Design and construction of a reciprocating coffee screening machine

Abstract

This report aims at designing and constructing an effective and efficient reciprocating coffee bean screening machine which enhances the roasting of coffee beans as desired by the customers. It was hypothesized that with relevant research, the developer of the machine can create all the necessary methods that aim at improving the efficiency and effectiveness of the existing screening machines. For the purpose of this project, these methods were defined by the developerbasically to improve effectiveness and efficiency of the machine, so the developer opted for those methods that could;  Substitute the vibratory motion with reciprocating motion.  Create delay of the coffee beans on the screen.  Control clogging of the beans in the screening media.  Improve on the spread of coffee beans on the screening media. For all those results to be obtained, the methods employed include (methodology);  Pulleys were introduced basically for the generation of reciprocating motion with power provided by the motor.  Rods were also used in the design running along the width of the screening media to create delay of the coffee beans on the screen as well as improving the spread of the coffee beans on the screen.  A manually operated cleaning mechanism was designed to control clogging of the coffee beans in the screening media. During testing, the results turned out to be a success rendering all my research, designs and improvements rightly applied. The machines was tested without rods in the first place and then with rods in the other place and the results were greatly differently i.e. efficiency was 0.67 in the case without rods and cleaning mechanism and 0.83 for the case with rods and cleaning mechanism. For the remaining percentage of the efficiency, recommendations were provided in chapter seven. For the ways how all that was catered for will be found in the report which was very carefully compiled in supervision of my main supervisor Mr. Andrew Ayor and co supervisor Dr. Norbert Mukasa with also help from my fellow students.