Infrared heat detectors boost productivity.

New infrared devices that detect heat rather than light allow faster ROI through greater protection, less downtime, improved processes, and decreased maintenance.

By some estimates, approximately two to three fires or explosions occur in various manufacturing facilities throughout the United States every day. Although any company that handles powders and bulk solids is susceptible, wood industries such as furniture manufacturers and panel producers that process solid wood and woodchips are particularly at risk. Paper and paperboard manufacturers also have high risk.

All plant managers and facilities engineers are well aware of these risks. They plan accordingly by installing protective systems. Many paper, wood, and bulk powder plants are using fire protection systems that rely on the detection of a visible flame or spark. These devices operate by detecting light not heat. This poses several drawbacks including false positives from normal light sources.

More importantly, the ignition temperature for dust clouds of dried pulp is 500[degrees]C. For wood, it is 480[degrees]C. Those temperatures are too low for spark detectors to sense since visible sparks and embers are not detectable at temperatures below 700[degrees]C.

"By the time a visible flame exists that a spark detector can see, sawdust or other wood particles have already caught fire," says Bill Stevenson, a risk analysis engineer for Cv Technology of West Palm Beach, Florida, USA. Cv Technology provides engineering and consulting services for process evaluation and explosion protection system design.

IMPROVED DETECTION TECHNOLOGY

Unlike spark detectors, new fire and explosion protection systems use infrared detectors that seek heat. One system offers an infrared detector that reacts to temperatures as low as 400[degrees]C, 250[degrees]C, or even 175[degrees]C. The detector measures the number of glowing particles and the highest registered energy value.

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A simple cable connects up to eight detectors to a control unit that can activate up to two explosive release mechanisms and eight solenoid valves for water or gas spraying. The system works by detecting a hot body before it can ignite any particles. It can initiate rapid action to remove the heat or hot body from the rest of the process product.

PRODUCTION SAVINGS

When Masonite commissioned its 3-mm molded door skin plant at Carrick-on-Shannon, Ireland, the company specified installation of an integrated prevention system. "We have a sister plant in Laurel, Mississippi, USA. This new plant was a mirror image," recalls Gary Scott, engineering manager for the Ireland factory. "Since the Laurel facility had a good record with their system, we installed it at this facility from the start."

"Because we run a dry process, the chance of fire is definitely high throughout the plant," explains Scott. "We have many pneumatic transport systems carrying the dry fiber around the plant to intermediate storage bins and forming and pressing areas. The transport system also moves the sawdust from cutting the boards back to our heat energy plant that burns waste material."

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Scott identified three areas of risk:

1. Initial fiber handling

2. Pressing process

3. Waste material transportation.

"We have the system throughout the ductwork and in all the various process vessels and storage bins where potential for a fire may exist," continues Scott. "Early detection and extinguishing of fires in the process have ensured safety, protected assets, and reduced the risk of plant downtime."

For more information about Cv Technology and Firefly, phone [phone]; fax: [phone]; or web: www.cvtechnology.com.