Note: Descriptions are shown in the official language in which they were submitted.
2016566
PIPE CONN~CTOR WITH THREADED SEAL IN N~. nKEADED CAVITY
BACKGROUND OF THE INVENTION
This invention relates to pipe connector devices, and
more particularly, to such connector devices for use in
temporary and quasi-permanent pipe flowlines.
Temporary and permanent flowlines are commonly used in
production, drilling, cementing, stimulation, injection and
testing of oil and gas wells. Flexible devices with quick
connections at the ends provide a quick and convenient
layout of the piping system and provide fluid tight seals
between the mating pipe element members. Some of the
flexible devices used are swivel joints, hoses, composite
structure pipe, and ball joints. Seals and separate
connections are required at each end of the device.
Connections include hammer type unions, flange clamps,
specialty couplings, and pipe threads.
SUMMARY OF THE INVENTION
The present invention discloses a pipe connector
device that can selectively serve as a swivel joint and as
a pipe connector. This reduces the number of seal leak
paths in the total piping system; reduces the number of
variations in pipe elements required; enhances the utility
of individual pipe elements; and reduces the cost of pipe
elements required. A pair of pipe retention members each
have an internal bore for receiving one of a pair of pipe
elements. Each of the retention members is secured to a
corresponding one of the pipe elements by a load element,
such as a load ring. The retention members are
interconnected by pipe threads or other means to secure the
pipe elements in a fixed end-to-end relationship. The
retention members can be interconnected with the pipe
elements positioned a distance apart and the retention
members rotated relative to each other to pull the pipe
elements into tight alignment. The retention members can
be readily disconnected from the pipe elements by merely
removing the load elements and the retention members
removed from the pipe elements.
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The pipe elements each have a central bore extending
lengthwise through the pipe element and each element has a
cavity adjacent to the central bore. A first one of the
pipe elements includes a substantially smooth inner
surface defining an outer boundary of its cavity. An
annular seal is mounted in the two cavities when the pipe
elements are connected, with the seal extending along a
portion of the lengths of the two pipe elements adjacent to
an end portion of each of the pipe elements. Thus, the
seal extends across a junction of the pipe elements to
prevent leakage at a joint between the pipe elements. The
annular seal includes an outer portion having a plurality
of threads which press against the smooth inner surface of
the cavity in the first pipe element. The seal can be
pressed into the smooth cavity causing the threads of the
seal to press against the surface of the cavity of the
first pipe so the seal remains in the cavity when the two
pipe elements are separated thereby preventing dropping and
losing the seal. The annular seal and its threads have an
outer diameter slightly larger than the diameter of the
smooth cavity so an outer portion of the threads press
tightly against the inner surface which defines the outer
boundary of the cavity. When a pair of threaded nuts are
used as the retention members the joined pipe elements can
be identical thereby reducing the number of different
elements to be manufactured. The profile of the pipe
elements of the present invention is small compared to
unions and similar devices in prior art connectors.
In accordance with an aspect of the invention, in a
pipe connector apparatus having interconnecting means for
selectively securing a pair of pipe elements in a fixed
end-to-end relationship and for sealing a junction between
the pipe elements to prevent leaks, an improved sealing
device comprises:
a first pipe element having a central bore extending
lengthwise through said first pipe element and having a
first cavity adjacent to said center bore in an end portion
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of said first pipe element with a substantially smooth
inner surface defining an outer boundary of said first
cavity;
a second pipe element having a central bore extending
lengthwise through said second pipe element and having a
second cavity adjacent to said center bore in and end
portion of said second pipe element; and
an annular seal with a center for mounting in said
first and said second cavities and extending along a
portion of the length of said first and said second pipe
elements adjacent to an end portion of each of said first
and said second pipe elements to prevent leakage at a joint
between said pipe elements, said annular seal including a
threaded outer portion having a plurality of radially outer
points which press against said inner surface of said first
cavity to retain said annular seal in said first cavity
when said first and said second pipe elements are
separated, each of said outer points being tilted toward
the center of the seal and relative to said outer portion
of said seal so said outer points are bent radially inward
by said inner surface of said first cavity, said outer
points pressing firmly against said inner surface of said
first cavity to resist attempts to move said seal i a
reverse direction out of said first cavity.
In accordance with another aspect of the invention, a
pipe connector sealing device in combination with retention
means for interconnecting a pair of first and second pipe
elements in a fixed end-to-end relationship and for sealing
a junction between the pipe elements to prevent leaks;
and wherein said first pipe element having a central
bore extending axially in said first pipe element and
having a first cavity adjacent to said center bore in an
end portion of said first pipe element with a substantially
smooth inner surface defining an outer boundary of said
first cavity;
and wherein said second pipe element having a central
bore extending axially in said second pipe element and
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having a second cavity adjacent to said center bore in an
end portion of said second pipe element, the sealing device
comprises:
an annular seal having a center bore for mounting in
said first and said second cavities adjacent to said center
bores of each of said first and second pipe elements to
prevent leakage at said junction between the interfacing
end portions of said pipe elements, said annular seal
having a serrated circumferential portion for holding said
serrated circumferential portion against said inner surface
of said first cavity to resist withdrawal of said annular
seal from said first cavity when said first and second pipe
elements are separated.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevation, partly in section, of
one embodiment of a pipe connector of the present
invention.
Figure 2 is an end section of the pipe connector of
Figure 1 taken along line 2 - 2 of Figure 1.
Figures 3 - 6 are partial sections of another
embodiment of the pipe connector of Figure 1 showing a
sequence of disconnecting the pipe elements.
Figure 7 is an enlarged side elevation, partly in
section of the pipe connector of Figures 3 - 6, showing
details of the threaded portion of the annular seal and of
the cavity.
Figure 8 is a further enlarged inside elevation of one
embodiment of a portion of the threaded seal of Figure 7.
Figure 9 is another embodiment of the threaded seal of
Figure 8.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Figures 1, 2 disclose a pipe connector device 9 having
a pair of pipe elements 10, 11 interconnected by a pair of
retention members 12, 13 and a pair of load elements 17.
Pipe elements 10, 11 are mounted in an internal bore 12a,
13a of the retention members 12, 13 and secured to members
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12, 13 by load elements 17, each mounted in a pair of
grooves 18a, 18b and 18c, 18d.
To assemble connector device 9, member 12 is
positioned about pipe element 10 with groove 18a adjacent
to groove 18b and member 13 is positioned about pipe
element 11 with groove 18c adjacent to groove 18d. A plug
19 is removed from a bore 20 of member 12 and a plurality
of load elements 17 are fed through bore 20 into grooves
18a, 18b to secure member 12 to pipe element 10 and plug 19
is replaced in bore 20. A plug 24 is removed from a bore
25 and a plurality of load elements 17 are fed through bore
25 into grooves 18c, 18d to secure member 13 to pipe
element 11. Plug 24 is replaced in bore 25 to keep load
elements 17 in place. A sealing member 26 is placed in a
portion of a cavity 30 adjacent to a center bore 31 of pipe
element 10. Pipe elements 10, 11 are positioned with
center bore 31 of pipe element 10 aligned with a center
bore 32 of pipe element 11. Member 12 is rotated relative
to member 13 so that a threaded portion 12b of member 12
mates with a threaded portion 13b of member 13 and draws
pipe elements lo, 11 toward the position shown in Figure 1.
A portion of sealing member 26 moves into a cavity 36
adjacent to center bore 32 to provide a fluid tight seal
between elements 10 and 11. Groove 18c is wider than
groove 18d so that retention members 12, 13 can be
partially threaded together before a rotation of member 12
relative to member 13 applies pressure to secure pipe
elements 10, 11 in tight abutment.
Another embodiment of the present invention 9a
disclosed in Figures 3 - 6 includes another wide groove 18e
in retention member 12d. Plugs 19, 24, disclosed in
Figures 1, 2, have been omitted from Figures 3 - 6 in order
to simplify the drawings but it should be understood that
such plugs are needed to install the load elements 17a,
17b.
When it is desired to disconnect pipe element 10 from
pipe element 11, to replace seal 26 or for other reasons,
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member 12d is rotated relative to member 13 causing the
members 12d, 13 to be spaced as shown in Figure 4. Further
rotation of member 12d relative to member 13 causes a
shoulder 37 of groove 18e to press against a load element
17a and a shoulder 38 of groove 18c to press against a load
element 17b to move pipe element 10 away from pipe element
11 as shown in Figure 5. The slight separation of elements
10, 11 allows any internal pressure in bores 31, 32 to
bleed off while threads 12b, 13b are still engaged and
prevent elements 10, 11 from being blown apart. still
further rotation of retention member 12d allows pipe
elements 10, 11 to be separated as shown in Figure 6.
The forced separation of pipe elements 10, 11 due to
rotation of members 12, 13 prevents elements 10, 11 from
sticking together and facilitates seal replacement or
dismantling of flowline systems.
In the embodiments disclosed in Figures 1 - 6 pipe
elements 10, 11 are identical which simplifies
manufacturing and reduces costs compared to connectors
using unlike pipe elements. The load elements 17, 17a, 17b
can also be identical to reduce costs.
An improved seal 26a for use in connector devices 9,
9a is disclosed in the enlarged drawing of Figure 7. A
threaded or serrated outer portion 26b of seal 26a is
pressed against a substantially smooth inner surface 30b of
cavity 30 to secure seal 26a to pipe element 10 when pipe
elements 10 and 11 are separated. This prevents seal 26a
from being dropped and possibly lost when retention members
12d, 13 are separated. The right hand portion (Figs. 3, 7)
of seal 26a is positioned in cavity 30 and the left hand
portion of seal 26a is in cavity 36 when pipe elements 10,
11 are locked together as shown in Figure 3. Since load
elements 17 are locked into grooves 18a - 18d the present
invention has no loose pieces when members 12, 13 are
separated. When seal 26a needs to be replaced, member 12d
is rotated relative to member 13 until members 12d, 13 are
separated. Seal 26a is pulled axially away from center
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~ 201656B
bore 31 until threaded portion 26b disengages from surface
3Ob of cavity 30. A new seal 26a is pushed into cavity 30
and retention member 12d rotated relative to retention
member 13 to reconnect the pipe elements in a fluid-tight
arrangement.
A plurality of threads or serrations 40 (Fig. 8) are
formed on seal 26a so they tilt toward a center groove 41
to facilitate moving seal 26a into cavity 30 (Fig. 7) with
threads 40 pressed against surface 30b of cavity 30. This
tilt also causes a plurality of radially outer points 42 to
press even more firmly against surface 30b when seal 26a
attempts to move from right to left in cavity 30. A
diameter D1 of seal 26a is slightly (.001" to .005')
greater than a diameter D2 of cavity 30 to insure a tight
fit of seal 26a in cavity 30. Threads 40 can be spiral
threads of the type used on bolts or threads 40 can be
formed in concentric circles. As shown in Figures 8 and 9,
the threads are preferably of the standard buttress machine
thread shape. An advantage of the spiral threads is, they
can be formed using a conventional thread die of the type
used on large bolts. The thread die also provides accurate
values of diameter to outer points 42 of seal 26a at a low
cost. An advantage of having threads which are circular
is easier replacement of seals 26a. Circular threaded
seals remain close to the center 46 of cavity 30 (Fig. 7)
as they are being removed, while spiral threads may cause
seal 26a to be forced away from the center line of cavity
30 and bind against surface 30b of cavity 30.
If greater holding power is desired the tilt of the
threads may be increased as shown in a plurality of threads
40a (Fig. 9). The outer points 42 of threads 40 (Fig. 8)
and 40 (Fig. 9) bend slightly when seal 26a is forced into
cavity 30 (Fig. 7).
The present invention uses few parts to provide a
connector device for swivel joints and for a pipe
connector. A threaded seal is attached to one pipe element
to prevent dropping the seal when a pair of pipe elements
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are separated. Other elements are also secured to the pipe
elements to prevent loose pieces from being dropped or
lost.
Although the best mode contemplated for carrying
out the present invention has been herein shown and
described, it will be apparent that modification and
variation may be made without departing from what is
regarded to be the subject matter of the invention.
