Industrial Roller Research Articles

Minimizing the Cycle Time of a Roller Hearth Furnace for Hot-Forming Die-Quenching

In most hot forming die quenching (HFDQ) processes, roller hearth furnace parameters, including roller speed, blank layout, and zone temperatures, are adjusted by trial-and-error. The resulting solution is always suboptimal and often leads to incomplete austenitization. This paper presents an optimization procedure for an industrial roller hearth furnace for minimizing cycle time, structured around a thermo-metallurgical model used to determine the total heat load, dropout temperature, and austenite phase fraction. Imposed constraints include minimum fraction austenite and burner capacity, and the optimization problem is solved using nonlinear programing. The outcome highlights the potential of improving process efficiency through design optimization, and the importance of high-fidelity metallurgical modelling.

Temperature Prediction Model for Roller Kiln by ALD-Based Double Locally Weighted Kernel Principal Component Regression

In the roller kiln of cathode materials for lithium batteries, the timely measurement of temperature is very important for effective process control. However, it is sometimes difficult or costly to measure the temperature timely. To handle this problem, a kind of soft sensor modeling framework with double locally weighted kernel principal component regression based on approximate linearity dependence (ALD) is proposed, which simultaneously carries out sample and variable weighted learning in the high-dimensional and nonlinear space to solve the process time-varying and strong nonlinearity problems. Moreover, a kind of just-in-time learning framework based on ALD is adopted for selectively updating the online local models. By setting a reasonable threshold of ALD, the prediction time can be effectively reduced, and the prediction accuracy can be maintained. The effectiveness of the proposed method is demonstrated on an industrial roller kiln. The results show that the proposed method can meet the requirements of prediction accuracy and time efficiency of the roller kiln of cathode materials for lithium batteries.

Glazed tiles produced using paper sludge, glass cullet and a natural red clay: an experimental study

The paper describes the production, in single fast firing, of tiles containing 30 wt% of a natural red clay and a mixture of 42 wt% of paper mill sludge and 28 wt% of glass cullet which were coated with a commercial ‘matt white’ glaze. Fired materials have been characterized as a function of the top temperature (1090 or 1140 °C) reached at the top of the fast sintering process made by an industrial roller kiln. It has been observed that tiles fired at 1090 °C display the best overall performances because the matt glaze well covers the substrate, thus ensuring that the mechanical and physical properties of the tiles conform to the official standard.

Model-based approach to the design and scale-up of wheat milling operations — Proof of concept

In this proof-of-concept study, we consider the problem of finding the conditions at which an industrial wheat milling process should be operated to provide a product with assigned quality from a given wheat variety. We propose an approach where mathematical models are used to assist the miller in determining the required operating conditions. The basic idea we explore is to move most of the experimentation from the industrial-scale equipment to a small-scale one where data can be obtained more quickly and at an inferior cost. The operation of an industrial roller mill, whose milling gap is the operating variable to be determined, is used as a test bed to assess the feasibility of the proposed methodology. An extended set of data deriving from experimentation in a small-scale mill are used jointly with a dataset from the industrial mill to design a multivariate statistical model based on latent variables, which is then inverted to find the desired operating conditions. The results show that the proposed approach is viable and is particularly effective when the industrial-scale dataset is limited. It is also shown that near infrared spectra can be effectively used to characterize the wheat feed.

Energy-Oriented Modeling and Optimization of a Heat Treating Furnace

In this paper, we develop an energy-focused model of an industrial roller hearth heat treating furnace. The model represents radiation heat transfer with nonparticipating gas and convective heat transfer. The model computes the exit temperature profile of the treated steel parts and the energy consumption and efficiency of the furnace. We propose a dual iterative numerical scheme to solve the conservation equations and validate its efficacy by simulating the dynamics of the furnace during startup, as well as for steady-state operation. A case study investigates energy consumption within the furnace under temperature control. We first consider a heuristic control strategy using simple linear controllers. A response surface approach is then used to find the optimal set points that minimize energy consumption while ensuring desired part temperature properties are met when processing is complete. With optimized set points, 4.8% less energy per part is required versus the heuristic set points.

Industrial Roller Milling Process Characterisation for Targeted Bread Quality Optimization

Out of all satisfying and palatable foods, wheat and other cereals play an essential role in human nutrition. In recent years, customers demand for functionalized flours with engineered properties contributing to well-being. This fuels the need for deeper understanding of the milling process and establishment of relationships between flour properties and product characteristics. To address this shortcoming, structural and functional aspects of starch and protein were investigated in all 33 flour passages obtained during the standard roller milling process of the most widely produced bread flour. Starch and protein alterations were examined on flour, dough and bread levels. Repeated milling cycles and higher impact towards tail-end passages result in compositional differences and increase in damaged starch. This creates weakened gluten networks exhibiting reduced elasticity and extensibility. Decreased viscoelasticity and hence gas-holding capacity result in low loaf volume. With multiple multivariate linear regression, a model could be established allowing for a 95% precise prediction of the loaf volume of the passages and composite flour produced with the same mill settings. This quality prediction of bread quality based on easily measurable parameters on flour levels offers a straightforward approach for a targeted optimization of the milling process.

Localized type Volkmann's contracture treated with tendon transfer and tension-reduced early mobilization

Rationale:For localized type Volkmann's contracture, in which degeneration of the flexor digitorum profundus (FDP) muscle to one or two fingers and restriction of finger extension occur, dissection or excision of the affected muscle is usually recommended. However, these surgical procedures need relatively wide exposure of the muscle, because the FDP muscle is in the deep portion of the forearm.Patient concerns:In this report, the case of a 35-year-old woman with localized type Volkmann's contracture is presented. Her left forearm had been compressed with an industrial roller 4 months earlier, and severe flexion contracture of the long finger and mild flexion contracture of the ring finger developed gradually.Diagnoses:localized type Volkmann's contracture.Intervention:Five months after the injury, transection of the FDP tendon to the long finger and transfer of the transected tendon to the FDP tendon to the index finger was performed after adjusting the tonus of these two tendons using a small skin incision. This procedure was followed by a tension-reduced early mobilization technique in which a tension-reduced position of the tendon suture site was maintained by taping the long finger to the volar side of the index finger, and then immediate active range of motion (ROM) exercise was started.Outcomes:Within 9 weeks after surgery, full ROM had been regained.Lessons:Using the treatment procedure presented in this case report, a good clinical result was obtained in a minimally invasive manner.

Wheat (Triticum aestivum L.) Bran in Bread Making: A Critical Review.

Wheat bran, a by-product of the industrial roller milling of wheat, is increasingly added to food products because of its nutritional profile and physiological effects. Epidemiological data and scientific studies have demonstrated the health benefits of consuming bran-rich or whole-grain food products. However, incorporation of wheat bran in cereal-based products negatively affects their production process. Furthermore, the organoleptic quality of the obtained products is mostly perceived as inferior to that of products based on refined wheat flour. This review summarizes the current knowledge on the impact of wheat bran on bread making, provides a comprehensive overview of the bran properties possibly involved, and discusses different strategies that have been evaluated up till now to counteract the detrimental effects of wheat bran on bread making.

Comparative evaluation of different thermally modified wood samples finishing with UV-curable and waterborne coatings

Thermally modified wood has been developed as an industrial method to improve durability and dimensional stability of wood and thus extends the range of uses and service life of wood-based products. Despite the improvements gained by treatment, surface finishing using coatings prevents esthetical changes such as color degradation or occasional growth of mold adding protection in outdoor use and extending the service life of products. The wood finishing process was carried out with commercially available waterborne and UV-curable coatings on industrially modified at 192, 200, 212°C and unmodified European ash (Fraxinus excelsior L.) wood, using an industrial rollers system and a laboratory brushing system. Changes caused by thermal treatment which could affect the surface finish were measured and compared with control samples, such as water uptake, wettability and acidity. Following the wood finishing, surface properties and esthetic changes were evaluated; as well as the coatings performance. Thermally modified wood presented improved adherence compared with unmodified wood with a significant improvement in samples modified at 212°C, which also present the highest hardness when UV-cured. Finishes with UV-curing maintain the hydrophobic effect of thermally modified wood, whereas waterborne finishes increase the surface wettability. Thermal modification did not negatively influence on the elastic properties of the coated substrate and thus allows this material to be finished with different coating systems in the same conditions as unmodified wood.

Hard α-Al2O3 Film Coating on Industrial Roller Using Aerosol Deposition Method

It is well known that α-Al2O3 forms very hard, highly insulating, smooth films. There is demand for the use of such films instead of conventional hard, smooth films; For example, industrial rollers such as calendering rollers etc. are always required to have a harder and smoother surface than conventional rollers. Therefore, this work investigated the specification of α-Al2O3 films, e.g., their wear resistance and chemical stability, using various tests. This paper also discusses whether α-Al2O3 film can take the place of Cr plating film as a hard, smooth film by comparing their wear resistance and chemical stability.

Industrial Rollers in PUR Made for Slaughterhouses

ndustrial rollers made in polyurethane, PUR, are made to be used in a conveyer system in slaughterhouses. The rollers are made by the company Dansk Gummiindustri A/S. During use the rollers or the materials give some problems with the durability. Break in the rollers come much earlier than expected. An intensively investigation of the rollers has therefore been made. The investigations have been on the mechanical and chemical properties of the rollers. During their lifetime the rollers are cleaned at least once per day with cleaning agents of different types. The mechanical forces on the rollers have been analysed. It has been assumed that the weight of the meat pieces have been 7 kg each. The force on the roller under use has been calculated by using Finite Element method, FEM. The strength of the roller has been determined to be 26MPa, and the maximum load on the roller under use has been calculated to be 1,8MPa, which is far from the 26MPa. The fatigue strength is not known, but from knowledge of PUR there should not be any risk of fatigue. The rollers can have different colours though they are made of the same type of material all of them. The colour differences of the rollers appear because the curing time is different for the rollers. Samples for testing if the curing parameters have any influence of the strength and the chemical resistance for the cleaning agents used in the slaughterhouses are made. The mechanical properties are not changed considerable because of different curing parameters, but the PUR in the rollers become more homogenous after long time curing compared with short time curing. Infrared spectroscopy has been used for proving that. Samples with different curing times have been influenced by cleaning agents, which are normally used at slaughterhouses. Five different agents are tested. Two of them are acidly agents and three of them alkaline agents. One of the acidly and two of the alkaline agents are further more oxidative agents. It can be concluded that the cleaning agents influence the properties of the rollers. If the temperature is increased the influence increases. The rollers influence most of oxidative and acidly products. The conclusion is that it can be recommended to cure the PUR to full cure. Furthermore it can be recommended only to clean them up with alkaline cleaning agents without oxidative agents added to the cleaning system.

CFD analysis of a syngas-fired burner for ceramic industrial roller kiln

Kiln burners for industrial tile production are usually fuelled by methane gas. However, the interest towards the use of coal or synthesis gases is rapidly increasing, mainly due to the opening of important markets in developing countries. The widely variable chemical composition of these fuels demands the gas burner to be adapted on case-by-case basis, since the firing parameters are strictly fixed, to guarantee the required temperature distribution within the kiln. In this context, computational fluid dynamics analysis represents a very convenient alternative to the traditional design based on experiments. In this article three-dimensional numerical predictions are presented for a syngas-fired burner. Three different fuels, two burner layouts and two burner nominal power are considered. Temperature, velocity and oxygen mass fraction distributions are discussed, and general design lines for low lower heating value gas burners are extracted.

Antioxidant properties of wheat mill streams

Knowing the quality of mill streams is very important for getting flours with improved quality. In the present work, 49 mill streams, obtained by milling common wheat with an industrial roller mill, were characterized in terms of phenolic content, antioxidant activity and iron content. The antioxidant activity was estimated using different methods: DPPH-radical scavenging, Trolox equivalent antioxidant capacity, and iron reducing antioxidant power. The break tailings and first tailings of the reduction passages had the largest contents of iron. The total phenolic contents (TPC) from flour streams ranged between 76.3 and 369 mg ferulic acid equivalent/100 g d.w. The highest TPC were obtained for the second fractions resulting from 1st and 2nd break rolls. The highest antioxidant activity was registered for flour streams collected from: the last two break rolls, the reduction rolls that process the tailings of the first three reduction passages and bran finisher. Trolox equivalent antioxidant capacity had the same trend as DPPH-radical scavenging activity. The highest iron reducing antioxidant power was found in the tailings of the reduction rolls. The knowledge provided by this study could be successfully applied for getting flour with improved antioxidant activity and iron content by mixing different types of mill streams.

Produção de revestimento cerâmico semi-poroso com adição de chamote de telhas

A indústria de cerâmica vermelha é em parte responsável pela degradação ambiental provocadas pelo jazimento das matérias primas, a queima dos produtos e o descarte dos resíduos cerâmicos após queima. Este trabalho tem como objetivo verificar a potencialidade de se produzir revestimento cerâmico, incorporando chamote de telhas a uma massa básica típica para produção de revestimento semi-poroso. A massa básica e o chamote foram caracterizados por fluorescência de raios X, análise mineralógica por difração de raios X. Corpos de prova foram confeccionados por prensagem uniaxial partir da massa básica aditivada com 5%, 10%, 15% e 20% de chamote, em seguida queimados em escala industrial em forno de rolo, com temperatura de pico a 1135ºC em um ciclo de 25 min, para depois serem avaliados do ponto de vista tecnológico: absorção de água, retração linear de queima, tensão de ruptura a flexão, porosidade aparente, massa específica aparente, perda ao fogo e por último analisados microestruturalmente por microscopia eletrônica de varredura. Os resultados encontrados mostraram que a adição de chamote de telhas provoca redução da resistência mecânica e aumento de absorção de água. Mesmo assim, os resultados encontrados para a formulação dopada com até 20% de chamote encontram-se dentro dos valores estabelecidos pela norma vigente.

Corrosion of high chrome wear part materials used in vertical roller mills

The corrosion resistance of two high chrome wear facings, manganese cold workable steel and heat treated white cast iron, was investigated. The addition of Cl− to the aqueous solution unexpectedly improves the corrosion resistance. Tribocorrosion experiments show that the current density increases but with magnitudes of no importance in industrial vertical roller mill applications. However, these corrosion magnitudes might show significant material losses in other industrial applications such as marine industries including oil drilling. The investigated wear part materials are not specifically designed to withstand abrasive marine conditions; however, the applied scientific approach might be used on such materials.

Vitamin A Fortification of Wheat Flour: Considerations and Current Recommendations

Vitamin A deficiency is a major public health nutrition problem, affecting an estimated 190 million preschool-aged children and 19 million pregnant and lactating women globally, and 83 million adolescents in Southeast Asia alone. Its consequences (disorders) include xerophthalmia (the leading cause of early childhood blindness), increased severity of infection, anemia, and death. Because vitamin A deficiency is largely due to chronic dietary insufficiency of preformed vitamin A and proactive carotenoids, food fortification can offer an effective approach to prevention. To provide guidance on fortifying wheat and maize flour milled in industrial rollers for national fortification programs in countries where vitamin A deficiency is considered a public health problem. Critical review of the literature on the dietary gap in vitamin A intake and levels of wheat flour intake among risk groups as a basis for determining vitamin A fortificant levels. Additional review of efficacy evidence, safety and cost considerations, and country experiences related to wheat-flour fortification with vitamin A. Mill-rolled wheat flour is a technically fortifiable, centrally processed food vehicle that, where routinely and adequately consumed by target groups, should be considered a candidate for fortification. Vitamin A can be stable in flour under typical, ambient conditions, with processing losses estimated at approximately 30%, depending on source and premix conditions. Factors to guide a decision to fortify flour with vitamin A include the extent of deficiency, availability of other food vehicle options, the centrality of milling, market reach and population intake distributions of the flour products, the dietary vitamin A intake required, and associated costs. Large gaps persist in knowledge of these factors, which are needed to enable evidence-based fortification in most countries, leaving most decisions to fortify guided by assumptions. Where flour can and should be fortified, guidelines are given for providing nearly 25% of the Recommended Dietary Allowance for vitamin A to vulnerable groups consuming varying ranges of flour products. The costs will vary according to the level of fortification.

Full Two-Dimensional Model for Rolling Resistance. II: Viscoelastic Cylinders on Rigid Ground

Following the previous paper, “Full two-dimensional model for rolling resistance: Hard cylinder on viscoelastic foundation of finite thickness,” addressing modeling of rigid cylinder rolling against viscoelastic foundation of finite thickness, this paper focuses on the development of a rigorous full two-dimensional semianalytical model for viscoelastic rollers with layered structure rolling against a rigid ground. In this model, the polar coordinate system is used, the solution is expanded into a set of Fourier series corresponding to the angular coordinate, the frequency domain master curves of G′ and G″ characterizing the general viscoelastic properties for a viscoelastic material are used to relate Fourier coefficients, and a special condensed structure model based on the Fourier series is developed to handle viscoelasticity and the rolling contact boundary condition. Examples are given to show the model capabilities to efficiently handle rolling resistance and contact stresses, and capture major characteristics of standing-wave phenomenon, such as sharp rise of rolling resistance, emergence of standing waves and material dynamic softening as the rolling speed approaches a critical value. The methodology may be of interest to industrial roller designers.

Use of Iranian steel slag for production of ceramic floor tiles

In this paper, the authors have tried to introduce the use of electric arc furnace steel slag as a raw material in the floor tile body. Experimental samples were prepared with different amounts of slag (10–50 wt-%) using the die pressing method. Fabricated samples were fired in an industrial roller kiln at 1140°C. Thermal behaviour of the samples was investigated by simultaneous thermal analysis and dilatometery. X-ray diffraction analysis identified Wustite (FeO), as the major phase in the used slag. The effect of slag addition on the strength of experimental samples was evaluated by four-point bending strength test. Sintering behaviour of different samples was investigated by measuring shrinkage, relative density and water absorption. Results showed that addition of more than 40 wt-% slag to the base body generates closed porosities in the specimens due to the bloating phenomenon which reduces the bending strength. The wear resistance test on this sample confirmed that it can be used as a standard floor tile.

Pyroplasticity in porcelain tiles

Clay bodies exhibit pyroplasticity when they are fired. Basically they get soft again in the heat of the kiln and can deform under their own weight. This property is especially important when firing products with very low porosity like porcelain tiles, due their content in melting materials. In this way, five raw materials, a kaolin, a talc, an albite, a phyllite and a clay were used in a study to form porcelain tile pastes resistant to pyroplasticity. After raw materials analysis (XRF and XRD), a mixture design with constraint limits was used to compose the pastes, resulting in 13 compositions (five factors and one centroid). All compositions were mixed, wet grounded (<44 μm), dried and pressed (450 kgf/cm 2) in rectangular plates (10 cm × 5 cm). The pyroplasticity was determined by the measure of the plate bending caused by temperature variation in an industrial roller kiln. All results were analyzed using response surfaces with data obtained by analysis of variance (ANOVA).

Primary Reconstruction of a Degloved Hand Using Multiple Toe Transfers on a Single Pedicle and a Reversed Radial Artery Flap

This case study reports one-stage reconstructive surgery on an 18-year-old man who was injured by an industrial roller machine and who presented with a degloved hand. Non-replantable delgloving occurred in all fingers, with the loss of the palmar and part of the dorsal skin. Multiple free contiguous toes were transferred based on a single dorsalis pedis artery pedicle. The artery was anastomosed to a reversed radial artery flap, which was used to cover the palm for primary reconstruction of the degloved hand. Multiple toes were harvested from the same foot, based on a single pedicle, to contain the potential morbidity to one foot, to enable primary reconstruction, and to decrease the length of the operation. The flaps healed well, and the patient demonstrated adequate tripod pinch and key pinch with the transferred toes, with a two-point discrimination of 12 mm at 1-year follow-up. The patient was satisfied with both the appearance and function of the hand and foot.