Electromagnetic Strategies for Locatable Plastic Pipe

Overview

Main Objective

Develop and validate two approaches for producing pipe that is locatable using electromagnetic sensing.

Public Abstract

Unlocatable utilities are a significant source of accidents throughout the US and add significant costs to construction from repair of accidental damage to locating the utilities. One of the largest issues is the widespread use of plastic pipe for gas transmission. These materials are difficult to detect with traditional utility locating systems even when their location is approximately known. This research program will investigate two strategies for fabricating plastic pipe that is intrinsically responsive to electromagnetic interrogation from the surface. The first strategy is to incorporate micro-encapsulated magnetic nanoparticles that will exhibit a strong response to EM radiation from the surface. This approach has two significant advantages when compared to previous attempts. First, microcapsules will reduce some of the deleterious effects on mechanical properties that the inclusion of conductive particles can have. Second, the potential for self-healing of crack damage is introduced. The second strategy is to investigate the production of antennas that can be used with either active or passive RFID systems to provide both location and pipe data. The data will provide visibility into the earth without the need for excavation, thereby reducing cost and increasing safety by eliminating the possibility of accidental utility damage. Items such as utility type, depth, and pipe size information will be investigated. Including additional data about neighboring pipes will also be investigated to enable a distributed map of the utilities to be provided by a collection of pipes. Critically, this strategy is focused on fabricating pipe structures in such a way as to produce a continuous production line to ensure cost-effective, locatable, plastic pipe. This research is a collaborative effort between three faculty members and two universities (The University of Tulsa and Oklahoma State University).

Summary and Conclusions

The project confirmed two strategies. Strategy #1: The incorporation of microencapsulated magnetic nanoparticles was investigated, but the capsules could not survive the manufacturing processes associated with PE pipe fabrication. However, when magnetic nanoparticles were incorporated, they were found to be sufficiently robust to survive compression molding. Magnetic testing indicated that the incorporation of magnetic nanoparticles significantly increased the magnetic signature of the PE host material. Strategy #2: The antenna approach resulted in the selection of two viable designs: a delay line-type antenna and a simple bowtie antenna. Simulated field tests used a ground penetrating radar (GPR) approach and were successful at increasing signal response significantly compared to the baseline control test (empty pipe). A two-phase conductive polyethylene (cPE) material was processed for use as an antenna material. Testing indicated that the conductive polymer could withstand the strains that would be expected during typical pipe handling and installation.

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