Design and construction of a dual powered meat grinder.

Abstract

Meat is one of the most essential nutritious food item needed for human consumption from which high quality proteins, minerals and essential vitamins are derived. However, certain categories of consumers such as the children, elderly and sick people might not be able to provide the requisite biting force for tough meat tissues. Thus they would only be able to consume meat in their grinded form. In order to address this problem, it becomes necessary to have a meat grinding machine; in order to ensure good and easy digestion of the meat in their system. This paper presents the design of an efficient single meat grinding machine with both manual and motorized mode of operation, which can be used at anywhere (urban and rural area) and at any time (during electric power outage). This design provides the kinematic arrangement of forces, materials selection and proportion of parts to ensure maximum strength and functionality of the machine. To avoid failure of the machine, the working stress (21 MN/m2) of the machine is kept within the value of its ultimate stress (30MN/m2). The dual powered meat grinder was constructed with locally available materials. The performance parameters obtained for an expected rotational speed of 420rpm when motorized and 40rpm wen manually operated indicated an efficiency of 75% and 51% respectively. The production rate of the machine was 98.4kgfh when motorized and 60kg/h when manually operated. The design of the various machine parts was carried out by analyzing forces acting on them. Force analysis led to selection of proper materials to withstand the forces to avoid failure. Stainless steels of various grades were the main materials recommended to be used because they are food grade, strong and durable. Engineering drawings of the various components were drawn before the various components were constructed and then machine parts fabricated. A fully functional prototype resulted after all the above operations. The meat grinder has a total cost of 1 100000Ugx which includes all the taxes, cost of material, machinery and hired labor to construct the machine plus overhead costs. The cost evaluation analysis of the project was based on the payback period method and the Net present value method. The project was evaluated to breakeven in 3 months.