Home Olive Oil Press
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Date
2012
Authors
Ahmed.N.Kolayb
Rafeek Daragmeh
Rizq.A.Ararawi
Yousef I. Hussein
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Abstract
During olive oil extraction the farmer will wait long time for his turn to extract his olive crop. This waiting time leads to storing the crop which affects the quality of the obtained oil. Furthermore, small olive fruit are normally wasted in the heavy olive presses during the extraction cycle. The majority of farmers in Palestine have small farms, thereto they collect a small quantity of olives and wish to extract their crop at the last day of harvest time in order to reduce time and cost. The aim of this project is to design and manufacture a home olive press that solves the above mentioned problems. This press will enable the farmer to extract the daily collected olive crop at the same day of harvesting with less effort and cost. Similar presses available will be investigated in this project, to fix the shortage problems in order to avoid them in this design. Afterwards, a new manufacture press will be designed. The last step is to examine the press and set it in operation experimentally. Grinding Process The grinding process is the first step in olive oil production cycle, the best way to grinding the fruit is by using a horizontal spiral conveyor rotates inside a cylinder, the rotating spiral pushes the olive fruits to the blade which is fixed on the end of the spiral, at the end of the cylinder there is a fixed plate which consists of many holes, the olive fruits compressed between the blades and the plate which leads to fruits crashing, then the crashed fruits flow out through the plate holes and forms olive paste, this paste will be processed in the next steps of the cycle in order to get oil Mixing Process During this phase the olive paste is slowly but continuously mixed to facilitate the aggregation of the oil in bigger and bigger drops in order to allow an easier separation from vegetable water. Mixers are made of a set of hollowed cylinders (generally three), placed one on the top of the other and open in the upper part. They have a central axis where blades are assembled in order to remove the paste. These cylinders are placed in such a position that the paste cascades from the upper cylinder to the one immediately underneath, after having been submitted to a mixing period. The cylinders have a closed external chamber where hot water circulates in order to heat the paste and favor the separation of the olive oil. Time and temperature of the mixing phase are the key parameters as far as quality is concerned. Temperatures should be kept below 25-30 C because higher values can cause oxidation of the oil and defects such as a taste of cooked and/or rancid oil. The mixing time should be chosen according to the olive cultivar, ripeness stage and milling system. It can vary from 15 minutes for ripe olives to 30 40 minutes for difficult olives. A prolonged mixing time will certainly cause a loss of quality because it causes oxidation of unsaturated fatty acids and degradation of the anti-oxidizing compounds. Time of mixing depends also on the type of crusher. During traditional milling the roller crusher itself while breaking the fruit, slowly mixes the paste so that the mixing phase can be skipped. Mixing is absolutely unavoidable when the milling is done by means of metal crushers. Squeezing Process In order to separate oil from the solid components a manual squeezing method are used, by putting the paste inside a cotton piece and press on the content. This pressure forced the oil to flow out through the cotton piece, which produces clean oil in a good quality and some impurities. The oil put inside a glass vessel in order to remove these impurities, by the time the oil float over the impurities and pure oil will be produced. This method is a traditional way, but it can be used in this project in a developed way, one of these ideas is to put the paste inside a container then applying a pressure on the container the oil will flow out. The pressure can be generated using a hydraulic piston, the disadvantages of this method that no continues production system. The other way is to put the paste in a worm, after a period of time the oil float on the water surface, the oil formed a thin layer on the surface, this oil is pure. This way is another traditional way to get oil, but it still unproductive method. Centrifugal Experiments Centrifugal method is a separate method that depends on the density differences between the paste components, the paste put inside a rotating tube, the oil components will be separated from each other and pure oil will be produced. The effect of centrifugal process was tested experimentally in the university by coordinating with chemical engineering department for using a centrifugal device. The experiment data give information about the rotating velocity, rotating time effect and the oil percentage produced