Challenge
A corn derived sweetener manufacturer was experiencing an issue with some of their customers regarding flowability of their products. Some of the powdery material would not flow sufficiently well to enable the required dispersion in their customer’s food making machinery. The cause of poor flowability of their products was high fines content, producing a very sluggish product. They had attempted to separate the fines with their existing high frequency screens but were unsuccessful. As a result, their market share was in jeopardy. Additional machinery space for the two lines was limited, and they wanted to be able to bypass the elutriators when producing some products for other customers who were not experiencing flowability issues in their equipment.
Approach
The customer contacted General Kinematics seeking a solution to their production issues. Following discussions with production personnel and examination of their products, the sales engineers at GK recommended lab demonstrations to evaluate fluidized bed elutriation of the fines. Lab demonstration results were very successful. Not only was GK able to achieve a very close “cut” for a specified particle size, they were able to adjust the air flow to separate a range of particles with remarkable definition at the micron level.
Solution
To meet the customers requirements GK designed two circular shape elutriation units with the feed and discharge spouts coincident in plan view. This enabled the incorporation of a simple manual insert device that permitted bypassing of the powder flow stream to downstream equipment. In order for the equipment to be installed in the necessary location in the plant, special modular design construction was used to allow the machine to be completely disassembled and brought into the factory in pieces then reassembled in its final location.
GKC provided complete system design, including supply air fans, ductwork, air flow controls, and VFD. The elutriated fines were to be delivered to existing dust collectors but the operating negative static pressure in the exhaust ductwork varied widely, with up to -14” WG static pressure. GKC engineers designed an exhaust air valve to enable variable pressure drop such that a slight negative static pressure could be maintained and assured in the elutriator’s hood under a broad range of supply air volume and exhaust air static pressures.
Results
Elutriation results are excellent and enable the user to make sharp cuts in the particle size distribution required to achieve the custom flowability characteristics of their customers.
