During what he later described as a "boring night at a factory test room", Carl Montelius sketched out an idea for a pump with three intermeshing screws, rotating in a manner that would make them mutually sealing.
A respected Swedish engineer with 60 patents already to his credit (including the first pay telephone), Montelius regarded the interesting rotors as an amusing intellectual puzzle, working almost every evening during 1923 to develop the mathematical algorithms of the threads. In 1931, Montelius linked with financier Bengt Ingestrom and formed Aktiebolaget IMO-Industri, taking the name IMO from their own names Ingestrom and Montelius.
His painstaking work produced the elegant design that was the world's first multiple screw pump. The precisely calculated profile of the rotor threads prevents vibration and makes the Imo screw pump smooth and silent even when running at high speeds and high pressure. The simplicity of the design is one of the reasons why literally millions of these pumps are now in service around the world, in thousands of different applications.