Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to a support member for use with
split rubber or ~raphite cones used in cone stuffing boxes and
more particularly -to a support disc which might be inserted into
the hollowed out portion of a heavy split bot-tom cone.
Stuffing boxes are ordinarily used to seal a valve stem
at its point of entry into a valve body to prevent leakage of
fluid from the valve. A stuffing box -typically comprises a cylin-
drical recess filled with packing which is compressed by a sleeve
or gland to effect a tight joint between the packing and the
valve stem. The packing used in stuffing boxes commonly employed
for use with oil well pumps comprises a combination of a number
of hollow conical seals stacked atop a solid or heavy bottom cone.
Each of the cones is formed with a split from top to bottom to
facilita-te its installation around the valve stem or piston rod
and to ensure a proper sealing action with both the gland and the
piston rod. The cones also function to strip oil and other fluids
away from the piston rod.
In use, the heavy bottom cone supports the three upper
cones and, unlike the upper split cones, remains relatively in-
flexible. Eventually, however, the continuous stresses to whichthe cones are subjected results in a permanent flattening or de-
formation of the cones. This is particularly true of the heavy
bottom cone. When deformed, the cones are no longer capable of
effectively sealing the piston rod, resulting in leakage of fluid
or perhaps a jamminy or binding of the piston rod. Obviously,
when leakage or jamming occurs, the oil pump must be shut down to
effect repairs, and just as obviously, a shutdown entails a con-
siderable loss in time, expense and production.
It has been found that by inserting a frusto-conical
annular support disc into -the recess formed into the bottom of the
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heavy split cone, the disc cooperates with -the cones to obviate
and mitigate the aforementioned difficulties. The annular sup-
port disc reinforces the heavy spli-t bot-tom cone and inhibits its
deformation due to stress. The annular ring also assists in
stripping oil away from the piston rod which in turn reduces the
stresses to which the conical seals, and particularly the bottom
seal, are subjected.
According to the present invention, then, there is pro-
vided a support member for use in a stuffing box having a plu-
rality of sealing members adapted to sealingly engage a recipro-
cating piston rod, said sealing members being stacked one atop
another within the body of the stuffing box with the lowermost of
said members being in contact with the base of said stuffing box
and wherein said lowermost member is formed with a recess in the
bottom thereof; said support member comprising a solid annular
ring having first and second planar surfaces in spaced parallel
relation to each other, and a bore hole to receive said piston
rod; wherein said annular ring is adapted to be inserted in said
recess so that said first planar surface engages a lower surface
of said lowermost sealing member and said second planar surface
engages the base of said stuffing box to thereby reinforce said
lower mos-t sealing member and to prevent deformation thereof.
There is also provided a stuffing box for mounting around
a reciprocating piston rod comprising a housing, a plurality of
stacked conical sealing members adapted to sealingly engage a
reciprocating piston rod and arranged in said housing, the lower-
most sealing member being supported from beneath by a support sur-
face or said housing and having a recess, and a rigid support mem-
ber contained in said recess, said support member comprising an
annular ring with a bore hole adapted to closely receive said
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pi.ston rod, wherein an upper surface of said ring engages and
supports at least a po.rtion of the surface of the recess and a
lower surface of said riny is suppor-ted on said support surface
of the housing, whereby said ring assists in preventing deforma-
tion of the lowermost sealing member.
An embodimen-t of the invention will now be described ln
greater detall and will be better understood when read ln conjunc-
-tlon wlth the followlng drawlngs, ln which:
Figure 1 ls a cross-sectlonal view of a typical stufflng
box;
Elgure 2 ls a perspectlve vlew of the support disc and
heavy split bottom cone.
Referring now to Figure 1, a single cone stuffing box
employing the present lnvention has a housing generally designated
by the numeral 1. Typlcally, the packlng employed in such boxes,
especially when used ln assoclatlon with oil well pumps, is a
stack of teflon impregnated rubber or graphite spllt frusto-
conical cones. Typically also, the upper cones, in this case ~i
there are three of them, are hollow split cones 2 whereas the
bottom split cone 3 is solid with the exception of a truncatedconical portion hollowed out of the bottom of the cone and which
forms a recess 5 therein. Each of the cones is formed wlth an
opening 6 to receive a polish or sucker rod 7. The stack of
regular spllt cones 2 ls supported by the heavy bottom cone 3 .
which in turn ls supported by the base 9 of housing recess 11.
The, prlmary function of the split cones is to seal the
piston rod at lts point of entry into the well casing (not shown)
to prevent any leakage of fluid. The seal between the cone
aper-tures 6 and the piston rod 7 is formed by compressing the
0 cones by means of gland 12 to make a tight joint. The pressure
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exerted by gland 12 main-tains the cones in tight contact with
piston rod 7 and the lnner surface 8 of housing 1. The amount
of pressure exerted by yland 12 may be varied by suitable ad-
justment of nuts la.
To prevent the flexing and ultimate collapse or flatten-
ing of heavy bottom cone 3, which in and of itself is not suffi-
ciently strong to withstand the pressures to which it is subject-
ed, an annular support disc 16 is inserted into recess 5.
Referring now to Figure 2, the support disc 16 may be
fabricated from brass or other suitable bearing-type material in-
cluding plastic, aluminum or fiberglass. Most commercially avail-
able split bottom cones are manufactured with a recess of the
shape illustrated in Figure 2, i.e., a recess having inclined
sides 19 (see Figure 1 as well). Accordingly, to provide maximum
support and reinforcement to cone 3, support ring 16 is formed
with inclined edges 20 corresponding in length and angle to recess
boundary 19. Hence the frusto-conical shape of the support disc.
It will be appreciated, however, that the support disc may be
formed to correspond to other recess shapes without departing
from the inventive concept described hereïn. Indeed, it is also
contemplated that the shape or cross-sectional configuration of
the support disc need not correspond exactly with the shape or
cross-sectional configuration of recess 5. By way of example, and
with particular reference to Figure 1, some reinforcement of cone
3 would be achieved by a support disc of cylindrical configuration
as denoted by the dotted lines. The diameter of the cylindrical
disc could be less than or equal to the diameter of recess sur-
face 22 but sufficiently greater than the diameter of aperture
24 to ensure proper support of cone 3 by the disc.
The support disc is inserted directly into recess 5.
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When subjected to the pressures exerted by gland 12, surfaces 20
and 21 of the disc make contact with surfaces 19 and 22 of recess
5 respectively whereas lower surface 23 of the disc engages base
9 of stuffing box recess 11. Accordingly, the disc is positioned
'~ absorb the stresses to which the cones, and particularly the
bottom cone, are subjected and to prevent deformation thereof.
A bore hole 25 is formed into support disc 16 such that
a clearance of approximately 1/16 of an inch is provided between
the hole 25 and piston rod 7. In this respect, excess wear of
the polish rod is avoided, while at the same time, the disc is
effective to strip oil away from rod 7 before the oil would other-
wise make contact with the split cones. Further, the diameter of
lower disc surface 23 is less than the width of stuffing box -~-
recess 11 such that if piston rod 7 is slightly off center, the
disc may, to a limited extent, self-center itself to prevent
excessive wear of the rod 7.
In one preferred emhodiment constructed by the applicant,
the depth of the ring is 3/8", the external diameter at the base
of the ring is less than three inches and the diameter of the bore `
hole is less than 1 1/4". This particular cone is suitable for a
bottom cone having a height of 1 7/8" and an external diameter !~ `'
slightly less than 3 1/2". It will be seen from the dimensions
of the preferred ring that the depth of the ring is less than one- -~
slxth the external diemeter ~hereof.
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