Design of a conveyor belt washer.

Abstract

The purpose of this project is to design a device to clean fish solids and plaque from plastic conveyor belts after they have been taken off fishing ships. This project involved a systematic design study along with an experimental investigation into the effectiveness of cleaning methods. While fishing factory ships are at sea, the plastic conveyor belts that are used to transport fish become tainted with a biological plaque that some bacteria create to protect themselves, and fish residue. A brief was evolved that required the development of a land based cleaning device to reduce the non-productive cleaning time at sea. A systematic design procedure was adopted for the design of the belt-cleaning device. Research showed that strongly alkaline solutions were the best method of cleaning protein-based biofilms. This research led to the most promising cleaning mechanism concepts being tested to quantitatively evaluate their cleaning effectiveness. The development of the final concept considered the requirements of New Zealand legislation and a professional code of ethics, materials issues due to the aggressive environment, structural design using finite element methods, and a heat and mass transfer analysis. The final design solution consisted of two units. Firstly, a tank to receive the coiled belt, another insulated tank to store the sodium hydroxide cleaning solution, an overhead crane to load/unload the belt, and a transfer pump and control system to control the flow of fluids. The second unit was a separate rinser to perform the water blasting. This study resulted in the final manufacturing information for the belt washer. This includes detailed drawings and a costing for all parts and construction.