No, they exist. My father-in-law, God rest his soul, had one in his last days. Unlike oxygen tanks, they don’t run out of oxygen - I think it processes the air or something.
That is an oxygen concentrator, or generator. No tank involved.
It creates oxygen by removing the nitrogen. It uses zircon. Under pressure it absorbs nitrogen. When the pressure gets to high it drops the pressure and the nitrogen goes back into the room. The oxygen level in the house does not really change.
They are call oxygen concentrators I think. And yes, my father had one in his house for years.
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I think what you’re talking about uses potassium chlorate and heat to release oxygen.
Mother had one. It’s an oxygen concentrator/generator.
Oxygen concentrator unit. Thats the kind that process the air.