When hunger strikes between meals, many of us reach for a sweet or savory granola bar. Whether with cereal, dried fruit, nuts, or chocolate, there are granola bar flavors for every craving.
amixon® mixers play a crucial role in the production of these tasty snacks. Capable of creating a highly homogenous mixture without crushing the individual ingredients that make each flavor of granola bar unique, the amixon® Twin-Shaft Mixer HM is an essential component of muesli and granola manufacturing lines.
When mixing cereals and grains, it is essential that the fragile ingredients are not crushed and that no dust is created during the mixing process. amixon® mixers were built precisely for challenging manufacturing processes like these.
The mixing vessel consists of two cylinders that have been fused together, and a helical mixing tool is mounted in the center of each cylinder. Both mixing spirals rotate in the same direction and are designed with a slight incline of 30°, a patented design called SinConvex®. The diameter of the mixing tool is wide enough to convey nearly a quarter of all the goods within the vessel in just a single rotation.
The mixing blades capture the ingredients on the periphery of the mixing vessel and guide them upwards, where they then flow downwards along the central shaft of the mixer. In the space between the upward flow on the periphery and the downward flow in the center, a three-dimensional current is created within the mixing goods. By creating a flow within the mixing goods that is free of dead-space, the HM Twin-Shaft Mixer is able to achieve a mixing homogeneity that is virtually impossible to improve. The mixing process is particularly gentle and energy efficient, with an adjustable peripheral mixing speed between 0.5 and 3 meters per second.
amixon® Twin-Shaft Mixer HM with 3000L production volume
Ideal mixing results can be achieved regardless of the handling characteristics of the goods to be mixed. Designed to create this three-dimensional flow even at extremely low filling levels, the Twin-Shaft Mixer HM can effectively create a homogenous mixture even with a volume of just 10 to 15 percent its capacity. An amixon® mixer with a volume of 10,000 liters could mix a thousand-liter batch just as well as a 10,000-liter batch. This versatility allows for the mixing of varying recipes with dramatically different ingredients or batch stipulations, all within the same device.
Formulations mixed on smaller equipment, such as laboratory mixers in product development settings, can be scaled up for production on larger equipment without compromising on mixing quality or process flow.
Verströmung im amixon® Doppelwellenmischer mit SinConvex® Mischwerkzeug
The motor and gearboxes are installed on top of the mixer, outside of the mixing vessel. This ensures that no product ever comes into contact with the mechanical components of the mixer, a hygienic design detail that complies with food safety regulations such as those laid out by the FDA.
When mixing potentially combustible ingredients, a dust explosion can be prevented by adjusting the peripheral speed of the mixer can be fixed to less than 1 meter per second. amixon® mixers can be designed and certified based on the zone divisions defined by the customer in accordance with the ATEX regulations.
The entire mixing vessel, including the shaft, blades, and all other surface areas that come into contact with the product, are welded and flush. Right angles are designed in accordance with current EHEDG regulations and 3-A sanitary standards. The finish on the surface material of the mixer can be customized as desired, while the finish on contact surfaces is always determined on a case-by-case basis in accordance with customer requirements. If extensive cleaning between batches is required, or if the product is prone to producing buildup, a smooth finish without crevices can be advantageous. Other factors to consider when choosing a surface finish include the color intensity of the mixing goods, and whether the mixer will be cleaned using dry or wet methods.
In the case of sweet granola bars, the often sticky ingredients mean that the mixer must be cleaned in between batches to keep the taste from impacting subsequent mixtures. amixon®’s patented WaterDragon® technology provides excellent wet-cleaning functionality, a crucial feature for manufacturers of varying granola bar blends.
WaterDragon® is permanently affixed within the mixing vessel, where it emerges from behind a closure flap during cleaning, and retracts during the mixing process. Driven by the pressure of the water it dispenses, the washing head rotates as seven nozzles spray the entire interior of the mixing vessel.
The mixer is designed to automatically begin the cleaning process after discharge, to empty itself of the residual water, and finally to dry itself. During drying, large amounts of warm air are funneled through the main nozzle of the WaterDragon®, past the rotary washing head, and into the mixing room. Once the interior of the mixing vessel is completely dry, the washing head then retracts and the closure flap seals shut, leaving the mixing vessel completely air-tight.
The cleaning process with rotary washing heads
WaterDragon® washing mode
WaterDragon® drying mode
The dimensions of the mixer can also be customized. Here too, we offer innovate solutions tailored to the exact needs of our customers. Using modular construction techniques, it is possible to visualize precisely how a mixer will integrate into a production line. This helps us proceed with a more holistic view of the customer’s vision, as well as to identify potential problems or bottlenecks in the production line.
The amixon® mixer can also be customized to accommodate a variety of filling methods. Whether ingredients are fed into the mixer individually in a fixed sequence or together all at once, the Twin-Shaft Mixer HM will still produce a perfectly homogenous mixture. Integration with upstream and downstream processing equipment can be achieved via standard connections or other methods according to the customer’s needs. For the production of sweet granola bars, the ingredients are typically loaded into the mixer via a common template weighting container.
In order to keep the ingredients at the correct warmth for subsequent production stages, the amixon® mixer is jacketed and equipped with temperature control that protects the product from undergoing any unwanted chemical changes. In the case of sweet granola bars, the temperature control within the mixer serves as a means to preheat the ingredients before they are coated with liquid chocolate during a later processing stage. In addition to mixing the goods, a goal of this processing stage is to disperse some liquid chocolate throughout the heated cereal mixture, thus enhancing the flavor.
The mixing vessel is heated via hot water, which flows between its double-walled surfaces. For certain applications, the mixing shaft and mixing blades can also be jacketed and heated.
After the mixing process, a closure flap opens and the heated goods are emptied out from an outlet flush with the bottom of the mixing vessel. amixon® mixers can be equipped with one or more electro-pneumatic outlets so that the mixing goods can be simultaneously discharged into two filling lines.
Example of a Twin-Shaft Mixer HM with a usable volume of 10 m³. The mixer includes four discharge outlets, each free of dead space and operating simultaneously. This model is equipped with eight CleverCut® inspection doors.