The McILROY Fluid Network Analyzer
The McILROY Fluid Network Analyzer was an early electronic analog computer that used an electrical network to model the flow of fluids through a piping network. Specialized vacuum tubes called "Fluistors" used the electrical resistance of tungsten filaments to simulate the resistance to flow of the various components of a piping network. Changes in electrical current represented changes in fluid flow; voltage drops represented pressure drops. The relative brightness of the glowing Fluistor tubes gave a rough indication of the relative pressure drops in the piping segments - the brighter the glow, the higher the pressure drop.
The prototype was developed in 1950 by Dr. Malcolm McIlroy at Cornell University. Dr. McIlroy's concept was awarded US Patent # 2,509,042 "Electric Analyzer for Fluid Distribution Systems"; the patent was assigned to the Standard Electric Time Company, which later built a number of these devices.
The following images are from a brochure printed in the early 1960s, just as analog computers were being replaced by digital computers for system modeling. One clue in dating this brochure is that none of the addresses have zip codes - these were not introduced until July 1, 1963, and their use was not mandatory until 1967.
Front
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Cover (214 KB)