Continuous Processing Line Research Articles

Continuous production machine for separating and shaping Taiping Houkui tea.

In response to the challenges of low automation and a lack of a continuous processing system for Taiping Houkui tea, this study proposed a design scheme for a continuous processing line and built a continuous processing prototype for testing by combining the production requirements of Taiping Houkui tea, the characteristics of withered leaves, and the existing relevant production equipment. First, the physical properties of Taiping Houkui tea were determined. A simulation was performed using the Hertz-Mindlin model, and the motion states of the tea leaves were obtained under different conditions to define the parameter design range of the experimental platform and verify its structural rationality. Then, the response surface methodology was used to optimize the working parameter ranges and obtain the best working parameters for the feeding and kneading mechanisms. Finally, a continuous production prototype was constructed for further production verification. The experimental results show that the success rate of continuous production on this platform was 70.68%, with an average output of approximately 0.4kg/h for Taiping Houkui dry tea on a single slide track, and the produced tea was similar to manually made tea. This demonstrates that the continuous production technique has high feasibility and provides a reference for continuous production of Taiping Houkui tea.

Drying capacity of a continuous vibrated fluid bed dryer – Statistical and mechanistic model development

The drying capacity of a continuous vibrated fluid bed dryer was studied using a DoE by varying microcrystalline cellulose content in the formulation, water amount in the twin-screw granulation, inlet air temperature, air flow rate and the acceleration of the horizontal fluid-bed. Temperature and humidity profiles were measured along the dryer using wireless sensors. For the parameter space explored in this study, acceleration was the most influential process parameter of the dryer regarding the resulting granule moisture content. An empirical model was developed that allowed for fast and accurate moisture content prediction that could be incorporated into an enhanced control strategy. In addition, a mechanistic model was formulated that allow for prediction of temperature and moisture profiles, and most importantly the moisture content of the granules inside the dryer. The mechanistic model can be integrated to other unit operation models to provide overall understanding of an integrated continuous process line. The mechanistic model also makes it possible to define the equipment design requirements (e.g., length of the dryer) to meet the specific needs in terms of drying capacity, temperature and moisture profile.

Intelligent data analysis in an automated system of input control of raw materials on a continuous process line for the production of meat products

The article considers conditions for partial grinding of a frozen meat block in case of detection of extraneous inclusion in it by the raw material input control system. The processing of raw materials occurs on an automated in-line production line for meat products using a single-stage chopping process. The authors stipulate a continuous inspection of all meat blocks with full automation of control operations. Localization of the layer of meat containing inclusion solves the trajectory problem of moving the block of raw materials in the guiding planes of the single-stage chopper with the establishment of a mandatory safe chopping zone. The analysis helps to determine the boundaries of the safety zone. When solving the trajectory problem, the authors accept the assumption of a rectilinear trajectory of movement of a block of meat during its single-stage chopping. The foundation of this presumption stems from a research study of the energy usage of the drive of the raw material cutting mechanism in the working mode. The calculation of estimates of numerical characteristics of the experimental distribution of power consumption of the electric motor drive of the cutting mechanism allows to judge about the reduction of dynamic loads in the technological system “shredder - meat block” causing deviations from the plane-parallel motion of the meat block, because of rigid fixation of the block in the cutting zone. Using the control system reduces the risks of using substandard raw materials within its competence while maintaining the productivity of the technological line.

Tableting model assessment of porosity and tensile strength using a continuous wet granulation route

This paper presents a comprehensive assessment of the most widely used tablet compaction models in a continuous wet granulation tableting process. The porosity models, tensile strength models and lubricant models are reviewed from the literature and classified based on their formulations i.e. empirical or theoretical and applications, i.e. batch or continuous. The majority of these models are empirical and were initially developed for batch tabletting process. To ascertain their effectiveness and serviceability in the continuous tableting process, a continuous powder processing line of Diamond Pilot Plant (DiPP) installed at The University of Sheffield was used to provide the quantitative data for tablet model assessment. Magnesium stearate (MgSt) is used as a lubricant to investigate its influence on the tensile strength. Whilst satisfactory predictions from the tablet models can be produced, a compromise between the model fidelity and model simplicity needs to be made for a suitable model selection. The Sonnergaard model outperforms amongst the porosity models whilst the Reynolds model produces the best goodness of fitting for two parameters fitting porosity models. An improved tensile strength model is proposed to consider the influence of powder size and porosity in the continuous tableting process.

Optimal Design of Hot-Dip Galvanized DP Steels via Artificial Neural Networks and Multi-Objective Genetic Optimization

This modeling and optimization study applies a non-linear back-propagation artificial neural network, commonly denoted as BPNN, to model the most important mechanical properties such as yield strength (YS), ultimate tensile strength (UTS) and elongation at fracture (EL) during the experimental processing of hot-dip galvanized dual-phase (GDP) steels. Once the non-linear BPNN is properly trained, the most important variables of the continuous galvanizing process, including initial/first cooling rate (CR1), holding time at the galvanizing temperature of 460 °C (tg) and the final/second cooling rate (CR2), are obtained in an optimal way using an evolutionary approach. The experimental development of GDP steels in continuous processing lines with outstanding mechanical properties (550 < YS < 750 MPa, 1100 MPa < UTS and 10% < EL) is possible by using a combined hybrid approach based in BPNN and multi-objective genetic algorithm (GA). The proposed computational method is applied to the specific design of an actual manufacturing process for the first time.

Year-Round Heap Leaching of Gold in Cryolithozone

The experience of heap leaching (HL) was analyzed in the following cold climate regions: Alaska, Western regions of the United States, Canada, Kazakhstan, and Russia. The disadvantages of the developed domestic mobile units were uncovered, and the potential for creating HL mobile units was assessed to enable a year-round use of the technology, including in the cryolithozone. The results are presented, which were obtained during investigation of the material composition of the study object, i.e., technogenic gold-containing deposits of the Transbaikal region. The main element content of the mineral raw materials of the technogenic deposits was as follows: Au — 0.35 g/m3, Ag — 3.9 g/m3, SiO2 — 69.3 %, Al2O3 — 15.4 %, Fe2O3 — 5.9 %, CaO — 0.21 %, and MgO — 1.15 %. The phase forms of gold included: cyanidable (intergrown) — 2.3 %, “sealed in quartz” — 13.5 %, “enveloped” — 28.6 %, in magnetite — 55.6 %. A continuous process line was developed, which included the following four unit modules: gravity concentration, first stage of leaching (tank leaching), second stage of leaching (heap leaching), and sorption. The layout of the continuous process line (HL option during the period of subzero temperatures) is provided. The optimal values of the main process parameters of gravity concentration, as well as the first and second stages of leaching have been established experimentally. Prior to tank leaching, an active multiple-reagent solution based on sodium chloride, water and ozone compounds was prepared in a sealed electrochemical reactor. The tank was partitioned into three sections, in which the following operations were carried out in series: chemical opening of the gold-containing minerals; chlorine removal from the geomaterial; and tank leaching of gold. The total duration of heap leaching was 365 days, which was achieved by using two technological options: option 1 (195 days) — classic HL method (from early April to mid-October), option 2 (170 days) — heap leaching in stationary concrete cuvettes using engineering solutions during the period of subzero temperatures (from mid-October to the end of March). A schematic layout of the stationary concrete cuvette constructed in a special way and buried within a 5 to 8 m layer of soil above the ground level with shielding of the upper surface of the stack (heat-insulating covering, clay, large pieces of ore, sulfide rocks) is provided. Product solution drainage was used at various heights, and perforated rigid PVC pipes were used for supplying warm air deep inside the material. The recovery of gold from the technogenic raw materials was increased on average by 27.1 % due to a year-round heap leaching with the use of two technological options: 1 — by 28.7 % (from 58.1 to 86.8 %) using a classic HL method, and 2 — by 27.4 % (from 58.1 to 85.5 %) by using HL in stationary concrete cuvettes. It is proposed to utilize the secondary waste of the HL field (total of five types) in the road-building and construction industries.

Continuus Pharma wins new funding

Continuus Pharmaceuticals, a 2013 spin-off from the Novartis-MIT Center for Continuous Manufacturing, has netted $5 million in its second round of financing. The firm, one of C&EN’s 10 Start-Ups to Watch in 2016, develops continuous technology for drug manufacturing. It’s also developing off-patent drugs in collaboration with pharmacies and hospitals. It recently completed studies for a pilot plant integrating synthesis with formulation in one continuous process line and anticipates starting to build a commercial facility this year.

Distribution of the Strip Tensions with Slip Control in Strip Processing Lines

The control of tension in processing lines for metal strips tackles several problems. The process of achieving high tension driven by a multi-motor drive system, where the motors are mechanically coupled by a strip, is affected by the maximal torque of each drive, by friction between the strip and the surface of the tension roll, and by the wrap angle. The friction itself and the wrap angle are described by the eµα factor, which can be also calculated as the ratio of tensions in the strip in the previous section and subsequent section of the multi-motor drive. In this paper, an algorithm for the proper distribution of tensions in the strip for a multi-motor drive system of a continuous processing line is revealed. The algorithm ensures the tension distribution among particular drives of the tension leveler while respecting the physical limits of the drives and also preserving the desired conditions of a constant ratio between the input and output tensions for all drives in the leveler. The algorithm also prevents overloading of the drives. Finally, the algorithm was implemented in a control system of a strip processing line, and the obtained results correspond with the simulations. This, in turn, confirms the correctness of the algorithm design.

Synthesis and properties of eco-friendly coatings using waterborne polyaspartic and blocked isocyanate

Polyaspartic coating is well known as one of popular eco-friendly coatings because of non VOC and excellent mechanical properties such as fast curing, abrasion resistance, chemical resistance, light resistance and so on. Despite of a number of advantages applying polyaspartic coatings to industries, there are limitations to replace conventional polyurea and waterborne coatings in particularly continuous processing lines because of its very short pot life and relatively high price. To improve short pot life, polyaspartic resin was dispersed in water using emulsifier and a blocked isocyanate as a curing agent was added. The curing reaction between -NH of aspartic and -NCO of blocked isocyanate and properties of coatings were analyzed by measuring viscosity, pencil hardness, FT-IR, weatherometer, yellowing, etc. The results showed that the pot life of waterborne polyaspartic coatings became much longer than that of conventional polyaspartic one without the change in light resistance.

Lyapunov Based Reference Model of Tension Control in a Continuous Strip Processing Line with Multi-Motor Drive

The article describes design and experimental verification of a new control structure with reference model for a multi-motor drive of a continuous technological line in which the motors are mutually mechanically coupled through processed material. Its principle consists in creating an additional information by introducing a new suitable state variable into the system. This helps to achieve a zero steady-state control deviation of the tension in the strip. Afterwards, the tension controller is designed to ensure asymptotic stability of the extended system by applying the second Lyapunov method. The realized experimental measurements performed on a continuous line laboratory model confirm the advantages and correctness of the proposed control structure: it is simple, stable, robust against changes of parameters, invariant to operating disturbances and ensures a high-quality dynamics of the controlled system prescribed by the reference model. To demonstrate effectiveness of the design, the performance of the controller was compared with properties of a standard Proportional Integral Derivative/Proportional Integral (PID/PI) controller designed in frequency domain.

Design of an one-sided transverse flux induction coil by using a numerical optimization algorithm

The transverse flux heating (TFH) concept offers very high electrical efficiency in combination with unique technological flexibility. Numerous advantages make this method beyond competition to be applied in e.g. continuous strip production and processing lines. However, all potential advantages of TFH can be realized in practice only by optimal design of the inductor shape and optimal control of the heaters, using numerical modelling and optimization techniques. The paper describes a successive approach to optimal design of a single layer induction coil, which will be used for onesided TFH of moving thin steel strip with constant width. The peculiarity of the design refers to the very slow movement speed of the strip and the target temperature, which is set below Curie.

Pharmaceutical excipients properties and screw feeder performance in continuous processing lines: a Quality by Design (QbD) approach

Screw feeder performance is a critical aspect in continuous manufacturing processes. Pharmaceutical excipients, such as mannitol, microcrystalline cellulose, lactose monohydrate, and anhydrous dibasic calcium phosphate can present problems in ensuring a continuous stable feed rate due to their sub-optimal flow properties. In alignment with Quality by Design (QbD) goals, the aim of this work was to identify and explain critical sources of variability of some powder excipients delivery by screw feeding, in particular to continuous processing lines. Pharmaceutical excipients with a wide range of material properties were selected, and the impact of their flow and density properties on screw feeder performance was investigated. The analysis of the powder conveying by the screws was performed at different hopper fills and different screw speeds. A multivariable model involving bulk density (CBD) and parameters from FT4 dynamic downwards testing (SI) and dynamic upwards testing (SE) explained 95.7% of excipients feed rates (p < .001). The study gathers valuable information about the screw feeder performance and input materials properties that can help process understanding and QbD-based development of solid dosage forms in continuous processing lines.

Experimental Determination of Continuous Cooling Transformation (CCT) Diagrams for Dual-Phase Steels from the Intercritical Temperature Range

The phase transformation kinetics under continuous cooling conditions for intercritical austenite in a cold rolled low carbon steel were investigated over a wide range of cooling rates (0.1–200 ∘ C/s). The start and finish temperatures of the intercritical austenite transformation were determined by quenching dilatometry and a continuous cooling transformation (CCT) diagram was constructed. The resulting experimental CCT diagram was compared with that calculated via JMatPro software, and verified using electron microscopy and hardness tests. In general, the results reveal that the experimental CCT diagram can be helpful in the design of thermal cycles for the production of different grades of dual-phase–advanced high-strengh steels (DP-AHSS) in continuous processing lines. The results suggest that C enrichment of intercritical austenite as a result of heating in the two phases (ferrite–austenite) region and C partitioning during the formation of pro-eutectoid ferrite on cooling significantly alters the character of subsequent austenite phase transformations.

Control of three different continuous pharmaceutical manufacturing processes: Use of soft sensors

One major advantage of continuous pharmaceutical manufacturing over traditional batch manufacturing is the possibility of enhanced in-process control, reducing out-of-specification and waste material by appropriate discharge strategies. The decision on material discharge can be based on the measurement of active pharmaceutical ingredient (API) concentration at specific locations in the production line via process analytic technology (PAT), e.g. near-infrared (NIR) spectrometers. The implementation of the PAT instruments is associated with monetary investment and the long term operation requires techniques avoiding sensor drifts. Therefore, our paper proposes a soft sensor approach for predicting the API concentration from the feeder data. In addition, this information can be used to detect sensor drift, or serve as a replacement/supplement of specific PAT equipment. The paper presents the experimental determination of the residence time distribution of selected unit operations in three different continuous processing lines (hot melt extrusion, direct compaction, wet granulation). The mathematical models describing the soft sensor are developed and parameterized. Finally, the suggested soft sensor approach is validated on the three mentioned, different continuous processing lines, demonstrating its versatility.

Stable and Robust Tension Controller for Middle Section of Continuous Line

The quality of tension control in the middle section of a continuous processing line significantly affects the quality of the line final product, whether it be the case of sheet metal, pipes, plastic film or paper production. The main requirement is that of constant and non-oscillating tension in the material during all operation states of a line, such as line start-up, line run finish, tension disturbance affects before and after the middle section of the line, changes in parameters (e.g. of the moment of inertia), etc. The paper discusses the design of a stable and robust tension controller for the middle sections of continuous lines designed on basis of the second Lyapunov method, and its application in the middle section of a concrete line with two machines. The properties of the designed control structure were verified by digital simulation in MATLAB. The results achieved confirm the rightness of the proposed control structure which is simple, robust and which can secure stability and good quality dynamics of the controlled system, as well as invariance against disturbances. DOI: http://dx.doi.org/10.5755/j01.eie.24.1.20148

Fuzzy Model for Middle Section of Continuous Line

The paper presents a methodology for designing a fuzzy model for the middle section of a continuous processing line for tension processing of various materials (sheet metal, tubes, foil, etc.), which is only described by input/output relations. The measured input/output data of the continuous line are the basis for creating its fuzzy model, which can be further applied in the design of a suitable controller and the verification of its properties by simulation. The first part of the paper describes the procedure of the fuzzy model construction; the second part presents the application of the model in the system of the middle section of a continuous processing line. The fuzzy model structure is based on the state space representation of the dynamic system in discrete form. The properties of the fuzzy model were verified by numerical simulation in Matlab. The obtained results have confirmed the rightness of the design method and its applicability to dynamic systems with multiple inputs and outputs.

Implementing the Gantt chart in Europe and Britain: the contributions of Wallace Clark

Purpose The purpose of this paper is to trace the European and British activities of Wallace Clark and his consulting firm with public sector agencies and private firms implement Henry L. Gantt’s chart concept. Design/methodology/approach Archival records and secondary sources in English and French. Findings Developed to meet the shipbuilding and use needs for the Great War (World War I), the Gantt chart was disseminated through the work of Wallace Clark during the 1930s in numerous public sector and private organizations in 12 nations. The Gantt concept was applied in a variety of industries and firms using batch, continuous processing and/or sub-assembly lines in mass production. Traditional scientific management techniques were expanded for general management, such as financial requirement through budgetary control. Clark and his consulting firm were responsible for implementing a managerial tool, the Gantt chart, in an international setting. Research limitations/implications Some firms with which Clark consulted could not be identified because the original records of the Wallace Clark Company were disposed of by New York University archival authorities. Industries were identified from the writings of Pearl Clark and Wallace Clark, and some private or public organizations were discerned from archival work and the research of French and British scholars. Originality/value This is the first study of the diffusion of a managerial tool, developed in America by Henry L. Gantt, into Europe and Britain through the contributions of Wallace Clark.

Strip lateral position control using electromagnets in continuous processing line

In continuous metal strip processing lines, such as pickling, annealing and surface treatment lines, lateral instability of strips is a common problem. Strip lateral movement has a bad influence on productivity of the processing lines. A simple and effective device to control a lateral position of a strip is required because conventional preventions such as a steering roll and crown roll are not effective. In this study, a method of controlling a strip lateral position using electromagnets was investigated. First, theoretical equations were derived to predict capability to control a strip. Next, the derived theory was verified compared with lab experiments. The results obtained can be summarized as follows: (1) The theoretical equations of velocity of lateral movement are derived from inclination when the strip is attracted by electromagnet(s). The inclination is calculable from geometric relation. (2) It is found that the theoretical equations are valid by lab experiments in the conditions of changing attracting displacement and line speed. Controlling lateral movement using electromagnets is possible, and the control capability can be estimated by the derived theory. (3) The velocity of lateral movement in the case of attracting the half of strip width is three times as fast in the case of attracting the edge of the strip.

Modeling and Analysis of Multi-motor Drive Properties in a Web Processing Continuous Line

One of the main objectives in web handling machinery is to reach a pre-set web speed while maintaining the constant web tension in sections of continuous processing line. The paper presents model of a multi-motor drive system in the continuous web-processing line where the motors driven the working rolls are mutually connected by elastic coupling caused by processed web. Control algorithms of such industrial application with the multi-motor drive system are advantageously verified by simulation. This enables to test driving system properties at large dynamic variations that occur commonly in such web tension applications. Results of the simulation show correctness of the developed control system algorithms with data of a real production line.

Simple Heat Treatment for Production of Hot-Dip Galvanized Dual Phase Steel Using Si-Al Steels

This work presents relevant metallurgical considerations to produce galvanized dual phase steels from low cost aluminum-silicon steels which are produced by continuous strip processing. Two steels with different contents of Si and Al were austenized in the two-phase field ferrite + austenite (α + γ) in a fast manner to obtain dual phase steels, suitable for hot-dip galvanizing process, under typical parameters of continuous annealing processing line. Tensile dual phase properties were obtained from specimens cooled from temperature below Ar3, held during 3 min, intermediate cooling at temperature above Ar1 and quenching in Zn bath at 465 °C. The results have shown typical microstructure and tensile properties of galvanized dual phase steels. Finally, the synergistic effect of aluminum, silicon, and residual chromium on martensite start temperature (Ms), critical cooling rate (CR), volume fraction of martensite, and tensile properties has been studied.