The automated handling of bulk materials: What sounds trivial, can quickly become an enormous challenge. Namely, when the raw material used turns out to be sticky, building bridges, lumpy etc. Such raw materials are the order of the day, especially in the field of textured vegetable protein (TVP), high moisture extrusion (HME) and the used plant-based proteins, fibers, cellulose and binders. Especially Soy, pea or wheat proteins can be both sensitive and thus sometimes tend to be stubborn, means either stick or bridge easily. The produced TVP can also be quite stubborn, meaning it sticks easily and has poor flow characteristics. So, you can see, it is not as easy as it seems and needs a lot of know-how on how to lay out the whole plant.
In order to be able to face possible challenges right from the start, you need a competent plant manufacturer at your side for the automation of such stubborn, free flowing or sensitive raw materials. And this is exactly where AZO comes in. The plant manufacturer from Osterburken, southern Germany, not only has more than 70 years of experience in the automation ofraw materials, but with its in-house laboratory for raw material it also has the possibility to analyze the raw materials to be able to precisely determine their physical properties and derive the resulting storage properties, eligibility, etc. Furthermore, almost all products can be conveyed on a trial basis in the pilot plant. This creates the perfect basic conditions for an optimal plant design and for all the raw material characters and challenges, AZO has an appropriate solution.
Artificial Meat: Already a permanent trend or still just a hype?
The market potential of artificial meat is enormous and should certainly be seen as a permanent trend and not just as hype. Soy, pea or wheat proteins, fibers, cellulose and binders are usually used in the production of such meat substitutes. But producing these substitutes and automating their handling into the production process poses some challenges. The Goal is clear: Feed the extruder with the blend of raw materials continuously, in the right time with the right quantity in addition with a consistently quality.
Automated raw material handling of proteins: The vacuum weighing system
Once, when the soybeans, pea or wheat are processed into a protein-flour, they get stored in big silos or big bags and are ready for the production of TVP or HME. This is where AZO’s expertise comes into play. The first challenge is to convey the proteins and additives out of silos or big-bags with a vacuum weighing system. But as already mentioned, some proteins and additives tend to flow poorly. A smooth and trouble-free unloading gets ensured by using discharge aids. The vibration bottom has become widely accepted as a discharge system since it is universally usable. It has smooth surfaces and no separate mechanically moved parts, making it very easy to clean as well as wear and maintenance free. Water condensation in the silo is avoided as no heated air is blown into bulk materials. In association with a correctly dimensioned silo cone, the vibration bottom provides symmetrical descent of the bulk material columns without funnel and bridge formation, thus guaranteeing “first in – first out”.
A dosing device is located under the discharge equipment for challenging raw materials into the conveying line: Either a rotary valve or a product feeder with rotating rotor, or a dosing screw with worm thread continuously transfer the needed raw materials into the conveying line. Dosing screws dose poorly flowing products with more precision than rotary feeder, if necessary.
But the job is not done yet:
Since proteins are only one part of a whole mixture to produce TVP or HME, it is necessary to take a closer look at the other essential conveying lines. Next to the proteins, other minor and major ingredients of the recipe, like flours, flavors or spices, fibers, cellulose and binders have to get added in the right quantity and time into a pre mixer.
Whether these raw materials are stored in silos, big bags or sacks – AZO has the right dispensing stations and discharge aids for every type of raw material. Due to the fact that major raw materials are usually easier to handle, it´s worth to have a closer look on the automation of minor and micro components for an economical production line.
System for minor ingredients automation and pre-mixing: AZO COMPONENTER® Family
The AZO COMPONENTER® in circular design is recommended when a small number of components need to be automatically weighed. Following this principle, the surge bins, such as feeding hoppers for sacks, pneumatically fed receivers or small silos are arranged in a circle above the collection vessel. They can be fed by vacuum or pressure conveying. Each component has its own discharge, dosing and scale unit, optimized to the specific raw material. Thus, parallel weighing processes and feeding of several mixing lines are possible.
The vibration bottom employed here ensures reliable transfer even for small components with poor flowing characteristics. The vibration dosing screw with locking device guarantees highly accurate dosing. The rotating / tipping scales project into a common collection vessel and empty intoit. From this point, the product is pneumatically transferred into the conveying scale, or depending on the application, transferred directly to the mixer. This AZO COMPONENTER® version can be used where intermixture of related products is permitted.
The AZO COMPONENTER® Step allows effective production planning
This system makes it possible toweigh minor and micro components automatically with accuracies down to a gram, such as colorings, flavoring agents, spices, fibers, cellulose and binders and numerous other micro quantities. The system improves product safety while simultaneously boosting production efficiency by reducing individual manual production steps to a minimum.
The system comprises two levels. The components are held ready in raw material storages on the upper level. Prior to filling, the raw materials can be identified using the barcode and allocated to the correct hoppers. This rules out mix-ups of a high numerous of products and ensures that raw materials can be traced back. The raw material storage can be filled from sacks or big bags; pneumatic filling is also feasible.
The target containers are positioned below the dosing points using a pneumatic drive. After the product is dosed with the quantity determined in the recipe, the target container is transported one step forward to the next dosing point. There are separate scales provided for each component for simultaneously weighing of components. This results in maximum time gain anda nearly infinity number of recipes that can get produced.
Once all raw materials are in the target container in accordance with the recipe, it is ready for the next process: The premixing of all your used components.
Get your all your components together
No matter in which way all the needed raw materials get dosed and conveyed: They get all together in the right quantity and time into a pre mixer. After all ingredients have been mixed, the finished blend is transferred to the next process step. This means that the mixer can produce a new batch immediately after emptying – regardless of the subsequent process. The buffer tank is again equipped with a discharge aiding vibrating floor and conveys the mixture further to a magnetic sieve and the proven AZO screening machine. In this way, possible impurities are immediately separated without the blend being segregated. A great advantage to ensure the quality of your end products.
Before the production of the TVP or HME can finally begin, another AZO system has to be used: The AZODOS® dosing system for volumetric dosing of products.
Time to feed the extruder with the AZODOS® system
The unit can be used in the food industry wherever production processes requirecoarse/fine flow at a uniform mass flow rate in connection with a weighing device. But how does it work? A weigh feeder consists of the basic unit mounted on a platform load cell or integrated in a 3-point weighing frame. The dosing screw meters the bulk material in coarse/fine flow to the downstream process. If the blend is still badly flowing, double screws can be used to aid. The amount of product that is metered out of the AZODOS® is weighed.
The system operates gravimetrically in accordance with the negative weighing principle. The AZODOS® becomes a loss-in weight feeder (DDW) when it is paired with a corresponding control system. The bulk material is discharged by the dosing screw. The actual loss in weight per unit of time (actualthroughput) is compared against the required setpoint, which is defined by the downstream process, e.g. extruder. Differences between the actual loss in weight per unit of time and the setpoint are corrected by changes in the screw speed.
The control process is briefly interrupted when the product in the AZODOS® reaches a preset minimum level and the surge bin is replenished. During the refill time the dosing screw output is set to a value based on empirical weight and output data gained from previous metering cycles. This leads to a maximum dosing accuracy with simultaneous easy to clean solution by means of an extraction device. Now it´s time to feed the extruder with the blend of raw materials continuously, in the right time with the right quantity. This all leads to a perfect quality of the final product
So it doesn’t matter what challenges arise when storing, conveying, mixing or dosing proteins, fibers, cellulose, binders and other raw materials: With an experienced and competent plant engineer like AZO, most problems can be eliminated before they even arise. “Don’t think in terms of problems. Think in terms of solutions,” as Johann Wolfgang von Goethe already knew.
