Without additional peripheral devices

The heart of the Master Plant is an inline dispersing machine that is directly mounted to the outlet of the mixing vessel. In contrary to conventional design and according to the required functions and the necessary process steps, the pumping and the dispersing areas have clearly been separated in this machine. A very effective stirrer is mounted in the inlet area of the machine type DBI 2000/.. (Direct Batch Inline). Its blades enter the conical section of the vessel and create strong turbulences which, in combination with the contra rotational spiral agitator, mounted in the cover of the vessel, result in a perfect homogenisation of the vessel content.

Below the agitator a fast running pump stage conveys the product to the dispersing machine DBI. By opening the integrated valve the product is led to the dispersing stage mounted below the pump stage. This dispersing generator consists of a fine rotor and a fine stator. Due to the resulting high shear stresses a very good dispersing quality is achieved. This guarantees for finest droplet and particle sizes as well as a high long term stability of the produced emulsions and suspensions. The special pumping rotor still admits big quantities of product to the dispersing generator, even at high viscosities of 100,000 mPas. This is an important advantage compared to conventional plants that allow conveying of big quantities only in combination with coarse, less effective generators. During dispersing the Master Plant can thus circulate the complete content of the vessel up to 20 times per hour, resulting in a clearly better quality within a rather short period of time. When dispersing is terminated by closing the valve, the product can smoothly be circulated, e. g. for cooling down while excluding avoidable shear stress. The product is discharged only by the conveying effect of the integrated pump stage. An additional discharge pump is not necessary.

After finishing the production process, the pump stage works as pure CIP-pump. The three spray nozzles integrated into the vessel cover are then fed with a cleaning liquid of 4 bar pre-pressure at highest speed. Since not all products are soluble, the Master Plant has been designed in a way that enables easy manual cleaning, too. A quick locking by a clamping ring, an electrically driven lifting unit for the upper part of the vessel as well as the possibility to pivot the upper part 135° allow a quick and easy opening of the plant.

The high flow speed between pumping and dispersing zone creates a vacuum of 20 mbar abs. Liquid or solid materials can thus be fed directly into the dispersing zone via the laterally mounted funnel – contrary to conventional processes – without an additional external vacuum pump. Since the additives are directly fed into the shear zone of the disperser, the particles are crushed immediately, thus avoiding agglomerates that are difficult to be wetted. The mixing vessel with conical bottom is equipped with a special type of spiral agitator that can directly be heated. Due to the turbulences created by the stirrer blades in the conical part and the high circulation capacity of the machine, a conventional contra rotating anchor stirrer is no more necessary. Moreover the spiral agitator can much easier be cleaned.

The complete spiral is made of stainless steel tube profiles and is fed with a thermal medium through a rotary union. The permanent contact of the agitator with fresh product results in a very effective heat transition. It has been proved by comparing measurements that the heating or cooling times could be reduced to about 50 % of that necessary in a conventional plant (no heat loss by an unheated stirrer). In order to avoid that material sticks to the vessel wall, the agitator has been equipped with movable PTFE scrapers that reliably remove the product from the vessel wall. Due to the conical bottom of the vessel even small quantities can be processed by the agitator without any problems. The spiral agitator has a radial as well as a tangential conveying effect and therefore achieves excellent mixing results even with high-viscous products.

The Master Plant is controlled via an industrial monitor with touch screen that is directly mounted to the plant. This allows to use the high flexibility of the plant and to trigger the different functions in a reproducible way for a constant product quality. The software is easy to understand, so that even a non-professional becomes familiar to it within shortest time and can operate the plant. The Master Plant is carried out in nine different standard sizes: 10 l, 25 l, 50 l, 100 l, 200 l, 500 l, 1,000 l, 2,000 l or 4,000 l useful volume. In order to reach a maximum flexibility regarding the batch sizes, the recirculation loop was equipped with two tangential runback sockets. By using the lower runback even a mini batch of 15 % of the nominal volume can be produced. Even in case of such small volumes an introduction of air can be avoided, since the runback always remains below the product level in the conical part of the vessel. When working with maximum filling the upper runback is used, i. e. a product flow over the total height and a recirculation of the complete batch. For exact dosing of the raw materials as well as the ready mixture, the vessel is equipped with load cells. This enables an exact weight measurement, since the periphery, like e. g. the stirrer, is separated from the weighing point of view. The described dispersing machine DBI can also be carried out as single machine for mounting to an existing vessel. It is provided in four different sizes and reaches capacities from 1,000 l/h up to 80,000 l/h.

The fields of application for which the Master Plant can be used are numerous. It is suitable for practically all dispersing tasks in the pharmaceutical or cosmetics industry, in the food industry and all corresponding processes in the chemical industry. Due to its technique and its great flexibility this plant can be used for R&D, as pilot plant for small quantities but also for industrial mass production. All standard applications like water-in-oil (W/O) as well as oil-in-water (O/W) emulsions are of course produced in best quality.

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