Archive for the 'OS Technology' Category

Sep 14 2009

Measuring Strain and Temperature in Light

Published by under General,OS Technology

In the past dozen years we’ve seen fiber optic sensors (FOS) being discovered by engineers around the world for myriad applications. With each new application, the unique capabilities of FOS (or more specifically, fiber Bragg grating (FBG) sensors) are leveraged and highlighted.

We’ve also seen that our most formidable competitor isn’t another FOS company; it is lack of awareness. One way we are reaching out is inviting the Atlanta chapter of the Society of Manufacturing Engineers to our offices for an introduction to FOS. Tom Graver will be presenting “Measuring Strain and Temperature in Light” on September 22 here at Micron Optics. We are excited to talk with a new group and to see what ideas they bring to us.

If you are in the Atlanta area and would like to attend, you can register at http://chapters.sme.org/061/events.htm.

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Jul 29 2009

FBG Sampling at High Speeds

Published by under Instruments,OS Technology

In 2005 Micron Optics developed an FBG interrogator capable of sampling a single FBG at 500kHz or up to four FBGs at 100kHz. It was not an official product, but an Alpha prototype meant as a technology demonstration platform. We expected to sell just a few.

Since then we’ve sold dozens of these si920 Optical Sensing Interrogators. Applications have ranged from blast tests and ballistic impact tests to analysis of vibration in medical devices when exposed to MRI energy and the propagation of sonic energy in composite panels used on spacecraft.

It’s clear to us that there is a need for this type of measurement tool. No other technology (that we know of) can make such high speed (500kHz) high resolution strain measurements (0.02microstrain) in harsh electromagnetic environments.

We’re interested in feedback from you on how we might proceed with formal product development. For example, higher sampling rates in the MHz are possible with more advanced DAQ technology. More sensors per instrument, and accommodating more sensors per fiber are also feasible. What are your applications? What instrument configuration might work best for you?

si920 Datasheet

Tom Graver
Vice President, Optical Sensing

Glossary of Terms:
DAQ = Data Acquisition
MRI = Magnetic Resonance Imaging
FBG = Fiber Bragg Grating

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Mar 31 2009

Chiapas Bridge—A Fiber Optic SHM Installation First in Mexico

Published by under General,OS Technology

In late 2008, a fiber optic structural health monitoring (SHM) system was installed on the Chiapas Bridge in Mexico. This installation represents the first SHM instrumented bridge in Mexico using optical fiber sensors and SHM techniques. The project was conceived and managed by the Structures Department within the Institute of Engineering at the National Autonomous University (UNAM) in Mexico, under contract from the Mexican Transportation Undersecretary. The system was designed by MCH Engineering LLC, equipment and sensors provided by Micron Optics Inc. and the system installed by Chandler Monitoring Systems Inc. (www.chandlermonitoring.net).

Aerial view of Chiapas Bridge
Figure 1: Aerial view of the Chiapas Bridge in Southwest Mexico

The Chiapas bridge was opened to traffic in 2003 and is the most important structure of an entire highway going through the state of Chiapas, in Southwest Mexico, and part of the Transamerican highway system. The superstructure is a continuous grade 50 steel orthotropic box of constant height comprising 8 spans, with a total length of 1208m. Piers heights range from 27 to 89 m measured from the bottom of the dam. Steel jackets of the offshore type, were used as the main elements of the piers.

Chiapas Sensor Network
Figure 2: Aspect and topology of the installed sensor network inside the bridge

During construction of the superstructure, a basic monitoring system was initially implemented to monitor and assess the structural behavior of the bridge. However, advances in SHM techniques and the importance of the Chiapas Bridge in the region, prompted the need for a new and advanced instrumentation system. The new solution is based on a multi-point, multi-sensor monitoring system based on optical fiber Bragg grating sensors and opto-electronic interrogators. The system is self contained, works as a stand-alone equipment and allows for the in-situ, real-time monitoring of the bridge as well as its long-term condition. A total of 82 fiber optic strain and temperature sensors were installed in key bridge locations. Local electric power is supplied by a solar panel system.

The monitoring system instrumentation is composed of a single optical interrogator (Micron Optics model sm130-500) with 4 optical channels, scanning at 1khz; a 4×16 channel sensor multiplexer (model sm041-416) and a sp130 controller and data acquisition module (Figure 3). The system can be configured to record data at any specific interval and to any threshold level.

Micron Optics Equipment
Figure 3: Micron Optics Interrogation System on Chiapas Bridge

Admin edited to add images 4/6/09

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Feb 06 2009

Applications of FOS technology are growing…

Published by under Instruments,OS Technology,Sensors

Applications of FOS technology are growing for industrial process monitoring. Engineers in plants producing glass, chemicals, metals, paper and plastics are using FOS to measure where other sensing technologies perform poorly or not at all. Fiber optic technology provides solutions for high EMI environments, areas where explosion risks persist, and where sensor density requirements make installation and cabling too expensive and cumbersome.

One recent example is an installation by Hatch Ltd. Hatch is a designer and supplier of custom designed furnaces and furnace components for the production of metals. They are using arrays of FBG sensors inside the furnaces used in smelting operations to provide a dense map of temperatures in the critical zones — information that can detect hot spots. FBG sensors provide superior temperature measurements and measurement density compared to thermocouples, which are traditionally used. This information guards against costly and potentially dangerous breaches of the furnace insulation systems and will allow maintenance to be driven by the actual furnace condition rather than a simple schedule for preventive maintenance. The use of FBG technology is part of an on-going effort by Hatch to develop a Diagnostic System (patent pending) for furnaces and other metallurgical reactors that will estimate the health or remaining life of the equipment.

Phil Shadlyn, a key engineer on this project, told me: “It really couldn’t have gone better. [Hatch's] sensor design worked as planned, and installation was smooth. [Our customer] was pleased with how easy it was to use the Micron Optics instruments and software. We will continue to monitor the installation and if everything progresses as planned, we’ll deploy several more installations throughout the next two years.”

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