This App is a great resource for calculating "Lohms" or liquid ohms.

Over the years, The Lee Company has developed the Lohm system for defining and measuring resistance to fluid flow. Just as the "ohm" defines electrical resistance, the "Lohm", or "liquid ohm" can be used as a measure of fluid resistance.
Lohm Laws generalize the Lohm definition and allow the system designer to specify Lohm requirements for a particular application based on the desired pressures and flow rates.
By using Lohms, one can specify performance without concern for coefficients for discharge, passageway geometrics, physical dimensions or tolerances. The resistance to any flow can be expressed in Lohms and confirmed by actual flow tests.


For over 60 years, the Lee Company has pioneered the development of miniature precision fluid control components for aerospace, down-hole oil tools, machine tools, medical/scientific instrumentation, and ink-jet printing. Lee's unique capabilities in miniaturization and engineering expertise — one in every eight employees is a graduate engineer — keep the company at the forefront of fluid flow technology.

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