How long should a mechanical seal last?
Too many users find that the average life of some of their mechanical seals is measured in weeks. However, notes consultant Ross Mackay, a number of methods for extending mechanical seal life have been proven for well over 15 years. Shaft strength is one key consideration, he explains.

Screw conveyor provides a novel twist
A veterinary products manufacturer needing a conveyor for a small manufacturing area chose a unit with a motor-driven screw inside 3-in-diameter plastic tubing. Low ceiling height necessitated a special arrangement to the conveyor’s discharge adapter, reports Paul Thomas.

Whither FDT/DTMs?
Field device tools/device type managers (FDT/DTMs) were a good idea when there was a diversity of fieldbuses and a divisive market. They no longer are important and only serve to mask important issues, argues Dick Caro of CMC Associates.

Ask the experts
Do you have a technical question? Get an answer online from authorities in 20 key areas, such as David Jensen on corrosion, Jim Grant on heat transfer, Rich Palluzi on pilot plants and Dennis Hendershot on process safety. Also see what questions and responses have been posted.

Spiral exchanger models get validation
Spiral heat exchangers offer a number of advantages such as compact size and good temperature control. Extensive testing at Heat Transfer Research Inc. has confirmed the validity of models for thermal and hydraulic evaluation, note Fernando J. Aguirre and Christopher A. Bennett. These models will be included in software to be released in 2006.

Well-proven tools spur process integration
Composite curves, the Problem Table Algorithm and the grand composite curve are well-established and documented tools for heat-exchanger-network design, explains Robin Smith of the Process Integration Consortium at the University of Manchester. They can lead to maximum heat recovery and optimum use of heating and cooling utilities.

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