Food Production Facility Gets Modernized

Established in 1946, Salina, Kansas-based Repco has provided the enrichment industry with ideas, services and products such as flour oxidation and maturing services, vitamin and mineral premixes, micro-ingredient dispensing systems and on-site field servicing. The division of the company that produces vitamin and mineral premix products decided to look into options for modernizing an outdated mechanical transfer system. The decade-old bucket elevator system that transferred the premixes from mixer to packaging was causing housekeeping and segregation issues, not to mention large amounts of product being lost during clean-out.

Repco contacted Coperion K-Tron to look into pneumatic conveying solutions that would clean up the process and ensure the finished blended product did not segregate during transfer to the packaging system. This process started with full-scale testing of blended materials at the Bulk Solids Innovation Center (BSIC), where Coperion K-Tron’s test lab resides in partnership with Kansas State University. After witnessing the full-scale tests of multiple blended premixes, Repco was convinced to go with Coperion K-Tron for the project because of its demonstrated ability to convey the blended products without segregation consistently and reliably.

Application and Process Details
The material handling system Coperion K-Tron provided includes an Omniveyor^TM dense phase pressure conveying system complete with pressure vessel, programmable logic controller (PLC), piping, diverter valve, specially designed hopper lids and modular cartridge bin vents. During testing at the BSIC, Coperion K-Tron determined the ideal method of conveying to ensure a constant and reliable blend was to use a dense phase pressure vessel pneumatic conveying system.

The first portion of this system transfers the finished product — a blend of vitamins and minerals — from an existing mixer into the pressure vessel below. From the pressure vessel, the material is transported through the convey line where a WZK diverter valve then directs the material into one of two holding tanks before packaging. To confirm an entire batch makes it all the way through the system, the holding hopper above the mixer, the dense phase conveyor and the destination hoppers are mounted on load cells with weights communicated back to the plantwide control system.

Dense Phase Pressure Vessel Pneumatic Conveying
The key component in the Omniveyor system is the pressure vessel, which allows the system to operate in a dense phase conveying mode. Dense phase pressure vessel systems use high air pressure, above 1 bar (g) [15 psi (g)], and low air volume as the motive force to convey powder or granular bulk solid materials through a pipeline at low velocity. The low velocity makes this type of conveying especially suitable for premixed materials, materials with high bulk density and materials that are abrasive, friable or tend to segregate.

The dense phase system uses a pressure vessel that is filled via until a high level control switch is activated. At this point, the pressure vessel’s inlet and vent valves are closed, and material is conveyed in low-velocity slugs to one of two destination receiver vessels. The conveying cycle will continue until the receiver vessel signals that no additional material is required. Communication between the Repco PLC and the Coperion K-Tron PLC ensures that the mixer outlet valve is open and the pressure vessel is filled. In addition, the automation system allows transfer of the blended product to the proper receiving vessel, utilizing control of an inline WZK diverter valve to direct the correct path of the material slugs.

Retrofitting Existing Hoppers
In addition to providing the Omniveyor dense phase system, the existing destination receiver lids were replaced so that Coperion K-Tron modular cartridge bin vents (MCBV) could be installed. Four MCBVs are installed on both destination hoppers to filter the displaced air properly as material is conveyed into the hoppers. This modification reduces product waste greatly by eliminating the product carryover that previously was experienced when venting the hoppers using a central dust collector. Coperion K-Tron’s MCBVs require lower headroom than traditional bin vents while still maintaining high filtration efficiency. In addition, the easy-clean and easy-access design make them ideal for quick changeovers to different products and recipe formulations.

A Successful Partnership
Repco’s continued focus on product quality and partnership with Coperion K-Tron has resulted in a state-of-the-art dense phase system that has allowed it to improve plant cleanliness, product quality and system reliability with full process automation. Travis Schubert, VP of Operations at Repco, says “Replacing our old mechanical system — which proved to be a wasteful sanitation nightmare — with the Coperion K-Tron dense phase system has made our facility cleaner and run much more efficiently, while improving the quality of our finished products due to zero segregation of the materials during transfer.”