Measuring and testing – Vibration – By mechanical waves
Reexamination Certificate
2001-11-30
2003-12-23
Chapman, John E. (Department: 2856)
Measuring and testing
Vibration
By mechanical waves
C073S592000
Reexamination Certificate
active
06666095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Endeavor
The present invention relates to pipe or other structure assessment and more particularly to ultrasonic pipe or other structure assessment.
2. State of Technology
U.S. Pat. No. 5,150,989 provides the following information, “It is generally well known that conduits or pipes which are employed for conducting fluids, for example, sanitary sewer pipes, storm sewer pipes, water lines and gas lines, frequently require repair due to leakage. The leakage may be inwardly, from the environment into the pipe, or outwardly, from the pipe into the environment. Leakage of this type may be due to improper initial installation of the pipe, deterioration of the pipe itself due to aging or the effects of corrosive materials, cracking of the pipe or pipe joints due to environmental conditions such as earthquakes or similar natural or man-made vibrations, or any other such causes. Regardless of the cause, such leakage is undesirable, at best, and may result in waste of the fluid being carried by the pipe, damage to the environment and the possible creation of public health hazards. Because of ever increasing labor and machinery costs, it is becoming increasingly more difficult, at least economically, to dig up and replace those pipes or portions of pipes, which may be leaking. As a result, various methods have been devised for the in situ repair or rehabilitation of the existing pipes, thereby avoiding the expenses and hazards involved in digging up and replacing the pipes.”
International Patent Application No. WO0042425 for a subsurface pipeline inspection probe by James Phillip Cull, published Jul. 20, 2000 provides the following information, “Traditionally, subsurface pipelines such as sewerlines and storm water drains have been inspected using manual access. This involves a person entering the pipeline system and carrying out a manual inspection of pipe walls. However, this method reveals only surface defects in the pipe walls and gives no information on defects in the surrounding soils. This method also has inherent dangers and health risks for the person carrying out the inspection. Remote controlled Closed Circuit Television (CCTV) has also been employed in inspecting subsurface pipelines. This method involves the use of a small camera which is mounted on the end of a long flexible cable. The camera is placed into the pipeline through an access opening and is then remotely controlled from the surface. This method removes the dangers involved in a person entering the pipeline, however, this method again reveals only surface defects in the pipe walls and gives no information on defects in the surrounding soils. In order to inspect the bedding of a subsurface pipeline and to detect defects in the surrounding soils, more elaborate techniques have been employed such as ground probing radar (GPR) and seismic methods.”
U.S. Pat. No. 6,101,951 for a robot for the repair of sewer pipes by Alwin Sigel, patented Aug. 15, 2000 provides the following information, “The use of robots in the repair of sewer pipes which are not man-sized is already known. Such robots, which are provided with a drive means for moving them through sewer pipes, are suitable, e.g., for the cleaning of sewer pipes, for grinding off irregularities or protrusions or for the mending of leaks. A known multi-segment robot for the above purposes is provided with a rotary head carrying a plurality of treatment tools and a camera. By means of a rotary motor, the rotary head and the robot arm connected thereto can be rotated in a controlled manner by up to 500 degrees about the longitudinal axis. Behind the rotary motor, which is supported on the sewer pipe wall by support wheels, a switch and relay unit is arranged for controlling the functions of the motor. If, for instance, the robot is used to fill leaks or other gaps, a press-out container will be arranged behind the switch and relay unit. The material to be applied is pressed via a hose from the press-out container to the tool arranged on the rotary head and thus can be applied by the tool. Arranged behind the press-out container is a carriage unit for moving the multi-segment robot through the sewer pipe under treatment. For this purpose, the carriage, serving as a tractor, comprises a plurality of wheels driven by a traction motor.”
U.S. Pat. No. 6,079,273 for EMAT inspection of header tube stubs by Paul J. Latimer, assigned to McDermott Technology, Inc. and The Babcock & Wilcox Company, patented Jun. 27, 2000, provides the following description, “A method for non-destructively testing closely-spaced objects, such as header tube stubs for a furnace or boiler using electromagnetic acoustic transducers (EMATs) having meander coil sensors. The small size of the sensor combined with the need to move the sensor only a small fraction of the circumference of a tube to scan the entire circumference of the tube under test permits easy and accurate testing of an entire tube, even when the tube is one of a closely-spaced bundle.”
U.S. Pat. No. 5,359,898 for hydrogen damage confirmation with EMATs by Paul J. Latimer, assigned to The Babcock & Wilcox Company, patented Nov. 1, 1994, provides the following description, “A method and apparatus for use in confirming hydrogen damage in a boiler tube comprises a pair of electromagnetic acoustic transducer coils which are mounted for movement toward and away from each other. An electromagnet produces pulses that generate acoustic beams across a chord and within the wall thickness of the boiler tube. For adapting to boiler tubes of different outside diameters, the transducers coils are mounted on a resilient member so that the coils can be pressed against the outer surface of coils having a variety of outside diameters. The angle of the acoustic beam between the coils must also be adjusted, however, and this is done by changing the frequency of energy applied to the coils.”
U.S. Pat. No. 6,148,672 for inspection of pipes by Peter Cawley et al, assigned to Imperial College of Science, Technology of Medicine, patented Nov. 21, 2000, provides the following description, “An apparatus and a method for inspecting elongate members, especially pipes, using Lamb waves. The apparatus and method provide for the propagation of an axi-symmetric Lamb wave of a single mode in one direction along the pipe. A receiver is provided to receive the Lamb wave after its passage along the pipe and convert the received wave for storage, processing and analysis to determine whether or not there are faults present in the pipe. The apparatus includes at least one and usually several excitation rings each having a plurality of Lamb wave exciters deployed in equiangular spacing in a ring clamping structure whereby each exciter can be pressed with equal force against the surface of the pipe under inspection.”
U.S. Pat. No. 5,767,410 for Lamb wave sonar probe for crack detection and measurement in thin-walled tubing by John P. Lareau et al, assigned to Combustion Engineering, Inc., patented Jun. 16, 1998, provides the following description, “A probe inspects steam generator tubing for defects. The probe includes a transducer which generates a localized sonar Lamb wave. The sonar wave is transferred to the tubing by a coupling medium, such as water, that physically couples the transducer and the tubing. Defects in the tubing reflect the sonar wave to the probe which detects the reflections. The results are then used to determine the length and depth of such defects as cracks, pitting, and thinning. The localized sonar wave performs an inspection sensitive enough to detect ligaments between crack segments. This allows highly accurate predictions of tubing integrity and rupture strength.”
SUMMARY OF THE INVENTION
Features and advantages of the present invention will become apparent from the following description. Applicants are providing this description, which includes drawings and examples of specific embodiments, to give a broad representation of the invention. Various changes and modifications within the spirit and scope of the in
Brown Albert E.
Kane Ronald J.
Levie Harold
Morrow Valerie L.
Thomas Graham H.
Chapman John E.
Scott Eddie E.
The Regents of the University of California
Thompson Alan H.
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