For the production of soaps, different base materials have to be provided for automatic further processing, depending on the recipe. The range extends from light-bodied oils or perfume base materials to semi-solid fats and color suspensions to tough waxes. After production, the sometimes corrosive and abrasive residues have to be disposed of. Modular and robust drum and air-operated diaphragm pumps are suitable for all these applications, because they gently and reliably convey a wide variety of media.

Today, the vast majority of soap variations are produced according to special formulations from many individual components. This begins with the selection of raw materials for the actual saponification process and continues with additives such as care substances, color pastes or waxes, and even perfume components. All components have different properties in terms of viscosity, chemical characteristics or flash point. Nevertheless, they must be reliably and safely fed into automatic production from the delivery containers. The Kappus Group, a traditional company founded in 1848, produces 20,000 tons of base soap annually. For this purpose, the company relies on proven feed pumps from Flux for the production of solid soap at its Heitersheim site, because the modular design consisting of pump and drive always allows the right pump configuration to be configured for the respective medium.

Flexible pumps convey a wide variety of raw materials
Modern soap production is largely automatic and mixes the individual components to the desired starting product according to specifications. For this purpose, the respective raw materials and additives delivered in different containers have to be transferred to the feed tanks in production. Despite the variety of substances, only three different pump models are used at the Heitersheim soap manufacturer. Ulrich Kneip, Head of Technology at Kappus, explains why: "Two barrel pumps of the type F 430 S and FP 42 4S and a stainless steel FDM 25 S/ TT air-operated diaphragm pump provide us with the required bandwidth for all the substances used in production, thus drastically reducing the effort required for spare parts storage, operating instructions and reserve pumps. The modular design, consisting of the actual pump and the drive motor, also allows us to change parts quickly if necessary. For example, a normal drive can be quickly exchanged for an explosion-proof model if necessary, or a more powerful motor can be used for highly viscous fluids to achieve the desired flow rate. In addition to easy motor replacement, however, quick disassembly for cleaning is also an advantage that should not be underestimated in order to react flexibly to changing product components."

Sophisticated pump technology
The modular system offers pump drives ranging from simple commutator motors to brushless motors for practically wear-free continuous operation, to three-phase gearmotors or a compressed air drive. On request, the motors can also be supplied with speed adjustment, e.g. for infinitely variable regulation of flow rates at any time. All drives are mounted on top of the shaft of the drive shaft in the two pumping units and tightened with just one nut. This makes them
easy and quick to change. Depending on the pump model, medium and drive, up to 220 l/min at a pressure of up to approx. 26 mWS (approx. 2.6 bar) can be pumped with the electric drives. The air motor achieves delivery rates of approx. 240 l/min at 30 mWS (approx. 3 bar). The suction geometry of the FP 425 model is designed for low residual volumes and allows, for example, drums to be emptied by more than 99%, i.e. almost completely. Two pump models in particular have proved particularly successful for soap production: the F 430 S model with a mechanical seal towards the drive shaft and the sealless version, type FP 424 S, with a specially designed shaft guide. All pumps used at Kappus in soap production are made of stainless steel with a special length of 1,500 mm (standard length is 1,200 mm for IBCs) so that they can be used universally. If required, materials such as polypropylene, polyvinylidene fluoride are also used, e.g. for special corrosive or caustic media.

Long service life
In both pumps, the outer delivery tube encloses the inner guide tube for the drive shaft. Good, smooth-running bearings for the drive shaft are important for pump function. Here, the pump specialists used two different approaches, depending on the medium: In the model with a mechanical seal, this seals the guide tube with the shaft at the bottom, directly on the pump, against penetrating medium. The shaft itself is supported and guided in several plain bearings inserted in the inner tube. This also allows, for example, the pumping of wax that has been heated up to 85 °C to reduce its viscosity. In contrast, the sealless model operates with a spiral-shaped guide bearing located approximately in the center of the shaft in the inner tube. During operation, this conveys penetrating medium back into the open, similar to an Archimedean screw. This design is therefore particularly suitable for low-viscosity fluids, including aggressive and fast-flowing fluids, which neither harden nor crystallize. The design prevents unwanted deposits inside, thus extending the pump service life enormously. Both pump models can be easily disassembled into their individual components for easy cleaning.

Diaphragm pump takes over disposal
In contrast, other pump characteristics are required for caustic solution preparation. For this reason, a robust stainless steel air-operated diaphragm pump with up to 178 l/min at 8 bar delivery pressure is used here. It pumps waste caustic from the collection sump into an intermediate tank for processing. Since the pump conveys even abrasive particles without any problems, it is ideally suited for waste disposal. The dry-running safe pump is dry self-priming and even flooding does not bother it. Its oil-free operation allows it to be used not only in soap production, but also in the pharmaceutical and food industries, as well as in applications involving wastewater, slurry, chlorine bleach
lye, cleaning agents, etc. Depending on the application, the pump is made of aluminum, stainless steel, PP or polyvinylidene fluoride. Despite the variety of substances to be pumped in soap production, only three universally applicable pumps and a few motor models are sufficient for production pumping. The modular design allows the
systems to always be set up in such a way that the finished pump is suitable for the particular material to be pumped. Maintenance costs, spare parts inventories and, last but not least, administrative expenses, e.g. for the necessary operating instructions, are reduced to a minimum.