Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-12-31
2001-03-27
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S287000, C156S294000, C264S269000, C264S573000
Reexamination Certificate
active
06206993
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates generally to the lining of pipes with a tubular material and, more particularly to the relining of a particular portion of a pipe.
The most common underground pipeline is a sewer pipe which conveys wastewater from residences and industry through a wastewater collection system to a wastewater treatment facility. Sewers are often buried underground and located underneath streets and roadways. Portions of the sewer system may become cracked or broken over time due a number of factors. Shifting of the earth, secondary surface loadings and weather conditions are examples of external factors which may affect the integrity of sewer pipes as well as other subterranean pipes. These external factors may result in broken pipe sections which compromise the ability and effectiveness of the sewer system to accomplish its collection and conveyance functions of wastewater.
Apart from the external factors set forth above, sewers and other pipelines may also have their effectiveness compromised by internal factors. For example, the inner surface of a sewer pipe may become eroded or roughened from continuous contact with wastewater and abrasive material suspended therein. Erosion of the interior surfaces of any fluid-conveying pipe results in an increase in the pipe's roughness coefficient. This coefficient is a measure of the resistance to fluid flow by the pipe. The greater the roughness coefficient, the greater the head loss experience by fluid passing through the pipe. Eroded pipes therefore make it more difficult to convey wastewater than pipes as originally designed and installed. This problem may be cured by relining or replacing the sewer pipe. Sewer pipes need to be replaced or relined on a regular schedule in order to reclaim the original design parameters of the sewer system.
It is known in the art that the above problems may be effectively cured by replacement or repair of the compromised portion of sewer pipe. Excavation of the area surrounding the sewer pipe and replacement of the broken portions is one solution, but it is a very expensive and labor intensive solution. This type of repair is also an inconvenience to residents living in the area and utilizing those roadways overlying the compromised area.
Another solution which is less expensive in labor and intensive is in situ relining of the sewer pipes. In situ relining methods typically utilize a resin-coated liner which is inserted into the existing sewer pipeline and unrolled against the sewer pipe. The unrolled liner is held against the existing sewer pipe while the resin cures to form a new pipe lining within the existing pipe which provides a new and relatively smooth interior surface having a low roughness coefficient which rivals or better than that of the original sewer pipe. These type liners also protect the existing pipe from attack by many chemicals found in wastewater fluid and reinforces the existing pipe to existing subterranean external loads imposed upon the pipes. These relining methods are well described in the patent literature.
One such relining method is described in U.S. Pat. No. 4,876,921 and utilizes a plastic liner known as the NuPipe®. The NuPipe® liner is an extruded thermoplastic sleeve which is heated to soften the liner and pulled through the sewer pipe. A rounding device is then propelled through the plastic liner to force the liner outwardly against the existing pipeline. This type of relining process is costly and the liner does not expand to a significantly large degree so that the installer needs to have a variety of different diameter liners on hand as inventory to effectively match the inner diameters of existing pipes.
Other methods described in the patent literature include the use of a woven textile liner laminated with multiple resin coatings. This type of liner and its method of installation of this type liner are described in U.S. Pat. No. 4,600,615, which issued Jul. 15, 1996, which discloses a pipe relining material consisting of a woven, air-impervious textile jacket which has an outer resin coating consisting of multiple polyester resin layers laminated to each other. These woven liners are inserted into an existing sever pipe and inflated against the existing sewer pipe walls by fluid pressure. Because of their woven construction, these lines do not significantly expand against the existing pipe walls and therefore the installer needs to carry a large amount on inventory on hand to fit the diameter of the pipe being repaired.
The patents identified above all describe liners which are commonly installed in pipes and extend from one accessway, or manhole, to another accessway. The length of the subterranean pipeline between these opposing accessways may range anywhere from 50 to 500 feet. Quite often, in such a large extent of pipe only one particular section of the pipe is compromised and needs to be relined. The prior art does not suggest an effective means of spot repair, i.e., repairing only the compromised section of the pipe, but rather suggests either relining the entire length of the sewer pipe or relining the sewer pipe from the nearest accessway to the compromised pipe section. Either of these two approaches results in an increased repair cost and usage of more relining material than is necessary.
The present invention therefore concerns itself with an apparatus and a method for reliably performing such spot repairs, in which only the compromised pipe section is repaired. The present invention represents a significant advancement over the prior art in that it permits the insertion into the existing pipe of a preselected length of a new pipe lining material and conveyed through the pipe until the lining material is located adjacent the compromised section pipe. The lining material is subsequently contacted against the inner surface of the existing pipe to form a new lining at the compromised pipe section only. By reliably locating the new liner material proximate to the compromised section and retaining it in place while the new lining material is cured in place, the present invention significantly reduces the expense and time and labor required to perform such spot repairs. Additionally, the present invention provides for the introduction into an existing pipeline of a pipe lining material which is impregnated with resin in a “clean” fashion, in which the risk of either contamination of the resin or contact between the resin-impregnated liner and the existing pipe or the individuals installing same is substantially eliminated. It further allows for accurate positioning of the new lining material at the compromised pipe section.
In accordance with one principal aspect of the present invention, a new pipe lining material is impregnated with a curable resin and is held in place within a carrier which conveys the resin-impregnated lining material to the compromised pipe section without contacting the walls of the existing pipe which might remove resin therefrom during positioning of the lining material within the pipe. A flexible envelope, or inflation bladder, which forms an extension of the carrier and provides a support for the lining material during installation when the lining material is everted out of the carrier. This flexible envelope expands radially under fluid pressure as it everts axially out of the carrier and into contact with the pipe wall inner surface.
In another principal aspect of the present invention, the lining material is attached to the inflation bladder by means of a frangible connection which fixes the position of the lining material with respect to the carrier the compromised pipe section. This frangible connection has a strength sufficient to withstand the eversion of the lining material out of the launching device, yet is weak enough to break after the lining material has cured and the carrier is removed from the pipe. This frangible connection permits the flexible envelope to anchor the tubular lining in position during installation and support it in place within the com
Kiest, Jr. Larry W.
VanAmeyde Gary
Ball Michael W.
LMK Enterprises, Inc.
Piazza Gladys
Vedder Price Kaufman & Kammolz
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