I sure don't blame you for being frustrated, ywp. This therapy can be frustrating when it doesn't work, and it can even be somewhat frustrating when it does work.ywp wrote:I am a mechanic, designer and installer of water pumps and air blowers. My cpap theraphy is not "" working"" "" And I probably over fixate on mechanics and logic.
Thank you for the though full replies. And please do not take this personally
But What goes out must come in. Maximum output = Maximum input. Not Maximin output + leak rate + lung effort + hope - denial = real out put.
You guys maybe right about it being a limitation on sensors for control and data. Maybe a velocity problem, laminare flow ? . Sounds like the blower has the "horse power" or performance. Guess that is what I will assume. Good explanation to keep an auto pap locked down to a narrow range or go back to cpap. Does make it harder to trust the data
Just mad at medical community
My earlier point was only that the machine spec submitted for discussion only describes impeller delivering capacity when interfaced to a nominal impedance-based reference circuit. And that reference spec does not describe maximum flow through the PAP machine's air intake of that final end-to-end system---when a second biologic contributing circuit is added. I agree that increased turbulent flow at higher velocities will increase overall impedance. For what it's worth, highly dynamic human airway resistance and diaphragmatic effort both factor in once that PAP machine interfaces to a living, breathing human. This equation highlights time-based parameter variations to account for varying airway resistance and pressure having to do with airway factors such as diaphragmatic elastic recoil, etc.:
PpatientR1(t)R2(t)*(% Set)*((R3(t)*(FA)({dot over (V)}))(R4(t)*(VA)(V))R5(t)*EPAP
So that's not your typical physics equation for an automotive water pump or Koi pond impeller. It's a biophysics equation, that factors dynamic diaphragmatic pressure and total airway resistances. Anyway, there are two separate but merged pressure/flow systems at opposite ends of a man/machine dual-interfaced system. And I agree with you that not only laminar flow but especially turbulent flow will factor into airway resistance---and thus final flow at any given pressure.
If you enjoy analyzing pressure/flow systems, take a Google search sometime at the Starling Resistor model, a model that SDB researchers often employ to analyze critical collapse pressure (Pcrit) in the human airway. I can think of two APAP algorithms (yours being one) that rely heavily on the measurement and analysis of that same Pcrit parameter.
Anyway, all PAP machine motors provide enough rotational velocity and torque to work with any mask. And all PAP machine plenum and tubing circuit combinations carry adequate flow-through capacity across that full PAP pressure spectrum as well. Good luck!
