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Solids Handling

Mechanical Centrifugal Air Classifiers

An improved understanding of air classifier systems and their application can help in selecting the right device Mechanical centrifugal air classifiers are used extensively to process aggregates, ceramics, chemicals, foods, minerals, metals, plastics, flyash and other materials. They are normally…

Ask the Experts: Discharging from bulk bags

Question:  Should we convert from manual dumping of sacks to discharging from bulk bags?    Answer: Dry, bulk chemicals have long been purchased in 50-lb (23-kg) paper and plastic sacks for several reasons. In volumes smaller than rail and truckloads,…

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Lessons in Feedstock Change

These days, there seem to be more reasons than ever to change feedstocks throughout the chemical process industries (CPI). Whether environmental, or more directly based on financial and market drivers, big benefits usually require big changes. This is especially true…

Focus on Feeding & Conveying

Feeder combines speed with accuracy Hapman The PosiPortion feeder (photo) offers a 2-in-1 feed screw option that dramatically improves batch accuracy without compromising speed. A two-speed delivery scheme, consisting of a fast turning “bulk-mode” and a slower “dribble-mode”, are used…

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Using Inserts to Address Solids Flow Problems

Storage of bulk materials in hoppers, bins and silos is ubiquitous in the chemical process industries (CPI), and so are the challenges that go along with it. Flow stoppage (bridging or arching), variability in mixture composition (de-mixing or segregation), erratic…

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A cross-section of insert patents

This table supports the article Using Inserts to Address Solids Flow Problems, CE, July 2010, pp. 32–37. U. S. Patents       Patent # Date Title Inventors 1,731,675 Oct. 15, 1929 Sawdust Feeder McCoy, John C. 2,843,274 Jul. 15,…

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Agglomeration Technology: Equipment Selection

A virtually endless number of process options are available for agglomerating powders in the chemical process industries (CPI). These processes can be divided into two main categories: agitation and compression. Agglomeration by agitation includes granulation processes, such as fluidized-bed, disc,…

Ask the Experts: Cake Prevention

Question:  What can we do to prevent caking? When our powders are packaged into bags at our plant, they appear to be free of agglomerates.  However, our customers report that when the bags are opened at their facilities, they observe…

Polysilicon Production

A rapid and ongoing expansion of polysilicon production capacity will likely generate an oversupply for the next several years, driving polysilicon manufacturers to further innovate processes and reduce operating costs in preparation for an impending wave of new demand. Drastic…

Particle Sizing Across the CPI

This survey of modern particle-measurement technologies demonstrates how selection criteria vary by application Particulate systems are everywhere; they are responsible for bright red sunsets, the texture of chocolate and the rate of drug delivery in the human body. Particulate processing…