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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Šroubový lis 50t / Screw press 50t

Švábenský, Pavel January 2014 (has links)
Diploma thesis is focused on desing of the screw press, which is used for laboratory testing of materials by ECAP. Thesis included design of individual scructural groups and their destcription, including the creating of 3D model.
2

Preliminary Design And Construction Of A Prototype Canola Seed Oil Extraction Machine

Sari, Pelin 01 June 2006 (has links) (PDF)
Growing energy demand in the world force people to investigate alternative energy sources. Unlike coal or other fossil fuels, renewable energy sources are promising for the future. Especially, seed oils are effectively used as energy sources such as fuel for diesel engines. The scope of this study is to develop an oil extraction machine specific to canola seed. In this study, seed oil extraction methods have been investigated and various alternatives for the extraction machine have been considered. For continuous operation, oil extraction with a screw press is evaluated as the most appropriate solution. Four different prototypes have been designed and manufactured. According to the results of testing of prototypes, they have been modified and gradually improved to increase oil extraction efficiency. The working principle of the selected screw press based on the rotation of a tapered screw shaft mounted inside a grooved vessel. The screw shaft is a single square-threaded power screw having an increasing root diameter from inlet to exit while the outside diameter of the screw shaft is 66 mm. Seeds are taken into the system at the point where the depth of the screw thread is maximum. Then they are pushed forward by the threads on the rotating screw shaft and pass through inside the vessel. So, the fed seeds are compressed as they move to the other side of the vessel. Recovered oil escapes from high pressure zone and drains back. The oil is drained out from the oil drainage holes that are machined on high pressure zone of the vessel. Besides, the cake is extruded at the end of the vessel and the screw shaft. The cake thickness is adjustable by the axial movement of the screw shaft. By adjusting the cake thickness, different pressures can be obtained. During the experiments, it is observed that four main features affect the oil recovery rate. These are the geometry of the grooves inside the vessel, the taper angle of the screw shaft, the operating temperature and the rotational speed. With the final prototype, an oil recovery efficiency of 62.5% has been achieved at 40 rpm with 15 kg/h seed capacity. Since the oil content of the seed is taken as 40%, oil recovery rate of the developed oil extraction machine is 3.75 kg/h. This efficiency is determined for a 0.8 mm cake thickness at 1.1 kW motor ower.
3

Spiral Fluted Columns and the Mechanical Screw: The History of a Mathematical Idea in Ancient Architecture and Mechanical Technology

Henderson, Georgina Jane 03 September 2013 (has links)
This thesis examines the stone-carved architectural spiral fluted column from second-millennium B.C. Mesopotamia to the fourth-century A.D. Roman Empire, and establishes its relationship to technological devices such as water screws, screw presses, and other machines. Evidence from literary sources and archaeological records shows the increasing architectural use of the helical spiral during that time, particularly in structures such as theatres, nymphaea, colonnades and decorative gateways. The use of spiral designs on coins, sarcophagi, pottery and wall paintings is also discussed. The thesis presents: the mathematics of the spiral as applied in Mesopotamian architecture; spiral use in the Aegean Bronze and Iron Ages and the Greek and Roman worlds; and its use in technology and mechanical devices, specifically those of Archimedes and Hero. The conclusion summarises the evidence, demonstrating that the construction of the spiral fluted column evolved from that of the Archimedean water screw. / Graduate / 2015-08-20 / 0324 / 0346 / 0579 / ghenders@uvic.ca
4

Spiral Fluted Columns and the Mechanical Screw: The History of a Mathematical Idea in Ancient Architecture and Mechanical Technology

Henderson, Georgina Jane 03 September 2013 (has links)
This thesis examines the stone-carved architectural spiral fluted column from second-millennium B.C. Mesopotamia to the fourth-century A.D. Roman Empire, and establishes its relationship to technological devices such as water screws, screw presses, and other machines. Evidence from literary sources and archaeological records shows the increasing architectural use of the helical spiral during that time, particularly in structures such as theatres, nymphaea, colonnades and decorative gateways. The use of spiral designs on coins, sarcophagi, pottery and wall paintings is also discussed. The thesis presents: the mathematics of the spiral as applied in Mesopotamian architecture; spiral use in the Aegean Bronze and Iron Ages and the Greek and Roman worlds; and its use in technology and mechanical devices, specifically those of Archimedes and Hero. The conclusion summarises the evidence, demonstrating that the construction of the spiral fluted column evolved from that of the Archimedean water screw. / Graduate / 2018-08-20 / 0324 / 0346 / 0579 / ghenders@uvic.ca
5

Návrh kotveného stojanu vřetenového lisu s přímým pohonem / Design of multiple-part frame of screw press with direct drive

Sobotka, Radek January 2016 (has links)
The subject of this term project is the design of cast multiple-part frame of screw press with direct drive with stated parameters for heavypressing. The first part consists of a research in the field of screw presses focused on the construction of the frame and current manufacturers of the screw presses. The second part is aimed at the design of the frame according to specified parameters. The thesis includes press layout drawing, frame assembly drawing, selected detail drawings and 3D model of the frame.
6

Sugarcane juice extraction and preservation, and long-term lime pretreatment of bagasse

Granda Cotlear, Cesar Benigno 17 February 2005 (has links)
New technologies, such as an efficient vapor-compression evaporator, a stationary lime kiln (SLK), and the MixAlco process, compelled us to re-evaluate methods for producing sugar from cane. These technologies allow more water and lime to be used, and they add more value to bagasse. Extracting and preserving the sugars, and lime pretreating the bagasse to enhance biodigestibility, all at the same time in a pile, was demonstrated to be unfeasible; therefore, sugar extraction must occur before lime treating the bagasse. Sugar extraction should occur countercurrently by lixiviation, where liquid moves in stages opposite to the soaked bagasse (megasse), which is conveyed by screw-press conveyors that gently squeeze the fiber in each stage, improving extraction. The performance of a pilot-scale screw-press conveyor was tested for dewatering capabilities and power consumption. The unoptimized equipment decreased megasse moisture from 96 to 89%. Simulation of the process suggested that eight stages are necessary to achieve 98% recovery from typical sugarcane. The cumulative power for the screw-press conveyor system was 17.0±2.1 hp•h/ton dry fiber. Thin raw juice preserved with lime for several months showed no sucrose degradation and no quality deterioration, except for reducing sugar destruction. The lime loading needed for 1-year preservation is 0.20 g Ca(OH)2/g sucrose. Shorter times require less lime. After preservation, the juice was carbonated and filtered, and the resulting sludge pelletized. Due to their high organic content, the pellets were too weak for calcination temperatures used in the SLK. The organics must be decreased prior to pelletization and sodium must be supplemented as a binding agent. Long-term lime pretreatment of bagasse showed two delignification phases: bulk (rapid) and residual (slow). These were modeled by two simultaneous first-order reactions. Treatments with air purging and higher temperatures (50 – 57oC) delignified more effectively, especially during the residual phase, thus yielding higher cellulase-enzyme digestibilities after 2 – 8 weeks of treatment. At temperatures > 60oC, pure oxygen purging is preferred. Fresh bagasse was of better quality than old bagasse. Treatment with NaOH yielded a larger bulk delignification phase than Ca(OH)2. Long-term lime pulping of bagasse was unsuitable for copy-quality paper, but it was appropriate for strawboard and other filler applications.
7

Étude et modélisation du pressage continu des graines oléagineuses / Study and modeling of continuous pressing of oilseeds

Bogaert, Laurine 08 December 2017 (has links)
Ce travail de thèse vise à améliorer la compréhension des phénomènes physiques se produisant durant le pressage en continu des graines oléagineuses et à développer un modèle phénoménologique décrivant le comportement mécanique de la matière au cours de sa compression le long de la vis. Les expérimentations ont été réalisées sur des graines de colza, en utilisant un pilote de presse à vis instrumenté (Reinartz, Allemagne). Deux arrangements de vis différents ont été étudiés et comparés, de manière à observer l’influence de la géométrie sur les performances opératoires, le développement des contraintes à l’intérieur de la cage et les propriétés mécaniques du gâteau de pressage. L’instrumentation de la presse a permis de générer des données précises de débits d’huile et de gâteau, capacité de traitement, rendement d’extraction et consommation d’énergie spécifique, pour des vitesses de rotation de la vis comprises entre 0 et 18,2 tr/min. Des profils de pression, teneur en huile et vitesse de déplacement ont également été déterminés pour les deux arrangements de vis, pour caractériser le fonctionnement de la presse. Ces données ont permis d’identifier une alternance de zones de compression et de transport le long de la vis, avec une présence éventuelle de phénomènes de reflux. Une représentation simplifiée a été proposée, pour décrire le pressage continu comme une succession de d’étapes de pressage discontinu. En se basant sur la théorie de filtration/consolidation, le coefficient de consolidation, le module de compressibilité et la résistance spécifique du gâteau de pressage ont étés calculés pour chaque zone de compression. Les propriétés mécaniques du gâteau de pressage ont finalement été utilisées pour développer une relation semi-empirique permettant de prédire le débit d’huile et le rendement d’extraction de la presse. Les résultats expérimentaux correspondent aux données estimées avec une précision satisfaisante. / This work was devoted to better understand the physical phenomena occurring during oilseeds expression in continuous screw presses and to develop a phenomenological model describing the compression behavior of the press cake along the screw. Experiments were conducted on canola seeds, using an instrumented pilot screw press (Reinartz, Germany). Two different screw arrangements were studied and compared in order to observe the influence of the geometry on the operating performances, the constraints development in the barrel and the press cake mechanical properties. Press monitoring provided accurate data about oil and cake flowrates, treatment capacity, extraction yield and specific energy consumption, for screw rotation speeds ranging between 0 and 18.2rpm. Pressure, deoiling and displacement velocity profiles were also determined for both arrangements to characterize the press operation. These data allowed to identify the alternation of compression and transport sections along the screw, possibly supplemented by oil reflux. A simplified representation was proposed, describing continuous pressing as a succession of multiple batch pressing steps. Based on the filtration/consolidation theory, the consolidation coefficient, compressibility modulus and press cake specific resistance were calculated in each compression sections. The press cake mechanical properties were finally used to develop a semi-empirical relation predicting the press oil flowrate and extraction yield. Experimental results fitted the estimated data with satisfactory accuracy.
8

Les productions d’huile et de vin dans les Alpes-Maritimes antiques / The productions of olive oil and wine in the ancient Alpes-Maritimes

Clément, Paul 13 June 2016 (has links)
L'étude a consisté à effectuer l'inventaire, dans l'actuel département des Alpes-Maritimes, des sites archéologiques ayant produit de l'huile d'olive et du vin et à établir le catalogue des mobiliers dédiés à ces productions. A fin 2015, 70 sites ont été répertoriés, comportant 250 éléments de mobiliers appartenant principalement à des installations de pressage, ainsi qu'à quelques moulins à broyer les olives de type mola olearia, qui ont fait chacun l'objet d'une fiche. Les installations de pressage ont connu leur plus fort développement au début de l'Empire romain. Alors que la plupart des installations vinicoles cessent de produire au IIe siècle ap. J.-C. ou au début du IIIe siècle, , la production d'huile d'olive, après un ralentissement au IIIe s., est relancée au Bas-Empire, jusqu'à l'Antiquité tardive. Cette étude donne un premier aperçu global des aspects technologiques et économiques des productions d'huile d'olive et de vin dans la région. / This work presents a catalogue of archeological sites and equipments related to the production of olive oil and wine in the present Département des Alpes-Maritimes. By the end of 2015, 70 sites had been indexed, including 250 archeological items , mostly concerning pressing facilities and some crushing mills (molae oleariae); all of which have been recorded on individual data sheets. The major development of the rural press settlements was found at the beginning of the Roman Empire. While most wineries stopped producing during the 2nd century A.C. or in the early 3rd century, the production of olive oil, after a slowing down in the 3rd century, experienced a revival during the Low Empire and until the Late Antiquity. The analysis has given a global first insight into the economic and technological dimensions of olive oil and wine production in the region

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