Internal pipe seal

A pipe sealing assembly for sealing a connection between a pair of pipes. The sealing assembly includes a generally cylindrical seal or gasket having a pair of axially spaced sealing portions joined by a bridge portion. Each sealing portion has a plurality of compressible sealing ridges, as well as an annular expansion band seat capable of receiving the expansion band of an expansion band assembly that is used to sealingly compress each sealing portion against a respective inner surface of a pipe. Additionally, each sealing portion may include a hollow section which houses the expansion band assembly, and may be provided with a small slit for installing the expansion band assembly and allowing access to the expansion mechanism of the expansion band assembly during installation, or a separate cover member for enclosing the expansion band assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an internal sealing assembly for sealingly connecting a pair of pipes and, in one embodiment, relates to a secondary sealing assembly that can be installed within an existing pipeline about an existing pipe-to-pipe connection to seal a leak.

2. Description of the Related Art

Underground pipes which are used in municipal water and sewer systems, for example, typically include bell and spigot ends that are attached to one another in a sealed manner. Typically, either the spigot end or the bell end of such pipes includes a rubber seal which is compressed between the ends of the pipes to provide a sealed joint when the spigot end of one pipe is inserted into the bell end of another pipe. Occasionally, these primary joint seals between adjacent pipes may leak after installation in the field, requiring a secondary sealing assembly to seal the connection.

What is needed is an improved sealing assembly for sealing pipe-to-pipe joints.

SUMMARY OF THE INVENTION

The present invention provides a pipe sealing assembly for sealing a connection between a pair of pipes. The sealing assembly includes a generally cylindrical seal or gasket having a pair of axially spaced sealing portions joined by a bridge portion. Each sealing portion has a plurality of compressible sealing ridges, as well as an annular expansion band seat capable of receiving the expansion band of an expansion band assembly that is used to sealingly compress each sealing portion against a respective inner surface of a pipe. Additionally, each sealing portion may include a hollow section which houses the expansion band assembly, and may be provided with a small slit for installing the expansion band assembly and allowing access to the expansion mechanism of the expansion band assembly during installation, or a separate cover member for enclosing the expansion band assembly.

In one form thereof, the present invention provides a sealing assembly, including a cylindrical seal, including a pair of axially-spaced, annular sealing portions, each sealing portion including an expansion band seat and a wall section defining an annular hollow space proximate the expansion band seat; and a bridge portion joining the sealing portions; and a pair of expansion band assemblies respectively received within the hollow spaces, each expansion band assembly including an expansion band, the expansion bands respectively received within the expansion band seats; and an expansion mechanism.

In another form thereof, the present invention provides a sealing assembly, including a cylindrical seal, including a pair of axially-spaced, annular sealing portions, each sealing portion including an expansion band seat and a separate cover member attachable to the sealing portion to define an annular hollow space proximate the expansion band seat; and a bridge portion joining the sealing portions; and a pair of expansion band assemblies respectively received within the hollow spaces, each expansion band assembly including an expansion band, the expansion bands respectively received within the expansion band seats; and an expansion mechanism.

DESCRIPTION OF THE INVENTION

Referring to FIGS.1and2A-D, four different embodiments of sealing assembly10of the present invention are shown. Except as discussed below, each sealing assembly10a-10dincludes a number of identical or substantially identical components, and identical reference numerals will be used throughoutFIGS. 2A-Dto designate identical or substantially identical components therebetween.

Each sealing assembly10includes a generally cylindrically shaped seal12having pair of axially spaced sealing portions14connected by a bridge portion16. Bridge portion16may include one or more undulations as shown in order to permit movement of sealing portions14toward and away from one another along their common axis, i.e., an axis passing through the center of seal12. Seal12may be made of extruded rubber, for example, in a manner in which a length of rubber section is extruded, and then is cut to a predetermined length, followed by splicing the ends of the section together to form the cylindrical seal12. Seal12may also be made of a resilient plastic material by an injection molding process, for example.

Each sealing portion14includes a plurality of sealing ridges18that are compressible against the internal surface of a pipe to provide a fluid tight seal. Additionally, each sealing portion14further includes an annular expansion band seat20, shown herein as an annular recessed area of sealing portions14, for receiving an expansion band of an expansion mechanism, as discussed below.

Additionally, as shown with respect to the embodiments ofFIGS. 1,2A and2C, each sealing portion14may also be provided with a thin wall section22defining an annular hollow section24in the sealing portion14which accommodates the expansion band and the expansion mechanism of the expansion band assembly. As discussed below, the thin wall section22may include a small slit23for installation of the expansion band and expansion mechanism and for accessing the expansion mechanism during installation for sealingly compressing the sealing portion12into fluid tight engagement with the interior surface of the pipe.

Expansion band assembly26may be, for example, of the type disclosed in U.S. Pat. Nos. 6,805,359 and 7,146,689, each assigned to the assignee of the present invention, the disclosures of which are expressly incorporated herein by reference. Each expansion band assembly26generally includes an expansion mechanism28operable to expand the diameter of an expansion band30of the expansion band assembly26to radially outwardly to compress a sealing portion14against the inner surface of a pipe. In particular, as best shown inFIG. 1and discussed in the above-incorporated U.S. Pat. Nos. 6,805,359 and 7,146,689, each expansion mechanism28generally includes a bolt32having oppositely-threaded ends and a central nut33. The oppositely-threaded ends of bolt32are threadingly received within a pair of oppositely-threaded block members34which are in engagement with the opposite ends30aand30bof expansion band30. In use, nut33of bolt32is engaged by a suitable tool to rotate bolt32and drive block members34apart from one another to thereby expand the diameter of expansion band30to radially outwardly compress a sealing portion14of seal10into tight engagement with the inner surface of a pipe.

In use, referring additionally toFIG. 3in which seal assembly10ais shown as an example, seal assembly10may be used to seal a defective primary seal in a pipe-to-pipe connection between pipes40and42, such as the connection between spigot end44of pipe40and socket end46of pipe42in which a primary seal (not shown), formed in an annular groove48of spigot end44of first pipe40, is ineffective. Alternatively, seal assembly10may be used a primary seal to seal pipes40and42upon initial connection and installation of pipes40and42.

Seal12is placed within the pipes40and42such that one sealing portion14is positioned adjacent spigot end44of pipe40and the other sealing portion14is positioned adjacent socket end46of pipe section42, with bridge portion16of seal12bridging the gap between pipes40and42. Thereafter, expansion mechanisms28of expansion band assemblies26are actuated in the manner described above to outwardly radially compress sealing portions14and their sealing ridges18of seal12into fluid tight sealing engagement with the inner surfaces50of pipes, respectively, thereby providing a fluid tight seal between pipes40and42.

In the embodiments in which sealing portions14include thin wall sections22, one or more slits23may be formed, or may be cut in the field, in wall sections22which allow for expansion bands30and expansion mechanisms28of expansion band assembly26to be slidably inserted within annular hollow sections24. The slit23may be disposed adjacent an expansion mechanism28to allow access to expansion mechanism28during installation to effect the seal as described above. Each slit23may extend around only a portion of the circumference of its wall section22, such as around as little as 5°, 10°, or 15°, or as great as 30°, 60°, 90° or more, for example, of the circumference of wall sections22, or alternatively, may extend around the entire circumference of wall sections22.

The adjacent portions22aand22bof thin wall sections22defined by slits23may be disposed in tight abutting end-to-end contact with one another, as shown in the embodiment ofFIG. 2A, for example, or may overlap one another, as shown in the embodiment ofFIG. 2C, for example, in order to minimize or prevent fluid entry into hollow sections24. Further, as shown inFIG. 3, the slits23may be optionally disposed on a side of sealing portions14opposite a direction of fluid flow along arrow A, such as at location23a,for example, to minimize or prevent fluid entry into hollow sections24. Also, the expansion mechanisms28may be positioned at the upper end of the pipes40and42which are normally above the fluid level of the pipes to prevent or eliminate fluid entry into hollow sections24.

Sealing assemblies10for small diameter pipes, such as up to 24 inches, may include one expansion mechanism28, while sealing assemblies10for larger diameter pipes, such as greater than 24 inches, may include more than one expansion mechanism28, as needed.

Referring toFIGS. 4A-C, sealing assemblies10e-faccording to further embodiments are shown, which, except as described above, are installed and function in the same manner as the embodiments discussed above, and identical reference numerals are used to identify identical or substantially identical components therebetween.

Sealing assembly10eofFIG. 4Aincludes a ramp portion52at each of the ends of sealing portions14thereof to aid in directing a smooth or laminar flow of liquid within pipes40and42over and around the sealing assembly.

Sealing assembly10fofFIG. 4Bincludes ramp portions52at each of the ends of sealing portions14thereof similar to sealing assembly10eofFIG. 4A, and also includes thin wall sections54similar to thin wall sections22of the embodiments discussed above, wherein thin wall sections54are also ramped complementary with ramp portions52to aid in directing the flow of liquid within pipes40and42over and around the sealing assembly.

Sealing assembly10gofFIG. 4Cincludes a pair of separately extruded, or otherwise separately formed, annular cover members56each having a pair of barbed ends58for snap-fitting engagement with a pair of respective grooves60in sealing portions14of sealing assembly10gthat are disposed in either side of the expansion band seats20. Cover members56are also ramped complementary with ramp portions52to aid in directing the flow of liquid within pipes40and42over and around the sealing assembly. In use, either before or after the seal10of sealing assembly10gis extruded, the expansion bands30and expansion mechanisms28are assembled in place, and an amount of adhesive, such as a liquid solvent adhesive, is applied within grooves60in sealing portions14. Thereafter, barbed ends58of cover members56are snap-fitted within grooves60to initially retain cover members56in place, covering expansion bands30and expansion mechanisms28until the adhesive cures to provide a more permanent connection of cover members56to sealing portions14.

Cover members56may also include slits, such as slits23described above, adjacent expansion mechanisms28for allowing access to expansion mechanisms during installation. Alternatively, cover members56that lack such slits may be secured to seal12in the manner described above after expansion mechanisms28are actuated following installation to thereby seal expansion mechanisms28within sealing assembly10gin a fluid tight manner.