Design and fabrication of a motorized mobile sand filter and separator.

Abstract

Construction of buildings requires sand as an important ingredient Sand is used at different stages in construction right from the foundation to the finishing work i.e. plaster. This sand is needs to be screened properly for various stages in construction, i.e. size of sand for construction work is slightly coarse whereas that used for plaster work is fine. Conventionally screening is normally done manually using fixed screens or machines. This manual process time consuming and laborious takes a lot of time and cost. It is also observed that the conventional machine prove of no or little help as the sand needs to be manually transported and material handling takes place twice to get different sizes of sand. These processes are carried out manually. The main objective of this research was to design and fabricate a sand filtering and separating machine. Sieving of sand is carried out using rectangular mesh which is inclined at certain angle. The sieve/filter box (containing sand) is set into a horizontal reciprocating motion through a connecting rod attached to a crank. The crank converts circular motion into reciprocating motion of the sand sieve box. The crank is driven by a power transmission mechanism ie Vbelt and pulley system with a motor providing the input power. The velocity of the sieve box accelerates the sand particles in a horizontal motion. This movement distributes the particles over the sieve while changing orientation. The particles interact with the sieve mesh thus passing through the larger openings as they move to and fro. The design factors, calculations and fabrication are consistent. The machine was tested in the workshop in kabanyoro Makerere University and it was confirmed in good working condition.The length of the belt calculated as 1168mm was considered the minimum. An allowable excess of 8mm was added to avoid losses. The fabrication was carried out under adequate precautionary measures, thus no accident occurred. The cost, as estimated, is considerable affordable and the machine is economical, in terms of time and effort. The efficiency, calculated, is 90% with a Sieving rate - Itonne-tonne/hr (5mm sieve); -800kgItonne/hr. (2.36mm sieve); -600-800kg/hr(2.00mm sieve) thus the machines durability is high, based on the discussion of results. It was concluded that the prototype is able to efficiently sieve sand and separate it from unwanted material. Further modifications are also are necessary on this machine, towards reducing cost, weight, and increasing efficiency and output while at the same time meeting the required standards.