01-28-2016, 10:10 AM
(This post was last modified: 01-28-2016, 10:16 AM by GP49.)
Detection of airflow for auto-on and auto-pressure may be affected by the stiffness of the plastic in the tubing, even at a level which cannot be discerned by a casual examination. In such an application the plastic functions as a high-cut filter; above a certain frequency, fluctuations in pressure will not be transmitted from one end of the tubing to the other. This characteristic is directly affected by the physical properties of the plastic compound and how it is moulded.
Transmission of high frequency pulses, too high to be detectable by the user, is what makes detection of obstructive apnea possible in auto-PAP and perhaps in this machine the auto-on is an adjunct to this same sensing-detection function.
We already know that there is a slight but measurable size difference, and that would affect the operation of this "high-cut filter" too.
In many fields, from replacement needles for high-quality vinyl record playback to knock-off auto parts from China, reverse-engineering often overlooks aspects of the original parts' design, and the OEM isn't going to tell the copycats. Add that to cost-cutting by the imitators, as in replacement smartphone batteries.
Now maybe we can add CPAP tubing to the list.
GP49, what you wrote, makes perfect sense to me.
My old Remstar Pro got very hesitant with (auto) turning on once I started to use Swift FX which has a short, small diameter hose. I keep my machine behind the headboard so, it's not that easy to reach to the ON or Ramp button but, I quickly found that I can easily get the machine to turn on by... quickly pulling my hose on the edge of the headboard so it would rattle a bit. Obviously, to turn on, the machine was more responsive to the frequency than to the pressure change.
Everything I post on this board is nothing more than an opinion expressed by an apneak. Normally, it's based on facts and experience but sometimes, I may get things wrong or not have all the facts.
I reserve the right to change my mind. Why? Because tomorrow I may know better.