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This is my first new ventilator design in 12 years.
So I looked for these tiny blowers. The reason they are small is not just so that they can be compact. They need to be high RPM with low mass of motor and impeller so that they can change the speeds very quickly so as to provide the desired pressure profile.
Such a pump is available, say from Digikey, but only a few dozen are in stock and then multiple weeks to order more. That won’t work for us. You could also get them from China. There are obvious supply chain problems there. One of my original requirements for the Pandemic Ventilator Project was that it be able to be built from parts that we already have around because I assumed supply chains would be disrupted by the pandemic as well. Well, that turned out to be true.
· What you actually now see is version 2. I reaarranged the layout to minimize dead space, I added the input tube for humidified oxygen increased air, and added a recirculation loop to minimize the waste of oxygen.
- The design should be reviewed by experts in ventilator use as well as engineers with experience in device control to be sure it is adequate and relatively optimized.
- Need to come up with a list of potential parts and interface criteria for sensors
- Specify control system processor, drivers etc.
- Specification list (state table) for all modes of the device to aid in programming
- Basic machine control program is written,
- Interface program for operator control, alarms and setup
- Modify interface look and feel to clone an existing popular ventilator design
- Functional, safety and usability testing
- Operators manual.
- All of these steps are of course iterative and involve testing and user feedback at each level