Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
2001-06-06
2004-02-17
Chambers, A. Michael (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C137S015120, C137S363000, C137S372000
Reexamination Certificate
active
06691727
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In general, the present invention relates to protective devices that are used to protect subterranean pipes from damage during excavation. More particularly, the present invention relates to devices that protect subterranean pipes in areas that will be excavated for the purpose of tapping the subterranean pipe.
2. Prior Art Statement
In modern civil engineering design, utility pipes for water, gas, sewer and the like are commonly laid underground. In a large construction site, primary utility pipes are buried in a trench that is dug through or around the construction site. As different buildings are built on the construction site, secondary pipes are laid between the buildings and the primary utility pipes. In order to attach a secondary pipe to the primary utility pipe, a section of the primary utility pipe must be excavated, so as to be accessible by workers. Once a segment of the primary utility pipe is excavated, the primary utility pipe is tapped. It is through the tapping procedure that the primary utility pipe is interconnected to the smaller secondary pipes that lead to the individual buildings.
In a well planned construction site, the points at which the primary utility pipes will be tapped are known. As the primary utility pipes are laid and buried, the tapping points are typically marked above-ground with a flag or marking stick. When the time comes to tap the primary utility pipes, excavation crews excavate the earth around primary utility pipes in the areas marked. Typically, an excavation crew will use a backhoe to dig a large hole down to the depth of the primary utility pipe. Once the hole reaches the depth of the utility pipe, workers typically manually finish the excavation using shovels. Manual digging is commonly used around the primary utility pipes to prevent the bucket of a backhoe from inadvertently damaging the primary utility pipe.
When an excavation crew excavates a section of a primary utility pipe, the excavation crew digs around the primary utility pipe so that a portion of that pipe is suspended in the air. Dirt must be removed from around and below the exposed section of pipe so that tapping equipment can be attached to the exposed section of pipe without interference from the surrounding earth. There are many types of tapping equipment used to tap primary utility pipes. Examples of the tapping equipment are shown in U.S. Pat. No. 4,978,255 to Gale, entitled, Tapping Fluid Supply Pipes; U.S. Pat. No. 5,170,813 to Francis, entitled, Tapping Bands; and U.S. Pat. No. 5,732,732 to Gross, entitled, Tapping Fitting. Such prior art tapping equipment typically requires that earth be removed below the pipe, leaving a gap of at least two inches between the remaining earth and the exposed section of pipe.
A problem that exists with markers is that markers used above utility pipes are sometimes misplaced, inadvertently moved or buried. As a result, excavation crews attempting to excavate the primary utility pipe do not always know the exact location and/or depth of the primary utility pipe. As a result, an excavation crew may believe the utility pipe is in one location, when in reality it is in another location. As a result, excavation crews sometimes inadvertently contact a utility pipe with the bucket of the backhoe during the excavation process. When the bucket of a backhoe contacts a utility pipe, it may immediately rupture that pipe. This rupture is repaired by replacing the damaged section of pipe. This is a highly labor intensive process that requires a large excavation, the removal of the damaged section of pipe, and its replacement with a new section of pipe. Such repairs add greatly to the cost and time of the construction project.
Many times, during excavation, a backhoe may contact a utility pipe, but not rupture that pipe. When this happens, the bucket of a backhoe may scar the surface of the utility pipe. When a backhoe scars a pipe, the protective covering of the pipe is damaged. This causes a point on the pipe that is vulnerable to rust or other degradation caused by exposure to the surrounding earth. Such a scarred section of pipe may fail years before the other undamaged sections of the pipe. In order to prevent this, the damaged section of the utility pipe must be cleaned and the scar in the protective coatings repaired. This also is an expensive and labor intensive procedure.
A need therefore exists for a device and method of protecting section, of a primary utility pipe from damage when those sections of pipe are excavated for tapping purposes. A need also exists for a device and method that simplifies the process of excavating around a utility pipe once it is exposed. These needs are met by the present invention as is described and claimed below.
SUMMARY OF THE INVENTION
The present invention is a system and method for protecting sections of a buried utility pipe that will eventually be excavated and exposed for tapping purposes. The system includes a protective collar having a first end and a second end. The protective collar defines an opening of a first diameter that extends between the first end and the second end. The protective collar is comprised of at least two separable sections that can be separated along common seams that run between the first end and the second end. The protective collar has an enlarged region between its first end and its second end that has an annular cross-section. The enlarged section includes an inner wall of diameter that matches the utility pipe, and an outside wall of a larger second diameter. A gap exists between the inside wall and the outside wall. The gap is preferably at least two inches wide.
To utilize the protective collar in a method, the collar is attached to a utility pipe before the utility pipe is buried. When the utility pipe is to be tapped, the earth above one of the protective collars is excavated. The protective collar protects the utility pipe from the excavating equipment. Once the protective collar is exposed, the protective collar is removed. The removal of the protective collar leaves a section of the utility pipe exposed that is clean and free from any surrounding dirt. The utility pipe can then be tapped at this location.
REFERENCES:
patent: 2649769 (1953-08-01), Kaiser
patent: 4497332 (1985-02-01), Sewell et al.
patent: 4978255 (1990-12-01), Gale et al.
patent: 5170813 (1992-12-01), Francis
patent: 5732732 (1998-03-01), Gross et al.
Chambers A. Michael
LaMorte & Associates
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