Case Study - Continuous cereal vacuum transfer system from cutter head to two destinations

At Ingredient Batching Systems we have designed and manufactured a vacuum transfer system to pneumatically convey expanded and extruded cereal shapes

From the cutter head outlet of the twin screw steam extruder, the individual cereal pieces gravity fall directly into an entrainment hopper. This forms the inlet of the vacuum conveying system.

The vacuum entrainment hopper is a mobile unit and is specially designed to be an exact fit with the cutter head. Our design also allows it to be removed and re-fitted quickly at run up, when scrap cereal is produced. Only when the cereal reaches the correct temperature will it expand correctly, and that is when the vacuum entrainment hopper must be pushed into position quickly as our uniquely designed system allows.

Our vacuum conveying system uses heated air to convey the cereal. Reaching up to 120^oC depending on the cereal type of cereal. The heated air is produced by an electric air heater assembly ducted to the top of the cutter head. Heated air is drawn across the cutter head and into the vacuum conveying line. This prevents the case hardening of the cereal which occurs if conveyed at ambient factory temperatures.

The cereal is conveyed to one of two destinations of downstream process where the cereal is received into cyclones and directly discharged via rotary valves. We have created the rotary valves with specially designed Ingredient Batching Systems inlet feeders to avoid product chopping. This was a crucial design aspect of the project. Each rotary valve is also fitted with quick release rotor assemblies, with slide bar rotor extraction to enable quick and easy cleaning between product changes.

The fragile nature of the cereal product requires a very lean phase vacuum transfer system. We designed this system using centrifugal fans to provide a high air volume at a very low negative conveying pressure. The high air volume provides an effective cushion of air around the product to protect it from damage, and this distinctive Ingredient Batching Systems method is extremely successful for all types of fragile cereal products, including flakes; pillow shapes and coated cereals.