Ingredient Handling: dense vs. dilute phase
Aug. 1, 2011
by Dan Malovany
Most US bakeries rely on dilute phase conveying to transfer powders and granular ingredients such as flour, starch, salt and minor ingredients. However, if a snack producer wants to move an ingredient that is friable or requires little or no particle breakage, as is often the case with nuts or whole-kernel corn, a dense-phase system might be preferred, noted Tom Leach, national sales manager, baking and snack industry, Horizon Systems, Lawrence, KS.
Dilute-phase systems generally operate using high air velocity and air volume but lower operating pressure or vacuum, explained Mark Ungashick, executive vice-president, Shick USA, Kansas City, MO. Dense phase is just the opposite, with lower air velocity and air volume and higher operating pressure or vacuum. “A dilute-phase system will usually employ a positive-displacement blower to provide the motive force,” he said. “Sometimes, a fan or regenerative blower can be used in a dilute-phase system. A dense-phase system usually uses a compressor, rotary screw or ring pump to develop the higher range of pressure or vacuum.”
Horizon Systems offers a continuous dense-phase conveying system that substantially reduces product degradation, according to Mr. Leach. Additionally, the company supplies vacuum dense-phase and traditional pressure pot dense-phase conveying, depending on the type of product that needs to be transferred along with the distance and rates required. Not only does the Horizon ConTran continuous dense-phase system require little energy to operate, but it also is designed to reduce segregation of material and product changeover delays, Mr. Leach said.