This week, Libby Wayman stopped by our meeting to follow up on how the team was doing since her last visit. While we were intending to discuss failure modes & other strategic methods for critically assessing our project, we ended up mainly troubleshooting the issue of back-flow into our water holding tank. This brainstorming session was super-helpful and produced the following idea:
Instead of trying to find the ideal placement of just one non-return valve, why not install two—one above and one below our aspirator? (We realized the reason we weren’t observing any chlorination of our water when we had installed a non-return valve below our aspirator was because of the imbalance between the poor check-valves in the pump and the perfectly-sealing check valve we had introduced.) We hope including a second, reliable check valve right above our aspirator will not only return the desired function of our aspirator but also allow us to isolate our actual working device as one contiguous unit that could readily be swapped into various pumps in Dhaka.
Some members of the group began testing this idea on Wednesday—expect more updates to follow!