CA2044348A1 - Coupling device for piping - Google Patents

Abstract

ABSTRACT

A pipe coupling designed for rigid coupling of pipe to form pipelines for the conveyance of liquids under pressure is described. The instant invention provides for the coupling of pipes to give a pipeline zero flex at the pipe end connections.

Description

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 ~0~9L34~3 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 Z~4~L3~3 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 2~ 3~3 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, 2(~443~8 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.

~O~L~3~
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.

~4~

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.

~0~3~

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 ;~0~434~

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, X~1443~3 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.

20~3~8 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 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.

Z~3~43~3 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.

Claims (20)

1. A pipe coupling for joining pipe, of the type including two arcuate coupling segments and a fastening means, each said coupling segment being 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 fastening 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 contacting 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 members.

2. In an improved pipe coupling of the type including plural arcuate coupling segments comprised of radial and axial walls providing a receptacle for a sealing means; each said arcuate coupling segment having radially inwardly extending engagement means, each said arcuate body terminating in bolt pads at both ends, said bolt pads being used as a means, in combination with a fastening means, for securing one coupling segment to another like coupling segment in end-to-end encircling relationship about said pipe with the lines of generation of the radii of the coupling segmnents forming an X-Y plane perpendicular to the longitudinal axis of the pipe and couplings, the improvement comprising:
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 radial wall having a configuration at its distal end contacting said pipe members such that a lower portion of the face contacting said pipe members is angled in an acute angle from the X-Y plane of the arcuate body.

3. In combination, a pipe coupling of claim 1 including a flexible sealing means, and a fastening means for the coupling.

4. The combination of claim 3 wherein the sealing means is an elastomeric gasket.

5. The combination of claim 4 wherein the gasket is circumferentially continuous.

6. The combination of claim 4 wherein the gasket is discontinuous.

7. In combination, a pipe coupling of claim 2 including a flexible sealing means, and a fastening means for the coupling.

8. The combination of claim 7 wherein the sealing means is an elastomeric gasket.

9. The combination of claim 8 wherein the gasket is continuous.

10. The combination of claim 8 wherein -the gasket is discontinuous.

11. A coupling segment, said coupling segment comprising:
an arcuate body comprised of radial and axial walls providing a receptacle for a sealing means; said radial wall 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;
said radial wall having a configuration at the end contacting said pipe members such that the end contacting said pipe members is angled on its inward face in an acute angle from an X-Y plane encompassing the lines of generation of the radii of the arcuate body and perpendicular to the longitudinal axis thereof;

said arcuate body terminating in bolt pads at both ends, said bolt pads being used as a means, in combination with a fastening means for securing one coupling segment to another like coupling segment in end-to-end encircling relationship about said pipe members.

12. The coupling segment of claim 11 when manufactured from metal.

13. The coupling segment of claim 12 wherein the metal is iron.

14. The coupling segment of claim 12 wherein the metal is steel.

15. The coupling segment of claim 14 wherein the steel is stainless steel.

16. The coupling segment of claim 11 when manufactured from plastic.

17. The coupling segment of claim 16 wherein the plastic is nylon.

18. The coupling segment of claim 17 wherein the nylon is reinforced nylon.

19. The coupling segment of claim 16 wherein the plastic is polyurethane.

20. The coupling segment of claim 19 wherein the polyurethane is reinforced polyurethane.