal thickness, it follows that each outer element in
succession is pressed against the surface to be packed and made tight with a
smaller pressure than its neighbour on the inner side.
The hydrostatic packing rings must be supported against each other, and this
can be done either by means of special annular pieces or by a corresponding
shape of the bydrostatic rings themselves. In this latter case the ring-shaped
hydrostatic packing bodies may be formed with aunular projections substitutes
for the special annular pieces as well on the concave side, that is to say
towards the next preceding element, as on the convex side, i.e. towards the next
following.
In order to make the hydrostatic packing rings (which for high pressures are
best formed in metal) equally tight for very low pressures, the concave surface
of each packing ring may be lined or covered with elastic material, projecting
slightly beyond the edge of the metal ring so as to lie against the cylindrical
surface to be packed or made tight. These internal elastic coverings of the
metal packing rings or elements are well adapted to be secured between the
metallic element itself and the supporting ring which may or not be firmly secured
to the said metallic piece.
In the second case, viz. with packings for glands and stuffing boxes, the varying
amount of the pressure per square unit of surface to which the cylindrical surface
to be packed and made tight is subjected by each packing piece or element is
produced by the elastic packing rings, which are subjected to the same pressure
throughout the stuffing box, having gradually decreasing external diameters from
inwards i.e. from the inner end of the piston or piston rod outwards, i.e. towards
the outer end of the piston or piston rod. In this manner the pressure, which is
produced by pressing down the gland, acts upon annular plane surfaces of elastic
packing rings of varying areas, and thus brings to bear in each a variable relative
At the same time the hollow annular space
pressure per square unit of surface.
within the stuffing box becomes larger in proportion to the contraction in the
external diameter of the successive packing rings or elements by steps as
it were.
The step by step decrease in the fluid pressure in the intervening spaces between
the packing rings or elements can be effected and maintained in various ways, as
e.g. by means of valves.
One such arrangement, which the inventor preferably adopts, consists in
connecting each intervening space with the one that precedes it as well as with

page_text: the one that follows it, and also similarly the innermost one with the inside of
the cylinder and the outermost one with the open air, or the low pressure
accumulator by a capillary caual of very great length. In this manner a very
small quantity of the fluid escapes from the cylinder through the packing rings
or elements into the open air or the low pressure accumulator, passing from one
intervening space to the next with a considerable diminution of pressure, owing to
the great amount of friction developed in passing through the capillary canal.
For instance, this may be so carried out that, of two adjacent intervening spaces,
the one with the higher pressure is connected with the wide end, the other which
has the lower pressure, with the narrow end of a conical boring wherein is fitted
a conical valve-like plug, in the conical surface of which is cut a spiral groove
of minute sectional area, running from one end to the other. These conical
borings are very well adapted for use with stuffing boxes, in the cylinder or gland,
with hydrostatic packing rings, preferably in the element itself.
For the hydrostatic packing elements also there is yet another arrangement to
be recommended, wherein the supporting ring (which may be cast in one piece
with the metal bucket-shaped piece, or separate therefrom) is made in two pieces,
one inside and one outside, of which the one carries the capillary helical
groove running round the inner surface of contact between the two parts.
this arrangement, the length of the capillary canal can be made extraordinarily
great.
With
The employment of cone-shaped plugs, as above described, has this advantage,
that they act as valves, whenever, for the purpose of filling the intervening spaces
and if required the cylinder, fluid is introduced, from outwards to inwards, through
the entire series of conical borings. A similar advantage may also be obtained
with the divided supporting rings, with spiral groove running round one of the
dividing surfaces, by making the said surfaces conical so as to enable the one or
the other of the divided parts to be lifted in the same manner as the conical
plugs. The same effect may be obtained by a third arrangement, in which a
bi-conical annular piece is fitted within the upper part of the undivided ring.
Fig. I represents a longitudinal section of a hydrostatic piston-packing constructed
according to my invention.
Figure II is a part of the same section on a larger scale.
Fig. III is a plan of the packing. The piston E is tightened within the
cylinder D by means of a series of packing rings A. B. C supported and
separated from each other by annular pieces R, R' R2. The packing chamber is closed
by a ring O which is pressed down by means of a second cover and screws P.
The intervening spaces between the packing rings A, B, C and the annular
pieces R, R1, R2 are supplied by channels H with the pressure fluid, each channel
being provided with a special device, for instance a weighted safety-valve, for
maintaining the pressure at a fixed amount decreasing gradually from the innermost
to the outermost element as above described.
Fig. 1V shows in a longitudinal section another arrangement of the hydrostatic-
piston packing, in which each packing ring and its supporting ring are formed
in one piece (1, 2, 3, 4), only one packing ring 5 of the common kind being
disposed at the outer extremity of the packing chamber. The step by step
decrease of the fluid pressure in the intervening spaces between the ring-
pieces 1, 2, 3, is effected by conical valve-like plugs X fitted in conical borings
so as to leave free spaces T above them and provided on their conical surfaces
with spiral grooves, through which the pressure-fluid of each intervening space
communicates with the fluid of lower pressure in the next outer intervening
space. The fluid passes from the interior of the cylinder D through the series
of intervening spaces and plugs and discharges at its arrival in the outermost
intervening space, which is closed by the packing ring 5, through a channel K into
the open air or into a low pressure accumulator. For filling the intervening spaces
and the cylinder, the pressure fluid is allowed to enter the channel K, whereupon
it lifts successively the plugs X.

page_text: Two arrangements, in which the concave surface of each packing ring is lined
with elastic material in the manner and for the purpose as above described, are
represented by the sectional views of the Figures V and VI. In Figure V two
separate rings line the wings H of the ring pieces 1, 2 and are secured by
pinching their inner edges between the supporting surfaces of the ring pieces.
In Figure VI each ring piece is divided into an outer ring (m m³) and an inner
ring (n) which are tightly fitted together by conical surfaces (b) b') so as to
allow the inner ring to be lifted in the same manner as the plugs X shown in
Figure IV. At the conical surface of the inner ring a spiral groove (o o¹) is
cut out for the same purpose as the spiral grooves of the plugs X. The lining
rings are held in their places by binding them upon the ring pieces, the inner
upon the wing to be lined of the inner ring the outer upon the bottom part a
of that outer ring, which precedes the outer ring, the wing of which is to be lined
by the ring i.
In the examples heretofore described the packing wings project from the top
of the ring pieces; in the modified arrangement shown in Figure VII these
wings (A. B) issue from the bottom part of the ring pieces. In the same figure
is shown another modification, by means of which the plugs X may be dispensed
with even in ring pieces, which are not as in Fig. V1 divided into two parts. In this
case a tapering annular piece Y is fitted with its both inner and outer slant
surfaces in the ring piece and provided on one of these surfaces with the spiral
groove o.
The piston packing represented in section by Figure VIII differs from those
shown in the Figures IV and VII by the ring pieces not having packing wings but
separate packing rings (A, B, C,) each divided into an outer and an inner
part and having bottom flanges pinched between two successive supporting
rings (R R2 R³).
In the example represented by Figure IX the outer packing rings and the
plugs X are both omitted, the supporting rings (R1 R2 R3 R4) being fitted with
their outer surfaces to the outer wall of the packing chamber and provided
thereon with spiral grooves (o' 02 03 04). The intervening spaces surrounding each
packing ring are connected by means of channels with annular spaces m, recessed
at the top outer circumference of each supporting ring so as to limit the spiral groove
of this ring at one end and to communicate with this spiral groove anl with the
spiral groove of the adjacent supporting ring next above.
The modification of the improved packing adapted to gland-boxes is shown by
way of an example in Figs. X to XII. Fig. X shows an end clevation, Fig. XI a
longitudinal section and Figure XII a side elevation of the improved stuffing box.
The elastic packing rings (D E F G) may be of a plane or flat or as shown of a
conical shape. The intervening spaces Z are recessed in the supporting
rings (HJ) and connected by means of channels (W V) in these rings with the
annular chambers (OR U) formed by the contractions of the supporting rings
and the corresponding contractions of the packing chamber. There plugs (K L M)
with spiral grooves effect the decrease of the fluid pressure, their conical borings
communicating with the above mentioned annular chambers by suitable channels.
The plug K is fitted by means of a conical boring within a box a provided with a
circular channel band a diametrical channel c connecting the channel 6 with the
conical boring, into which channel the pressure-fluid flows from the cylinder after
having passed the inlet channel d. The box a is held on its place by a cover m
and screw-nuts n and the plug K may be pressed down by a special screw p. The
recess in the body A of the cylinder which holds the box a communicates by a
channel N with the above mentioned annular chamber O, from which the pressure
fluid passes through the channel P, the spiral groove of the plug M, the channel Q,
the annular chamber R, the channel S, the spiral groove of the plug L and finally
the bifurcated channel X of one of the screws Y, by means of which the plugs L
and M may be lifted so that the current of the pressure fluid washes their spiral
grooves. A channel T connects the space between the plug L and the channel X

page_text: with the annular chamber U. Packing rings are employed to tighten the
accessory parts of the stuffing box.
Fig. XIII shows a plane or flat and a conical stuffing box packing-ring, in
section and both in a common plan c. I use preferably the conical ring a, the
tightening pressure which acts on the edge in this form being more intense than
with a plane packing ring such as b.
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. A piston-packing with intervening spaces between two successive packing
rings each space being filled with a fluid the pressure of which is maintained at
such amount that the fluid pressure decreases gradually with each intervening
space from the high pressure end to the low pressure end of the piston packing the
packing rings being pressed against the surface to be tightened with intensities
decreasing gradually in the same direction substantially as shown and described.
2. A packing for glands and stuffing-boxes the elements of which are constituted
as specified in the first claim and constructed with packing rings of different
exterior diameter so that a different pressure per square unit is obtained substantially
as shown and described.
3. In a piston-packing of the kind specified in the first claim obtaining the
differences in the fluid pressure by capillary canals of very great length,
substantially as shown and described.
4. In a piston packing such as described in Claims 1 and 3 the arrangement of
the capillary canals as spiral grooves on the surface of conical plugs or ring-pieces,
substantially as shown and described.
5. The general arrangement of piston packings substantially as shown and
described.
Dated this 23rd day of October 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.