Extruder Barrel Research Articles

Optimization Design for Cooling Channel of the Single Screw Extruder Barrel

To solve the issue of machine barrel skewed to one side, when the XJ150×25 was running. Under the conditions that the needs of strength was met, by designed three types of cooling channels and analyzed the temperature field for the barrel by using ANSYS, as well as thermal deformation. The results show that cooling channel of center symmetric form can solve the problem that uneven temperature field causing the barrel to produce thermal deformation. It can guarantee the coaxial degree between screw and barrels and can improve the quality of products.

The extrusion of plasticized poly(vinyl chloride) in an extruder with a modified feed zone. Part 1: extrusion process

Abstract The work presents the results of experimental studies of plasticized poly(vinyl chloride) (PVC) extruded by a single-screw extruder with a modified feed section. The variable factors were the feed opening width, the feed pocket depth in the extruder barrel, and the rotational speed of the screw. The following parameters were studied: extrudate temperature Tw (°C), screw torque M (Nm), polymer mass flow rate G (kg/h), unit consumption of energy supplied to the extruder Ejc (J/g), and extrusion process energy efficiency κ (%). It was found that the increase in the depth of the pocket and the decrease in the width of the feed opening influence the extrusion process in a positive way.

Infrared melt temperature measurement of single screw extrusion

An infrared temperature sensor has been used to provide real time quantification of the thermal homogeneity of polymer extrusion. The non‐intrusive sensor was located in the barrel of a single screw extruder, positioned such that it provided a measurement of melt temperature in the channel of the metering section of the extruder screw. The rapid response of the technique enabled melt temperature within the extruder screw channel to be monitored in real time, allowing quantification of the thermal stability of the extrusion process. Two polyethylenes were used in experiments with three extruder screw geometries at a range of screw speeds. Data generated by the infrared sensor was found to be highly sensitive to thermal fluctuations relating to the melting performance of the extruder screw. Comparisons made with an intrusive thermocouple grid sensor located in the extruder die suggested that the infrared technique was able to provide a similar level of information without disturbing the process flow. This application on infrared thermometry could prove highly useful for industrial extrusion process monitoring and optimization. POLYM. ENG. SCI., 55:1059–1066, 2015. © 2014 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers

Effectiveness of polyethylene extrusion in a single-screw grooved feed extruder

The paper presents a description of a modern direct screw drive carried out by a torque motor of a torque 300 Nm, maximum rotational speed 500 rpm and power 15.7 kW. The operation of the torque, its advantages and disadvantages were described. In the extruder plasticizing system in the feed opening zone and part of the feed zone, an exchangeable smooth sleeve and a grooved sleeve with 6 or 8 longitudinal grooves were used. For research, low density polyethylene of the commercial name Malen E and symbol FGNX 23-D006 was used. In the extruder barrel, a special screw was mounted 25 mm in diameter and L/D = 24, with elements of intensive shearing and mixing, constructionally adapted to the grooved section. The research was conducted in the wide range of rotational screw speeds from 1.67 to 8.33 rps.

Continuous manufacturing of solid lipid nanoparticles by hot melt extrusion.

Solid lipid nanoparticles (SLN) can either be produced by hot homogenization of melted lipids at higher temperatures or by a cold homogenization process. This paper proposes and demonstrates the formulation of SLN for pharmaceutical applications by combining two processes: hot melt extrusion (HME) technology for melt-emulsification and high-pressure homogenization (HPH) for size reduction. This work aimed at developing continuous and scalable processes for SLN by mixing a lipid and aqueous phase containing an emulsifier in the extruder barrel at temperatures above the melting point of the lipid and further reducing the particle size of emulsion by HPH linked to HME in a sequence. The developed novel platform demonstrated better process control and size reduction compared to the conventional process of hot homogenization (batch process). Varying the process parameters enabled the production of SLN below 200 nm (for 60 mg/ml lipid solution at a flow rate of 100ml/min). Among the several process parameters investigated, the lipid concentration, residence time and screw design played major roles in influencing the size of the SLN. This new process demonstrates the potential use of hot melt extrusion technology for continuous and large-scale production of SLN.

Efficiency of thermomechanical reclaiming of ground tire rubber conducted in counter-rotating and co-rotating twin screw extruder

In this article the results of research on a continuous thermomechanical reclaiming process of ground tire rubber (GTR) conducted in a twin screw extruder are presented. The effects of the rotation direction (co-rotating/counter-rotating), design of co-rotating plasticizing units and the rotational speed of the screws on the extruder working parameters, sol fraction and the degree of reclaiming in the obtained products were described. The influence of secondary vulcanization on cure characteristics as well as mechanical properties of revulcanizates, and blends of reclaimed rubber and styrene-butadiene rubber (SBR) were determined. Based on the obtained results, it was concluded that the application of counter-rotating plasticizing system (i.e. screw profile A), consisting mainly of transport elements with different pitch, increases the time during which ground tire rubber is exposed to the barrel temperature. The use of co-rotating plasticizing system, equipped with kneading elements and characterized by constant pitch, causes that the retention time of ground tire rubber in the extruder barrel is much shorter. In the case of co-rotating plasticizing system, it is also higher shear forces (then in counter-rotating screw configuration), besides temperature, acts on ground tire rubber, and converts mechanical energy into heat. Testing of styrene-butadiene rubber-ground tire rubber/reclaimed ground tire rubber (SBR-GTR/dGTR) compounds confirmed that the reclaiming process has positive influence on properties of obtained products.

Flow and mixing efficiency characterisation in a CO2-assisted single-screw extrusion process by residence time distribution using Raman spectroscopy

Hot-melt extrusion of a bio-sourced polyamide has been implemented in a single-screw extruder with supercritical carbon dioxide injection. CO2 acts as a plasticiser in the extruder barrel and as a physical blowing agent at the die. To insure a better mixing and dissolution of the CO2 into the polymer melt, addition of a static mixer between the screw tip and the die was tested. The effect of both the static mixing element and the CO2 injection on the melt flow behaviour has been elucidated. A recent technique of in-line Raman spectroscopy was implemented to make a residence time distribution study, using titanium dioxide as a tracer. The use of a static mixer exerts a major modification on the flow behaviour: it improves mixing by enhancing dispersion. In addition, the structure of the manufactured products was studied: the static mixer led to more homogeneous porous structure. The broad range of CO2 incorporation (up to 25%, w/w) into the melt led to the manufacture of foams with adjustable porosity from 15 to 70%.

Effect of feed composition, moisture content and extrusion temperature on extrudate characteristics of yam-corn-rice based snack food.

Blends of yam, rice and corn flour were processed in a twin-screw extruder. Effects of yam flour (10-40%), feed moisture content (12-24%) and extruder barrel temperature (100-140°C) on the characteristics of the dried extrudates was investigated using a statistical technique response surface methodology (RSM). Radial expansion ratio differed significantly (p ≤ 0.05) with change in all the independent variables. Highest expansion (3.97) was found at lowest moisture content (12%) and highest barrel temperature (140°C). Increased yam flour level decreased the expansion ratio significantly. Water absorption index (WAI) increased significantly with increase of all variables. However, water solubility index (WSI) did not change with change in yam flour percent. Hardness of extrudates that varied from 3.86 to 6.94 N was positively correlated with yam flour level and feed moisture content, however it decreased significantly (p ≤ 0.001) with increase of barrel temperature. Yam percent of 15.75 with feed moisture and barrel temperature at 12.00% and 140°C respectively gave an optimized product of high desirability (> 0.90) with optimum responses of 3.29 expansion ratio, 5.64g/g dry solid water absorption index, 30.39% water solubility index and 3.86N hardness. The predicted values registered non-significant (p < 0.10) differences from the experimental results. Further study would include the sensory properties enhancement of extruded snacks and little emphasis on the chemistry of interaction between different components.

Investigation of the poly(vinyl chloride) extrusion process using a feed throat with a feed pocket

The effectiveness of the extrusion process depends on a number of factors, the most important being barrel design, e.g., longitudinal or helical grooves; screw, feed opening, and polymer hopper designs are significant in this respect, too. The effect of these factors on the extrusion process has been thoroughly discussed in the available literature. This notwithstanding, there is little information providing insight on the effect of a feed pocket made below the feed opening, on the side of the barrel toward which the screw rotates, on the main characteristics of the extrusion process. For the experiments, five special profile inserts with different feed pocket depths were made and then mounted in the extruder barrel equipped with a 25‐mm diameter screw. The extrusion of plasticized poly(vinyl chloride) (PVC) at the screw speed ranging from 30 to 150 rpm was investigated. Presented graphically as charts, the obtained results show the dependences of extrudate temperature, extruder screw torque, polymer output, power supplied to the extruder and conveyed by the polymer, unit energy consumption and energy efficiency on the feed pocket depth, and screw speed. It has been found that the feed pocket made in the extruder barrel has little effect on the course and effectiveness of plasticized PVC extrusion and does not worsen the studied properties of the received extrudate; yet, it should be taken into account to ensure the highest polymer output and lowest energy consumption. POLYM. ENG. SCI., 54:2037–2045, 2014. © 2013 Society of Plastics Engineers

Effect about Axial Vibration on Solution Viscosities of PS/Supercritical CO&lt;sub&gt;2&lt;/sub&gt;

In this paper, a technology of determining the melt viscosity of a polystyrene(PS)/supercritical CO2solution using a linear capillary tube die mounted on a foaming dynamic extruder is presented. CO2was injected into the dynamic extrusion barrel. Single-phase PS/CO2solutions were formed using a microcellular extrusion system and phase separation was prevented by maintaining a high pressure in the capillary tube die. Bymeasuring the pressure drop through the die, the viscosity of PS/CO2, solutions was determined. The dynamic extruder foaming apparatus was developed and using it to study the effects of CO2content and vibration on viscosity of PS/CO2solution. The blow agents and vibration can plastic the polymer viscosity. A theoretical model based on the generalized Cross-Carreau model was proposed to describe the shear-thinning behavior of PS/CO, solutions at various shear rates. The zeroshearviscosity was modeled using a generalized Arrhenius equation to accommodate the effects of temperature, pressure, CO2content, and vibration.

CHEMICAL, SENSORY, PHYSICAL AND MICROBIOLOGICAL EVALUATION OF THREE NOVEL MILK BEVERAGES FOR CHILDREN

Abstract This work was carried out to study effect substitution of corn grits with 5 % sweet potato or pumpkin grits for processing corn snacks using extrusion cooking techniques . The most favorable conditions for operator device were determined namely: feed moisture content , speed screw and extruder barrel temperature .Sensory evaluation such as color, taste, appearance, crispness and over all acceptability on the final product characteristics were studied. Three factors were identified for the operation as follows :feed moisture contents(16, 18 and 20%), screw speed(120, 140, 160rpm) and barrel temperature(130, 150 and 170 ° C) and the impact on the physicochemical properties such as bulk density (BD), expansion rate(ER) and water solubility index %( WSI %). The results indicated that the suitable expansion ratio were 2.01 and 2.62 gm/ cm3 and the swelling percentage were 3 .5 to3.4 %, respectively checks at 16% and 18% moisture for blend snacks1 ( 95% corn grits + 5% sweet potato grits )and blend snacks2 ( 95% corn grits + 5% pumpkin grits),while the proper screw speed ( 120 and 140 rpm ) by high barrel temperature ( 130 and 150 oc). The results showed significant differences in the color, taste, appearance, crispness and over all acceptability in each of the blend 1 and 2 as compared to the control (100% corn grits snacks) and had a best appearance of the blend 1 and the highest values ​​for color, taste and over all acceptability for the blend 2. So, it can be concluded that the process of extrusion device cooking heat the most suitable for operation is content feed humidity 16% ,temperature130 °c and the speed screw120rpm for a blend1 and 18% moisture ,150° c and 140rpmfor the blend 2to produce a product acceptable corn Snacks, and on the other the use of 5% of the sweet potatoes grits or pumpkin grits for the production of corn snacks contributed positively to show the desired qualities of a product such as increasing the expansion rate , improved crispness, taste and overall acceptability. This study highlights the importance of the selection experimentally the impact of new ingredients on different variables when manufacturing snacks from corn snacks. Keywords: Extrusion, Snacks, Screw Speed, Sweet Potato, Pumpkin, Corn grits and sensory.

THE EFFECT OF USING SWEET POTATO AND PUMPKIN GRITS ON PRODUCING CORN SNACKS BY EXTRUSION COOKING.

Abstract This work was carried out to study effect substitution of corn grits with 5 % sweet potato or pumpkin grits for processing corn snacks using extrusion cooking techniques . The most favorable conditions for operator device were determined namely: feed moisture content , speed screw and extruder barrel temperature .Sensory evaluation such as color, taste, appearance, crispness and over all acceptability on the final product characteristics were studied. Three factors were identified for the operation as follows :feed moisture contents(16, 18 and 20%), screw speed(120, 140, 160rpm) and barrel temperature(130, 150 and 170 ° C) and the impact on the physicochemical properties such as bulk density (BD), expansion rate(ER) and water solubility index %( WSI %). The results indicated that the suitable expansion ratio were 2.01 and 2.62 gm/ cm3 and the swelling percentage were 3 .5 to3.4 %, respectively checks at 16% and 18% moisture for blend snacks1 ( 95% corn grits + 5% sweet potato grits )and blend snacks2 ( 95% corn grits + 5% pumpkin grits),while the proper screw speed ( 120 and 140 rpm ) by high barrel temperature ( 130 and 150 oc). The results showed significant differences in the color, taste, appearance, crispness and over all acceptability in each of the blend 1 and 2 as compared to the control (100% corn grits snacks) and had a best appearance of the blend 1 and the highest values ​​for color, taste and over all acceptability for the blend 2. So, it can be concluded that the process of extrusion device cooking heat the most suitable for operation is content feed humidity 16% ,temperature130 °c and the speed screw120rpm for a blend1 and 18% moisture ,150° c and 140rpmfor the blend 2to produce a product acceptable corn Snacks, and on the other the use of 5% of the sweet potatoes grits or pumpkin grits for the production of corn snacks contributed positively to show the desired qualities of a product such as increasing the expansion rate , improved crispness, taste and overall acceptability. This study highlights the importance of the selection experimentally the impact of new ingredients on different variables when manufacturing snacks from corn snacks. Keywords: Extrusion, Snacks, Screw Speed, Sweet Potato, Pumpkin, Corn grits and sensory.

Visualization and Process Understanding of Material Behavior in the Extrusion Barrel during a Hot-Melt Extrusion Process Using Raman Spectroscopy

The aim of this research was to improve understanding of material behavior in pharmaceutical hot-melt extrusion by implementing a Raman probe in each section of the barrel. Fourier-transform infrared spectroscopy measurements were performed to confirm the Raman observations. Metoprolol tartrate (MPT) concentration (10 and 40% in Eudragit RSPO), extrusion temperature (100, 120, and 140 °C), and screw speed (80 and 160 rpm) were varied to examine their influence on polymer-drug solid state throughout the barrel. When extruding a formulation with a 40% MPT concentration, the broadening of MPT peaks indicates melting of MPT between sections 2 and 3, caused by the first kneading zone. Decreasing the concentration to 10% shows an additional spectral difference (i.e., peak shifts indicating interactions between MPT and the carrier) between sections 5 and 6, due to formation of a solid solution. At a 10% MPT load, increasing the extrusion temperature does not influence the solid state or the barrel section where the final solid state is obtained. At a drug load of 40%, the solid state of the end product is reached further down the barrel when the temperature decreases. Doubling the screw speed when processing a 10% MPT formulation does not affect the solid state of the product or the location where it is obtained. In contrast, at a 40% drug load, the section where the final product is produced, is situated earlier in the barrel, when applying a higher speed. The Raman spectra provide real-time information about polymer-drug behavior throughout the barrel, facilitating process understanding and optimization.

The effect of low shear on the development of fortified extruded rice products

AbstractFortified extruded rice presents promising commercial opportunities for delivering nutrients and other functional ingredients to the global rice consuming population. Its formulation may be changed to suit the nutritional requirements of different target markets. The objective of this study was to develop a product line of prototypes that resemble the texture and appearance of natural rice grains, and have good retention of added nutrients. Extruded fortified rice was manufactured in a controlled mechanical shear extrusion process by first combining a mixture of fortified rice flour and water in a pre‐conditioner, then advancing the mixture along the length of an extruder barrel with a terminal extrusion die inserts in the shape of rice kernels. Extruded rice grains were evaluated for the degree of gelatinization, texture profile, and starch depolymerization. Retention of added vitamins and minerals was also measured. The cooked extruded grains had comparable texture to cooked commercial rice with good sensory characteristics. Based on the results, the key strategy in producing good quality extruded fortified starch is to achieve as high a degree of starch gelatinization in the extruded rice kernel as possible without inducing excessive starch breakdown.

Modelling and Control of Extruder Barrel Temperature Field

Modelling and control of the extruder temperature field is discussed, a process governed by a nonlinear partial differential equation. Utilizing finite element approximation a discretized input/output representation of the system is created with the inputs being powers of heaters and output the extruder temperature field. Local linearization is applied at the operating point and the controller is designed based on the lumped-input and distributed-parameter-output systems approach, using the time-space decoupling of system's dynamics.

Screw Extrusion Pretreatments to Enhance the Hydrolysis of Lignocellulosic Biomass

The conversion of biomass to biofuels begins with biomass pretreatment. Most traditional pretreatment methods are chemical or physical. Each method has a specific effect on cellulose, hemicellulose, and lignin fractions. The main goal of pretreatment is to remove or weaken the tight linkages among cell wall components, thus increasing enzyme accessibility and improving the hydrolysis of cellulose. In recent studies, the use of the extrusion process has been described as a new, potentially viable development in the pretreatment of lignocellulosic materials and the hydrolysis of cellulose. The hypothesis is that extruder screw speed and barrel temperature may disturb biomass structure, thereby increasing accessibility of cellulose for hydrolysis. This manuscript aims to provide an overview of the major representative progress and development on the use of the extrusion process for biomass pretreatment and cellulose hydrolysis. Extrusion can be used as a physical pretreatment method in biofuel production.

Mechanism of Nanofibre Fabrication by Meltblowing

Fabrication of nanofibres has become a growing area of research because of their unique properties (i.e. smaller fibre diameter and higher surface area) and potential applications in various fields such as filtration, composites and biomedical applications. The mechanism of nanofibre fabrication by meltblowing process with the injection of different fluids (such as air and water) has been investigated in this paper. In the meltblowing equipment the fluids were injected at a vent port along the extrusion barrel, for the fabrication of nanofibres. The injection of water resulted in better fibre morphology compared to the injection of air. Nanofibres were fabricated by the drafting action of the high-velocity flow of the heated air and the steam in the extruder. The fibres collected were straight prior to the fluid injection and coiled fibres were collected with the injection of fluids. Three types of fibres such as ribbon shaped, fused and branched fibres were obtained in addition to the circular fibres.

Polymer Extrusion: From Control System Design to Product Quality

As a major polymer processing technique, polymer extrusion is a continuous process, during which material properties, machine variables, and process variables interact with each other to determine the final product quality. Precise control of key process variables such as barrel temperatures and melt pressure are crucial to ensure a good product quality in the extrusion process. In this paper, the overall extruder control system is constructed by two independent control loops, a single-input–single-output (SISO) control of the melt pressure at die output, and a multiinput–multioutput (MIMO) control of the barrel temperatures. The dynamic behaviors of melt pressure and barrel temperatures were analyzed first. The characteristics of the melt pressure dynamics were as follows: nonlinear and time-varying while the extruder barrel temperatures were nonlinear, slow response, and different zones were highly coupled. Advanced control algorithms were adopted to control these key variables. Experimental results demonstrate the fast response, near-zero overshoot, and precise tracking performance of the proposed control strategies. The robustness of the entire control system was verified through different operating conditions including materials and set points. Ultimately the performance of the entire control system was verified by product quality. The product quality improved significantly with the proposed controller.

Upscaling and in-line process monitoring via spectroscopic techniques of ethylene vinyl acetate hot-melt extruded formulations

The aim of the present work was to evaluate drug release and quality of EVA/drug matrices at different PEO 7M concentrations (5 and 15%), manufactured using two different hot-melt extruders: a lab-scale mini extruder and a pilot-scale extruder. The process parameters used on both extruders (temperature and screw speed) and drug release from the matrices were compared. On the lab-scale extruder all formulations were extruded at 90 °C, whereas on the pilot-scale extruder the temperature of the die was adjusted to 100 °C in order to achieve a constant pressure at the extrusion die, hence constant material flow through the die to yield smooth extrudates. Screw speed was also adjusted from 60 rpm (lab-scale extruder) to 90 rpm (pilot-scale extruder) in order to obtain a balance between feeding rate and screw speed. Drug release from the obtained matrices on both extruders was also assessed. Despite the differences in diameter (diameter of 2 and 3mm for the lab-scale extruder and pilot-scale extruder, respectively), temperature and screw speed, drug release per surface area was similar. DSC analysis of a formulation [EVA40/MPT (50/50, w/w) with 5% PEO] indicated small changes in its solid state after extrusion on both extruders: drug crystallinity was reduced by max. 20%, PEO recrystallized after cooling and EVA remained semi-crystalline. Extrusion experiments on the pilot-scale extruder of EVA/MPT, 50/50 (w/w) formulations were also monitored in-line using Raman and NIR spectroscopy in order to evaluate the material behavior at a molecular level in the extrusion barrel as function of the process settings (extrusion temperature: 90, 110 and 140 °C; screw speed: 90 and 110 rpm). At 90 and 110 °C the crystallinity of the drug was reduced, but the majority of MPT remained in its crystalline state as specific peaks in the Raman spectra of the drug became broader. These differences were accentuated when extrusion was performed at 140 °C as the drug completely melted. Peak shifts to lower frequencies [(CO) groups of the drug and (CH(3)COO) groups of EVA] were registered at all extrusion temperatures, with maximum effect at 140 °C indicating molecular interactions. Increasing the screw speed did not result in peak shifts of Raman spectra. NIR confirmed these observations and showed an additional peak in the spectra characteristic of (OH) bounds.

In‐line near‐infrared spectroscopy: A tool to monitor the preparation of polymer‐clay nanocomposites in extruders

AbstractIn‐line diffuse reflectance and on‐line transmission near‐infrared spectroscopy (NIR) measurements are performed at the same location of the barrel of a twin screw extruder during the preparation of a polypropylene/clay nanocomposite. Their performance is evaluated by means of a 7‐parameter chemometric model using off‐line rheological and structural (FTIR) data obtained from samples prepared under different screw speed, compatibilizer content and clay loading, as well as a process‐related thermomechanical index. Despite the higher variability of the diffuse reflectance signal, the two models present analogous high quality indices. The aptness of the reflectance measurements is thus validated, which has direct practical advantages, as this probe can be fixed in any typical melt pressure transducer port. The probe is then used for the real‐time in‐line monitoring of the production of the same nanocomposite but now using different throughputs, and the chemometric‐based predictions are compared with experimental off‐line characterization data. The nonlinear effect of throughput is correctly anticipated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013