Hot-melt granulation (HMG) by twin screw extrusion is undoubtedly a good novel technology for the continuous processing of pharmaceuticals but assurance must still be gained regarding whether the environment affects medicine real estate. In this preliminary study, granulation was studied for a version product including lactose monohydrate and active ingredients of differing drinking water solubility, namely ibuprofen versus caffeine. The formulations had been granulated at 220 rpm and 100C with polyethylene glycol binders of differing molecular weights and at concentrations between 6.5% and 20%. In terms of granule extruder barrel properties, the reduced melting point of ibuprofen acquired a dominant impact by producing larger, better granules, whereas the caffeine items were more much like a blank made up of no active component. Drug degradation was study by differential scanning calorimetry, X-ray diffraction, and high-pressure liquid chromatography. The only real detected switch was the dehydration of lactose monohydrate for the caffeine and blank goods, whereas the lubricating affect of the ibuprofen secured its granules. The short residence period (60 s) was consider to get influential in minimizing destruction of the drug despite the temperature and shear related to HMG in the twin screw extruder.
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Extrusion is a "black-box" process. We can not see how are you affected inside an extruder, hence we rely on instruments. We must make sure that all sensors are working and readouts happen to be calibrated correctly.
Single-screw extruders will be the most common machines found in plastics processing. Though straight forward in function basically, they are subject to many destabilizing factors that can bring about out-of-spec item or a shutdown. When problems strikes, you will need a strategy for identifying the complexities quickly. An essential part of that strategy is the troubleshooting timeline. In this article we'll identify what it is and how it could be used to solve one common extrusion problem-melt fracture in tube and account extrusion. Start with sensors Prerequisites to effective troubleshooting include good machinery instrumentation, current and historical process data, detailed feedstock info, complete maintenance records, and operators with a good understanding of the extrusion process. Extrusion is a "black-box" process. We can not see what goes on inside an extruder, hence we rely on instruments. We have to make sure that all sensors are working and readouts happen to be calibrated correctly. They are the important process variables to monitor: Melt pressure, typically about 100 times/sec. Melt temperature every 1-10 sec with an immersion probe or every 1-10 millisec with an infrared sensor. Temp of the feed housing (whether it's water-cooled). Barrel temperatures (a couple of sensors per zone). Die temperatures (one to 30 or more sensors, based on die type). Heater power found in kw. Cooling power, measured simply because fan rpm if air-cooled or water-temperature maximize and flow charge if water-cooled. Screw speed. Motor load in amps. Line speed. Finished-product dimensions. Other process variables could be monitored about upstream devices such as dryers, blenders, conveyors, and feeders-and on downstream devices just like gear pumps, screen changers, calibrators, water troughs, laser gauges, pullers, and winders. In order to solve extrusion problems, you need to understand the procedure. So operators new to extrusion should have classes covering material qualities and machinery features such as instrumentation, handles, and screw and die style. Many extrusion operations, on the other hand, rely primarily on on-the-job training, though this is actually the least single screw extruder effective and frequently, in some respects, probably the most expensive technique. Improper procedure of an extruder by untrained staff can lead to costly damage as well as injuries. Troubleshooting timeline To understand why an activity isn't behaving effectively, you will need to compare current task conditions to previous conditions when the problem didn't exist. Constructing an activity timeline helps determine what changes in conditions upset the process. The timeline requires records from periods of process stability through the real point when the process upset was noticed. You'll need data of most process data-temps, pressures, and dimensions. Make sure to list all events that could have affected the procedure (see Fig. 1), just like a electric power outage, switch of screw, or a fresh resin lot. Some important events are less clear potentially, such as construction for the reason that area of the plant, changes in substances handling, maintenance activities on the plant's drinking water system, or the start of a new operator. Note that not absolutely all events have an instantaneous effect. There may be a considerable incubation time prior to the effects of a noticeable modification are noticeable, so it's important not to jump to conclusions. You'll want to take up a timeline far plenty of back, several months before the problem appeared even. Stopping melt fracture A good troubleshooting timeline helped a tubing processor chip to isolate the foundation of a processing difficulty. One extrusion range started making tubing with surface area roughness caused by melt fracture suddenly. Melt fracture can take a variety of appearances-slip-stick (or "bamboo"), palm-tree, spiral, or random roughness (Fig. 2). The timeline showed that the tube line ran well for nearly six months before processor switched to a different resin. The timeline likewise showed that a thermocouple had been changed-another suspect. The thermocouple was examined for accuracy, and it turned out to be calibrated and was reading temperature ranges accurately properly. That kept the resin as the utmost likely culprit. It was a metallocene-type polyolefin, which is commonly more susceptible to melt fracture since it maintains larger viscosities at bigger shear rates-i.e., it is less shear-thinning. In general, melt fracture involves stresses in the die and is without question resin-related often. It can be healed by either material or mechanical means. In this full case, the processor could not change the material. Melt fracture can be reduced or eliminated by streamlining the die move channel, reducing shear stress in the land location, using a processing aid, adding die-land heaters, operating above the critical shear anxiety for melt fracture (known as "super extrusion"), or adding ultrasonic vibration-a little known but successful technique highly. Streamlining the die's stream channel is always a good idea to quit melt fracture, but it adds cost. For a high-volume product it seems sensible to give for a fully streamlined die, but that could not be worthwhile for a small-volume product. Reducing shear strain in the area region can be done by raising the die gap, minimizing the extrusion price, increasing die-land heat, increasing melt heat range, or minimizing melt viscosity. Viscosity can be reduced with a process aid or lubricant. When 500 to 1000 ppm of fluoroelastomer is usually put into a polyolefin, a coating is formed by it on the die. This coating takes from five minutes to over one hour to form. Other common answers to melt fracture are to set up a heater to raise die-land temperature to the stage where the shear stress drops below the important shear stress for melt fracture. Residence period of melt found in the die-land area is indeed short that temperature ranges there can be set relatively high. HDPE, for example, which procedures at about 400 at, can go through a die l and F575 F without degrading. Die-land heaters could be retrofitted on the outside of the land area of a tubing die. A die-land heater can also reduce die-head pressure and present up to 20% higher extrusion throughputs while keeping good product appearance and dimensional tolerances. Super-extrusion is a method in which shear stress found in the die-land region is well in this article the critical shear price for melt fracture. That is possible with HDPE and selected fluoropolymers (FEP and PFA types), which exhibit another region of stable extrusion at higher shear than in the zone where melt fracture arises (Fig. 3). Ultrasonic vibration of the die with externally attached transducers also causes shear thinning of plastics. Limited information is on this technique, nonetheless it can lessen melt viscosity by orders of magnitude when the price of deformation is great enough. The plastic melt coating at the die wall structure is most exposed to high-frequency deformation, resulting in a significant drop in melt viscosity at the die wall structure. This reduces die-brain pressure, die swell, melt fracture, and die-lip drool. -Edited by Jan H. Schut Chris Rauwendaal has worked in extrusion for 30 years nearly. He heads his unique consulting company in Los Altos Hills, Calif., which gives screw and die patterns and process troubleshooting products and services. Work done in the Extruder Processing Zone of a co-rotating twin-screw extruder plastic recycling extruder machine results in the desired quality of compounded materials and outcome level. The Extruder Processing Zone (EPZ) is the heart of a Co-rotating Twin-Screw Extruder that helps to achieve the required performance.
In the EPZ, several actions are carried out on the material as it performs its way through the extruder and exits from the die. With respect to the character of work being completed, these zones are known as Intake, Melting, Atmospheric Venting, Mixing, Vacuum Metering and Venting. Proper configuration with a good choice of barrels and elements optimizes the performance of every zone. Solids conveying in Intake, Softening of Polymer in Melting, Degassing in Venting, Distribution and dispersion associated with Kneading actions in Mixing, Discharge control in Metering will be the functions of the many zones. Conveying screws, Kneading Blocks and various other Mixing Elements are the working associates in each zone. Producing the right selection among numerous factors and configuring them in the right order needs knowledge of the functional attributes of each element. This article attempts to throw additional light in understanding the zones and attributes of elements. Configuration of Screw Elements in EPZ The adage diverse strokes for unique folks holds good when one attempts to cope with the EPZ (Extruder Processing Zones) of a Co-rotating Twin-Screw Extruder. In this EPZ location the key to accomplishment lies with the precise design of the Element and Barrel Configuration. In the overall game of Chess, a very good formation is essential to achieve an absolute result, since parts in isolation cannot perform. This is true in the case of Compounding also. Elements work ideal in some combinations, plus some elements are more strong than others. Certainly, it really is true! Importantly, 1. The design must deliver the right amount of work on the product for mixing and melting. 2. The design should have the capability to take the product in and out of the extruder. 3. Lastly, the design should allow volatiles or gases to flee without the product leaking out through Vents. It can be imagined there are different zones (area) inside the extruder performing a number of specific functions. Like a relay competition, each area passes on the baton (the materials being processed) to another zone and before final stage. Extruder functionality measured by energy consumption, quantity and top quality of output, largely depends on the design of the processing zones. The effective collection of factors is the first step in design. The proper combination and amount of elements is the next step. We will go over these various zones and outline the aspect characteristics, its potential use and certain design principles Effects of Processing Conditions on Single Screw Extrusion of Feed Ingredients Containing DDGS10/20/2015 Distillers dried grains with solubles (DDGS), a good feed coproduct from the gasoline ethanol market, has been shown to become a viable potential choice protein origin for aquaculture feeds. To investigate this, three isocaloric (3.5kcal/g) component blends containing 20, 30, and 40% DDGS, with a net protein adjusted to 28% (wet basis, wb), were prepared for use due to Nile tilapia feed. Extrusion processing was then conducted using three DDGS contents (20, 30, and 40%, wb), three moisture contents (15, 20, and 25%, wb), three barrel temperature gradients (90-100-100C, 90-130-130C, and 90-160-160C), and five screw speeds (80, 100, 120, 140, and 160rpm) utilizing a solitary screw laboratory extruder.
Countless processing parameters, including mass flow fee, net torque required, certain mechanical energy consumption, obvious viscosity, and pressure and temperature of the dough in the barrel and die, were measured to quantify the extrusion tendencies of the DDGS-established blends. For all blends, as the temperature account increased, mass flow pace exhibited a slight decrease, die pressure reduced, and obvious viscosity exhibited a slight decrease as well. Likewise, the net torque requirement, particular mechanical energy intake, and apparent viscosity reduced as screw rate increased, but mass move rate increased. Additionally, as china plastic machinery moisture articles increased, die pressure decreased. At higher temperatures in the barrel and die, the viscosity of the dough was lower, leading to lower torque and specific mechanical energy requirements. Increasing the DDGS content, on the other hand, resulted in an increased mass flow rate and decreased pressure in the die. As demonstrated in this study, selecting suitable temperature and wetness content levels are crucial for processing DDGS-based element blends. Corn distillers' dried grains with solubles (DDGS) was first extruded with corn meals in plastic recycling machine a good pilot plant single-screw extruder at different extruder die temperature ranges (100, 120, and 150C), levels of DDGS (0, 10, 20, and 30%) and preliminary moisture contents (11, 15, and 20% wb). Generally, there was a decrease in normal water absorption index (WAI), water solubility index (WSI), radial expansion, and L* worth with a rise in DDGS level, whereas a* value and bulk density increased. Increase in extruder die temperature resulted in an increase in WSI and WAI but a decrease in L* and mass density. Peak load was highest at 30% DDGS in comparison with 0, 10, and 20% DDGS extrudates. Die heat of 120C and initial moisture content of 20% led to least peak load. The a* benefit remained unaffected by improvements in extruder die temperature. Radial growth was highest at extruder die temperatures of 120C. Optimum WAI, WSI, radial growth, and L* benefit were obtained at 15% initial moisture content. An increase in initial moisture content material, in general, decreased L* value and mass density but raised a* value of extrudates.
Our work is approximately the extraction of sunflower seed oil in a twin-screw extruder with or without plastic extrusion die the injection of 2-ethylhexanol and acidified 2-ethylhexanol. 2-Ethylhexanol is mixed with phosphoric acid. The essential oil recovery is risen to 90% by the co-injection of acidified liquor. Combining phosphoric acid with the liquor enhances the lability of the oily spherosomes. Its addition increases the destruction of the membranes enveloping the lipid-including organelles to release the oil more easily. Phosphoric acid exhibits an extracting and a degumming purpose. The best oil top quality was obtained at a low extraction temp (80C), when 88% of the oil was removed. After alcoholic distillation, the essential oil exhibited a total acid value (mineral acidity plus organic and natural acidity) of 4 mg KOH/g of essential oil and a natural phosphorus content below 30 ppm.
Extensive experimental studies on silica agglomerate breakup during compounding with polymer melts of various viscosities and polarities on a modular corotating twin-screw extruder were conducted. To avoid a subjectivity of the effect, due to small size contaminants involved, silica agglomerates were characterized by measuring their mass typical ideals. Increasing the screw swiftness, melt viscosity, and silica concentration were found to increase the silica agglomerate breakup. The result of these parameters on agglomerate breakup was rated the following: silica concentration > polymer viscosity screw revolutions per minute (rpm). An excellent correlation between silica agglomerate breakage and power type was also found. Based on the experimental dispersion and info method, a composite modular kinetic style for evaluating silica agglomerate breakup during compounding in a corotating twin-screw extruder was examined. The kinetic constants of breakup and reagglomeration of silica agglomerates were calculated in line with the stresses applied to the agglomerates and their cohesive strength. These constants for silica agglomerates were found to be not plastic compounding machines distinctive at high concentrations significantly. The latter was in contrast to experimental data from obtainable literature on compounding of calcium carbonate with polypropylene where the substantial reagglomeration kinetic constants of calcium carbonate in comparison to those of breakup enjoyed a major purpose in the agglomerate breakup. Assessment of the experimental and calculated outcomes on the silica agglomerate size development during compounding with polymer melts indicated an acceptable arrangement between them at great rotational speeds.
1. Introduction
Up to now HME has emerged seeing as a good novel processing technology found in growing molecular dispersions of active pharmaceutical materials (APIs) into many polymer or perhaps/and lipid matrices which has led this technique to demonstrate time controlled, modified, extended, and targeted medicine delivery [1-4]. HME has now provided opportunity for usage of materials as a way to mask the bitter preference of active substances. Because the industrial software of the extrusion method back in the 1930s, HME has received considerable attention from both pharmaceutical market and academia in a range of applications for pharmaceutical dosage varieties, such as tablets, capsules, movies, and implants for drug delivery via oral, transdermal, and transmucosal routes [5]. This makes HME an excellent alternative to other available techniques such as for example roll spinning and spray drying conventionally. Not only is it a proven manufacturing procedure, HME meets the purpose of the US Food and Medication Administrations (FDA) method analytical technology (PAT) scheme for designing, analyzing, and controlling the making process via quality control measurements during dynamic extrusion process [6]. In this chapter, the hot-melt extrusion technique is reviewed based on a holistic perspective of its various pieces, processing technologies, and the resources and novel formulation developments and design in its varied applications in oral drug delivery systems. 2. Method Technology of Hot-Melt Extrusion (HME) Hot-melt extrusion strategy was first invented for the developing of lead pipes at the end of the eighteenth century [7]. Since that time, it has been found in the plastic, rubber, and food production industry to create items ranging from pipes to bags and sheets. With the advent of huge throughput screening, currently over fifty percent of all plastic products including totes, bed sheets, and pipes are constructed my HME and for that reason various polymers have already been employed to melt and sort different shapes for a number of industrial and domestic applications. The technology (HME) has proven to be a robust approach to producing numerous medication delivery systems and therefore it's been found to come to be valuable in the pharmaceutical sector aswell [8]. Extrusion is the process of pumping raw materials at elevated controlled heat and pressure through a heated barrel into a product of uniform condition and density [9]. Breitenbach first introduced the production of melt extrusion procedure in pharmaceutical manufacturing procedures [10]; even so, Follonier and his coworkers earliest examined the hot-melt technology to produce sustained release polymer-based pellets of varied freely soluble drugs [11]. HME requires the compaction and change of blends from a powder or a granular mix into a product of uniform shape [9]. In this process, polymers happen to be melted and created into goods of different shapes and sizes such as plastic bags, bed sheets, and pipes by forcing polymeric ingredients and active substances incorporating any additives or plasticisers through an orifice or die under controlled temperature, pressure, feeding cost, and screw speed [9, 12]. However, the theoretical approach to understanding the melt extrusion procedure (Figure 1) could be summarized by classifying the complete process of HME compaction in to the following [13]:(1)feeding of the extruder through a hopper,(2)mixing, grinding, reducing the particle size, venting, and kneading,(3)circulation through the die, and(4)extrusion from the die and additional downstream processing. Amount 1: Schematic diagram of the HME process [12]. The extruder generally includes one or two rotating screws (either corotating or counter rotating) in the stationary cylindrical barrel. The barrel is normally often stated in sections so as to shorten the residence time of molten resources. The sectioned parts of the barrel are in that case bolted or clamped along. An end-plate die is undoubtedly connected to the finish of the barrel which is determined based on the form of the extruded materials. 3. Single-Screw and Twin-Screw Extruder A single-screw extruder consists of one rotating screw positioned inside a stationary barrel at most fundamental level. In the more advanced twin-screw systems, extrusion of materials is conducted by the corotating or counter-rotating screw configuration [9]. Regardless of type and complexity of the function and process, the extruder should be with the capacity of rotating the screw at a chosen predetermined rate while compensating for the torque and shear generated from both material becoming extruded and the screws used. However, whatever the size and kind of the screw inside the stationary barrel a typical extrusion set up includes a motor which acts as a drive unit, an extrusion barrel, a rotating screw, and an extrusion die [13]. A central digital control unit is connected to the extrusion unit as a way to control the procedure parameters such as for example screw speed, heat, and pressure [14] therefore. This electronic control unit functions as a monitoring device as well. The normal length size ratios (L/D) of screws positioned inside the stationary barrel happen to be another important characteristic to consider if the extrusion hardware is a single-screw or twin-screw extruder. The L/D of the screw either in a single-screw extruder or a twin-screw extruder commonly ranges from 20 to 40?:?1 (mm). In the event of the application of pilot plant extruders the diameters of the screws drastically ranges from 18 to 30?mm. In pharmaceutical scale up, the production machines are much bigger with diameters commonly exceeding 50-60?mm [15]. Furthermore, the measurements of a screw change over the length of the barrel. In the most advanced processing tools for extrusion, the screws could be separated by clamps or be extended in proportion to along the barrel itself. A basic single-screw extruder includes three discrete zones: feed zone, compression, and a metering area (Figure 2). Beneath the compression zone that is basically referred to as processing zone could be associated with few other techniques such as blending, kneading, and venting [13, 15]. Number 2: Schematic diagram of a single-screw extruder [10]. The depth combined with the pitch of the screw flights (both perpendicular and axial) differ within each area, generating dissimilar pressures across the screw size (Figure 3). Normally the pressure within the feed area is very low in order to allow for regular feeding from the hopper and soft mixing of API, polymers, and additional excipients and then the screw flight depth and pitch happen to be kept bigger than that of other zones. At this time of the process the pressure within the extruder is very low which subsequently gets increased in the compression area. This process results in a gradual upsurge in pressure along the amount of the compression area, which successfully imparts a high amount of mixing and compression to the material (by reducing the screw pitch and/or the trip depth) [9, 15]. In addition the major aim of the compression zone is not only to homogenize but as well compress the extrudate to guarantee the molten materials reaches the final portion of the barrel (metering zone) in an application appropriate for processing. Finally the ultimate section which is referred to as the metering area stabilizes the effervescent stream of the matrix and ensures the extruded merchandise includes a uniform thickness, condition, and size. A continual and continuous uniform screw air travel depth and pitch helps to maintain constant high pressure guaranteeing a uniform delivery pace of extrudates through the extrusion die and hence a uniform extruded item. Figure 3: Screw geometry (extrusion) [9]. As well as the above-mentioned systems, downstream auxiliary accessories for cooling, cutting, and collecting the finished product is normally employed also. Mass move feeders to meter products into the feed hopper accurately, pelletizers, spheronizer, roller/calendaring device so as to produce continuous films, and procedure analytical technology such as near infrared (NIR) and Raman, ultrasound, and DSC systems are as well options. Through the entire whole process, the sheet extrusion line manufacturer heat in all zones is normally controlled by electrical heating system bands and monitored by thermocouples. The single-screw extrusion system is easy and offers plenty of advantages but still does not acquire the blending capability of a twin-screw equipment and for that reason is not the preferred approach for the production of most pharmaceutical formulations. Moreover, a twin-screw extruder presents much greater versatility (method manipulation and optimisation) in accommodating a wider range of pharmaceutical formulations causeing this to be setup a lot more constructive. The rotation of the screws in the extruder barrel may either end up being corotating (same route) or counter-rotating (opposite course), both directions being equivalent from a processing perspective (Figure 4). A larger level of conveying and much shorter residence times will be achievable with an intermeshing set up. Furthermore, the application of reverse-conveying and forward-conveying elements, kneading blocks, and different intricate patterns as a way of improving or controlling the level of mixing required can help the configuration of the screws themselves to be varied [16]. Figure 4: A twin-screw extruder and screws [9]. 4. Benefits and drawbacks of HME HME offers several positive aspects over conventionally obtainable pharmaceutical processing techniques including (a) increased solubility and bioavailability of drinking water insoluble substances; (b) solvent-free nonambient method; (c) economical process with reduced production period, fewer processing guidelines, and a continuous operation; (d) capacities of sustained, modified, and targeted launching; (e) better content material uniformity in extrudates; (f) no requirements for the compressibility of substances; (g) uniform dispersion of great particles; (h) good stability at changing pH and wetness levels and safe software in individuals; (i) reduced amount of unit functions and production of an array of performance dosage varieties (j) a range of screw geometries [17-21]. However, HME has most disadvantages as well. The primary drawbacks of HME include thermal process (drug/polymer stability), use of a limited number of polymers, high move properties of polymers, and excipients required and not suitable for high heat sensitive molecules such as for example microbial species and proteins relatively Multiparticulate oral dosage forms contain gained considerable popularity since their industry introduction because of the numerous pharmaceutical and technological advantages and their suitability for pediatric make use of (1-3). From a pharmaceutical perspective, pellets can reduce the variants in gastric drug levels, reduce inter- and intraindividual variations, minimize side effects and high native concentrations, and invite modified-release kinetics. In addition they enable incompatible substances to be combined in a single dosage form otherwise. In pediatrics, pellets provide advantages of administration with meals and the chance of adjusting doses based on the child's body mass. The major technical advantage of pellets is usually their capacity to be adapted to effective coating functions (e.g., for a sustainedrelease diltiazem formulation). Furthermore, pellets enhance flow houses during capsule filling, provide a narrow size distribution of contaminants, and offer low friability.
Among the different methods to produce pellets, the process of extrusion-spheronization is of particular appeal (1, 3). Extrusion-spheronization is definitely a semicontinuous procedure organized in five product procedures: blending, wet granulation, extrusion, spheronization, and drying (4). This process, fast and robust, limitations the use of organic and natural solvent and enables medicine loading as high as 90%, based on the active houses, in the blend. When used to make finished products, extrusion-spheronization produces well-densified pellets, supplies a narrow particle-size distribution, yields low friability, ensures frequent sphericity, and maintains good flow properties. The properties of the final product depend on the physicochemical properties of the raw materials and the amount of each component in the formulation (5). Numerous process variables affect the quality of the pellets also. These variables are the type and quantity of solvent put into the powder mixture; mixing speed and time; type of extruder, design of the display screen, and charge of extrusion; spheronization acceleration, period, load, and plate design; and drying fee and time (2-4). Because various extruder patterns are available to get ready extrudates from the wet mass, numerous authors have studied the effect of different extruders on process characteristics and pellet homes. Extruders can be divided into three main types, according with their feed system: screwfeed (i.e., single- or twin-screw), gravity-feed (i.e., sieve, equipment, cylinder, and basket), and ram extruders (3, 4). Few studies compared any extruders with the ram extruder to supply rheological information also to validate the latter extruder's prediction power. Some authors drew parallels between a ram extruder and a equipment extruder or a cylinder extruder, in terms of extrusion features and pellet real estate (6-8). Others compared a twin-screw extruder with a gear extruder or with a rotaring-die press by examining the extrusion process and pellet quality (9, 10). A roll-press cylinder as well was weighed against a basket and a single-screw extruder regarding pellet characteristics (11). Variances in pellet and process homes between a cylinder, an axial single-screw, a radial basket display, and a ram extruder were studied (12, 13). The authors underlined superb differences between your feeding systems, as a result demonstrating that it had been not always practical to transfer a formulation immediately from one type of extruder to some other. Few authors have compared various extrusion systems with the same extrusion-feed mechanism. This approach seems to be particularly beautiful for screw-feed extruders, which can be classified in three categories according to the design of the display (i.e., axial, dome, and radial) (3). The comparative influence of radial and axial single-screw extruders on the extrusion process qualities and on the caliber of final item was studied using different formulations (14-16). Other authors compared two twin-screw axial extruders for continuous granulation on pellet quality (17). Nevertheless, no author includes compared dome technology to the two other screw-feeding systems. Few authors have studied the dome extruder as a simple tool for extrusion (18-21). Numerous authors showed the influence of water quantity in extrudate or pellet properties when using a ram extruder, a gravity-feed extruder, a single-screw extruder, or a twin-screw extruder (5, 9, 11, 22-33). Additional authors showed that extrusion speed influenced pellet or extrudate top quality in ram extruders, gravity-feed extruders, single-screw extruders, and twin-screw extruders (27, 31, 33-37). More than a few authors showed extrusion systems' different sensitivities to normal water content also to extrusion speed (10-14, 17). In this context, studying the influence of drinking water extrusion and quantity velocity is an interesting method to highlight differences between extrusion systems. The authors aimed to compare the three devices of single-screw extrusion-radial, dome, and axial-in terms of efficiency and the homes of pellets made by extrusion-spheronization. To highlight variances between the three extrusion systems, different levels of water extrusion and content twin screw extrusion material speeds were tested. A majority of previous studies indicated that these two parameters have wonderful influence. The authors setup a response surface design of experiments to reveal the variables' influence and to identify the kind of extruder that yielded the very best productivity and pellet top quality. |
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December 2015
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