CA2313426A1 - Stab joint for pipe assembly incorporating compressible gasket secured by compression strap - Google Patents
Stab joint for pipe assembly incorporating compressible gasket secured by compression strap Download PDFInfo
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- CA2313426A1 CA2313426A1 CA 2313426 CA2313426A CA2313426A1 CA 2313426 A1 CA2313426 A1 CA 2313426A1 CA 2313426 CA2313426 CA 2313426 CA 2313426 A CA2313426 A CA 2313426A CA 2313426 A1 CA2313426 A1 CA 2313426A1
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- gasket
- corrugated pipe
- engagement surface
- bell
- pipe
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Abstract
A stab joint, pipe assembly, and method of forming a seal between a corrugated pipe and a bell utilize an annular gasket secured to a corrugated pipe through the use of a compression strap that applies a compressive force to the gasket to form a seal between the gasket and the outer engagement surface of the pipe. The annular gasket overlays an adjacent crest and valley on the outer engagement surface of the pipe and is formed of a compressible material having an uncompressed radial thickness that is greater than the radial distance between the inner engagement surface of the bell and a crest on the outer engagement surface of the pipe. When compressed by the compression strap, at least a portion of the annular gasket has a diameter that is greater than that of the strap such that the annular gasket forms a seal with the inner engagement of the bell when the pipe is inserted into the bell.
Description
Atty Docket No. CTH/104 STAB JOINT FOR PIPE ASSEMBLY INCORPORATING COMPRESSIBLE
GASKET SECURED BY COMPRESSION STRAP
Field of the Inv ne tion The invention is generally related to connecting pipes, and in particular to connecting pipes through the use of a stab joint.
Backc,~round of the Invention Forming a seal between adjoining spirally or helically formed corrugated mEaal pipes has been problematic in a number of drainage and culvert applications. One particular difficulty associated with forming such seals stems from the availability of a wide array of diameters of corrugated pipe, available, for example, in diameters between 12-144 inches.
11: is desirable for a seal formed between adjoining lengths of pipe to be both reliable and easy to assemble. One conventional practice is to recorrugate the ends of helically formed pipe with annular corrugations. A
gasket, typically an O-ring, is placed within an annular corrugation. The pipe is then placed in an abutting relationship with a similar recorrugated pipe having a similar 0-ring disposed in an annular corrugation thereof. A
compression hand is then placed around both pipes and tightened through the _2_ use of bolts, which tension the bands and compress the gasket between the outer surface of each pipe and the inner surface of the band.
While the aforementioned type of joint usually forms a reliable seal, in practice the joint is difficult and time consuming to assemble in the field - especiall'y in trenches or ditch-like conditions where a large percentage of corrugated pipe is used. Particularly when extremely large diameter pipe is used, recorrugating the pipe ends, orienting a band around abutting pipes and tightening the band to achieve the seal is extremely unwieldy and inefficient to assemble.
As an alternate to the use of a compression band, various types of stab joints have been developed. With a stab joint, a pipe, acting as a spigot, is inserted into a larger diameter bell formed on another pipe, or alternatively, on a sleeve that functions as a bell for adjoining pipes.
Typically, the joint is formed by initially placing a gasket on either the outer surface of the pipe or the 'inner surface of the bell. A seal is then formed between the gasket and the other structure by inserting the pipe in a direction along its longitudinal axis into the bell. Tightening of a band within the field is typically not required, and as such, a stab joint is often faster and less difficult to install.
Conventional stab joints, however, also have a number of drawbacks. A number of stab joint designs, for example, are not suitable for use with spirally formed corrugated pipe, and thus often require pipe end recorrugation to form annular corrugations. Moreover, for those joints that do not require recorrugation, often a gasket material is wound within the valley . w. _ of a single corrugation without any form of retainer. Without such a retainer, however, a risk exists that the gasket will become dislodged during insertion of the pipe into the bell. Any dislodgement of the gasket may compromise the seal and cause leakage lif not corrected.
Some stab joint designs also incorporate a retaining ring to initially secure a gasket to the inner surface of a bell or an annular outer surface of a pipe. Typically, the engagement with the opposing structural member, however, is formed through the use of one or more deformable lips. In practice, such joints require a consistent circurnferential profile of both the bell and the pipe to form a reliable seal, and thus" such joints are not suitable for use with spirally formed pipe. Moreover, the ~deformable lips typically do not completely fill 'the space between the pipe and bell, and as such, may not provide for a reliable seal in all circumstances.
Therefore, a significant need continues to exist in the art for a reliable and easy to install sealing arrangement for use with spirally formed corrugated pipe.
Summary of the Invention The invention addresses these and other problems associated with the prior art by providing a stab joint, a pipe assembly incorporating the same, and a method of forming a seal between a corrugated pipe and a bell in which an annular gasket is secured to a corrugated pipe through the use of a compression strap that applies a compressive force to the gasket to form a seal between the gasket and the outer engagement surface of the pipe. The annular gasket overlays .an adjacent crest and valley on the outer engagement surface of the pipe and is formed of a compressible material having an uncompressed radial thickness that is greater than the radial distance between the inner engagement surface of the bell and a crest on the outer engagement surface of the pipe. When compressed by the compression strap, at least a portion of the annular gasket has a diameter that is greater than that of the strap such that the annular gasket forms a sea/ with the inner engagement of the bell when tine pipe i,s inserted into the bell.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawing:c, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.
Brief Descr~tion of the Drawings FIGURE 1 is a partially-exploded elevational view of a pipe assembly consistent with the invention, with portions thereof cut away to illustrate internal components of the assembly.
FIGURE 2 is a cross-sectional view illustrating the profile of the annular gasket in the pipe assembly of Fig. 1 .
FIGURE 3 is an alternate cross-sectional profile to that of Fig. 2.
FIGURE 4 is an enlarged fragmentary cross-sectional view illustrating the seal formed upon insertion of an annular pipe into the sleeve of Fig. 1 .
FIGURE 5 is an elevational view of an alternate pipe assembly consistent with the invention, incorporating a recorrugated pipe.
FICiURE 6 is another alternate pipe assembly consistent with the invention, incorporating a spiral rib-type pipe.
FIGURE 7 is yet another alternate pipe assembly consistent with the invention, incorporating a sleeve having a plurality of deformable tongues for use in securing a corrugated pipe within the sleeve.
FIGURE 8 is an enlarged fragmentary cross-sectional view of a seal formed between the sleeve and pipe of Fig. 7.
Detailed Description Turning to the Drawings, wherein like numbers denote like parts throughout the several views, Fig. 1 illustrates a pipe assembly 10 consistent with the invention. Pipe assembly 10 is illustrated including first and second corrugated pipes 12, 14 joined in an abutting relationship by an annular sleeve 24. Each corrugated pipe 12, 14 is illustrated as a spirally wound pipe including a plurality of corrugations 16 defined on an outer engagement surface 18 of the pipe. The corrugations 16 form a plurality of alternating crests 20 and valleys 22 that are spirally wound on the outer surface of the pipe. It will be .appreciated that each pipe 12, 14 may have an inner surface having the same; profile as the outer surface of the pipe, or in the alternative, a liner may be secured to the inner surface of the pipe to provide a smooth profile for the pipe.
Sleeve 24 includes first and second bell portions 26, 28, which respectively receive the ends of pipes 12, 14 to effect a joint therebetween.
An annular center stop 30 is optionally provided between bell portions 26, 28 to prevent insertion of the sleeve too far onto a pipe when the sleeve is first inserted over a first pipe, as well as to prevent movement of the sleeve when a second pipe is inserted into the sleeve.
An inner engagement surface 32 is defined along the interior of each bell portion 26, 28, and sleeve 24 also optionally includes annular entry flares 34, 36 formed on the end portions thereof to facilitate alignment of a pipe with the sleeve during assembly.
Each of pipes 12, 14 and sleeve 24 may be formed of a number of different mai:erials, including various metals and alloys, as well as different plastics that provide suitable rigidity for the application. Moreover, while Fig.
1 illustrates thc: use of a sleeve having opposing bell portions for joining two lengths of pipe, it will also be appreciated that the sleeve may be permanently secured to or formed on the end of one length of pipe, whereby formation of a seal between pipes requires only the insertion of another length of pipe into the sleeve. The sleeve, for example, may be integrally formed on the end of a pipe through molding or metal forming, or may be a separate member that is secured in ainy number of fashions to the end of a pipe prior to use in the field.
To effect a seal between each pipe 12, 14 and inner engagement surface 32 of sleeve 24, a seal 40, including a gasket 42 and compression strap 44, is initially secured to the end of each corrugated pipe.
As best shown in Fig. 2, gasket 42 includes inner and outer engagement surfaces 46, 48, which are respf:ctively configured to engage the _ 7 _ pipe and the bell portion of sleeve 24. The gasket also includes a tapered leading edge 50 that facilitates alignment of the sleeve prior to assembly onto the pipe. An annular groove 52 is formed by a pair of annular shoulders 54, 56 intermediate the leading edge 50 and outer engagement surface 48 of the gasket. Groove 52 is sized and configured to receive strap 44 and compress the gasket onto the spiral corrugations of a pipe.
Strap 44 is typically formed of metal or plastic, and is used to compress the gasket onto the outer engagement surface of the pipe. For this reason, gasket 42 is preferably formed of a compressible material such as a low durometer rubber. ~'Vhile various natural or synthetic rubber compositions (including multiple layers and other combinations of materials) may be used to form gasket 42, closed cell formed rubber is preferably utilized in the illustrated embodiment.
The material used to form the gasket preferably has less than about a 45 (Shore 00) durometer, more preferably a durometer of less than about 30 (Shore 00), to permit the gasket to account for the variable compression to which the gasket is subjected across the inner engagement surface 46 thereof. Specifically, as can be seen in Fig. 1, inner engagement surface 46 of the gasket overlays at least one adjoining crest and valley forming a corrugation. In many instances, more than two valleys and/or crests may be overlaid by the gasket, and as such, it is often desirable to provide a sufficiently low durometer gasket material to permit the gasket to completely fill each overlaid corrugation valley while sufficiently compressing over each overlaid corrugation crest. As such, a reliable seal around the entire _ 8 _ circumference o~f the pipe may be provided regardless of the particular profile of the outer enc,~agement surface thereof.
A wide variety of alternate profiles may be utilized for gasket 42 consistent with the invention. For example, as shown in Fig. 3, a gasket 42' may include a lip 60 disposed distal from the leading edge of the gasket relative to a groove 62 to provide additional material and thereby form a tighter seal between the pipe and the sleeve. As another example, it may be desirable to utilize a different leading edge profile, including one without a taper.
The use of a tapered leading edge, however, does facilitate the alignment of the sleeve and also minimize, the bulging of the gasket proximate the leading edge thereof. In addition, alternate groove profiles may be utilized in a gasket, and in some implennentations it may be possible to omit the groove and simply allow the strap to compress the gasket along the outer engagement surface thereof. In addition, while the illustrated gasket includes a smooth, circular cylindrical profile, the inner engagement surface of the gasket may assume other profiles as well. It is important to note, however, that the profile of the inner engagement surface, when in an uncompressed state, usually need not match the cross-sectional profile of the overlaid portion of the outer engagement surface of the corrugated pipe. As will become more apparent below, permitting the inner engagement surface of the gasket to assume the profile of the pipe through a compression permits the gasket to be assembled onto pipes of varying profiles, and without the need to align the gasket at any specific orientation relative to the profile of t:he pipe.
A~; shown in Figs. 2 and 4, gasket 42 preferably has an uncompressed radial thickness t that is greater than the radial distance d~
between the inner engagement surface 32 of the sleeve and a crest 20 formed on the outer engagement surface 18 of the pipe. By providing such a thickness, the c,~asket is ensured of forming a seal at least between the crest of a corrugation and the sleeve. Moreover, it is desirable for the uncompressed thickness t of the gasket to also be greater than the radial distance d~ between the inner engagement surface 32 and a valley 22, such that sufficient rnaterial is provided in the gasket to completely fill the adjacent valley 22 of the pipe. However, in some implementations, it may not be necessary to provide sufficient thickness in the gasket to completely fill each valley overlaid by the gasket.
In operation, a joint is formed between a corrugated pipe and a sleeve by first securing gasket 42 to the end of pipe 12 through the use of strap 44. Typically, gasket 42 is placed in a circumscribing relationship over the end of pipe 12, and strap 44 is placed around the gasket and tightened by means of a manual or pneumatic tensioner. A wide variety of strap constructions and tightening mechanisms may be utilized consistent with the invention, e.g., various band angles or other 'fasteners. It will be appreciated that securing the gasket to the pipe may be performed in the field, or more typically, prior to delivery of the pipe to the field.
Tightening the strap performs two functions. First, the strap compresses the gasket to fill the corrugation valleys or other areas between the corrugations and l:hereby form the seal between the gasket and the corrugated pipe. Second, the strap holds the gasket in place while the stab sleeve is assemlbled onto the pipe, and serves to reduce the risk of the gasket rolling or pushing ahead of the sleeve when the joint is assembled. It is also desirable for at least a portion of the annular gasket to bulge outwardly to provide a diameter greater than the strap after compression to assist in forming a seal with the inner engagement surface of the sleeve.
Once the gasket is secured to the pipe, the joint is formed by inserting the end of the pipe into the sleeve in a longitudinal direction until the end of the pipe contacts the center stop formed in the sleeve. Doing so forms a compression ;seal within the gasket and the inner engagement surface of the sleeve.
Se:curement of a second pipe 14 to the opposite bell 28 formed in sleeve 24 occurs in the same manner as for pipe 12. Moreover, it should be appreciated that the sleeve may be secured to one of the pipes prior to delivery of the pipe to the field, whereby adjoining a sequence of pipes merely requires that each pipe be supplied with a sleeve secured to one end thereof, with the opposing end of each pipe sequentially inserted into the exposed sleeve end of a preceding pipe.
It may be seen that the compression of the gasket into the valleys of the annular corrugations, combined with the compression of the bulged " areas of the outer edge of the gasket adjacent the strap by the inner s engagement surface of the sleeve assists in forming a water-tight seal between the pipe and the sleeve.
The herein-described sealing arrangement may also be utilized to form other joint assemblies consistent with the invention. For example, as illustrated by joint assembly 10' in Fig. 5, seal 40 may be utilized to form a seal between sleeve 24 and a recorrugated pipe 12' having an end thereof recorrugated to form annular corrugations 70 including adjacent crests and valleys 72, 74. Similarly, as illustrated by pipe assembly 10" in Fig. 6, seal 40 may also bE: used to form a seal between sleeve 24 and a spiral rib-type corrugated pipe 12" including a spiral formed rib 80 defining alternating crests and valleys 82, 84.
In certain implementations, it may be desirable to specifically configure the gasket and strap 42, 44 of seal 40 for use with specific types of corrugated pipe. However, one advantage of the invention is that in many instances the same gasket and strap configuration may be utilized for a given diameter of corrugated pipe, regardless of the specific type of corrugations utilized thereon.
Aa another alternative, Fig. 7 illustrates a joint assembly 10"' in which a corrugated pipe 12 is secured to a sleeve 24' through the use of seal 40. In addition to the compression seal formed by seal 40, sleeve 24' includes a plurality of deformable tongues 90 formed around the periphery thereof.
Each deformable tongue; is cantilevered with a free end 92 extending generally ' in the direction of insertion of the pipe. As best illustrated in Fig. 8, after pipe s 12 is inserted into sleeve 24', the deformable tongues 90 may each be pressed downvvardly into engagement with the outer engagement surface of pipe 12 ltypically on the back side of a crest 20) to restrict removal of the pipe from the sleeve.
Typically, deformable tongues are integrally formed on a metal sleeve, and are defined by slots 94 circumscribing the free end 92 of each tongue 90. The tongues typically may be deformed by simply hammering down on the tongues after the pipe is inserted into the sleeve. Various tongue profiles, including U-shaped, V-shaped, semi-circle-shaped, etc. may be used to define each i:ongue, and any number of tongues may be disposed about the periphery of the sleeve. Other modificatians will be apparent to one of ordinary skill in the art.
Various additional modifications may be made without departing from the spirit .and scope of the invention. Therefore, the invention lies in the claims hereinafter appended.
llVhat is claimed is:
GASKET SECURED BY COMPRESSION STRAP
Field of the Inv ne tion The invention is generally related to connecting pipes, and in particular to connecting pipes through the use of a stab joint.
Backc,~round of the Invention Forming a seal between adjoining spirally or helically formed corrugated mEaal pipes has been problematic in a number of drainage and culvert applications. One particular difficulty associated with forming such seals stems from the availability of a wide array of diameters of corrugated pipe, available, for example, in diameters between 12-144 inches.
11: is desirable for a seal formed between adjoining lengths of pipe to be both reliable and easy to assemble. One conventional practice is to recorrugate the ends of helically formed pipe with annular corrugations. A
gasket, typically an O-ring, is placed within an annular corrugation. The pipe is then placed in an abutting relationship with a similar recorrugated pipe having a similar 0-ring disposed in an annular corrugation thereof. A
compression hand is then placed around both pipes and tightened through the _2_ use of bolts, which tension the bands and compress the gasket between the outer surface of each pipe and the inner surface of the band.
While the aforementioned type of joint usually forms a reliable seal, in practice the joint is difficult and time consuming to assemble in the field - especiall'y in trenches or ditch-like conditions where a large percentage of corrugated pipe is used. Particularly when extremely large diameter pipe is used, recorrugating the pipe ends, orienting a band around abutting pipes and tightening the band to achieve the seal is extremely unwieldy and inefficient to assemble.
As an alternate to the use of a compression band, various types of stab joints have been developed. With a stab joint, a pipe, acting as a spigot, is inserted into a larger diameter bell formed on another pipe, or alternatively, on a sleeve that functions as a bell for adjoining pipes.
Typically, the joint is formed by initially placing a gasket on either the outer surface of the pipe or the 'inner surface of the bell. A seal is then formed between the gasket and the other structure by inserting the pipe in a direction along its longitudinal axis into the bell. Tightening of a band within the field is typically not required, and as such, a stab joint is often faster and less difficult to install.
Conventional stab joints, however, also have a number of drawbacks. A number of stab joint designs, for example, are not suitable for use with spirally formed corrugated pipe, and thus often require pipe end recorrugation to form annular corrugations. Moreover, for those joints that do not require recorrugation, often a gasket material is wound within the valley . w. _ of a single corrugation without any form of retainer. Without such a retainer, however, a risk exists that the gasket will become dislodged during insertion of the pipe into the bell. Any dislodgement of the gasket may compromise the seal and cause leakage lif not corrected.
Some stab joint designs also incorporate a retaining ring to initially secure a gasket to the inner surface of a bell or an annular outer surface of a pipe. Typically, the engagement with the opposing structural member, however, is formed through the use of one or more deformable lips. In practice, such joints require a consistent circurnferential profile of both the bell and the pipe to form a reliable seal, and thus" such joints are not suitable for use with spirally formed pipe. Moreover, the ~deformable lips typically do not completely fill 'the space between the pipe and bell, and as such, may not provide for a reliable seal in all circumstances.
Therefore, a significant need continues to exist in the art for a reliable and easy to install sealing arrangement for use with spirally formed corrugated pipe.
Summary of the Invention The invention addresses these and other problems associated with the prior art by providing a stab joint, a pipe assembly incorporating the same, and a method of forming a seal between a corrugated pipe and a bell in which an annular gasket is secured to a corrugated pipe through the use of a compression strap that applies a compressive force to the gasket to form a seal between the gasket and the outer engagement surface of the pipe. The annular gasket overlays .an adjacent crest and valley on the outer engagement surface of the pipe and is formed of a compressible material having an uncompressed radial thickness that is greater than the radial distance between the inner engagement surface of the bell and a crest on the outer engagement surface of the pipe. When compressed by the compression strap, at least a portion of the annular gasket has a diameter that is greater than that of the strap such that the annular gasket forms a sea/ with the inner engagement of the bell when tine pipe i,s inserted into the bell.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawing:c, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.
Brief Descr~tion of the Drawings FIGURE 1 is a partially-exploded elevational view of a pipe assembly consistent with the invention, with portions thereof cut away to illustrate internal components of the assembly.
FIGURE 2 is a cross-sectional view illustrating the profile of the annular gasket in the pipe assembly of Fig. 1 .
FIGURE 3 is an alternate cross-sectional profile to that of Fig. 2.
FIGURE 4 is an enlarged fragmentary cross-sectional view illustrating the seal formed upon insertion of an annular pipe into the sleeve of Fig. 1 .
FIGURE 5 is an elevational view of an alternate pipe assembly consistent with the invention, incorporating a recorrugated pipe.
FICiURE 6 is another alternate pipe assembly consistent with the invention, incorporating a spiral rib-type pipe.
FIGURE 7 is yet another alternate pipe assembly consistent with the invention, incorporating a sleeve having a plurality of deformable tongues for use in securing a corrugated pipe within the sleeve.
FIGURE 8 is an enlarged fragmentary cross-sectional view of a seal formed between the sleeve and pipe of Fig. 7.
Detailed Description Turning to the Drawings, wherein like numbers denote like parts throughout the several views, Fig. 1 illustrates a pipe assembly 10 consistent with the invention. Pipe assembly 10 is illustrated including first and second corrugated pipes 12, 14 joined in an abutting relationship by an annular sleeve 24. Each corrugated pipe 12, 14 is illustrated as a spirally wound pipe including a plurality of corrugations 16 defined on an outer engagement surface 18 of the pipe. The corrugations 16 form a plurality of alternating crests 20 and valleys 22 that are spirally wound on the outer surface of the pipe. It will be .appreciated that each pipe 12, 14 may have an inner surface having the same; profile as the outer surface of the pipe, or in the alternative, a liner may be secured to the inner surface of the pipe to provide a smooth profile for the pipe.
Sleeve 24 includes first and second bell portions 26, 28, which respectively receive the ends of pipes 12, 14 to effect a joint therebetween.
An annular center stop 30 is optionally provided between bell portions 26, 28 to prevent insertion of the sleeve too far onto a pipe when the sleeve is first inserted over a first pipe, as well as to prevent movement of the sleeve when a second pipe is inserted into the sleeve.
An inner engagement surface 32 is defined along the interior of each bell portion 26, 28, and sleeve 24 also optionally includes annular entry flares 34, 36 formed on the end portions thereof to facilitate alignment of a pipe with the sleeve during assembly.
Each of pipes 12, 14 and sleeve 24 may be formed of a number of different mai:erials, including various metals and alloys, as well as different plastics that provide suitable rigidity for the application. Moreover, while Fig.
1 illustrates thc: use of a sleeve having opposing bell portions for joining two lengths of pipe, it will also be appreciated that the sleeve may be permanently secured to or formed on the end of one length of pipe, whereby formation of a seal between pipes requires only the insertion of another length of pipe into the sleeve. The sleeve, for example, may be integrally formed on the end of a pipe through molding or metal forming, or may be a separate member that is secured in ainy number of fashions to the end of a pipe prior to use in the field.
To effect a seal between each pipe 12, 14 and inner engagement surface 32 of sleeve 24, a seal 40, including a gasket 42 and compression strap 44, is initially secured to the end of each corrugated pipe.
As best shown in Fig. 2, gasket 42 includes inner and outer engagement surfaces 46, 48, which are respf:ctively configured to engage the _ 7 _ pipe and the bell portion of sleeve 24. The gasket also includes a tapered leading edge 50 that facilitates alignment of the sleeve prior to assembly onto the pipe. An annular groove 52 is formed by a pair of annular shoulders 54, 56 intermediate the leading edge 50 and outer engagement surface 48 of the gasket. Groove 52 is sized and configured to receive strap 44 and compress the gasket onto the spiral corrugations of a pipe.
Strap 44 is typically formed of metal or plastic, and is used to compress the gasket onto the outer engagement surface of the pipe. For this reason, gasket 42 is preferably formed of a compressible material such as a low durometer rubber. ~'Vhile various natural or synthetic rubber compositions (including multiple layers and other combinations of materials) may be used to form gasket 42, closed cell formed rubber is preferably utilized in the illustrated embodiment.
The material used to form the gasket preferably has less than about a 45 (Shore 00) durometer, more preferably a durometer of less than about 30 (Shore 00), to permit the gasket to account for the variable compression to which the gasket is subjected across the inner engagement surface 46 thereof. Specifically, as can be seen in Fig. 1, inner engagement surface 46 of the gasket overlays at least one adjoining crest and valley forming a corrugation. In many instances, more than two valleys and/or crests may be overlaid by the gasket, and as such, it is often desirable to provide a sufficiently low durometer gasket material to permit the gasket to completely fill each overlaid corrugation valley while sufficiently compressing over each overlaid corrugation crest. As such, a reliable seal around the entire _ 8 _ circumference o~f the pipe may be provided regardless of the particular profile of the outer enc,~agement surface thereof.
A wide variety of alternate profiles may be utilized for gasket 42 consistent with the invention. For example, as shown in Fig. 3, a gasket 42' may include a lip 60 disposed distal from the leading edge of the gasket relative to a groove 62 to provide additional material and thereby form a tighter seal between the pipe and the sleeve. As another example, it may be desirable to utilize a different leading edge profile, including one without a taper.
The use of a tapered leading edge, however, does facilitate the alignment of the sleeve and also minimize, the bulging of the gasket proximate the leading edge thereof. In addition, alternate groove profiles may be utilized in a gasket, and in some implennentations it may be possible to omit the groove and simply allow the strap to compress the gasket along the outer engagement surface thereof. In addition, while the illustrated gasket includes a smooth, circular cylindrical profile, the inner engagement surface of the gasket may assume other profiles as well. It is important to note, however, that the profile of the inner engagement surface, when in an uncompressed state, usually need not match the cross-sectional profile of the overlaid portion of the outer engagement surface of the corrugated pipe. As will become more apparent below, permitting the inner engagement surface of the gasket to assume the profile of the pipe through a compression permits the gasket to be assembled onto pipes of varying profiles, and without the need to align the gasket at any specific orientation relative to the profile of t:he pipe.
A~; shown in Figs. 2 and 4, gasket 42 preferably has an uncompressed radial thickness t that is greater than the radial distance d~
between the inner engagement surface 32 of the sleeve and a crest 20 formed on the outer engagement surface 18 of the pipe. By providing such a thickness, the c,~asket is ensured of forming a seal at least between the crest of a corrugation and the sleeve. Moreover, it is desirable for the uncompressed thickness t of the gasket to also be greater than the radial distance d~ between the inner engagement surface 32 and a valley 22, such that sufficient rnaterial is provided in the gasket to completely fill the adjacent valley 22 of the pipe. However, in some implementations, it may not be necessary to provide sufficient thickness in the gasket to completely fill each valley overlaid by the gasket.
In operation, a joint is formed between a corrugated pipe and a sleeve by first securing gasket 42 to the end of pipe 12 through the use of strap 44. Typically, gasket 42 is placed in a circumscribing relationship over the end of pipe 12, and strap 44 is placed around the gasket and tightened by means of a manual or pneumatic tensioner. A wide variety of strap constructions and tightening mechanisms may be utilized consistent with the invention, e.g., various band angles or other 'fasteners. It will be appreciated that securing the gasket to the pipe may be performed in the field, or more typically, prior to delivery of the pipe to the field.
Tightening the strap performs two functions. First, the strap compresses the gasket to fill the corrugation valleys or other areas between the corrugations and l:hereby form the seal between the gasket and the corrugated pipe. Second, the strap holds the gasket in place while the stab sleeve is assemlbled onto the pipe, and serves to reduce the risk of the gasket rolling or pushing ahead of the sleeve when the joint is assembled. It is also desirable for at least a portion of the annular gasket to bulge outwardly to provide a diameter greater than the strap after compression to assist in forming a seal with the inner engagement surface of the sleeve.
Once the gasket is secured to the pipe, the joint is formed by inserting the end of the pipe into the sleeve in a longitudinal direction until the end of the pipe contacts the center stop formed in the sleeve. Doing so forms a compression ;seal within the gasket and the inner engagement surface of the sleeve.
Se:curement of a second pipe 14 to the opposite bell 28 formed in sleeve 24 occurs in the same manner as for pipe 12. Moreover, it should be appreciated that the sleeve may be secured to one of the pipes prior to delivery of the pipe to the field, whereby adjoining a sequence of pipes merely requires that each pipe be supplied with a sleeve secured to one end thereof, with the opposing end of each pipe sequentially inserted into the exposed sleeve end of a preceding pipe.
It may be seen that the compression of the gasket into the valleys of the annular corrugations, combined with the compression of the bulged " areas of the outer edge of the gasket adjacent the strap by the inner s engagement surface of the sleeve assists in forming a water-tight seal between the pipe and the sleeve.
The herein-described sealing arrangement may also be utilized to form other joint assemblies consistent with the invention. For example, as illustrated by joint assembly 10' in Fig. 5, seal 40 may be utilized to form a seal between sleeve 24 and a recorrugated pipe 12' having an end thereof recorrugated to form annular corrugations 70 including adjacent crests and valleys 72, 74. Similarly, as illustrated by pipe assembly 10" in Fig. 6, seal 40 may also bE: used to form a seal between sleeve 24 and a spiral rib-type corrugated pipe 12" including a spiral formed rib 80 defining alternating crests and valleys 82, 84.
In certain implementations, it may be desirable to specifically configure the gasket and strap 42, 44 of seal 40 for use with specific types of corrugated pipe. However, one advantage of the invention is that in many instances the same gasket and strap configuration may be utilized for a given diameter of corrugated pipe, regardless of the specific type of corrugations utilized thereon.
Aa another alternative, Fig. 7 illustrates a joint assembly 10"' in which a corrugated pipe 12 is secured to a sleeve 24' through the use of seal 40. In addition to the compression seal formed by seal 40, sleeve 24' includes a plurality of deformable tongues 90 formed around the periphery thereof.
Each deformable tongue; is cantilevered with a free end 92 extending generally ' in the direction of insertion of the pipe. As best illustrated in Fig. 8, after pipe s 12 is inserted into sleeve 24', the deformable tongues 90 may each be pressed downvvardly into engagement with the outer engagement surface of pipe 12 ltypically on the back side of a crest 20) to restrict removal of the pipe from the sleeve.
Typically, deformable tongues are integrally formed on a metal sleeve, and are defined by slots 94 circumscribing the free end 92 of each tongue 90. The tongues typically may be deformed by simply hammering down on the tongues after the pipe is inserted into the sleeve. Various tongue profiles, including U-shaped, V-shaped, semi-circle-shaped, etc. may be used to define each i:ongue, and any number of tongues may be disposed about the periphery of the sleeve. Other modificatians will be apparent to one of ordinary skill in the art.
Various additional modifications may be made without departing from the spirit .and scope of the invention. Therefore, the invention lies in the claims hereinafter appended.
llVhat is claimed is:
Claims (25)
1. A stab joint assembly, comprising:
(a) a bell having an inner engagement surface;
(b) a corrugated pipe received in the bell and including an outer engagement surface having a plurality of corrugations defining alternating crests and valleys;
(c) an annular gasket interposed between the bell and the corrugated pipe, the annular gasket overlaying an adjacent crest and valley defined on the outer engagement surface of the corrugated pipe, the annular gasket including a compressible material and having an uncompressed radial thickness that is greater than the radial distance between the inner engagement surface and a crest defined on the outer engagement surface; and (d) a strap circumscribing the gasket and applying a compressive force thereto to form a seal between the gasket and the outer engagement surface of the corrugated pipe, and wherein, when compressed, at least a portion of the annular gasket has a diameter that is greater than that of the strap such that the annular gasket forms a seal with the inner engagement surface of the bell.
(a) a bell having an inner engagement surface;
(b) a corrugated pipe received in the bell and including an outer engagement surface having a plurality of corrugations defining alternating crests and valleys;
(c) an annular gasket interposed between the bell and the corrugated pipe, the annular gasket overlaying an adjacent crest and valley defined on the outer engagement surface of the corrugated pipe, the annular gasket including a compressible material and having an uncompressed radial thickness that is greater than the radial distance between the inner engagement surface and a crest defined on the outer engagement surface; and (d) a strap circumscribing the gasket and applying a compressive force thereto to form a seal between the gasket and the outer engagement surface of the corrugated pipe, and wherein, when compressed, at least a portion of the annular gasket has a diameter that is greater than that of the strap such that the annular gasket forms a seal with the inner engagement surface of the bell.
2. The assembly of claim 1, wherein the compressible material includes a low durometer material.
3. The assembly of claim 2, wherein the compressible material includes closed cell foamed rubber.
4. The assembly of claim 2, wherein the compressible material has less than about a 30 (Shore 00) durometer.
5. The assembly of claim 1, wherein the annular gasket has an uncompressed radial thickness sufficient to completely fill the overlaid portion of a valley when compressed by the strap.
6. The assembly of claim 1, wherein the gasket is configured to bulge outwardly from the outer engagement surface when compressed by the strap.
7. The assembly of claim 1, wherein the annular gasket includes first and second axially spaced annular shoulders defining an annular groove adapted to receive the strap.
8. The assembly of claim 1, wherein the annular gasket includes a leading edge tapered along the direction of insertion of the corrugated pipe into the bell.
9. The assembly of claim 1, wherein the annular gasket has an inner engagement surface configured to engage with the outer engagement surface of the corrugated pipe, the inner engagement surface of the annular gasket having a cross-sectional profile that when uncompressed differs from the cross-section profile of the overlaid portion of the outer engagement surface of the corrugated pipe.
10. The assembly of claim 9, wherein the inner engagement surface of the annular gasket defines a circular cylinder.
11. The assembly of claim 1, wherein the plurality of corrugations on the corrugated pipe are helically wound.
12. The assembly of claim 11, wherein the corrugated pipe includes an engagement end that has been recorrugated with at least one annular corrugation.
13. The assembly of claim 11, wherein the corrugated pipe includes an engagement end having at least one helical corrugation; whereby the corrugated pipe is not recorrugated.
14. The assembly of claim 1, wherein the corrugated pipe is a first corrugated pipe, wherein the bell is defined on a sleeve including first and second ends, the first end configured to receive the first corrugated pipe, and the second end configured to receive a second corrugated pipe.
15. The assembly of claim 1, wherein the bell includes a plurality of deformable tongues deformed inwardly from the bell to engage with at least one corrugation on the corrugated pipe.
16. A pipe assembly, comprising:
(a) a corrugated pipe including an outer engagement surface having a plurality of corrugations defining alternating crests and valleys;
(b) an annular gasket overlaying an adjacent crest and valley defined an the outer engagement surface of the corrugated pipe, the annular gasket including a low durometer compressible material; and (c) a strap circumscribing the gasket and applying a compressive force thereto such that at least a portion of the gasket fills an overlaid portion of the overlaid valley and forms a seal between the gasket and the outer engagement surface of the corrugated pipe, and such that at least a portion of the annular gasket bulges outwardly from the outer engagement surface to provide an outer engagement surface on the annular gasket that has a diameter greater than that of the strap.
(a) a corrugated pipe including an outer engagement surface having a plurality of corrugations defining alternating crests and valleys;
(b) an annular gasket overlaying an adjacent crest and valley defined an the outer engagement surface of the corrugated pipe, the annular gasket including a low durometer compressible material; and (c) a strap circumscribing the gasket and applying a compressive force thereto such that at least a portion of the gasket fills an overlaid portion of the overlaid valley and forms a seal between the gasket and the outer engagement surface of the corrugated pipe, and such that at least a portion of the annular gasket bulges outwardly from the outer engagement surface to provide an outer engagement surface on the annular gasket that has a diameter greater than that of the strap.
17. A method of forming a seal between a corrugated pipe and a bell, the method comprising:
(a) circumscribing a corrugated pipe with an annular gasket, with the gasket overlaying an adjacent crest and valley defined by at least one corrugation on an outer engagement surface of the corrugated pipe, wherein the annular gasket includes a compressible material and has an uncompressed radial thickness that is greater than the radial distance between a crest defined on the outer engagement surface and an inner engagement surface of a bell when the corrugated pipe is received in the bell;
(b) securing the gasket to the corrugated pipe using a strap that circumscribes the gasket, including applying a compressive force to the gasket with the strap to form a seal between the gasket and the outer engagement surface of the corrugated pipe, wherein, when compressed, at least a portion of the gasket has a diameter that is greater than that of the strap; and (c) inserting the corrugated pipe into the bell such that the gasket forms a seal with the inner engagement surface of the bell.
(a) circumscribing a corrugated pipe with an annular gasket, with the gasket overlaying an adjacent crest and valley defined by at least one corrugation on an outer engagement surface of the corrugated pipe, wherein the annular gasket includes a compressible material and has an uncompressed radial thickness that is greater than the radial distance between a crest defined on the outer engagement surface and an inner engagement surface of a bell when the corrugated pipe is received in the bell;
(b) securing the gasket to the corrugated pipe using a strap that circumscribes the gasket, including applying a compressive force to the gasket with the strap to form a seal between the gasket and the outer engagement surface of the corrugated pipe, wherein, when compressed, at least a portion of the gasket has a diameter that is greater than that of the strap; and (c) inserting the corrugated pipe into the bell such that the gasket forms a seal with the inner engagement surface of the bell.
18. The method of claim 17, wherein the compressible material includes a low durometer closed cell foamed rubber.
19. The method of claim 17, wherein the annular gasket has an uncompressed radial thickness sufficient to completely fill the overlaid portion of a valley when compressed by the strap.
20. The method of claim 17, wherein applying the compressive force to the gasket causes the gasket to bulge outwardly from the outer engagement surface.
21. The method of claim 17, wherein securing the gasket to the corrugated pipe includes positioning the strap between first and second axially spaced annular shoulders on the gasket.
22. The method of claim 17, wherein gasket includes an inner engagement surface defining a circular cylinder.
23. The method of claim 17, wherein the plurality of corrugations on the corrugated pipe are helically wound throughout an engagement end of the corrugated pipe.
24. The method of claim 17, wherein the corrugated pipe is a first corrugated pipe, wherein the bell is defined on a sleeve including first and second ends, the first end configured to receive the first corrugated pipe, and the method further comprising inserting a second corrugated pipe into the second end of the sleeve.
25. The method of claim 17, further comprising deforming a plurality of tongues defined on the bell inwardly to engage with at least one corrugation on the corrugated pipe and thereby secure the bell to the corrugated pipe.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US41586499A | 1999-10-08 | 1999-10-08 | |
| US09/415,864 | 1999-10-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2313426A1 true CA2313426A1 (en) | 2001-04-08 |
Family
ID=23647527
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2313426 Abandoned CA2313426A1 (en) | 1999-10-08 | 2000-07-05 | Stab joint for pipe assembly incorporating compressible gasket secured by compression strap |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2313426A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101956879A (en) * | 2010-06-04 | 2011-01-26 | 周佰兴 | Spiral corrugated pipe rubber ring |
| CN108036139A (en) * | 2017-12-21 | 2018-05-15 | 鹤山联塑实业发展有限公司 | A kind of new steel belt helical corrugation tube multifunctional jointing |
| CN110230741A (en) * | 2019-07-11 | 2019-09-13 | 芜湖泰和管业股份有限公司 | A kind of bellows of the hard seal nipple unit of corrugated stainless steel tubing and the application connector |
-
2000
- 2000-07-05 CA CA 2313426 patent/CA2313426A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101956879A (en) * | 2010-06-04 | 2011-01-26 | 周佰兴 | Spiral corrugated pipe rubber ring |
| CN108036139A (en) * | 2017-12-21 | 2018-05-15 | 鹤山联塑实业发展有限公司 | A kind of new steel belt helical corrugation tube multifunctional jointing |
| CN110230741A (en) * | 2019-07-11 | 2019-09-13 | 芜湖泰和管业股份有限公司 | A kind of bellows of the hard seal nipple unit of corrugated stainless steel tubing and the application connector |
| CN110230741B (en) * | 2019-07-11 | 2023-08-22 | 芜湖泰和管业股份有限公司 | Stainless steel corrugated pipe hard sealing joint unit and corrugated pipe applying same |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| FZDE | Dead |