High-Temperature Remote Video System Penetrates Walls of Reheat Furnaces

A high-temperature, long-lifetime remote-video monitoring system penetrates the walls of reheat furnaces in steel, aluminum, glass and other industries, providing excellent picture quality as it directly views burner flames, materials position and other process conditions.

The CCTV (Closed Circuit TV) furnace camera system, available from Lenox Instrument Co., Inc., withstands temperatures as high as 4,000 deg. F. It enables control room personnel to continuously observe the interior of furnaces that heat materials to high temperatures during processing.

Incorporating a temperature-resistant housing, the system is one of the only ones that monitors burners and materials in glass furnaces where temperatures reach 3,400 deg. F. The camera also views steel slabs at the beginning, middle and end of the reheat process during which they are rolled to final flat strip, bar or plate steel, at temperatures between 2,400 deg. F and 2,600 deg. F. An operator in a control room immediately may see if one slab is on top of another, which would result in a cold spot, or if a slab hits the side wall. The furnace system likewise observes aluminum reheat furnaces under similar temperatures.

"Operators viewing monitors can immediately spot problems and stop the process before a more serious situation develops," said Donald Demsky, head representative for the John M. Pultz Div. of Lenox. Pultz developed the high-temperature camera in collaboration with the University of Heidelberg in Germany.

"The opening on the system's housing is only 3/16 of an inch in diameter, flush with the interior wall, rather than being behind a furnace window," Demsky added. "This provides as good a picture as a hand camera.

The system's pinhole CCTV lens is available from 3.8mm to infinity. It may be changed to provide whatever field of view is desired, including 30 degrees, 45 degrees and 90 degrees.

The lens is screwed on a solid-state TV camera, without intermediate prisms, providing clear images. As there is only one lens between the camera and the target, there is minimum interference along the image transmission line.

The CCTV system, usually mounted through a hole bored in the refractory wall, is protected by a water-cooled stainless steel enclosure 6-3/8 inches in diameter. The lens usually is purged by compressed air under minimum pressures (two psi to seven psi), which substantially reduces costs compared with other systems as it requires only a small amount of purge air. Other purge gases may be used when required.

The length may be custom made, according to the thickness of the wall and the angle desired. A standard model is 30 inches long. It also is available in 18 inches, 24 inches and other lengths.

The system, which weighs 70 pounds, offers easy and permanent installation. The furnace walls that it penetrates are usually 14 inches or 16 inches thick.

Lenox purchased the John M. Pultz Company of Mokina, Ill., a worldwide supplier, in April 2000, and offers the complete line of Pultz products, which is manufactured at the Lenox headquarters in Trevose, Pa., a Philadelphia suburb.

The furnace system usually provides color TV, though black and white TV also is available when desired. It also allows the process to be videotaped for quality control archives or other purposes. The water-cooling for the enclosure applies an exclusive laminar flow design. This removes heat very efficiently, keeping the housing and camera at acceptable temperature levels. The durable camera system may remain in the furnace wall for long periods of time.

"The furnace camera system offers great clarity through a simple design and is available at a substantial price reduction over competitive systems," said William J. Lang, vice president of Lenox. "We are already delivering systems which can withstand up to 4,250 degrees F, complementing our FireSight line of high temperature CCTV systems. Lenox offers over 225 furnace camera products through our combined Lenox-Pultz: expertise, which includes world-recognized systems in glass and other industries."

Lenox Instrument Co. is the world's largest manufacturer of high-temperature TV systems for monitoring conditions inside boilers and furnaces in all industries.

Founded in 1920, Lenox also manufactures a wide range of rigid and flexible borescopes and waterproof video probes for viewing otherwise inaccessible areas inside pipes, tubing, engines, valves, castings and other products.

      For more information contact:
      W.J. Lang
      Lenox Instrument Company, Inc.
      265 Andrews Road
      Trevose, PA 19053
      215-322-9990
      Fax 215-322-6126