U.S. patent application number 11/506277 was filed with the patent office on 2006-12-21 for flexible pipe coupling.
This patent application is currently assigned to Victaulic Company. Invention is credited to Douglas R. Dole.
Application Number | 20060284420 11/506277 |
Document ID | / |
Family ID | 34653283 |
Filed Date | 2006-12-21 |
United States Patent
Application |
20060284420 |
Kind Code |
A1 |
Dole; Douglas R. |
December 21, 2006 |
Flexible pipe coupling
Abstract
A mechanical pipe coupling permitting relative axial, torsional
and angular deflections between pipes joined together by the
coupling is disclosed. Rings, each having a greater outer diameter
than the pipe, are attached to each end of the pipes to be joined.
Each ring has a circumferential groove that receives an O-ring
seal. A band is positioned coaxially around the rings. The band has
an inwardly facing surface that sealingly engages the O-rings. A
housing is clamped around the rings and the band. The housing has
first inwardly facing shoulders that engage the rings and limit the
axial and angular displacement of the pipes within the housing, and
second shoulders that engage end faces of the band.
Inventors: |
Dole; Douglas R.;
(Whitehouse Station, NJ) |
Correspondence
Address: |
SYNNESTVEDT & LECHNER, LLP
2600 ARAMARK TOWER
1101 MARKET STREET
PHILADELPHIA
PA
191072950
US
|
Assignee: |
Victaulic Company
Easton
PA
|
Family ID: |
34653283 |
Appl. No.: |
11/506277 |
Filed: |
August 18, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10734040 |
Dec 10, 2003 |
|
|
|
11506277 |
Aug 18, 2006 |
|
|
|
Current U.S.
Class: |
285/367 ;
285/364; 285/406; 285/410 |
Current CPC
Class: |
F16L 27/1012
20130101 |
Class at
Publication: |
285/367 ;
285/364; 285/406; 285/410 |
International
Class: |
F16L 23/00 20060101
F16L023/00 |
Claims
1. A coupling assembly for flexibly joining pipes to one another
end to end and permitting relative axial, torsional and angular
deflection between said pipes, said coupling assembly comprising: a
first ring attachable to an end of one of said pipes, said first
ring having an outer diameter greater than said pipe and an
outwardly facing circumferential groove therein; a first sealing
member positionable within said groove of said first ring and
extending circumferentially therearound; a second ring attachable
to an end of another of said pipes, said second ring having an
outer diameter greater than said other pipe and an outwardly facing
circumferential groove therein; a second sealing member
positionable within said groove of said second ring and extending
circumferentially therearound; a band positionable in overlying
relation with and surrounding said first and second rings, said
band having an inwardly facing surface sealingly engageable with
said first and second sealing members and having a width sufficient
to allow a gap between said pipes; and a housing positionable in
overlying relation with and surrounding said rings and radially
spaced apart from said band, said housing having a pair of first
shoulders positioned in spaced apart relation, each said first
shoulder being engageable with one of said rings for limiting axial
and angular deflection of one pipe relative to the other, and a
pair of second shoulders, each said second shoulder being
positioned on an opposite side of said band, each said second
shoulder being engageable with an end face of said band for
maintaining said band engaged with said sealing members.
2. A coupling assembly according to claim 1, wherein one of said
rings has an inner diameter sized to receive said pipe end in
substantially coaxial engagement.
3. A coupling assembly according to claim 1, wherein said housing
comprises a plurality of housing portions attachable to one another
end to end to extend around said pipe ends.
4. A coupling assembly according to claim 1, wherein said rings are
attached to said pipe ends by welding.
5. A coupling assembly according to claim 1, wherein said sealing
members comprise O-rings.
6. A coupling assembly according to claim 1, wherein said band
comprises a single piece.
7. A coupling flexibly joining pipes to one another end to end and
permitting axial, torsional and angular deflection between said
pipes, said coupling comprising: a first ring attached coaxially
around an end of one of said pipes, said first ring having an
outwardly facing circumferential groove therein; a first sealing
member positioned within said groove of said first ring and
extending circumferentially therearound; a second ring attached
coaxially around an end of another of said pipes, said second ring
having an outwardly facing circumferential groove therein; a second
sealing member positioned within said groove of said second ring
and extending circumferentially therearound; a band positioned
coaxially surrounding said first and second rings, said band having
an inwardly facing surface sealingly engaging said first and second
sealing members and having a width sufficient to allow a gap
between said pipes; and a housing coaxially surrounding said rings
and said band, said housing being radially spaced apart from said
band and having a pair of circumferential rims positioned in
longitudinally spaced apart relation, each said rim extending
radially inwardly and being in spaced relation with said pipes,
said rims being engageable with said pipes upon angular deflection
thereof for maintaining substantially co-axial, radially spaced
relation between said housing and said band, said housing having a
pair of first shoulders positioned in spaced apart relation facing
one another, said rings being positioned between said first
shoulders, each said first shoulder being engageable with one of
said rings for limiting axial and angular deflection of one pipe
relative to the other, and a pair of second shoulders, each said
second shoulder being positioned in spaced apart relation on an
opposite side of said band, each said second shoulder being
engageable with an end face of said band for maintaining said band
engaged with said sealing members.
8. A coupling assembly according to claim 7, wherein said housing
comprises a plurality of housing portions attached to one another
end to end to extend around said pipes.
9. A coupling according to claim 8, further comprising fasteners
attaching said housing portions to one another.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 10/734,040, filed Dec. 10, 2003.
FIELD OF THE INVENTION
[0002] This invention concerns mechanical pipe couplings for
joining pipes together, and especially couplings allowing axial,
torsional and angular flexibility between the pipes.
BACKGROUND OF THE INVENTION
[0003] Piping networks for conveying fluids (liquids, gases,
powders, slurries, sludges and the like) are used in a wide
spectrum of industries including the petroleum industry, the
chemical industry, mining, construction, manufacturing, as well as
in municipal water service. It is advantageous to assemble piping
networks using pipe segments sealingly joined to one another with
mechanical fittings. Mechanical fittings typically comprise
couplings that engage the pipe ends and are held together by
removable fasteners.
[0004] Mechanical fittings are advantageous because they avoid the
use of open flame or electrical arc, as required in welding, to
effect a fluid tight joint between pipe ends. The assembly of
mechanical fittings requires less skill than welded or brazed
joints, and they are, therefore, less expensive to fabricate.
Mechanical fittings also provide greater versatility for
modification or repair of the piping network since repairs can be
effected or new sections can be added by simply unbolting existing
couplings and making the new connections as desired.
[0005] A problem common to all piping networks, regardless of how
the pipes are connected, is the lack of joint flexibility axially
(lengthwise along the pipe), torsionally (rotation about the long
axis of the pipe) and angularly (the relative angle between one
pipe and another to which it is connected). Rigid joints mean that
the tolerances to which the pipes are cut and the angles at which
they are joined must be maintained within relatively close limits
so that the piping network will fit together as designed, without
significant deviation from the plan. It is expensive and not always
possible to maintain the necessary tight tolerances on pipe
lengths, especially when the networks are assembled in the field as
opposed to in a workshop where conditions for cutting and assembly
are under greater control.
[0006] Flexible pipe joints are also advantageous for piping
networks that must expand or contract and yet maintain fluid-tight
connections. In one example, a piping network for the pneumatic
transport of pulverized coal from the coal crushing station to the
furnace in a power plant must have enough flexibility to maintain
its connection to the furnace, which expands in size when in
operation due to the heat generated when the coal is burned.
[0007] Furthermore, pipes in a chemical plant or refinery, for
example, that carry fluids that are hotter or colder than ambient
conditions, are subject to cycles of heating and cooling, and the
associated changes in length that such cycles occasion. These
piping networks typically require multiple expansion joints or
loops to avoid over-stressing the pipes due to expansion and
contraction, especially for long pipe runs. Pipes joined by
flexible couplings readily accommodate the deflections due to
thermal expansion and contraction and thereby eliminate the need
for special expansion joints or loops in the network.
[0008] Piping networks may also be subject to significant motion,
for example, when built over seismically active regions of the
earth. Deflections of pipes during tremors and minor earthquakes
may be accommodated by flexible couplings that maintain the fluid
integrity of the joints.
[0009] There is clearly a need for pipe couplings which provide a
degree of flexibility to the joints of a piping network that will
enable the network to be assembled in the field, according to
design, without maintaining close tolerances or the need for
modifications that deviate from the plan substantially, and
accommodate thermal expansion and contraction as well as other
deflections without compromising the integrity of the joints.
SUMMARY OF THE INVENTION
[0010] The invention concerns a coupling assembly for flexibly and
sealingly joining pipes to one another end to end and permitting
axial, angular and torsional deflections between them. The coupling
assembly comprises a first ring attachable to one of the pipe ends.
The first ring has an outer diameter greater than the pipe and an
outwardly facing circumferential groove. A first sealing member is
positionable within the groove of the first ring. The first sealing
member extends circumferentially around the first ring. A second
ring is attachable to another of the pipe ends to be joined. The
second ring has an outer diameter greater than the pipe and an
outwardly facing circumferential groove. A second sealing member is
positionable within the groove of the second ring and extends
circumferentially around the second ring. A band is positionable in
overlying relation with and surrounding the first and second rings.
The band has an inwardly facing surface sealingly engageable with
the first and second sealing members. A housing is positionable in
overlying relation with and surrounding the rings and the band. The
housing is radially spaced apart from the band allowing the band to
float on the sealing members. The housing has a pair of
circumferential rims positioned in longitudinally spaced apart
relation to one another. Each rim is sized and toleranced to
maintain the aforementioned spaced relation between the housing and
the band. The housing also has a pair shoulders positioned in
spaced apart relation and facing one another. Each shoulder is
engageable with one of the rings for limiting axial and angular
deflection of one pipe relative to the other.
[0011] The invention also includes a method of sealingly and
flexibly attaching pipes to one another end to end. The method
comprises the steps of:
[0012] (A) attaching a first ring to one pipe end, the first ring
having an outwardly facing circumferential groove therein;
[0013] (B) attaching a second ring to another pipe end, the second
ring also having an outwardly facing circumferential groove
therein;
[0014] (C) inserting the first ring through a circumferentially
extending band such that the band does not overlie the
circumferential groove in the ring;
[0015] (D) positioning a first sealing member within the groove of
the first ring;
[0016] (E) positioning a second sealing member within the groove of
the second ring;
[0017] (F) bringing the first and second rings adjacent to one
another in co-axial alignment;
[0018] (G) sliding the band circumferentially around the rings, the
band having an inwardly facing surface sealingly engaging the first
and second sealing members; and
[0019] (H) positioning a housing circumferentially around and in
spaced relation to the band and the rings, the housing having
shoulders in spaced relation and facing one another, the shoulders
being engageable with the rings to limit axial and angular
deflection of the pipes relative to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an end view of a coupling according to the
invention;
[0021] FIG. 2 is a side view of the coupling shown in FIG. 1;
[0022] FIG. 3 is an end view of another embodiment of the coupling
according to the invention;
[0023] FIG. 4 is a cross-sectional view of the coupling taken at
line 4-4 of FIG. 1;
[0024] FIG. 4A is a cross-sectional view of another embodiment of
the coupling according to the invention;
[0025] FIG. 5 is a cross-sectional view of the coupling
illustrating angular displacements of the pipe ends permitted by
the coupling according to the invention; and
[0026] FIG. 6 is an exploded view of the pipe coupling assembly
according to the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] FIGS. 1 and 2 show the mechanical pipe coupling 10 according
to the invention. Preferably, the coupling 10 has a housing 12
formed of a plurality of housing portions 14 and 16 attached to one
another end to end to surround and engage the ends of pipes 18 and
20, shown in phantom line. The housing portions 14 and 16 are
attached to each other using fasteners such as bolts 22 and nuts 24
that bear against lugs 26 and 27 that extend outwardly from each
housing portion 14 and 16 respectively. The fasteners 22, 24 clamp
the lugs 26 and 27 to one another in what is called "pad-to-pad
engagement" to hold the housing portions end to end around the
pipes 18 and 20. The bolted attachment is advantageous because it
allows the coupling to be easily disassembled for repair or
modification. FIG. 3 illustrates an alternate embodiment of the
housing 12 having four housing portions 14a, 14b, 16a and 16b
attached end to end by fasteners 22, 24.
[0028] FIG. 4 shows the coupling 10 in cross-section. Housing
portions 14 and 16 each have a pair of rims 28 positioned in
longitudinally spaced apart relation to one another lengthwise
along the housing 12. Rims 28 extend radially inwardly and are
sized and held to tolerances so as to maintain a separation 29
between themselves and the pipes 18 and 20. The separation 29 is
made possible by the pad-to-pad engagement of lugs 26 and 27 which
holds the rims 28 at a diameter slightly greater than the outer
diameter of pipes 18 and 20 and thereby permits relative axial,
torsional and angular deflections between the pipes. Preferably the
radial faces 31 of rims 28 are angled outwardly so as to further
facilitate angular pipe deflections. The rims 28 are also sized so
that, during any deflection between the pipes, contact that does
occur between the housing portions 14 and 16 and the pipes 18 and
20 is made between the rims 28 and the pipes, and not between other
portions of the housing 12 and other components comprising the
coupling 10 as described below.
[0029] Each housing portion 14 and 16 also has a pair of shoulders
30, also positioned in longitudinally spaced apart relation to one
another. Shoulders 30 face each other and engage other components
of the coupling to limit axial and angular displacement of the
pipes 18 and 20 as described below.
[0030] As further shown in FIG. 4, each pipe 18 and 20 has a
respective ring 32 and 34 attached at or near its end. Rings 32 and
34 are preferably co-axially mounted on the pipe ends 18 and 20 and
held in place by welds 36. Alternatively, as shown in FIG. 4A,
rings 32 and 34 may be butt welded to the ends of the pipes 18 and
20. Referring again to FIG. 4, rings 32 and 34 have larger outer
diameters than the pipes 18 and 20 to which they are attached and
engage the shoulders 30 on housing portions 14 and 16. The housing
portions 14 and 16 have sufficient length 38 between shoulders 30
to accommodate the rings 32 and 34 with a gap 40 between the ends
of pipes 18 and 20. Gap 40 allows for axial deflection of the pipes
18 and 20 relative to one another, and the engagement of the rings
32 and 34 with shoulders 30 limits the range of this deflection and
holds the ends of pipes 18 and 20 within the housing 12. As shown
in FIG. 5, the relative deflection of the pipes 18 and 20 can
manifest itself in an angular displacement 42 between them. This
occurs when one side of the pipe moves outwardly toward the
shoulder 30 while the opposite side of the pipe moves inwardly away
from the shoulder. It is preferred to size the rings 32 and 34 and
the spacing between the shoulders 30 so as to limit the maximum
angular deflection 42 to between 2.degree. and 4.degree. depending
upon the application to which the piping network is dedicated. This
preferred range of angular displacement, along with the permitted
axial and torsional deflections, ensure that the joints created by
the coupling 10 are flexible enough to compensate for motion of the
piping network due to thermally related expansion and contraction,
motion induced by limited seismic activity, as well as to
compensate for the typical tolerances encountered during network
fabrication, and yet are not too flexible so as to compromise the
fluid integrity of the joints formed by the couplings.
[0031] As shown in FIGS. 4 and 5, each ring 32 and 34 has an
outwardly facing circumferential groove 44 that receives a sealing
member, such as an O-ring 46. To effect a seal that is independent
of the housing 12, a band 48 is positioned in spaced relation
radially away from housing portions 14 and 16. Band 48 surrounds
the rings 32 and 34 and has an inwardly facing surface 50 that
sealingly engages the O-rings 46 to effect a fluid tight seal
around the ends of pipes 18 and 20. The pad-to-pad engagement of
lugs 26 and 27 ensures that a radial separation 52 is maintained
between the band 48 and the housing portions 14 and 16. Radial
separation 52 allows band 48 to float on the O-rings 46 and
maintain concentricity with the pipes 18 and 20. By remaining
substantially concentric, band 48 maintains substantially equal
pressure circumferentially around the O-rings 46 and thus ensures a
fluid tight seal at the joint formed by coupling 10 despite the
permitted axial and angular displacement of pipes 18 and 20.
Housing portions 14 and 16 have a second pair of shoulders 33.
Shoulders 33 are positioned on opposite sides of band 48 to engage
the band end faces and help maintain its engagement with O-rings 36
to ensure the fluid tightness of the joint. The separation 29
between rims 28 and pipes 18 and 20 is controlled relative to the
radial separation 52 between housing portions 14 and 16 and band 48
such that if contact occurs, it occurs first between the rims 28
and the pipes 18 and 20, thereby preventing further contact between
the housing portions 14 and 16 and band 48.
[0032] Assembly of the coupling 10 according to the invention is
illustrated in FIG. 6. Rings 32 and 34 are welded onto ends of
pipes 18 and 20, respectively. Next the ring 32 is passed through
the band 48, the band being positioned such that it does not
overlie the circumferential groove 44. O-ring sealing members 46
are then positioned within grooves 44, and the pipes 18 and 20 are
positioned adjacent to one another in coaxial alignment. Band 48 is
then drawn from ring 32 toward ring 34, the inwardly facing surface
50 sealingly engaging the O-rings 46 on each ring. Housing portions
14 and 16 are next positioned around band 48 and rings 32 and 34
and attached to one another end to end using bolts 22 and nuts 24
to bring lugs 26 and 27 into pad-to-pad engagement.
[0033] Flexible pipe couplings according to the invention allow
piping networks to be assembled that are sufficiently flexible to
accommodate significant thermally induced deflections, motion due
to seismic forces as well as deviations in dimensions due to
accumulation of tolerance errors without compromising the integrity
of the joints formed between the pipe segments.
* * * * *