DESIGN AND FABRICATION OF A PALM FRUIT DIGESTER

CHAPTER ONE
1.1    INTRODUCTION
The digester machine is used for the removal of mescals from the palm fruit. The processes used in the digestion vary according to fundamental technological developments, which affect the system of operation. The digestion of palm fruit is as old as mankind. The various level of social development change the phase of the digestion action. The relative humidity content of the palm fruit and other associated, physical sand chemical composition of the palm fruit affect the choice of processes for the digestion of palm fruit.
The digester system within the African countries is usually done in pastel and mortar. The palm fruit is fed in a hermitical cross-sectional mortar and pounded with many reciprocatory up and down blows. This action tends to remove the monocarp from the palm fruit in marshy oil dropping from. This mashy – oil – dropping form now give why for pressing operation which will lead to the bringing out the palm oil. The digester system within the African countries can also bed done in a horizontal sump of about 6ft x 3ft with 8 3ft depth where the palm fruit will be poured when that is done a person will stand on the palm fruit right in the hole and be matching on it for a short period after which the monocarp will be removed from the Nut when it is pressed the oil will come out. In the fundamental technological development, engineering designs encouraged the construction of different – proto type of digester which aids in the production of more digestible mashy fruit. There are different types of digesters. They are classified into:
1.   Manual digester
2.   Motorized digester.
 
1.2   MANUAL DIGESTER
Manual digesters are built with different shapes and patterns. These is a ways a handle which is used to turn the palm fruit in the barrel the shaft of the digester is designed and welded onto with flanges of barrel depending on the size of the barrel used the operation is efficient but very slow and involve a lot of human effort for high production. This method of operation can not go on for industrial use because of its low production rate. Above all human effort tends to dominate the whole operation manual digesters are mostly common in industrial African villages and communities where there is no rural electrification.
 
1.3   MOTORIZED DIGESTER
Motorized digesters consist of a machine with a power driver pulley from the electric motor. The source of power transmission is belt from the driver (i.e) elector motor pulley to the driven digester pulley. The pulley is keyed to the shaft which is supported on two ball bearings located on each end of the shaft. The type of shaft used is the step shaft with the flanges welded unto the bigger correctional part of the shaft. The shaft assembly and flanges are enclosed in a barrel which is usually cylindrical, and the barrel internal surface is about 2cm – 5cm depending on the verities of palm fruit intended for digestion.
 
1.4   TYPES OF MOTORIZED DIGESTER
Horizontal types of the motorized digester are classified depending on the axis of mounting of the barrel and shaft. The horizontal digester are designed with shaft and barrel parirel to the horizontal axis and will incorporate an electric motor that will generate power to the system that will enable the system to function accordingly the vertical digester are this type which the axis are built at right angle to the horizontal axis, the shaft and barrel are positioned in a vertical direction to work effectively. Most designers prefers this type of vertically mounted system because of it high efficiency and easy construction and even good out put in terms of digestion.