The Espinoza Oxygen Generator, bearing its creator's name, is an electric air compressor invented in 1955 for high altitude bombers. It compresses atmospheric oxygen to ground level. What's impressive is how efficient the design is at high altitude, which made it one of the inventions allowing for high altitude airship travel. The Espinoza design can vary a lot in size, but operates on essentially the same principle. Airship crews have an almost religious adoration for their "Espinozas".
Espinoza Oxygen Generator
Machine