Failure analysis and redesigning of an automatic hand washing machine

Abstract

The outbreak of dangerous epidemic diseases such as the COVID 19 pandemic led to the development of different types of hand washing machines that use different mechanisms to operate and in so doing also an automatic hand washing machine called the TW-20 kit was born in the process which was designed and fabricated by the Badaye Technologies Limited. A TW-20 kit is a touchless hand washing machine that uses a sensor to sense heat from a human body close to the its nozzle then dispenses liquid soap then water which are pumped from their respective reservoirs by two pumps which are known as washer pumps one connected to the water reservoir and the other to the liquid reservoir. Most of these kits were donated to various public places such as markets, Universities and hospitals but unfortunately all of them are no longer in use. And this is where I came in to analyze the failure of the kit that was donated to Makerere University Hospital. I was granted permission to carry out my research on the kit at the University Hospital by the Director of the hospital Prof JK Byamugisha. And I managed to carry out my tests and then I found out that for the kit at the university hospital the fault was with the pump that is supposed to pump the liquid soap which I replaced and the kit was good to go. On top of that, I managed to make some modifications and the most important one was the selfrefilling water jerry can that is connected directly to the water supply like a tap and when the level of water reaches a desired level set by me then the ball valve cuts off any more water supply automatically.