Hydraulic and earth engineering – Subterranean or submarine pipe or cable laying – retrieving,... – By means advancing along terrain and guiding pipe or cable...
Reexamination Certificate
1999-02-19
2001-11-20
Novosad, Christopher J. (Department: 3671)
Hydraulic and earth engineering
Subterranean or submarine pipe or cable laying, retrieving,...
By means advancing along terrain and guiding pipe or cable...
C037S003000, C037S142500, C037S360000, C037S391000
Reexamination Certificate
active
06318930
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to preparation of trenches for laying underground pipelines and more particularly, to efficient preparation of trenches for laying underground pipelines.
2. Description of the Related Art
Typically, underground pipelines are used to deliver oil and gas products and other products, e.g., coal slurries and water, in the world-wide pipelining industry. Pipelines often must be laid in remote or undeveloped areas. Also, frequently pipelines must be laid in climates with extreme weather, such as Alaska. These soil conditions may make construction of pipelines difficult.
Trenches are dug to allow the pipelines to be placed underground, thus aiding in protecting them from the environment and avoiding obstructions such as rivers, bridges, railroad tracks, etc. Typically, when a pipeline is to be laid, a machine excavates a trench, delivering the excavated soil and rocks to one side of the trench, the excavated material forming a row of “spoil” along the side of the trench. The pipeline requires padding along the base of the trench to protect against damage from rough, sharp or pointed rocky materials that may be present along the lower portion of the trench. After placement of the pipeline, another layer of padding material is added on top of the pipeline to protect it further.
Care must be taken to surround the pipeline with trench filling that will not damage the pipeline. The pipelines are also covered with a cathodic coating to protect the pipe from rust and corrosion. Rocky material may damage the coating of the pipeline. Thus, the “padding” that constitutes the trench filling must be a fine material such as sand or fine soil that will maintain the integrity of the pipe.
As is known in the art, the padding material may be shipped to the pipeline construction area and then used to cushion the bottom of the trench and as protective filling around the pipe. The problem with this approach is that it is usually quite costly to transport the padding material. The distance for transport is usually considerable and the terrain may make transportation difficult. Also, there is an added labor cost for transporting the padding material.
In an attempt to lower the cost of transporting padding material to the pipeline construction site, in some instances, pulverizing machines have been conveyed to the construction site. Material from the site of construction was typically pulverized, screened to remove larger particles, and then used for padding material.
U.S. Pat. Nos. 3,701,422 and 4,633,602 relate to machines that move along the trench, picking up and screening the excavated material, and placing it on a longitudinally extending, rearwardly inclined conveyor that deposits the screened material on top of the pipeline as cover padding. Unfortunately, simply retrieving and screening the material that is excavated often does not provide sufficient material to pad the trench adequately.
However, the prior art techniques fail to maximize extraction of padding material from the excavated material. There is a need to provide an apparatus and method for obtaining a maximal amount of padding material from the excavated material so that a more efficient, cost effective process is achieved.
SUMMARY OF THE INVENTION
The present invention provides an apparatus and an associated method for efficiently and cost-effectively obtaining a maximal amount of trench-padding material from material excavated from the trench. One embodiment provides a trench-padding apparatus and method with a lead assembly mounted on the front of the apparatus, wherein the lead assembly may be pivoted and raised and lowered to facilitate pickup of excavated material. The lead assembly has a feeder housing and rotating unit that may be a drum/barrel with protrusions that aids in breaking up clumps of excavated material. The protrusions are generally stubby teeth, sharp teeth or blades, arranged at predetermined intervals to maximize excavation material clump-breaking. Generally, the rotating unit is coupled to the frame immediately in front of an elevator device and is configured to force excavated material between teeth/blades of the rotating drum/barrel and the surface of the base of the feeder housing. The front end of the elevator device is positioned to receive the excavated material, and the rear end of the elevator device is positioned to deliver the excavated material to a first mesh screen. Usually, the elevator device is at least partially protected by a detachable cover.
A rotating drum at the rear of the trench-padding device is attached to the frame and rotates in a direction to increase backward flow of the particles too large to pass through the mesh screen to avoid material buildup.
In one embodiment the method of the present invention includes the steps of: A) using a trench-padding apparatus that includes a lead assembly with a feeder housing to pick up the excavated material; and B) using a front rotating unit with protrusions, the front rotating unit being attached to a frame of the trench-padding apparatus immediately in front of an elevator device to force clumps of the excavated material between the front rotating unit and a base of the feeder housing to aid in reducing clump size. Generally, using the front rotating unit includes using a rotating drum with protrusions that are blades, fingers, or teeth. A detachable cover may protect at least part of the elevator device from rain, snow and the like. In addition, where selected, the method may include using a rear rotating unit, pivotally attached to a rearward portion of the frame of the trench-padding apparatus, that rotates in a direction to increase backward flow of excavation material too large to be used as padding material.
In another embodiment, the trench-padding-excavating apparatus is additionally configured to provide for excavation, and performs as a trench-padding-excavation apparatus. In this embodiment, the trench-padding-excavating apparatus includes a lead assembly having a feeder housing configured to excavate material, with a feeder housing having a front rotating unit with protrusions, wherein the front rotating unit is attached to a frame of the trench-padding-excavating apparatus immediately in front of an elevator device, and the front rotating unit forces clumps of the excavated material between the front rotating unit and a base of the feeder housing to aid in reducing clump size.
In one embodiment, the apparatus of the present invention provides efficient and cost-effective excavation of a trench and maximizes conversion of excavated material to trench-padding material. The apparatus includes: a frame adapted for movement along or astride a trench being formed by the apparatus; a lead assembly, having a feeder housing configured to excavate the trench and having a rotating toothed/bladed drum that is attached to the frame immediately in front of an elevator device, for retrieving and pulverizing the excavated material; the elevator device, being attached to the frame immediately behind the drum, for receiving and transporting the excavated material to at least a first mesh screen; the at least first mesh screen, attached to the frame and situated to receive the excavated material from the elevator device, for separating the excavated material into at least two grades of material; a conveyor for transporting material that passes through the at least first mesh screen to the trench; and a pulverizer and conveyor for pulverizing and transporting material that fails to pass through the at least first mesh screen.
REFERENCES:
patent: Re. 31818 (1985-01-01), Clonch
patent: 1901523 (1933-03-01), Millet
patent: 3091873 (1963-06-01), West
patent: 3452461 (1969-07-01), Hanson
patent: 3503450 (1970-03-01), Day
patent: 3934363 (1976-01-01), McMurray
patent: 4185875 (1980-01-01), Swisher, Jr. et al.
patent: 4283867 (1981-08-01), Brown
patent: 4676688 (1987-06-01), Caradot
patent: 4864748 (1989-09-01), Boyer
patent: 4912862 (1990-04-01), Bishop et al.
patent: 49
Greenberg & Traurig, LLP
Novosad Christopher J.
LandOfFree
Efficient method and pulverizer for pipeline trench padding does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Efficient method and pulverizer for pipeline trench padding, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Efficient method and pulverizer for pipeline trench padding will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2614159