Automated continuous mixing delivers real-time process assessment and consistency round the clock. Continuous mixers allow for all parameters to be constantly monitored and saved digitally, including ingredient stream rates, dough temperature, mixing energy input, throughput, mixer shaft speed, coolant temperatures, starts and stops, ingredient refill status, ingredient totalizers, dough totalizers, and many others.
Systems ready for the unexpected: Exact Mixing
Exact Mixing’s continuous mixing systems, for example, are fully automated, meaning that the operators need only respond to alarms in case readings show parameters deviate from preset values, which doesn’t happen very often. The collected data is saved and used to generate graphs to compare actual values against set points. Information quantifying the dough production is also available, with details about its current progress, the amount completed per shift, or sorted by any other criteria that are useful to production.
“In the control system, all parameters are constantly monitored, and statistical analyses of parameters are available. The available information is only limited by the imagination of the person seeking the data,” Jim Warren, Vice President, Exact Mixing, explains.
“Technology is constantly improving”
To ensure accurate ingredient metering into the mixer, Exact Mixing is ensured using technology including loss-in-weight dry metering technology and mass flow liquid metering technology. The measurements recorded are continuously compared with the setpoint data to adjust the process if necessary, or issue warnings if automated corrections are not possible, to protect consistent dough quality.
The company has recently developed systems that accurately meter ingredients such as solid shortenings, nut-butters, diced cheese, and dried fruit. Its continuous mixing technology also receives regular improvements. “For example, we now offer five distinct continuous mixing models for different applications and customer requirements. The HDX Mixer is just one example of technology expansion,” he details. More recent technology breakthroughs include the high-speed developer and Hydrobond Technology instant hydration unit, which can be fitted onto existing systems.
In addition to these advancements, automation features can be included, with many options available to choose from, such as the automated control of the ingredient and water temperature, automated dough re-work, automated control of the dough hopper level downstream – to name a few.
VMI in the mix: VERYMIX
VMI’s VERYMIX continuous mixer also monitors and controls several parameters, including the energy throughout the process. “From premixing to the end of the mixing process, the viscosity and the formation of the gluten network are monitored thanks to the energy tracking,“ explains Mélanie Gay, Marketing & Digital Development at VMI. Everything can be managed from the HMI, from recipe formulation, dosing, programming, to monitoring and traceability.
Pre-hydration can also be controlled; VMI’s horizontal pre-mixer (HPM) integrates ingredients in the bowl in two zones, one for powders and one for liquids in the form of spray droplets, and a third zone specific to mixing. “Flour, sugar and other baking ingredients are combined with water and immediately form a homogeneous dough and the beginning of a gluten network,” VMI’s specialist explains. These steps are designed to make the mixture more homogeneous and the process more effective, allowing for a wider range of hydration, from 40% to 110%. The HPM works directly above the VERYMIX, and continuously transfers hydrated raw materials into the mixer underneath, where the dough is mixed to the required consistency.
To maximize efficiency, the VERYMIX offers a wide range of mixing parameters that can be used according to the production criteria, and quality required: the mixing rotor is adapted to the dough, the bowl shape is optimized for continuous operations and times and mixing intensities are adjustable. This level of process control allows for flexibility.
Very accurate dosing
The VERYMIX continuous mixer automates powder and liquid ingredient dosing as well as scrap dough management. Flour, salt, sugar, powdered milk, gluten, improvers and other raw materials are weighed by three stainless steel load cells. These load cells can be fed automatically by intermediate hoppers, or by manual loading hoppers (big-bags). Water, egg, milk, liquid yeast, flavorings, liquid sugar and brine are also precisely dosed. The system features dosing pumps and electromagnetic or mass flow meters to weigh liquids.
The quantity of scrap to integrate can also be dosed: “Scrap dough should not be neglected: for bread, it can amount up to 25% of the weight of the flour and for some puff pastry, it can even surpass 50%,” Gay highlights. The VERYMIX continuous mixers make it possible to automate the flow management towards resting phases or for a transfer to the line, while also reintegrating the dough scraps.
The new modular Codos® kneading system
Zeppelin’s new CODOS® mixing and kneading system also brings innovations for continuous operations. After modernization and reworking, the Codos® system concept has been repositioned and introduced to the market as Fresh-Up, a modular mixing and kneading system with new components. The complete system consists of a CODOS® tower, a DymoMix® and a CODOS® NT kneader. The CODOS® tower is the initial unit in the system. It consists of a storage container with a mixing tool and a differential weigh feeder positioned underneath to produce a continuous and constant mass flow of powdered raw materials.
The DymoMix® hydration system can be used as a premixer in the Codos® system and as a complementary production step between dosing and kneading of doughs or other further processing steps. “The special feature is that powdery components are hydrated with water or oil, immediately forming a homogeneous mixture. This procedure allows the production of improved-quality dough. Hydrating with water or oil is accomplished by a specially-designed nozzle built into the rotating shaft of the unit. This forms a liquid film through which the powdered particles must pass, becoming hydrated. Unlike conventional systems, a high-pressure water jet is not used for hydration. As a result, even with low moisture contents, a high-quality product can be produced, ready to be processed immediately without intermediate steps,” Dr. Christian Faber, Senior Technology Consulting, Zeppelin Systems, elaborates. The CODOS® tower and DymoMix® and CODOS® NT kneaders can be used in different combinations, for different applications.
The dough is formed in the horizontally operating continuous CODOS® NT kneader. “Special helical interlocking twin shafts apply the energy required for kneading to the dough. This forms the gluten structure of the wheat dough.
The bow shape of the kneading attachments on the twin shafts ensures gentle kneading without cutting the dough. The energy input required for the specific product can be controlled via the speed of the kneading shafts, as can the dwell time of the dough. Thanks to a double-walled, temperature-controlled trough design, the dough always maintains the desired temperature. This allows the specified temperature of the dough to be maintained within narrow limits,” Faber explains.
With an output range between 500 and 6,000 kg/h, the new generation of CODOS® NT is a step up in terms of capacity and efficiency over previous models. Advantages include precise temperature control, raw material metering accuracy, and low energy and maintenance requirements. The main area of application for the CODOS® system are monolines, where production can run around the clock. The same system can be used for doughs with broadly differing requirements and characteristics.
Read the full article in Baking+Biscuit International, issue 2.
Lead photo credit: VMI
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