Pipes and tubular conduits – Repairing
Reexamination Certificate
2000-08-25
2001-09-18
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
Repairing
C138S094000, C138S089000
Reexamination Certificate
active
06289935
ABSTRACT:
BACKGROUND
1. Technical Field
This invention relates to plumbing devices for preventing the flow of water in pipes, and more particularly, to a test plug device for sealing drainpipes.
2. Related Art
Devices for plugging pipes into prevent the flow of water are commonly used when testing pipe systems for leaks in homes, apartments or other buildings. When testing for leaks, the main drainpipe in a building is typically sealed or plugged via a side opening or clean-out pipe attached to the main drainpipe at a point near the main sewer line that serves the building. The building's pipe system is then typically pressurized by filling the system with water. The pressurized system is then inspected for leaks. Following completion of leak inspections, the device used to seal or plug the drain is removed to drain the water from the pipe system.
One type of plug device used to seal drainpipes is an inflatable cylindrical plug that is inserted into a drainpipe, and then pressurized with either air or water to block the flow of water within the drainpipe by expanding to completely seal the pipe. However, the pressure in a piping system filled with water increases in direct proportion to the height of the piping system. Consequently, devices used to seal main drainpipes in buildings must withstand an increasing amount of pressure as the height of the building increases. Inflatable cylindrical plugs are limited as to the external pressure they may withstand. As the pressure in a drainpipe begins to exceed the pressure within the inflatable plug, the plug will tend to compress, thereby allowing water to flow within the drainpipe. Increasing the pressure in the inflatable plug to compensate for increased pressure within the pipe increases the risk of rupture of the inflatable plug. Further, such devices tend to bleed pressure over time, thereby again allowing water to flow within the drainpipe. Consequently, the utility of such devices tends to be limited by the height of the piping system in which they are used, the pressure within that system, and the length of time that the device is pressurized.
Other devices have been developed that involve the use of solid plugs to seal or plug a drainpipe. Various mechanisms have been used to position such plugs within a drainpipe, and to hold the plugs in place when they are exposed to pressure in the drainpipe. For example, one device uses an elliptical plug coupled to an arm that is bolted to a cap, which in turn is coupled to the open end of a straight pipe. However, because this device is designed for use with a straight pipe it is not useful for plugging a pipe via a side opening or clean-out pipe attached to the main drainpipe.
Another device uses a solid plug that is inserted into a T, or 90-degree opening in the side of a pipe. A locking lever arm coupled to the plug is used to position the plug within the drain, and to lock the plug into position during use. However, as with the previously mentioned solid plug device, this device is not useful for plugging a pipe via a drain clean-out where the clean-out is at an angle other than approximately 90 degrees to the main drainpipe.
Therefore, in order to overcome the limitations of current pipe plug devices, what is needed is a plug device that is capable of withstanding increased pressure within a drainpipe for any desired length of time. Further, such a plug device should have the capability of being easily inserted through a drain clean-out or any other side opening to plug the drainpipe. Finally, such a plug device should be simple, capable of being easily fabricated and used, and should be inexpensive and durable.
SUMMARY
The present invention involves a new device for plugging a drainpipe via an opening such as a drain clean-out or any other side opening. This device satisfies all of the foregoing needs. The drainpipe test plug device of the present invention is capable of being easily inserted through an opening in a drainpipe to plug the drainpipe. Further, the drainpipe test plug device is capable of maintaining a seal against fluid pressure in a piping system for any desired length of time without bleeding or leakage past the drainpipe test plug device. In addition, the drainpipe test plug device is adapted for use with a range of sizes of pipes by using a plug sized to for the pipe under test. Finally, the drainpipe test plug device can be easily and inexpensively fabricated, preferably having rigid or semi-rigid members of metal, plastic, or ceramic and a flexible plug of a durable rubber, plastic, or silicon compound.
A drainpipe test plug device according to present invention has a plug or seal that is rotatably coupled to a pivot arm, which is in turn rotatably coupled to a lever arm or handle for positioning the drainpipe test plug device within a drainpipe. Consequently, the plug is capable of rotating about two axes simultaneously to effect a seal within the drainpipe. In addition, a brace coupled to the lever arm provides a positive stop for locking the plug into a sealing position within the drainpipe by stopping the rotation of the pivot arm. In one embodiment, a positioning arm may be coupled to the plug for rotating and positioning the plug within the drainpipe during use.
In further embodiments of the drainpipe test plug device, a latch is coupled to either or both the lever arm and the positioning arm to allow for a controlled pressure release when disengaging a seal in a pipe under pressure. This controlled pressure release is achieved by disengaging a first portion of the plug from the interior wall of the drainpipe to break the seal between the plug and the interior wall while maintaining a second portion of the plug in contact with the interior wall of the drainpipe. Either or both of the latches are used to limit the rotation and displacement of the plug relative to the interior wall of the drainpipe to effect the controlled release of pressure.
The lever arm is a rigid or semi-rigid member preferably formed of metal, a high-density polymer, ceramic, or other suitable material. The lever arm is used to insert the plug into the drainpipe, manipulate the plug within the pipe, and support the pivot arm and plug against pressure within the pipe. The lever arm has a brace on one end for bracing the pivot arm as the pivot arm locks into place during use. As the plug rotates into a sealing position during use, the pivot arm simultaneously rotates through 90 degrees relative to the lever arm and locks into place against the brace. The brace is preferably integral to the lever arm. However, in an alternate embodiment, the brace is coupled to the lever arm using conventional methods such as, for example, bolts, welds, rivets, adhesives, or screws.
The pivot arm is rotatably attached to the lever arm to allow the plug to rotate about the lever arm. Further, because the plug is rotatably connected to the pivot arm, the plug also rotates about the pivot arm. Consequently, the plug is capable of rotating about the lever arm and the pivot arm simultaneously. As a result, the plug is capable of rotating into position to form an effective seal within the pipe.
The plug is designed to seat securely within the interior walls of a pipe, and may be circular, elliptical, or any other shape sufficient to completely seal the pipe when the plug is locked into place during use. The plug is capable of forming a mechanical seal with the pipe. Further, once the mechanical seal is formed, the lower surface of the plug is supported by the pivot arm, which is in turn locked into position against the brace as described above. Consequently, as pressure is applied to the upper surface of the plug from within the pipe during use, the plug compresses longitudinally, thereby expanding radially against the internal walls of the drainpipe to further improve the seal within the pipe. Additionally, the pressure applied to the upper surface of the plug also tends to cause a rotational force in the pivot arm in the direction of the brace. Therefore, pressure applied to the plug tends to force the pivot
Brinson Patrick
Lyon Richard
Lyon, Harr & DeFrank
Watson Mark
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