Established in 1912, Fulflo was incorporated in 1933 under its present name and trademark. Patents for the original guided piston, direct-acting relief valve were obtained in 1935, coincident with the onset of fluid power systems. The need for providing large flows without excessive bulk was subsequently met by the pilot-valve-controlled relief valve, a patent on which was issued to Fulflo in 1943 (U.S. Patent No. 2,333,522). Fulflo is located in Blanchester, Ohio just 30 miles northeast of Cincinnati, close to some of the state's largest manufacturing centers. Blanchester is served by air from Greater Cincinnati Airport and alternately from Dayton