Cleaning and liquid contact with solids – Processes – Hollow work – internal surface treatment
Reexamination Certificate
2001-02-07
2003-04-22
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Processes
Hollow work, internal surface treatment
C134S022120
Reexamination Certificate
active
06550486
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for scarifying the interior surface of a pipe or other similar elongated passageway.
BACKGROUND OF THE INVENTION
Pipes used to carry liquids and gases commonly transport all types of materials including water, natural gas, solid and liquid sewage, as well as various other accumulations from the pipe.
The interior surface of a pipeline carrying solids, liquids and gases generally degrades over time as the pipe walls interact chemically and physically with the substances flowing through them. Over time, these pipes require servicing and cleaning.
In particular, a sewer system's interior walls corrode and deteriorate because corrosive materials contaminate the surface degrading the metal and concrete used to build the sewer. The corrosive material arises from both the sewage and wastewater itself, and also from the digestive by-products of bacteria found in the sewage that proliferate in the anaerobic environment. The corrosion causes the walls of the sewer pipe to physically decay, eventually reducing their overall thickness.
The principal source of corrosion is sulfuric acid, which arises as a product of the materials transported in a sewer pipe and the sewer environment itself. Various metal sulfates found in the sewage quickly convert into hydrogen sulfide by: reducing to sulfide ions in the waste water, combining with hydrogen in the water and outgassing above the liquid as hydrogen sulfide gas. Additional hydrogen sulfide originates from bacteria containing contaminants that accumulate on the relatively rough concrete below the maximum liquid level. Bacteria found in these accumulations thrive in the anaerobic sewer environment producing hydrogen sulfide gas as a respiratory bi-product. Oxygen from the liquid below and oxygen condensing from the water in the air react with the hydrogen sulfide on the pipeline walls creating the highly corrosive sulfuric acid. The sulfuric acid attacks the calcium hydroxide in the concrete sewer walls leaving calcium sulfates, which ultimately crumble and fall off of the interior of the wall substantially reducing its thickness.
The waste water level varies over the course of a 24-hour period. The flow is at its lowest level between 1:00 AM and 6:00 AM in the morning but it rises distinctly in the daytime and the pipe may operate near capacity. Because of the gaseous nature of the hydrogen sulfide, the pipe walls are predominately corroded in the portions of the wall above the minimum liquid level. Portions of:the walls which are always below the water level are not subjected to such high concentrations of hydrogen sulfide gas or sulfuric acid and consequently do not experience the same levels of decay.
Eventually the sewer walls must be restored or they can suffer permanent damage leading to great expense. The restoration process is a two-step operation that consists of first scarifying the interior surface of the pipe and then applying a protective coating over the newly scarified pipe surface. Scarifying involves the removal of all of the contaminants and the outer layer of corrupted concrete from the interior surface of a sewer pipe or other elongated passageway.
Attempting to apply a protective coating without first scarifying the pipe surface is futile because it does not stop the decay that has already began underneath the coating. Furthermore, the protective coating itself does not adhere well to the contaminated surface. Thus, scarifying is an essential element of the restoration process.
As previously mentioned, a sewer system typically operates at high capacity during the day with decreasing flow overnight. In order to restore the sewer pipes without diverting the flow (a costly and sometimes impossible alternative), a bulk of the work must be done at night during the brief period when the flow is at a minimum. As previously outlined, the restoration process involves both scarifying the pipe surface and applying a protective coat. In practice, the rate of restoration is impaired because manual scarification takes a proportionally greater amount of time than does the application of the protective coat.
Consequently, it is an object of this invention to provide a new and improved scarifying apparatus. Such an apparatus will improve the rate of scarifying of the pipeline's interior walls making restoration without diversion a cost-effective possibility.
It is another object of this invention to provide a scarifying apparatus to automate the process of scarification to ensure that the same intensity of scarification is applied to the entire surface without the quality variation that is inherent in manual execution.
SUMMARY OF THE INVENTION
These and other objects of the invention are provided in a new and improved scarifying apparatus. In general, references to pipe include a sewer pipe or other similar elongated passageway. As described in the background, scarifying involves the removal of all contaminants and the outer layer of corrupted concrete from the interior surface of a pipe.
The scarifying apparatus of this invention includes a vehicle that is capable of traversing the interior of a pipe and a scarifying assembly removably secured to the vehicle. As the vehicle moves, the scarifying assembly scarifies a selected region of the interior surface of a pipe.
In general, the scarifying assembly may include a fluid coupler having a flow control valve coupled between a source of pressurized fluid and a fluid nozzle. The fluid nozzle may direct a jet of pressurized fluid against the interior surface of a pipe.
The scarifying assembly may further include an arm mounted at one end to the vehicle chassis, a fluid nozzle assembly rotatably mounted to the arm, and an exchanger coupled between the fluid coupler and the fluid nozzle assembly.
The scarifying assembly arm and/or fluid nozzle assembly may be adjustable so as to position that fluid nozzle assembly in proximity to the interior surface of a pipe. The exchanger may distribute fluid from the fluid coupler to the various components of the fluid nozzle assembly.
The fluid nozzle assembly may further comprise a plurality of branches that may be rotatably attached to the exchanger. The branches may be rotatable about a common axis and may conduct fluid from the exchanger. Each of the branches may be equipped with at least one fluid nozzle. The fluid nozzles may be operative to receive pressurized fluid from the branches and expel it against the interior surface of a pipe.
The scarifying apparatus is adaptable to scarify the interior surface of a pipe in many different fashions. A first scarifying assembly is adjustable so that one of the scarifying assembly arm and/or the fluid nozzle assembly is positionable so as to locate the fluid nozzles adjacent to the interior surface of the pipe and to scarify a longitudinal swath of the interior of a pipe in a direction of travel of the vehicle.
Alternatively, the scarifying assembly arm and/or fluid nozzle assembly may be configured so as to rotate about an axis substantially parallel to the longitudinal axis of the pipe, so that the pressurized fluid expelled from the fluid nozzles impacts an entire circumferential swath of the interior surface of a pipe.
The scarifying assembly arm and/or fluid nozzle assembly may also be positionable so as to locate the nozzles adjacent to a bottom surface of the pipe. The pressurized fluid expelled by the nozzles may then clean a longitudinal swath along the bottom surface of a pipe.
The vehicle may comprise a chassis, a track assembly, a motor and a power coupler. The chassis of the vehicle may be adjustable to accommodate pipes having various shapes and sizes. The chassis also supports the scarifying assembly. The track assembly operates to propel the vehicle along a longitudinal direction of the pipe. A motor may be mounted on the chassis and coupled to the track assembly so as to drive the track assembly. A power coupler may be mounted on the chassis to conduct power from a power source to the vehicle and the scarifying as
Bose Vernon
MacNeil David
MacNeil Gerard
MacNeil Gordon
Hall Priddy Myers & Vande Sande
Mac & Mac Hydrodemolition Inc.
Stinson Frankie L.
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