You can freely build on How Early Electromagnetic Pumps Moved Liquid Metal Using Magnetic Fields
This patent expired in 1944. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1927
Expired
1944
Forward citations
7
What this patent covers
The patent describes a device that moves electrically conductive fluids, such as liquid metals, by applying a magnetic field and an electric current perpendicular to each other. This interaction creates a Lorentz force, which pushes the fluid through a conduit. Because the force acts directly on the fluid itself, the design eliminates the need for traditional mechanical components like gears, valves, or rotating blades that would otherwise wear out or leak when handling harsh molten materials.
What is now free to use
All 0 claims of US 1647147 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover pumps designed for non-conductive fluids like water or oil.
Does not cover mechanical pumping mechanisms that rely on physical impellers or pistons.
Does not cover systems that lack an integrated electromagnetic field source.
Who is building on this today
Modern nuclear energy companies and research labs working on molten salt reactors continue to refine electromagnetic pumping to manage high-temperature, corrosive coolants safely.
Products built on expired version of this technology
Liquid metal cooling loops in fast-neutron nuclear reactors
Molten salt processing in chemical manufacturing
Industrial die-casting equipment for molten aluminum
How to cite this patent in your documentation
Individual. US Patent 1647147. Electromagnetic pump. Granted 1927, expired 1944. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.