Are there container mixers directly compatible with 200-litre standard drums, including validatable cleaning?
Yes, there are container mixers and drum mixers that work directly with standardised 200-litre drums. The drum itself serves as the mixing vessel. The product is thus mixed in its original container. Transfer operations are reduced. At the same time, product losses, dust generation and the risk of cross-contamination fall.
Steel drums, stainless steel drums or drums made of HDPE can be processed, for example. The use of liners is also possible. Such disposable bags are particularly suitable for single-use concepts.
Container mixers for standard drums usually work on the free-fall or tumbling principle. The drum is fixed in a holder and moved about one or more axes. The product is mixed by gravity and repeated relocation. Internal mixing tools are not required. The system thereby remains closed. This is of particular interest for hygienically demanding applications.
A further variant combines rotation with an eccentric tilting or tumbling movement. The mixing effect with poorly flowing or slightly cohesive powders can thereby be improved. For liquids, drum agitators are also an option. Here an agitator element is introduced through the lid or the bung hole. This principle does, however, create additional product-contact surfaces and increases the effort required for cleaning validation.
For safe operation, the drum must be held and locked reliably. Positive-locking clamping devices, centring aids and mechanical or pneumatic clamps hold it in a defined position. Sensors can monitor whether the drum has been inserted correctly and the locking device is closed. Only then may the mixing process start.
The total weight, the fill level and the position of the centre of gravity must also be taken into account. Depending on the mixing principle, the suitable fill level frequently lies between approximately 40 and 70 per cent. Only then can the product move sufficiently within the drum and be mixed uniformly.
There are two fundamental concepts for validatable cleaning. In the single-use principle, a disposable drum or a liner is used. After the mixing process, the product-contact insert is disposed of. The actual product contact area does not have to be cleaned. Validation concentrates on material suitability, chemical resistance and possible interactions between the product and the packaging material.
In the reusable concept, drums, lids, seals and, where applicable, adapters are cleaned after every batch. Product-contact parts must be of hygienic design. Dead spaces, crevices and areas that are difficult to access are to be avoided. For stainless steel components, a defined surface roughness of Ra ≤ 0.8 µm is frequently required.
Cleaning usually takes place in separate drum washing plants or specially designed cleaning stations. There, internal and external surfaces are cleaned with spray balls or rotary nozzles. Temperature, water pressure, detergent concentration and cleaning time are defined and monitored. The programmes can be stored and documented product-specifically.
A robust cleaning validation usually comprises DQ, IQ, OQ and PQ. In addition, limits for permissible product residues are established. MACO calculations, worst-case considerations and analytical recovery studies can form part of this.
Various methods are used to verify the cleaning effect. Riboflavin tests show whether all relevant surfaces are fully wetted. In addition, swab samples, rinse samples, conductivity measurements, TOC analyses or product-specific chemical detection methods can be used.
A container mixer for 200-litre standard drums can thus represent a hygienic and validatable solution. The prerequisites are a secure drum mounting, a suitable mixing principle, a clearly defined cleaning or single-use concept as well as complete qualification and validation documentation.
Drum- and IBC-based mixing concepts from amixon®: EM and COM
Yes, amixon® offers mixing systems in which the container itself is used as the process and mixing vessel. For small batches in a standard drum, the single-shaft mixer EM is available. Larger batches in IBCs and Mixtainers® are processed with the container mixer COM. Both systems reduce transfer operations, dust emissions, product losses and the risk of cross-contamination.
Single-shaft mixer EM: mixing directly in the standard drum
The single-shaft mixer EM is designed for batch sizes of approximately 5 to 200 litres. It is particularly suitable for small production runs, development tasks and just-in-time processes. The standard drum serves directly as the process vessel.
For filling and emptying, the mixing chamber can be rotated and inclined by up to 25 degrees. In the inclined mixing chamber, an intensive cross flow arises. Dry, moist and suspended solids are thereby mixed uniformly.
The EM requires little additional infrastructure. In many cases, standard drums, scales and a hand pallet truck are sufficient. Elaborate conveying technology is not necessary. The system can therefore also be integrated into existing production rooms.
The mixing intensity can be adapted to the particular product. For demanding tasks, cutting rotors or HighShearBlades are available. Microfine liquid additions can also be mixed uniformly into powders. The possible fill level ranges from approximately 10 to 100 per cent.
Depending on the design, the EM can be laid out for ATEX Zone 20. Formulations and process sequences can be controlled via a PLC. ERP connections, barcode capture and batch-related real-time documentation are also possible.
Container mixer COM: the IBC becomes the mixing chamber
The container mixer COM is designed for larger batches of approximately 100 to 4,000 litres. Here a Mixtainer® or a suitable standard IBC serves directly as the mixing vessel.
The SinConvex®-MultiPlane® mixing tool enters the container from above. The vessel is then sealed gas-tight. The mixing tool produces a three-dimensional restratification of the entire contents. Even component ratios of up to 1:100,000 can be distributed homogeneously.
After the mixing process, the mixing tool is unscrewed out of the container in reverse. The product remains in the closed container. Weighing in, mixing, intermediate storage and filling can thereby be separated spatially from one another.
The dockable Washtainer® is available for cleaning. It takes over the automatic wet cleaning of the mixing tool. Product changes can thereby be carried out quickly and reproducibly.
Less transferring, less contamination
With the EM and with the COM, the product remains in its container during the mixing process. Additional transfer points are avoided. This reduces dust, product losses and cleaning effort. At the same time the risk of cross-contamination falls.
Both systems achieve a high mixing quality even at low fill levels. They are therefore particularly suitable for contract mixers, formulation operations and productions with frequently changing batch sizes.
Hygienic design and validatable cleaning
The hygienic execution forms the constructional basis of the amixon® systems. Product-contact components have few or no joints. The mixing chamber and mixing tool are welded and ground to a high standard.
The mixing tool is mounted exclusively above the mixing chamber. A lower shaft passage is dispensed with. A particularly critical potential point of contamination is thereby avoided.
Large Clever-Cut® inspection doors provide good access to the product-contact surfaces. The OmgaSeal® seal, which has few dead spaces, supports permanently hygienic sealing. Discharge elements and transitions are also designed to be cleaning-friendly.
Depending on the application, integrated washing lances and fully automatic wet cleaning systems can be used. Dry and wet cleaning can thereby be clearly defined, carried out reproducibly and documented. Designs in accordance with EHEDG guidelines, FDA specifications and 3-A Sanitary Standards are possible project-specifically.
Verification through trials in the amixon® pilot plant
Before an investment, amixon® can examine the suitable mixing and container concept in the pilot plant in Paderborn. There, 35 test units of various sizes are available. Further pilot plants are located in Japan, India, Thailand, China, South Korea and the USA.
The trials are carried out with the original product. Real fill levels, batch sizes and the intended temperature and pressure conditions can be taken into account. Mixing quality, product protection, energy input, cleanability and reproducibility are examined, among other things.
The results are evaluated and documented together with the amixon® experts. This produces a robust technical and economic basis for decision-making on the choice between standard drum, IBC and Mixtainer® concepts.