Monster Steel Ball Forms Air Cure Hospital In the 1920s Dr. Orval J. Cunningham was a leading exponent of hyperbaric therapy. In the mid-1920s, he operated the then largest hyperbaric chamber in existence, in Kansas City. An industrial tycoon, H.H. Timken, heard about this work and gave Cunningham $1,000,000 to build what would end up being the largest hyperbaric chamber ever constructed. Timken’s industry, ball bearings, was based in Canton, Ohio, but the chamber was built in Cleveland, to Cunningham’s specifications. While in existence it was known as the “Timken Tank” and the “Cunningham Sanitarium.”