Berkeley, Calif., November 29, 2011 — A group of Berkeley physicists and engineers have developed a new safety system to monitor and prevent pipeline ruptures by using MRI (magnetic-resonance imaging) medical technology to remotely monitor the structural integrity of metal pipelines.
The new technology would help prevent failures such as the PG&E pipeline incident in San Bruno as well as other leaks, explosions and disruptions, according to the scientists at 4D Imaging, Inc., the Berkeley company which invented and patented the MRI-based pipeline monitoring system.
The system transmits the status of a pipeline to the internet and gives pipeline operators a real-time picture of the health of the pipeline, checking for fractures at welds or support systems and corrosion failure.
“We are excited to present this new technology,” says Dr. Glen Stevick, president and co-founder of 4D Imaging. “Our systems will lead the way to safer and more dependable pipeline operations for industry and the public.”
Stevick’s team includes emeritus UC-Berkeley physicist Professor Jerome R. Singer, the co-inventor of MRI, used in hospital radiological departments.
Singer has more than 20 patents and has founded 8 companies. He stated that their pipeline safety system provides the opportunity to closely monitor pipelines in a way that would prevent disastrous breakdowns. He said the new technology has been dubbed Magnetic Response Imaging.
4D Imaging staff are all connected to UC-Berkeley. Stevick and Dr. David Rondinone took their Ph.D. degrees at U.C. and Singer taught there for 25 years. Rondinone provided the computer program for this system that transmits all of the graphical data on the health of the pipeline.
After installation of the MRI monitoring system, the status of the pipeline can be visualized via the internet. The monitoring is constant, and any change in the mechanical health of the pipeline is measured and transmitted immediately to operating officers and pipeline managers.
The MRI system can be installed on any pipeline, small or large, and is cost effective. The pipeline MRI works by wrapping the pipe in wire coils which accomplishes two things:
First, one set of coils is electrified which magnetizes the steel pipe (over 90 percent of the world’s pipelines are steel). Next, another, second set of coils detects the magnetic field being given off by the now magnetized pipe. Conveniently, when steel corrodes and degrades it becomes less magnetic, so variations in the pipes magnetism represent areas that may have corroded or become compromised.
If the level of corrosion exceeds 0.008 of the pipe the system will issue a warning that the area of pipe has become compromised. The pipe’s temperature is also measured, both to account for changes in magnetism unrelated to corrosion and to keep track of the heat or cold stresses that the pipe has been under.
To minimize electricity usage, the coils electrify and record their data one at a time in sequence along the length of the pipeline. It takes the system about 3 seconds to thoroughly test a segment of pipe. Once the check has been performed the data is sent back to a computer and can be plotted against a schematic of the pipe, displaying which areas might require attention.
“As you can imagine, glancing at a computer screen to monitor pipeline safety beats the pants off of digging up miles of pipeline as a method of monitoring,” Stevick said.
4D Imaging began its research five years ago. The principle behind its technology is it determines the number of magnetic domains that remain intact in a pipeline. Corrosion will diminish that number, and the signals that directly determine the corrosion of the pipeline can be accurately measured.
For example, steel pipe is ferromagnetic; when looked at microscopically, it has trillions of small groupings of atoms called magnetic domains. These domains of roughly a few hundred thousand atoms are aligned such that neighboring domains cancel out the apparent magnetic field.
However, when an external magnetic field is applied to the pipe — for example, by sending a current through a wire coil wrapped around the pipe — the domains are forced to line-up in the direction of the external field, which is aligned along the length of the pipe. As the current in the coil is increased, the domains grow larger and their alignment rotates to conform with the length of the pipeline, so that the pipe becomes one magnet.
Magnetic domains are greatly weakened and destroyed by corrosion. Therefore, a measurement of the magnetism in the pipe can be directly correlated to the corrosion of domains. This allows the 4D safety pipeline safety system to interrogate the magnetic domains of steel pipe as a source of information.
If the steel has corroded, (usually to form iron oxide, iron sulphide or iron chloride), then there is a loss of magnetic domains because corrosion compounds are not ferromagnetic, which will set off an notification to monitors to alter them in advance of a pipeline failure.