Cleaning and liquid contact with solids – Processes – Using solid work treating agents
Reexamination Certificate
2000-07-20
2002-04-09
Chin, Randall E. (Department: 1744)
Cleaning and liquid contact with solids
Processes
Using solid work treating agents
C015S104061
Reexamination Certificate
active
06368418
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tool and method for cleaning deposits, scale and other buildup on the inside surfaces of pipelines.
2. Description of the Prior Art
Petroleum, geothermal, sewage, and other pipelines utilized to conduct fluids often develop buildups of deposits, scale, and other materials on the inner wall surfaces of the pipes that make up the pipeline. Continued buildup of accretions on the walls of a pipeline reduces the volume of fluid that flows through the pipeline and increases the resistance to flow through the line. Eventually the opening through the center of the pipeline decreases in cross-sectional area to such a degree that cleaning of the pipeline is imperative in order for it to continue to be useful for the conduction of fluids.
In conventional practice, maintenance to unclog pipelines in which clogging deposits can be scoured by water alone may be performed by creating an opening in a pipeline and inserting a cleaning hose into the opening. The hose is directed toward a remote end of the section of pipeline to be cleaned. A cleaning liquid ejection nozzle is located at the end of the pipeline cleaning hose and is equipped with jets that are directed rearwardly back from the end of the hose. To clean the pipeline, the operative end of the cleaning hose that bears the jetting nozzle is inserted through the pipeline opening and into the pipeline. Water under pressure is then pumped through the hose. This water is emitted from the rearwardly directed jets at the operating end of the cleaning hose from the cleaning ejection nozzles. The water discharged through the jets is thereby directed back along the pipeline toward the opening through which these cleaning hose is inserted.
The jets of water under pressure ejected from the hose nozzle serve to propel the operating, ejection end of the cleaning hose further along the pipeline, away from the opening. Also, the jets scour the walls of the pipeline as the operating end of the hose is propelled along the pipeline. The pipeline cleaning hose is wound on a large hose spool or reel located near the opening in the pipeline. As the operating end of the cleaning hose propels itself along the pipeline, additional lengths of cleaning hose are fed off of the reel to permit the operating end of the cleaning hose to continue to travel along the pipeline, going ever further from the access opening.
In other situations the nature of the buildup on the interior walls of the pipeline is such that the application of water pressure alone is entirely inadequate to dislodge the accumulated build up. For example, the buildup of minerals and compounds on the inside of pipelines used in geothermal applications can rarely be removed by water pressure alone. A much heavier-duty pipeline cleaning system is required in such situations.
One conventional heavy-duty pipeline cleaning system that is currently in use to clean geothermal pipelines is operated by EP & Associates, located in California. This system involves a tool having a plurality of notched discs of increasing diameter mounted on its forward, or downstream end, and also radially outwardly directed rollers also located on the downstream end. On its upstream end the EP & Associates' tool employs a steel disc that has a plurality of short fingers or fins located about its periphery. This disc with its hinged fingers provides a backing for a disc-shaped Kevlar® seal located upstream therefrom.
The EP & Associates' pipeline cleaning tool also has significant operating problems. It requires a very high operating pressure, typically between five hundred and six hundred pounds per square inch of water to exert a force against the upstream surface of the Kevlar® disc to propel the tool through the pipeline. Also, this tool is subject to extreme damage as it advances through a clogged pipeline. It can typically be utilized to clean only about six hundred linear feet of a fourteen inch diameter pipeline before it must be rebuilt. Also, the pipeline has to be cut frequently since the tool becomes so degraded that it will not travel far before becoming hopelessly lodged in a pipeline having a heavy build up of clogging accretions.
SUMMARY OF THE INVENTION
The present invention involves a rugged pipeline cleaning tool that is constructed quite differently from prior pipeline cleaning tools and which has very important operating advantages. The pipeline cleaning tool of the present invention, like the EP & Associates' tool, is propelled by the application of water pressure to the upstream sealing face of the tool. Unlike the EP & Associates' tool, however, the pipeline cleaning tool of the invention requires an operating water pressure about 120-180 psi. This reduction in water pressure is possible due to the unique construction of the folding propulsion system. Furthermore, the pipeline cleaning tool of the invention can clean over two thousand feet of clogged, twenty inch diameter pipe before requiring any refurbishment of components. Also, the pipeline cleaning tool of the invention is able to clean pipe throughout a much greater range of diameters without requiring disassembly and reassembly of different components than has heretofore been possible. Moreover, when it is necessary to install larger diameter components on the tool, the disassembly and reassembly process takes only about ten minutes.
The pipeline cleaning tool of the invention is relatively simple in construction, yet is highly durable. Also, it requires far less time and manpower to operate than conventional pipeline cleaning tools.
In one broad aspect the invention may be considered to be a pipeline cleaning tool comprising: an elongated support member; a rigid cutting unit; a folding propulsion assembly; a rotation limiting barrier; and a backing seal. The elongated support member has opposing first and second ends. The rigid cutting unit has a periphery, preferably with cutting teeth thereon, and is secured proximate the first end of the support member. The cutting unit projects radially outwardly from the support member. The folding propulsion assembly includes a hub, a plurality of sector panels, and expansion flaps. The hub is secured to the support member proximate the second end thereof. The sector panels are arranged about the periphery of the hub and are each hinged separately thereto for rotation independently of each other about axes tangentially oriented relative to the periphery of the hub. Each of the sector panels has opposing upstream and downstream faces and first and second side edges. The side edges of the sector panels diverge radially outwardly from each other. In this way the sector panels fan radially outwardly from the hub and define gaps therebetween.
An expansion flap is provided for each of the sector panels. The expansion flaps extend the lengths of the first side edges of the section panels and are hinged thereto. In this way the expansion panels bridge the gaps and overlap portions of the upstream faces of the sector panels immediately adjacent the sector panels to which they are hinged. The rotation limiting barrier is anchored to the elongated support member to prevent rotation of the sector panels past the hub in one direction of rotation relative thereto, and to permit free rotation of the sector panels relative to the hub in an opposite direction relative thereto. The backing seal is a disc-shaped structure formed of a flexible, water impervious material and anchored to the elongated support member on a side of the hub opposite the rotation limiting barrier.
The cutting unit may be formed of a flat, disc-shaped metal plate serrated at its outer periphery to form radially projecting cutting teeth. In many instances it is necessary to propel the cleaning tool of the invention through a section of pipe to be cleaned several times if the build up on the interior pipe wall is quite hard. This is because only a portion of the buildup can be removed in a single pass. When several passes of the tool through
Chin Randall E.
Thomas Charles H.
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