Upon return from our site visits we compiled observations, evaluated needs, and generated several project ideas. I chose to work on the oxygen concentrator projects which include sieve beds, filters, and education with Vincent, Harvey and Christine.
Though the problem with a specific concentrator was difficult to pinpoint by the technicians at Zomba, they mentioned that contaminated sieve beds and worn compressor parts are the most common issues. They estimated that sieve beds were the issue about 50% of the time. This is due to the aluminum silicate binding with water in the air. We are exploring methods of zeolite regeneration, so that sieve beds could be reused instead of being replaced by the manufacturer. So far the method of opening up the sieve bed and heating the zeolite for several hours seems promising, but we doubt the feasibility of this extensive process in a hospital or PAM workshop setting. Heating gas and running it through the sieve bed itself would be better, so that the canister would not have to be opened.
Fun opening sieve beds
Lack of filters was not mentioned as a common mode of failure, which may be due to the fact that it is a cause of contamination, but not the part of the concentrator that actually breaks. Mr. Khonje did mention that the bacterial filters were black from use and should be replaced periodically, but that they do not replace them. We noticed that most of the concentrators did not have their original gross particle filters, and Mr. Khonje said that they had been lost in the ward. However, for some of the concentrators, he had improvised a new gross particle filter out of a yellow piece of foam. Similar improvisation attempts were also observed at the other sites, so we decided to take on the project of finding the best local material for filter improvisation. We walked around Limbe for a few hours, going into all of the hardware stores and looking for materials that could be used as a filter. We found several candidates, including different types of sponges, foam, cloth, and wire mesh. We have developed tests to evaluate the different materials based on dirt retention, airflow restriction, drying time and durability.
A very dirty concentrator missing both the gross particle and intake filters (are you surprised it’s broken?)
A gross particle filter improvised by Mr. Khonje
In order to ensure the sustainability of our filter solution, we are developing simple, pictorial instructions for basic cleaning procedures (like washing the gross particle filter). These instructions will be laminated and fixed to the concentrators in the wards so that nurses and cleaners will be aware of the periodic maintenance which could prevent so many concentrators from failing. We have already seen different examples of pictorial instructions around the hospitals (some are shown below), so we are hopeful that they will be effective.
