Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
TO WHOM IT MAY CONCERN: 204434~
Be it known that I, Daniel P. Corcoran, residing in the
City of Grand Rapids, State of Michigan, a citizen of the
United States of America, have invented nlew and useful
improvement~ ~n
A COUPLING DEVICE FOR PIPING
of which the following is a speciication.
F ELD OF INVENTION
This application is a continuation-in-part of U.S.
Serial number 537,417, filed June 12, l990, now pending.
The invention disclosed herein deals with a coupling
device for piping for pipeline assemblies employed for
conveying fluids under pressure and in particular relates to
a coupling comprising plural arcuate coupling segments having
engagement means on their inner per1phery for engagement with
grooved or beaded pipe ends~, and which have an internal
channel in which a sealing means such as a sealing gasket is
received .
BACKG~Ol~ND OF T~IE INVENTION
Pipeline systems and methods of assembling them have
been known for a long time. The prior art is replete with
patents directed to the couplings used to assemble such
systems and to such methods. The advantages of being able to
join variou~ segments of pipe with quick connect coupl:ing
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devices is obvious when compared to pipelines which are
joined b~ other means such as welding. Thus, the use of
segmented mechanical couplings ~or joining the ends of pipes
has attained wide commercial acceptance and the. coupling
.industry has grown steadly over the past few years.
The couplings commonly used today comprise arcuate pairs
of coupling segments which embrace the ad~acent ends of a
pair of pipes. Typically, the coupling segments have a
provision for including a sealing gasket within an internal
chamber of the segments which interfaces with the pipe ends
and prevents them from leaking. When the segments are bolted
together they extend in essentially a continuous ring about
the circumference of the pipe ends and attempt to immoblize
the pipe ends and eliminate all gaps between the segments.
~owever, differences in the diameter of stock pipe of the
same nominal diameter result in a less than optimal
immobilization of the pipe ends, or other problems arise
which cause the pipe ends to flex from the center axis of the
pipe, relative to each other, resulting in leaks and sags in
long runs of pipe and other problems.
It would thus be desirable to completely immobilize the
ends of the pipes to prevent such problems. Such complete
immobilization is called in the art, zero flex.
One attempt at solving the problem of flex in joint ends
is set forth in Gibb et al., U.S. Patent 4,471,979, wherein
there is disclosed thin-walled piping which is inherently
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capable of moving out of round under compressive stresses
produced by the tightening down of the coupling. This patent
teaches the deliberate formation of the coupling segments for
them to subtend an angle of less than 180 degrees at their
end faces, to permit the center of curvature o the
respective coupling segments to move beyond and to the
opposite side of the diametral plane of the coupling. Thu~,
the end faces of each coupliny member are coplanar with the
axis of generation of the coupling member as in prior known
construction, the end faces of the coupling members are
formed for them to be substantially planar and for each said
end face to lie in a plane which is parallel to, but spaced
from, a radial plane which includes the central longitudianl
axis of generation of the coupling bore and which lies beyond
the associated end of the coupling member. The selective
deformation of the pipe ends by the coupling provides for
rigid clamping of the coupling onto the pipe ends without
regard to whether the pipes are oversized or undersized
within the range o manuacturing tolerances. This
construction, however, is of little utility for use with
conventional pipe that is not readily deformable by a
coupling, and does not eliminate the need for extrusion
shields in those instances where the bolting pads do not come
into face engagement with each other.
U. S. Patent 2,752,173, in the name of Kroos, teaches
flexure of the coupling segments to move the end~ thereo in
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a radially inward direction for them to clamp onto pipes of
less than maximum diameter within the range of manufacturing
tolerances. While this will produce clamping in the
diametra]. plane of the end faces, flexure of the coupling
segments as described .in this patent will produce an increase
in the ef~ective length of ~he inner periphery of the
coupling and preclude clamping of the coupling onto the pipe.s
other than at the ends of the coupling segments. Further, in
this design, fl~xure of the coupling segments results in
movement of the end ~aces away from each other and increases
the possiblity of gasket extrusion and increased flex.
U. S. Patent 4,561,678 discloses a typical coupling
means wherein the coupling has at least one securing means
which is a hinge for the coupling segment and another of the
securing means provides a closure and locking means for the
coupling.
U.S. Patent 4,611,839 describes adjacent coupling
segments at an obli~ue angle to the diametral plane of the
coupling. The end faces slide relative to each other as the
coupling is tightened down for them to reduce the effective
circumferential length of the inner periphery of the
coupling, and thus permit the coupling to clamp onto and
secure a pipe having an external diameter or groove diameters
within a given range.
~ inally, there is a series of U.S. Patents dealing with
co~plings wherein var.lous arrangements of grooves and keys,
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and pegs and slots, are used to couple pipes together,
such patents being: U.S. 3,756,629; U.S. 4,522,434;
U.S. 4,601,495; U.S. 4,702,499, and U.S. 4,702,500.
What all of these couplings have in common, is -that none
of them make any provision for a means to prevent flexing of
the fitted, grooved or beaded pipes to attain essentially
zero flex, and all of them suffer from excess weight in an
attempt to give them strength in order to attempt to prevent
flex of pipe~
THE I NVEN'rI ON
The device of the present invention overcomes the prior
art problem of flex associated with incompletely coupled pipe
ends. The device of the instant invention allows for
essentially zero flex, that is the coupling of this invention
allows for no flex, that is the coupling of this invention
allows for no flex of coupled pipes, wherein "flex" is
defined infra.
This significant advantage is provided by the unique
design of the instant coupling, wherein there is provided on
the coupling, a radially inwardly extending wall, which
extends radially inwardly from the axial wall wherein each
radial wall has a configuration at its lower end contacting
the pipe members such that the end contacting the pipe
members is angled on its inward face in an obligue angle from
the X-Y plane of the arcuate body.
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Thus, this invention comprises a pipe coupling for
joining pipe, of ~he type including two arcuate coupling
segments and a fastening means, each said coupling segment
bein~ configured essentially identical to the other, each
said coupling segment comprising an arcuate body comprised of
radial and axial walls providing a receptacle for a sealing
means; each radial wall of each said arcuate body being
radially inwardly extending from the axial wall to provide an
engagement means for clamping engagement with ends of pipe
members arranged in juxtaposed relationship; each said
arcuate body terminating in bolt pads at both ends, said bolt
pads being used as a means, in combination with a fastenlng
means, for securing one coupling segment to another like
coupling segment in end-to-end encircling relationship about
said pipe; each said radial wall having a configuration at
the end contactinq a respective one of said pipe members,
which configuration comprises a~face inclined at an angle
relative to a plane perpendicular to the longitudinal axis of
the coupling whereby as the fastening means of said arcuate
bodys are secured and tightened, sliding line contact between
the inclined face and the pipe causes a drawing together of
the pipe ends.
Thus, the instant invention comprises "Zero flex" and
for purposes of this invention it means that the pipe that is
coupled with the device of this invention will not separate
at the coupled ends. Flex is measured as the degree
of deviation of the pipe ends from each other in the Z
direction and is observed by a gap or separation between the
ends of the joined pipe segments when flex is preGent. In
the simplest format, th~ invention comprises a slngle
construc-tion which is comprised of two arcuate coupling
segments and a fastening means, each said coupling segment
being configured essenti.ally identical to the othar and each
arcuate body comprised of radial and a~ial walls providing a
receptacle for a sealing means; each radial wall of each said
arcuate body being radially inwardly extending from the axial
wall to provide an engagement means for clamping engagement
with ends of pipe members arranged in ju~taposed relationship
and each said radial wall has a configuration at the end
contacting said pipe members such that the end contacting
said pipe members is anglad on its inward face in an oblique
angle from the X-Y plane of the arcuate body to allow
circular line contact of the inclined face with the inside
wall of the grooves of the pipe members.
~RIE~ DESCRIPTION OE THE DRAWINGS
Fig. 1 is a front elevation and a partial cross-section
of a pipe coupling of the present invention, showing the
interrelationship of the coupling segments to form a coupling
of this invention, and the arrangement of a gasket
therewithin.
Fig. 2 is a bottom plan view of one of the arcuate
coupling segments of this invention showing the detail of the
angling of the lower edge of the radial walls.
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Fig. 3 is a cross sectional side view of a coupling
assembled from two coupling segments with a full side view of
the pipe members on which it is mounted.
DETA I LED DESCRI P.TI ON OF T~E I ~VE~TI O~
Referring now to Fig. 1, there is shown a front
elevation and partial cross-sectional view of a pipe coupling
1 of the present invention showing the coupling segments 10
and 12, a pipe end 2, a gasket 3, and a fastening means 4,
shown herein as a threaded bolt.
Referring now to Fig. 2, there is shown a bottom plan
view of one of the arcuate coupling segments 10 of this
invention wherein there is shown an arcuate sealing groove or
channel member 5 comprised of radial walls 6 and an axial
wall 7, for the reception of a sealing gasket 3 (pictured in
Fig. 1). It should be noted by those skilled in the art that
the inventive coupling of this invention does not have axial
projections beyond the radial walls as is required in the
prior art coupling systems. The gasket 3 spans the adjacent
ends of pipe 2 (and a similar pipe not pictured), held by the
coupling 1, and seals against the pipe ends and prevents
leakage therefrom.
The gasket 3 may be of any re~lired cross-section, and
may be either a circumferentially continuous gasket, a split
gasket, or, plural gasket segments which are respectively
secured within and carried by the coupling segments.
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The coupling segments 10 and 12 as indicated above, each
consist of radial walls 6 which are formed in an inteyral
piece with, and are essentially inwardly directed extentions
of, the axial wall 7 and which terminate at their inner
periphery in an inclined face 8 for engagement within
circular groove~ 11 in the ends of pipe 2 (ully shown in
Fig. 3~, or for engagemant behind beads of bead-rolled pipe
ends (not shown). The angle of inclination of the lower
inward face of tha radial wall in this specification and in
these claims is defined by reference to the three mutually
perpendicular respective axe~, with reference to Fig. 1, in
which the X axis is shown as running horizontally and midway
between the two coupling segments 10 and 12 and the Y axis is
shown vertically and the Z axis is the long axis of the pipe.
Thus, with minor variations, the X axis includes and passes
through the centar of the assembled coupling, or provides a
bisector of a lina extending between the lines of generation
of the radii of the respective coupling segments. For
convenience, the X axis has been illustrated in a horizontal
orientation. It will, however, be appreciated that the X
axis may be in any orientation in actual use of the coupling.
The Y axis is an axis ext~nding through the line of
generation of the radii of the respective coupling segments,
and which is perpendicular to the X axis and together with
the X axis forms the X-Y plane which encompasses all radii of
the coupling segments. The Z axis generally corresponds to
g
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the pipe axis, and is -the lonyitudinal axis of the coupling
which extends through the point of inkersection of the X axis
and the Y axis, the Z axis thus ex-tending perpendicular to
the X~Y plane. As will be described here.inafter, the
inclined faces 8 of the couplings form an a:ngle relative to
tha X-~Y plane to cause a drawing together of the pipe ends
along the Z axis AS the coupling is tightened. Preferred
for this invention is an angle of less than 90 with the X-Y
plane, more preferred is an angle of less than 45, and most
preferred is an angle less than about 35 with the X-Y plane.
The contact of the inclined face~ 8 with the pipe is
found only at a circular line of contact, at each pipe member
respectively, at the top edge of the groove in the pipe
designated at point P in Fig. 3.
The coupling segment as shown in Fig. 2, shows a pair of
perforated lugs 9 integrally formed at each end of each
coupling segment, for the reception o bolts 4 therethrough.
In one embodiment, the shanks of the bolts are other
than of circular transverse cross section and are received
within correspondingly shaped apertures in the perforated
lugs or optionally, the bolts may be such that they have a
neck portion which is rectangular in transverse cross
section, or the neck portion can be formed in oval or other
non-circular transverse cross section.
The coupling member is readily adaptable to various
types of pipes including cast, drawn, or seam welded pipe,
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thin walled pipe such as is typically formed from stainless
steel, extruded thermoplastic pipe and the like.
Each coupling segment 10 and 12 is preferably identical
in all respects with each other coupling segment, the
respective coupling segments being configured such that they
can be assembled to each other by reversing one of the
coupling segments end-to-end with respect to the other.
In use, the coupling segments 10 and 12 are fitted with
a gasket 3 and fitted over pipe 2 containing grooves 11 as is
illustrated in Fig. 3. The coupling segments 10 and 12 are
then fitted with bolts 4 (not shown in Fig. 3), and the nuts
13 are tightened to draw the coupling segments 10 and 12
together in opposite directions along the Y axis to compress
the gasket 3 against the outer surface of the pipe 2 and at
the same time, the inclined faces 8 of the radial walls 6
make circular line contact with the inside wall 14 of the
groove 11 and cause a drawing together along the Z axis, of
the ends of the pipe members 2. It should be understood by
those skilled the art as it is first taught herein, that as
the coupling segments are drawn together and the inclined
face 8 contacts the inside wall 14 of the groove 11, the
inclined face allows for slight slippage of the radial walls
6 into the grooves 11 so that the radial walls 6 never have
to bottom out in the groove 11 which causes the most intimate
contact of the ends of the pipe members 2 with each other.
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Tha most unexpected result of the use of the just
described inventlon is that as known, shown and clecribed in
the prior art, axial walls that are lateral to the external
surface of khe radial walls 6 and which encircle the pipe
are not needecl to give stabilization to the connected pipes.
Furthermore, th0 Z axis alignment of the ends of the
pipe members is so complete that the pipe ends are forced to
match essentially perfectly and therefore, there is no
impediment to the flow of water through the pipe.
However, it must be recognized by those skilled in the
art that this coupling requires that it be manufactured from
metal, such as cast iron, or stainless steel, or tough
plastics such as nylon or polyurethane, especially reinforced
nylon or polyurethane, in order to have the strength to
withstand the tremendous pressures that are encountered in
connected pipe. Thus, there is a big weight savings factor
with the use of the device of the instant invention.
Further, it is unexpected that such inclined face radial
walls would give a sure hold of the pipe ends, without
slipping out under the pressure, and create a stable
connection such that the joined pipes do not fle~ enough to
form a gap anywhere at the interface of the connecting pipes.
The strength required to separate the pipe end is
analogouæ to the strength required to pull a solid steel bar
apart along the ~ axis. The applicant herein believes, but
~hould not be held to such a theory, that this configuration
12
3~
directs strength towards the center of the pipe by the
circular line con-tact of the coupling, crea-t:ing the strongest
hold one can possibly have in a coupling arrangement.
The prior art couplings are manufactured by costly
methods and cannot be manufactured by Deisamatic equipment,
and the instant inventive couplings have the advantage tha-t
they can be manufactured by Deisamatics.
A coupling of the prior art was testecl for flex in a
standardized test, by coupling two grooved pipe ends together
and bolting them securely. The prior art coupling was a
coupling having the commercial name "Sprink-Kupl", 4", 705.
The pipaline thus formed was a 20 feet long, 4 inch diameter
steel pipe. To test for water leaks, 1000 psi water was
injected and held in the pipe. There were no leaks at the
coupling site. Thereafter, the coupling was tested for flex
by laying the coupled pipe down on two supports, wherein each
of the supports were about one foot from each distal end of
the joined pipe and about nine feet from the centerline of
the coupling, with no additional support in between the two
end supports. The pipe was pressurized with 350 psi water. A
weight of 2650 lbs by hydraulic means, was applied directly
down on the coupled pipe at the center line of the coupling
and the coupling was checked to determine if the pip~ ends
had separated. The amount of separation (fle~) as measured
was about 7,
For comparison purposes, a similar test was carried out
on a 4" coupling o this invention.
13
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No water at all leaked from the pipeline during the 1000
psi water test and there was zero flex. In addition, the
weight was bounced up and down on the joint with considerable
orce for three or four minut:es. The pipeline bent sliyhtly,
but no water at all leaked from the pipeline ater this
treatment and there was still zero fle~.
It is thus apparent that the coupling of this invention
did not allow the pipeline to flex while the coupling of the
prior art did allow the pipeline to flex and cause leakage.
Thus, this device allows for the construction of large
diameter pipelines without earthquake bracing, a considerable
savings in the cost of installation of large diameter piping.
What has been described ls a device which prevents flex
in pipe which has been coupled with the device.
