The present invention is directed to a restrained pipe joint and method of making same and, more particularly, to a pipe joint including a gasket containing locking segments configured for preventing the separation telescoping plastic pipes during fluid pressurization.
Pipe joint gaskets including anti-slip segments for preventing the separation of interconnected, telescoping metal pipes in applications where a fluid such as water for fire mains is held under high pressure are known in the art. Exemplary gaskets are described in U.S. Pat. Nos. 5,295,697 and 5,464,228 in which a rubber gasket, serving as a fluid seal, includes toothed metal segments spaced around its inner perimeter. The toothed metal segments bite into the outer surface of the spigot of the inserted pipe and prevent withdrawal of the inserted pipe from a bell end of the other pipe. A shortcoming of such gaskets is that during fluid pressurization of the interconnected pipes, excessive axial thrust force generated by the resulting hydrostatic pressure can cause the metal segments to exert destructive radial loads upon the inner axial surface of the bell end and the outer axial surface of the spigot end. In many instances, these radial loads are great enough to fracture the spigot and bell ends of the metal pipes.
Since anti-slip segments are known to destructively impinge upon metal pipes, the use of gaskets containing such or similar segments for preventing the separation of interconnected plastic pipes has been limited, especially in high pressure applications. Instead, plastic pipes, such as those formed from thermoplastic materials including polyethylene, polybutylene, polypropylene and poly(vinyl chloride) or PVC, are joined together by means of a bell-and-spigot gasket-sealed joint utilizing gaskets referred to as Reiber gaskets.
A Reiber gasket consists of a continuous steel band either externally or internally bonded to an elastomer annular body. The Reiber gasket is locked into place within an annular groove of the bell and functions to prevent the gasket from becoming dislodged therefrom. The Reiber gasket fails however to sufficiently restrain axial separation of plastic pipes along a joint upon fluid pressurization of the pipe at high pressure. Accordingly, there is a need for a gasket that is capable of forming a seal between plastic pipes, while preventing separation of the pipes at high pressure.
The present invention is directed to a gasket for preventing the separation of a pipe joint formed between plastic pipes such as pipes manufactured from PVC. The invention is based upon the discovery that gaskets containing metal locking segments can form seals between joined plastic pipes and prevent separation of the pipes upon pressurization without the metal segments destructively impinging upon the pipes. According to one aspect of the invention there is provided a restrained pipe joint including a first pipe including a bell with a spigot entryway and a substantially V-shaped annular groove. The annular groove includes a front radial wall and a rear radial wall and a gasket seated in the annular groove. The gasket includes an inner radial face, an opening defined by the inner radial face and an outer radial face with a front radial section located adjacent to the front radial wall of the annular groove and a rear radial section located adjacent to the rear radial wall of the annular groove. The gasket also includes a sealing portion having an indentation formed between a pair of arms extending away from the spigot entryway of the first pipe.
A plurality of restraining segments is at least partially embedded in the gasket. Each restraining segment includes an inner wall having a first tooth extending towards the opening in the gasket, an outer wall having a second tooth extending towards the front radial wall of the annular groove and a nose portion formed by an intersection of the inner wall and the outer wall. The nose extends towards the spigot entryway and into a space defined between the spigot and the front radial wall of the annular groove, a tip of the nose being located forward of the first tooth and the second tooth. The first tooth and the second tooth are arranged to impinge upon the spigot and the front radial wall of the annular groove, respectively, upon pressurization of the pipe joint. This occurs without the nose impinging upon the annular groove or the spigot.
According to another aspect of the invention there is provided a method of forming a restrained pipe joint. The method includes providing a first plastic pipe having a bell with an annular groove, the annular grove including a gasket, a front radial wall and a rear radial wall, inserting a spigot of second plastic pipe into the bell and through an opening of the gasket, impinging a first tooth of a restraining segment against the spigot and a second tooth of the restraining segment against the front radial wall and wedging a nose portion of the restraining segment between the bell and the spigot.
According to yet another aspect of the invention, there is provided a plastic pipe including a bell including an annular groove with a front radial wall and a rear radial wall. A gasket is seated in the annular groove, the gasket including an inner radial wall defining an opening through the gasket and an outer radial wall. One or more restraining segments are at least partially embedded in the gasket, each restraining segment including an inner face from which a first row of teeth extends towards the opening of the gasket and outer face from which a second row of teeth extends towards the front radial wall of the bell. The inner wall and the outer wall of the restraining segment define respective planes that intersect one another at an angle of about 40° to about 50° to form a rounded nose, the inner wall, the nose and the outer wall forming an essentially V-shaped cross-section.
The present invention is directed to a restrained pipe joint formed between plastic pipes. Generally, the pipe joint includes a bell end 10 of a first plastic pipe 11, a gasket 12 seated within bell end 10 and a spigot end 14 of a second plastic pipe 13 inserted through gasket 12, gasket 12 forming a seal between pipes 11 and 13. Locking segments 16 are embedded within and circumferentially arranged around gasket 12. Locking segments 16 are arranged to impinge upon pipes 11 and 13 upon pressurization of the pipe joint thereby restraining axial movement of spigot end 14 out of bell end 10. To prevent over-impingement of locking segments 16 into pipes 11 and 13 and further resist axial separation of the pipes, locking segments 16 each include a rounded nose portion 18 that, upon pipe pressurization of the pipes, functions as a wedge between pipes 11 and 13. The foregoing is accomplished without the use of a joint gasket gland or a Reiber gasket.
More particularly, as illustrated in
Gasket 12 is composed of an annular rubber body having a generally triangular cross-section defined by front outer face 20, rear outer face 22 and an inner face 24. As depicted in
Inserted into gasket 12 are locking segments 16. As depicted in
Referring to
Referring to
Referring to
As a consequence of pressurization of the pipe joint and translation of segments 16 and gasket 12 distally, the proximal sealing portion of the rubber body of gasket 12, which is formed in part by third corner portion 30, is moved from a section of the annular retainer groove having a smaller volume to a larger volume. This occurs because the distance between rear radial wall 17 of the annular groove and spigot end 13 increases gradually moving distally. Despite the distal movement of third corner portion 30 of gasket 12 from a smaller volume to a larger volume section of the annular groove, which causes some decompression of the third corner portion, the sealing engagement between pipes 11 and 13 along the third corner portion is maintained since arms 34, being biases outwardly, press against rear radial wall 17 and spigot end 13 by virtue of the flared configuration of the arms.
As will be apparent to one skilled in the art, various modifications can be made within the scope of the aforesaid description. Such modifications being within the ability of one skilled in the art form a part of the present invention and are embraced by the claims below.
Number | Name | Date | Kind |
---|---|---|---|
4030872 | Parmann | Jun 1977 | A |
5213339 | Walworth | May 1993 | A |
5295697 | Weber | Mar 1994 | A |
5464228 | Weber | Nov 1995 | A |
5988695 | Corbett, Jr. | Nov 1999 | A |
6105972 | Guzowski | Aug 2000 | A |
6688652 | Holmes, IV et al. | Feb 2004 | B2 |
7284310 | Jones et al. | Oct 2007 | B2 |
7401791 | Andrick et al. | Jul 2008 | B2 |
7461868 | Allen | Dec 2008 | B2 |
7537248 | Jones | May 2009 | B2 |
7774915 | Darce | Aug 2010 | B2 |
7784798 | Walworth et al. | Aug 2010 | B2 |
7815225 | Jones et al. | Oct 2010 | B2 |
7845686 | Steinbruck | Dec 2010 | B2 |
8096585 | Vitel | Jan 2012 | B2 |
8235427 | Jones et al. | Aug 2012 | B2 |
8444186 | Jones | May 2013 | B2 |
8490273 | Copeland et al. | Jul 2013 | B1 |
8511690 | Holmes, IV et al. | Aug 2013 | B2 |
8511691 | Holmes, IV et al. | Aug 2013 | B2 |
8533926 | Holmes, IV et al. | Sep 2013 | B2 |
8544851 | Holmes, IV et al. | Oct 2013 | B2 |
8857861 | German | Oct 2014 | B2 |
8870188 | Holmes, IV et al. | Oct 2014 | B2 |
9057467 | Copeland et al. | Jun 2015 | B2 |
9400071 | Copeland | Jul 2016 | B1 |
9400073 | Lopez-Chaves | Jul 2016 | B2 |
9593787 | Monteil et al. | Mar 2017 | B2 |
20060119100 | Jones | Jun 2006 | A1 |
20080018104 | Walworth et al. | Jan 2008 | A1 |
20090060635 | Jones | Mar 2009 | A1 |
20100078937 | Jones | Apr 2010 | A1 |
20100225111 | Owen | Sep 2010 | A1 |
20120025471 | Andrick et al. | Feb 2012 | A1 |
20130043656 | Copeland et al. | Feb 2013 | A1 |
20130113208 | Liao | May 2013 | A1 |
20140339773 | Holmes, IV et al. | Nov 2014 | A1 |
20140374994 | Monteil | Dec 2014 | A1 |
20140374995 | Monteil | Dec 2014 | A1 |
20150204468 | Jones | Jul 2015 | A1 |
20160245436 | Monteil | Aug 2016 | A1 |
20170370505 | Copeland | Dec 2017 | A1 |
Number | Date | Country | |
---|---|---|---|
20170328503 A1 | Nov 2017 | US |