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The underlying paper examines the material behaviour of paperboard during three-dimensional forming, especially deep drawing with concave shape elements in the base geometry of the bottom. Therefore, a parametric geometrical description of the concave section is established. Experimental investigations to the material displacement and to appearing wrinkles and fractures at the wall of the samples related to stepwise increasing levels of the concave geometry prove a proposed material displacement theory as well as the hypothesis that material overflow from convex sections is delivered into concave sections. Secant length and concave radius turn out to be of significant influence for the load that is applied to the material. Paperboard early reaches its maximum strain at break in concave sections and thereby should reveal close limits for concave shapes. However, a considerable concave level can be formed without structural damage of the material. Furthermore, the investigations show that there are possibilities to support the strain conditions in the concave section. Copyright © 2014 John Wiley & Sons, Ltd.

Optimization of the quality of deep-drawn cups requires methods for precise measuring of quality criteria. This paper presents new objective methods to describe the quality of deep-drawn packaging components made of paperboard. The state of the art for quality analysis in three-dimensional paperboard forming is presented. Methods for the analysis of visual quality using image analysis and for the analysis of shape accuracy using surface scans are developed. Experimental results are used for the verification of the methods and for the investigation of influences of main process parameters. The new methods are found to be both precise and objective. A large blankholder force has been shown to cause an increasing number of wrinkles and has a negative influence on the shape accuracy. A high die temperature also increases the number of wrinkles but enhances the shape accuracy. The punch temperature has no effect on the number of wrinkles, but high punch temperature has a significant and positive effect on the shape accuracy. Copyright © 2014 John Wiley & Sons, Ltd.

The cleaning action of stationary coherent liquid jets impinging (a) vertically downwards on horizontal plates, and (b) horizontally on vertical plates, was investigated using three soft-solid model soil layers: (i) PVA glue on glass and polymethylmethacrylate (Perspex) substrates; (ii) Xanthan gum on stainless steel; and (iii) petroleum jelly on glass. The liquid stream nozzle sizes, mass and volumetric flow rates and mean jet velocities investigated were: PVA, 2 mm, 17-50 g s(-1) (0.06-0.139 m(3) h(-1)), 5.3-15.9 m s(-1); Xanthan gum, 0.39-3.3 mm, 2.1-148 g s(-1) (0.008-0.53 m(3) h(-1)); 4.5-31.7 m s(-1); petroleum jelly, 2 mm, 7.8-50 g s(-1) (0.06-0.139 m(3) h(-1)); 2.5-15.9 m s(-1). For all three soils, rapid initial removal of soil from the jet footprint was followed by the growth of a nearly circular, clean region centred at the point of jet impingement. The rate of removal of soil decreased sharply when the cleaning front reached the hydraulic or film jump. The data for the radial growth removal stage were compared with a mathematical model describing removal of the adhesive soil layer, where the force on the cleaning front was evaluated using the result reported by Witsun et al. (2012): their theory gave the momentum of the liquid film; this momentum was balanced against the soil strength, giving a simple relation between the cleaned radius and time. All three soils showed reasonable agreement with the model, across the range of flow rates and temperatures studied. The kinetic constant in the model was sensitive to soil layer thickness and the nature of the soil. Cleaning tests on the petroleum jelly soils at different temperatures, and separate theological measurements, showed that the kinetic time constant for coating removal was proportional to the (critical shear stress)(-1.8). There was good agreement between resultsobtained with vertical and horizontal plates for the PVA and Xanthan gum soil layers. The petroleum jelly results differed, which is partly attributed to differences in preparing the layers of this theologically complex material.

Die Reduzierung des Ressourcenaufwandes fur Reinigungen in der Lebensmittelproduktion ist okonomisch und okologisch sinnvoll. Deshalb wird hier durch die Identifikation relevanter Verfahrensparameter das Potenzial der pulsierenden Spritzreinigung zur Steigerung der zeitbezogenen Reinigungseffizienz aufgezeigt. Der Einfluss der Frequenz sowie der relativen Einschaltdauer bei variiertem Volumenstrom wurde untersucht und ein signifikanter Einfluss der relativen Einschaltdauer nachgewiesen. Mit geeigneten Pulsationsparametern sind erhebliche Einsparungen von Reinigungsflussigkeit moglich. The reduction of resources needed for cleaning in food processing plants is economically and ecologically sensible. In this paper, the potential of the pulsating jet cleaning to increase the time-based cleaning efficiency is demonstrated through the identification of relevant process parameters. The influence of the frequency as well as of the duty cycle was studied at varied flow rate on a model soil, and a significant effect of the duty cycle has been demonstrated. With suitable pulsation parameters substantial savings of cleaning fluid are possible.

Paper and paperboard are widely used in various types of packaging. Paper-based packaging is a recyclable, biodegradable, renewable and sustainable product, which gives it certain advantages over most plastic-based packaging materials. Although paper-based packaging, in some areas, lacks attractiveness in terms of visual appearance, 3D forming is an important method for producing advanced shapes from paper and paperboard, suitable, for instance, for modified atmosphere packaging. That said, very little is known about the deformations experienced by paper-based materials in 3D forming. Understanding the role played by the mechanical properties of paper and paperboard in the 3D forming process is key to improving performance. This paper presents experimental results obtained using three different forming devices designed to be used with paper-based materials and links the formability data with specific mechanical properties of the paperboard samples. Paperboard properties that were found to correlate with formability were as follows: compressive strength and strain, tensile strain, paper-to-metal friction and out-of-plane stiffness. The requirements for formability are different for the fixed blank forming process and sliding blank forming process. Copyright © 2013 John Wiley & Sons, Ltd.

The enhancement of the cleaning efficiency of cleaning-in-place (CIP) systems is playing a key role in improving food production. Cleaning models based on computational fluid dynamics (CFD) can be a tool that enables identifying locations in a plant that are difficult to clean and enhances the cleaning efficiency by appropriate fluid dynamics, that is, the application of transient flow. A CFD cleaning model was developed that is based on the assumption of a mass transfer controlled cleaning process. The physical basis of the model is the analogy between heat and mass transfer. A validation of the cleaning mechanism, using experimental data of local cleaning times in several complex geometries with varied static and transient flow velocities, was carried out. A modified waxy maize starch with phosphorescent tracers was used as model food soil. The received results show a good agreement between the measured and simulated cleaning times. The cleaning model is suitable for the calculation of the cleaning prog...

The ultrasonic sealing (USS) is a new and modern possibility to seal peel films for packaging, for example for food and for medical packages. The heat conductive sealing (HCS) in contrast is already well described in science and practice. This study is a comparison of the effectiveness of both the USS and the HCS method using low-density polyethylene/isotactic polybutene-1 peel films. The influence of the recipe of the film, i.e., the amount of the peel component used and the thickness of the peel layer, as well as the sealing parameters, i.e., the sealing temperature, time, and pressure in case of HCS and the sealing force, time, and amplitude in case of USS, on the peel behavior were investigated. To characterize the peel behavior, the peel force, the maximum peel force, and the fracture mechanics, energy release rate were used. The sealing force has a strong impact on the peel properties. This behavior is similar to the influence of the sealing temperature. The peel behavior can be adjusted by varying the content of isotactic polybutene-1. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Zbog sigurnosti potrošača i osiguranja visoke kvalitete proizvoda nužno je provesti pouzdane postupke čišćenja u prehrambenoj industriji. Za održavanje konkurentnog položaja potrebno je kontrolirati troškove tih cleaning in place (CIP) postupaka, na primjer troškove za slatku i otpadnu vodu, deterđente, i svesti na minimum vrijeme prekida rada proizvodnih pogona. Čišćenje mrlja od hrane raspršivanjem vode veoma je slabo istraženo, naročito matematički prikaz postupka. U ovom radu pokazujemo da se model visokog tlaka autora Leu et al. može, uz neznatne adaptacije, primijeniti na čišćenje mrlja raspršivanjem vode niskog tlaka. Primijenili smo postojeći analitički model za relaciju čišćene širine kao funkcije standoff udaljenosti i razmotrili različitu strukturu raspršene vode kao i specifično ponašanje mrlje pri čišćenju. Potvrdili smo analitički model eksperimentalnim rezultatima mijenjanjem promjera mlaznice., To meet consumer safety and high product quality there is a need of reliable cleaning processes in the food industry. To keep competitive position it is necessary to control costs of those cleaning in place (CIP) processes e.g. expenses for fresh and waste water, detergents and to minimize downtime of the production facilities. The removal of food soils with water droplet sprays are very little researched, especially the mathematical modelling. In this paper we show that the high pressure model of Leu et al. can be applied to low pressure spray cleaning of a food soil with marginal adaptations. We used an existing analytical model for the relation of cleaned width as a function of the standoff distance and considered the different structure of the water spray as well as a food specific cleaning behaviour. We validated the analytical model with experimental results by varying the equivalent nozzle diameter.

The deep drawing process of paperboard has proven to be comparable to deep drawing of sheet metal in only a few aspects due to the nature and completely different behaviour of the material. However the blank holder also plays a key role with regard to quality and rupture prevention at 3D-structures. The aim of this paper is to describe the capabilities of variable blank holder force trajectories to improve the distribution of wrinkles and the quality of 3D-structures. The results show that the blank holder force should be adapted to the punch position keeping the highest possible force level. The force can be increased during the drawing process and needs to be strongly reduced short before the blank is drawn out of the blank holder completely. The introduced force trajectories lead to a significantly improved visual quality increasing the initial height where wrinkles occur encouraging fibre to fibre movement at the beginning of the process. The results furthermore contribute to a better understanding of the rupture behaviour. The increase of the circumference towards the border of the blank can be used to generate a blank holder force design that does not lead to ruptures but is able to make more intensively use of the capability the material exhibits to avoid wrinkles or distribute them as uniform as possible over the wall.

High-intensity focused ultrasound is widely applied in tissue treatment as well as for heating of solid polymer materials. Previous studies investigating the heating effect in polymer materials utilized sound transmission through water or other fluids at low HIFU power. In this study, the ultrasonic transducer possesses a solid sound conductor made of aluminum and a high HIFU power of above 100 W was applied to heat solid PE-LD samples. Temperature measurements were performed by calibrated non-invasive infrared thermal imaging. A strong heating effect with heating above melting temperature and evaporation temperature within less than 1 s of irradiation was observed. Furthermore, the acoustic coupling defined by the force applied by the ultrasonic applicator to the polymer material was found to be fundamental to induce the heating effect. This investigation reveals HIFU for new applications in the field of polymer processing.

a b s t r a c t The improvement of the cleaning efficiency in cleaning in place (CIP) systems is playing a key role in enhanced food production. To achieve this goal it is essential to understand the mechanisms controlling complex cleaning processes. In this work, cleaning tests are conducted that combine complex geometries with complex food soils using a novel test method based on the local optical detection of phosphorescence (LPD). It combines (i) a cohesive food soil, (ii) complex pipe geometries and (iii) continuous observation of the cleaning progress to investigate the mechanisms of cleaning in immersed CIP systems. The experimental work is supported by CFD simulations. The obtained results show that for the specifications tested the cleaning process can be described as diffusion-controlled. This assumption is supported by CFD simulations that correspond well with the measured local cleaning times. Furthermore, the knowledge of the mechanisms that control cleaning is essential for any optimization of these processes. Based on the presented results it is now possible to visualize the effect of complex pipe geometries or inappropriate hygienic design.

The closure process for packaging is a key process. It ensures the protective function of packaging and assures the packaged goods a long life. In this context, efficient and reliable sealing processes are essential for the production of sustainable packages. In this paper, several characteristics of the ultrasonic sealing process will be discussed and accompanied by experimental results. The introduction provides an insight into the ultrasonic sealing process, its heating mechanisms and the process steps. A comparison is made with conduction sealing. Furthermore, basic principles of heating and energy dissipation are related to the influences of the sealing parameters on the seam strength. The experimental studies were carried out on typical packaging films, such as polyamide-polyethylene laminates. The seam strength in ultrasonic sealing is compared with that in conductive sealing. A lower seam strength was found for ultrasonic sealing in all the tested films. Furthermore, the sealing behaviour of the packaging films contaminated with different kinds of foods was analysed for both sealing methods. Although the ultrasonic sealing method has marginal advantages for bulk materials such as wheat flour, conduction sealing was shown to be better for other products. A comparison of the energy consumption during the ultrasonic and conduction sealing verified the advantages of ultrasonic sealing. In particular for thick packaging films, the amount of energy required for bonding is significantly lower than for conduction sealing. In summary, this paper provides a survey of the characteristics of the ultrasonic sealing method in packaging applications – its advantages and limitations. Copyright © 2011 John Wiley & Sons, Ltd.

SUMMARY Three-dimensional forming is a key technology for the application of sustainable materials, like paperboard, in packaging technology. Until now, deep drawing is not considered as a suitable process for manufacturing of packaging components with advanced geometrical design because of the sensitive process and a large number of failure mechanisms. To better understand and apply the physics of deep drawing, the process was studied by experimental investigations. Therefore, an evaluation strategy for formed parts was developed to describe their quality by measurable values. The influence of the technological parameters temperature configuration, moisture content of material and blank holder force on the quality of formed parts was described by a statistic regression model. This model gives an indication of the quantity and the direction of effects that parameter changes have on the quality of 3D-formed parts. An optimization of the process according to quality criteria showed that, in a first step, the quality of cylindrically drawn paperboard parts was increased drastically compared with that of the state of the art. Furthermore, the existing limits in the height of formed parts were exceeded, and the geometrical shape of the base offered far more opportunities for packaging design than expected. The process turned out to be suitable for a flexible manufacturing of packaging components for multipart packages from paperboard, which are highly sustainable in terms of recycling and reuse of fibres and thereby able to compete in the marketing-oriented packaging sector. Copyright © 2011 John Wiley & Sons, Ltd.

The use of slow (∼1 Hz) flow oscillation imposed on a stationary flow of liquid has been shown to enhance shear stresses imposed on a surface and to mitigate fouling or enhance cleaning. Examples of the application of pulsed flow are presented in this paper. A new measuring technique in combination with tailored CFD simulations was developed for monitoring the cleaning of complex piping equipment with pulsed flow. A time-independent and isotropic approach to model the wall shear stress is introduced. The optical monitoring procedure uses a model food soil consisting of starch as matrix material and phosphorescent zinc sulfide crystals as optical tracer. Investigations of pulsed flow cleaning published prior to this work focused on tests with straight pipes, whereas difficulties in industrial cleaning operations more often arise while operating piping systems and plant components with complex geometries. Therefore cleaning experiments were performed in a CIP test rig simulating industrial cleaning processes. The results with pulsed flow show an enhancement of cleaning efficiency at locations difficult to access using stationary flow.

Eine aktuelle Untersuchung gibt Aufschluss uber den Einfluss der energetischen und topographischen Oberflacheneigenschaften auf die Verschmutzungsneigung und Reinigbarkeit verschiedener modifizierter Oberflachen bei Lebensmittelverschmutzungen.

Efficient cleaning is crucial in the food industry due to increasing safety needs, cost pressure and diminishing size of production batches. In Cleaning in Place (CIP) systems different flow types provide the cleaning effect by interaction, wherein falling liquid films make a significant contribution to cleaning. The flow of falling films can be significantly influenced by the design of the surface and, for example, of the tilt angle. In a previous publication it was shown for a low tilt angle of 30 degrees that for resource efficient cleaning a low wetting rate is suitable. It was pointed out that mean wall shear stress and mean flow velocity have an influence on the cleaning progress. In this paper the investigations are extended to describe the influence of the surface inclination in the range of 30-90 degrees on the flow and cleaning behavior of zinc sulfide/Xanthan gum soil layers on stainless steel for film Reynolds numbers of 1190-3110. The results show that the tilt angle has a major impact on the film thickness, wall shear stress and the mean cleaning rate. Cleaning results for three different stainless steel surfaces show that a low surface roughness does not necessarily lead to a better cleaning result.

The removal of layers of a model food soil (dried Xanthan gum containing fluorescent ZnS particles) by a vertical water jet impinging normally on to the plate, generated by a solid stream nozzle which moves across the plate was reported by Kohler et al. (2014) . Their experiments investigated nozzle pressures from 0.5 to 2.0 barg; nozzle diameters from 0.84–2.66 mm, nozzle-layer separation of 20 mm, and nozzle traverse speeds of 2.1–126 mm s−1. The flow parameters and separation are smaller than those typical of industrial jet cleaning operations. The model developed by Wilson et al. (2014) [Chem. Eng. Sci. 109, 183–196] for cleaning of similar layers by a stationary impinging jet was modified to describe the case of moving nozzle. This new model predicted the trends observed in the experiments, and analysis of the data yielded a similar cleaning rate constant to that obtained previously for cleaning of similar layers by stationary jets. The model predicted a non-circular cleaning front which matched that extracted from new experiments in which the flow was interrupted in order to capture this feature. The model allowed the cleaning performance indicators suggested by Kohler et al. (2014) to be expressed quantitatively: these indicated that higher nozzle traverse speeds give increased cleaning time, energy and liquid consumption performance.

Energie- und signalverarbeitende Systeme vgl. Bd. 2, Teile I, VII, IX, Bd. 3, Teile I, II, III und IX.

The term processing machines refers to a large variety of machines and equipment for the mass production of consumer goods. Processing machines are often specially tailored according to the particular processing task they have to fulfill, such as pasteurising milk or packing goods. Furthermore the vast majority is characterised by large production outputs, demanding high processing velocities and fast moving parts. A special application is that of the food and drug processing area. Due to high quality standards there are special requirements for material surfaces to be considered if surfaces are in contact with the manufactured product. This chapter deals with the special demands concerning dedicated engineering materials that occur from state of the art processing machines. Specific requirements ranging from high damping abilities for support components to high stiffness and low weight for fast moving tools are presented by means of a general classification of processing machines into four functional areas. Accordingly, the proposed hollow sphere structures and similar material classes are presented and applied on each of these four areas.