Wow, for a bunch of folks who pride themselves on being on the leading edge of technology it sure doesn't take much deviation from strongly conventional thinking to cause one to be shot down in flames. Now I know how the alternative engine folks feel!
My question regarding the use of an O2 concentrator to fill tanks met with some, to put it politely, uninformed responses.
As an example of the equipment to which I was referring, Invacare makes a concentrator/compressor stack - see attached photo and description below.
This is the type of equipment which might be handy for an aviator to own rather than running a bunch of big welding bottles and transfilling at high pressure. The price isn't totally over the top and the tank fill times aren't unreasonable if one has more than one cylinder and can keep a spare cylinder available to be topped off at home. Heck, one might even leave this unit in the hangar and fill bottles while working on the airplane.
If one doesn't want the hassle of hiding the truth from welding gas suppliers, this might be a decent way to go. Or not. That's why I was asking the question, in hopes that perhaps some fine soul already had gone down this path and was willing to share their experiences here.
Perhaps from this new baseline we might get some better-informed feedback.
=====================
HomeFill II Oxygen Compressor - The Invacare HomeFill II complete home oxygen system will revolutionize ambulatory oxygen by allowing patients to fill their own high-pressure cylinders from a concentrator. The HomeFill is a multi-stage pump that simply and safely compresses oxygen from a specially equipped Invacare 5-liter or 10-liter concentrator into oxygen cylinders in size ML4, ML6 and M9(c).
Features
Connection and controls are designed for ease of operation
Fill cylinders while patient continues to receive oxygen from concentrator
Virtually eliminates the high service costs of frequent deliveries of cylinders and-or liquid oxygen
Gives ambulatory patients greater freedom and independence
Small and lightweight
Specifications:
Electrical:120 VAC +- 10% at 60 Hz
Power:Consumption: 200 watts
Rated Current Input:2.0 amps
Pressure:14 - 21 psi
Oxygen:Output from concentrator: 0 - 3 lpm (while filling cylinder)
Input: 0 - 2 lpm
Dimensions:20.25"W x 15"H x 16"D
Product Weight:33 lb
Cylinder Filling Times:M6: 1 hr 25 min
M9: 2 hr 20 min