Posted by NickD (24.240.212.148) on April 12, 2001 at 23:57:19:
This is what one looks like, the indent in the upper left hand corner is for a humidifier. This unit is essentially a small air compressor that draws room air that is 20% oxygen and 80% nitrogen, the two tall canisters contain a natural material called zeolite that absorbs the nitrogen from the air, a four way valve directs the 94% pure oxygen out through the metering valve through the humidifier and into the mask, this air is also filtered three times with dust and carbon filters, the nitrogen is expelled out a vent near the bottom. The unit can acutally be pushed to 8 liter per minute at around 89% oxygen, still very strong. The unit runs on standard 117 VAC current and draws about 375 watts, in my neck of the woods that costs less than 2 cents per hour to operate, the air is free least last time I checked. First maintenance is due at 10,000 hours of use, running full bore that's close to 5 million liters of oxygen, maintenance consists of a compressor rebuilt kit at a cost of $60.00 and a carbon filter for another $20.00, the sign of compressor wear is reduced O2 output as shown on the rate meter, the electronics and four way valve are warranteed for life, I was lucky to find mine on ebay.com using oxygen concentrator in the search bar that came in the original Invacare box with less than 200 hours for $375.00, a new one cost about $3,100.00. As opposed to lugging O2 tanks back and forth and not know the quality of the air you are getting, a concenstrator is a very wise investment, thought I would share this with you, if you have any questions, please ask. I don't sell these, but mine has eliminated thousands of hours of pain.