If a mixer is designed specifically to achieve a given level of product quality based on a given set of input parameters, then altering any one of these inputs can result in poor quality product and even damage the mixer, according to Rene Medina, executive vice president of process equipment manufacturer Gericke USA, Somerset, NJ. Medina offers three, key considerations for effectively mixing dry ingredients:

• Moisture Content: As dry, wintry air gives way to the heat and humidity of summer, stored flour, sugar and other powders may absorb the ambient moisture. A seemingly small increase from three percent moisture to five percent is often enough to increase the particle size, distort the particle shape, and cause enough agglomeration and bridging to clog equipment upstream from the mixer. A sifter and/or lump breaker may be used to return agglomerated materials to the proper particle size but it's more efficient to prevent the issue by storing the materials in a climate-controlled location.
• Bulk Density: Milk powder is 0.55 g/cm³ and sugar is .90 g/cm³. If a mixer designed for sugar is fed a very light density material such as fine milk powder then it's unlikely to encounter a serious problem. But if a mixer designed for a light product is fed a very high density material such as sugar then the mixer will struggle under the additional strain. Paddles, shafts, bearings, motors, and other parts specified for lighter duty may fail. Check the bulk density before mixing new or different materials to avoid downtime.
• Temperature: The temperature as the material enters the mixer typically needs to be identical for every batch, or at all times for a continuous process. Unexpectedly high material temperatures can increase viscosity, change the particle size and shape, and affect product quality while also stressing mechanical parts and seals. Climate-controlled material storage and temperature sensors are recommended.

For more information, contact Gericke USA, Inc., 14 Worlds Fair Dr. Suite C, Somerset, NJ 08873-1364; (855) 888-0088; sales.us@gerickegroup.com; or see GerickeGroup.com.