Strength With Starch

In the food industry, numerous starches such as wheat, tapioca, rice and potato starch are manufactured and processed, as are modified starches. To an extent, they all demonstrate very different material characteristics that can be challenging in their handling, such as during pneumatic conveying. Fine starches are often more difficult to convey, due to their ability to fluidize; coarser starches, in contrast, are easier. Handling freshly produced starch is different as well, due to its higher internal moisture. These different material properties must be considered when planning and implementing the conveying system.

In the actual manufacturing process, or when processing starch, rotary valves are typically used to discharge product from silos, hoppers, or big bags into the pneumatic conveying line. Depending upon the type of starch, hard product layers can build up in the rotary valve's housing which then leads to increased friction between the rotor and housing. Due to this friction, significant noise can develop that manifest as loud squeaking and rattling, even from a distance. In the worst case, such material buildup leads to a full blockage of the rotary valve and thus to machine shutdown.

Such problems can be avoided upfront. With years of experience in this area, Coperion can select the rotary valve configuration that is suitable for the product being conveyed. For example: to minimize product layers that arise within the rotary valve, particularly when working with potato starch, knives can be mounted both on the valve perimeter and laterally. With each rotor revolution, product layers are scraped off the valve housing, keeping the buildup to a minimum and averting squeaking and rattling.

Further measures include installing a modified gap between the rotor and housing to alter the specific friction combination. Moreover, selecting an appropriate surface finish, or treating the surface using anti-stick technology such as Coperion Smart Glide Finishing (SGF) reduces adhesion.

When it comes to hygiene for the food industry, Coperion’s rotary valve product design impresses users with good cleanability. The rotary valves are equipped with a quick cleaning option that allows the rotor to be easily pulled out for inspection and cleaning.

When processing starch, oftentimes the danger of dust explosion requires explosion protection within the machine. Coperion offers these rotary valves in various sizes and versions that are designed as an ATEX protective system, pressure shockproof and flameproof.

Comprehensive expertise and years of experience make Coperion the ideal partner when selecting the right rotary valve for starch conveying applications. The proper valve design is selected, based on specific material characteristics of the starch being conveyed. Certain measures can be implemented to optimize the conveying process. Coperion test centers around the world are some of the most advanced facilities for studying bulk solids handling and processing. This global reach has allowed Coperion to accumulate and develop a comprehensive database for materials such as different starches. This elaborate material database is used to form the basis for ongoing component development.