开云体育

Hi, I was thinking of using a check valve to pressurize my Toro jar-top exhalation valve. The idea is to not need an extra solenoid valve to get the dwell time. The pressure to close the valve would be supplied through a check valve, then the valve could stay closed after the closing air pressure stops. After a dwell delay the solenoid, already on the modified sprinkler valve, could be activated to release the pressure and open the exhalation path. In looking for ways to construct a one way check valve, I realized I had a reasonable supply of one valves already sitting around the house, in the humble hand soap pump dispensers. Tom wb6b ----------- ----------- -----------

Please help make the exhalation valve last one million cycles at 20 PSI! build instructions here: https://simulation.health.ufl.edu/technology-development/open-source-ventilator-project/build-test-instructions/ later today we will post version 2 with a similar exhalation valve build

Hi Erich, I found some cheat sheets and was able to figure out OpenSCAD well enough to produce this exploded view drawing. Basically the valve consists of five layers of plexiglass sheet sandwiched together. Likely 2.38mm thick. The top manifold layer is twice or more thicker. This is just a first rough concept drawing, with no premature optimizations included. An overpressure poppet valve and a negative pressure one way valve should be added to the valve body. A strip on enclosed foam elastomer of some sort could replace the small gap barrier across the bottom of the valve disk in the "air chamber" layer of the valve assembly. It could be a safety feature in that it is possible to allow some play of the valve disk against the top valve plate (the layer below the manifold). The air pressure will hold the valve disk against the top plate. If supply pressure is lost and a positive pressure be exerted by the patient, or negative pressure from the patient the valve disk could lift away from the top valve plate and provide an air path. However, it will be reverse to the normal flow. Inline filters should be included in the supply and exhaust lines if enabling this "safety" breathing path is desired. I'm waiting on the RC servos I ordered to arrive to see how well this design works. Tom, wb6b ----- -----

I suggest that the pressure sensor be mounted in a 1" PVC T with a threaded leg using a threaded cap. The sensor can be mounted in the cap and wires brought out through a hole easily drilled in the flat cap. If the sensor fails it can be easily replaced.

I wonder if anyone in this group is working on solutions that work on 12VDC (or 3S Lithium batteries) to be used in field setting and/or facilities without availability of compressed air? Thanks --Ron N7FTZ

Folks, it is time to FINISH the software. This is Saturday, and I plan to build a physical hardware today, The team at UF needs a freeze on the hardware and needs to have something that WORKS. The FDA requires FAR LESS testing than we get done very single day now. We have now conquered the I2C issue, whether optimally or not. Now in my view we only need two more things: (1) SOME WAY for the user to be able to notify the software "Now is the time to gather our baseline pressure, or zero this or that" -- as needed for sensors. Because we can't just assume that on a restart that the patient is disconnected, and the clinician may require a change in a pressure, or a timing, or add positive-end-expiratory-pressure (PEEP) that CHANGES the baseline pressure that our system sees in the BMP280. So we need a way to allow the user to indicate "now is the chance to grab your baelines for this or that" (2) SOME WAY for the user to modify the Alarms. I don't really care how fancy, and I don't think the FDA cares either. And we don't have infinite memory available. -- The LOW PRESS alarm needs to fire if the inspiratory pressure never increases above 3 cm above baseline during inspiration. (The baseline will CHANGE if the clinician adds more PEEP mechanically.) -- The HI PRESS alarm needs to be in some way adjustable. Find a way. Default is 35 cm H2o above "baseline" and range is probably 20-60 cmH2O -- The TIDAL VOLUME needs low and high alarms and they need to be adjustable in SOME WAY-- either in reference to what is happening, or even more simply (and QUITE WORKABLE) just set to absolute numbers. For example, a reasonable set of tidal volume alarms might be: (THIS IS A SUGGESTION NOT A REQUIREMENT) Tidal Alarms LOW HIGH 1 100 300 2 200 400 3 300 600 4 400 700 5 500 800 6 600 900 7 700 1000 8 800 1100 (all values are cc (equivalent to milliliters) If you can individually just set low and high tidal volumes, --- that probably even BETTER. Being able to set high and low to specific values is how most aneshtesthisa equipment that I used in my career normally worked. But this is not "normal" anymore. We just need a way to make some setting..... I don't particularly care at this moment exactly HOW and I don't think the FDA cares either. But we need it FINISHED THANKS!!! Gordon Gibby My current crappy code enclosed. NO WARANTEE FOR ANY PURPOSE WHATSOEVER. But it now survives removing an I2C line.

I'm located in Silicon Valley (Mountain View, CA) surrounded by idle electronic design and assembly resources. A number of us would love to get a viable ventilator built and donated where needed quickly. Please let us know how we can help. Regards, Phil Marcoux BSEE UF '70