News | November 18, 2003

Selecting the Right Blade to Optimize Mixing

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The key to solving tough blending problems and meeting ambitious goals for throughput and product quality is often unconventional thinking. Faced with the challenge of blending a slurry of extremely dense materials, then drying the batch to form a light, fluffy powder, your first thought would probably be to rely on a traditional vacuum dryer. As the density of the ingredients rises, conventional wisdom tells us to reduce batch size to minimum levels, or slow down the blending rate to enable the hardworking blender/dryer to handle the job. In extreme cases, you might also reinforce the unit with such additions as a heavy-duty drive system and more wear-resistant materials of construction. But many processors are finding that instead of sticking to predictable solutions, a completely different kind of blender/dryer can handle the heaviest of materials easily and produce dramatic gains in end-product quality and throughput.

Specifically, they have discovered that in many high-density applications the aggressive mixing action of a double planetary mixer, combined with carefully controlled heat and vacuum, can transform the mixer into a vacuum dryer/granulator that can outperform familiar blender/dryers by a wide margin.

Tungsten carbide
During the last several decades, the demand for extremely tough and durable materials has exploded in industries worldwide.Wherever surfaces are subjected to intense heat, impact, compression, friction and other stresses, a high performance material can provide critical protection to improve performance and prolong operating life. The immense benefits offered by these materials are apparent today in markets from aerospace and automotive manufacturing to industrial tools and machinery.

Perhaps the best known of these high performance materials is tungsten carbide. The introduction of tungsten carbide more than 50 years ago helped to revolutionize productivity in hundreds of industries. When tungsten carbide was first used in cutting tools, the cutting speed for turning and milling steel increased from 80 ft/min., to 800 ft/min. In the mining industry, tungsten carbide tips on rock drills increased the life of the drill by a factor of 10 over steel-based drilling tools.

Today, the virtues of tungsten carbide are well understood, and the industry is intensely competitive. Manufacturers compete in a mature market where contracts hinge on fast delivery and extremely subtle differences in product quality. A 48-hour advantage in filling a production order is often decisive in securing a contract. Especially since tungsten carbide parts are subjected to such extreme conditions, the quality of each part is measured on a microscopic level because microscopic flaws can ultimately lead to catastrophic failures in use.

Charles Ross and Son Company