Simulation of the Extruder Screw Parameters

Extrusion of feed ensures a high quality of the fi nished product.(Research purpose) To increase structural elements durability of the press extruder by optimizing their strength characteristics.(Materials and methods) The authors studied the technological principle of extrusion. The experiment planning method was applied. They examined the process of press extruder operation with a variable pitch screw during the lentils processing. The strength characteristics of the press-extruder elements were checked during design or strength calculations.(Results and discussion) The authors showed the role of the main geometrical parameters of the extruder screw – the slope of the turn and the cutting step – in the preparation of high-quality grain feed. It was found that the turn pitch should be calculated depending on the friction coeffi cient of the starting material against the press-extruder body, the type and properties of the supplied material. The auger fatigue stresses were determined as a result of constant sign shear load and temperature eff ects. The drive power, the extruder productivity were calculated to clarify the screw characteristics, as well as the hydraulic resistance of the matrix output head, the distance of the technological zones. It was confi rmed that the prefabricated screw structure, consisting of sections with diff erent pitch, gave the press extruder versatility.(Conclusions) The authors found that the key was one of the most loaded structural elements of the press-extruder screw. The maximum calculated voltage from a constant load was calculated – 26.98 megapascals. It was determined that the stress in the cross-section of the key under temperature action was 591 megapascals, which exceeded the yield stress for the selected material, equal to 360 megapascals for steel 45. In the course of experimental studies, a value of impact strength was obtained that corresponded to the standard value of the initially selected steel grade (38 kilojoules per cubic meter), but didn’t meet the requirements for this structural element (at least 50 kilojoules per cubic meter).

The Influence of Corn Straw Extrusion Pretreatment Parameters on Methane Fermentation Performance

The aim of the study is to determine the energy consumption of the extrusion-cooking process of corn straw under various conditions (screw speed, moisture content), water absorption measurements and water solubility indices as well as biogas efficiency evaluation. The extrusion-cooking of corn straw was carried out using a single screw extruder with L/D = 16:1 at various rotational screw speeds (70, 90, and 110 rpm) and with various initial moisture content of raw material (25 and 40%). Prior to the process, the moisture content of the raw material was measured, and next, it was moistened to 25 and 40% of dry matter. For example, at 70 rpm extruder screw speed, the temperature range was 126–150 °C. Energy consumption of straw pretreatment through extrusion-cooking was assessed in order to evaluate the possibility of using the process in an agricultural biogas plant. Biogas and methane efficiency of substrates after extrusion was tested in a laboratory scale biogas plant and expressed as a volume of cumulative methane production for fresh matter, dry matter, and dry organic matter. Pretreated corn straw moistened to 25% and processed at 110 rpm during the extrusion-cooking processing produced the most advantageous effect for methane and biogas production (51.63%) efficiency as compared to corn straw without pretreatment (49.57%). Rotational speed of the extruder screw influenced biogas and methane production. With both dry matter and dry organic matter, the increase of rotational speed of the extruder screw improved the production of cumulated biogas and methane. Pretreatment of corn straw has a positive effect on the acquisition of cumulated methane (226.3 Nm3 Mg−1 for fresh matter, 243.99 Nm3 Mg−1 for dry matter, and 254.83 Nm3 Mg−1 for dry organic matter). Preliminary analysis of infrared spectra revealed changes in the samples also at the molecular level, thus opening up the possibility of identifying marker bands that account for specific degradation changes.

Influence of the Design Solutions of Extruder Screw Mixing Tip on Selected Properties of Wheat Bran-Polyethylene Biocomposite

The study investigated the impact of the extruder screw design solution—the intensive mixing tip used—on the course of the extrusion process and the properties of the obtained biocomposite extrudate. A lignocellulosic wheat bran biocomposite based on a low-density polyethylene matrix was extruded. Three mixing tips of the screw were used interchangeably: apineapple tip, a cut rings tip, and a Maddock tip. The experimental tests carried out included the production of an extrudate with a mass content of bran altered within the range from 10% to 50%. Processing properties such as the melt flow rate (MFR) and mass flow rate of the extruded biocomposite were determined. Selected physical, mechanical, and structural properties of the biocomposite extrudate obtained with the use of the three tested mixing tips at five bran contents were tested.

Evolution of The Extruder Screw-Disk Plasticizing System Construction

The search for new polymer processing ways has become necessary due to the rapidly growing technology and market needs. The time of manufacturing products, as well as the impact of process parameters and the design itself on the properties of materials have become very important. Therefore, the creation of assumptions allowing the construction of a compact device whose construction will allow, for example, high process efficiency at low screw rotational speeds or a high degree of material homogenisation, is expected by the market. However, this requires the design of new or continuous modifications and improvements to existing structures.

The effect of polyester recycled tire fibers mixed with ground tire rubber on polyethylene composites. Part II

This work reports on the mechanical (tension, flexion, and impact) and physical (density and hardness) properties of polyester recycled tire fibers (RTFs) mixed with ground tire rubber and linear low-density polyethylene with and without styrene–ethylene–butylene–styrene grafted maleic anhydride as a compatibilizer. In particular, the effect of RTF content (10, 25, and 50 wt%), extruder screw speed (110, 180, and 250 r/min), and temperature profiles (extrusion and injection molding) was studied. The results showed that the best properties were obtained at the highest RTF content (50%) and extruder screw speed (250 r/min) combined with the lowest temperature profile in both extrusion and injection molding when the compatibilizer was added.