How Albert Einstein and Leo Szilard Designed a Silent Refrigerator
A 1930 patent by Albert Einstein and Leo Szilard for a refrigerator that uses electromagnetic pumps instead of moving mechanical parts to circulate coolant.
Original patent title: “Refrigeration”
A 1930 patent by Albert Einstein and Leo Szilard for a refrigerator that uses electromagnetic pumps instead of moving mechanical parts to circulate coolant. Granted to Electrolux Servel Corp in 1930 with 22 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The patent describes an absorption refrigerator system that eliminates the need for moving parts like pistons or electric motors, which were prone to failure and leaks in early refrigeration technology. It uses an electromagnetic pump to circulate a refrigerant fluid through a closed loop. By leveraging the interaction between an electric current and a magnetic field, the system moves the liquid coolant without any mechanical wear, aiming for a design that is silent and durable.
The gap
What does this patent NOT cover?
- Does not cover standard vapor-compression refrigerators that use traditional electric compressors.
- Does not cover refrigerators using chemical refrigerants like Freon or modern hydrofluorocarbons.
- Does not cover systems that rely on mechanical pumps or rotating fans to move coolant.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in using an electromagnetic pump to move liquid metal or other fluids, completely removing the need for mechanical seals that were the primary point of failure for early home refrigerators.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Experimental absorption refrigeration prototypes
Early silent cooling systems for laboratory use
Why it matters
The bigger picture
This patent represents a rare intersection of theoretical physics and household appliance engineering. While the specific Einstein-Szilard design did not become a commercial standard due to the emergence of safer, more efficient compressor-based systems, it highlights the inventors' focus on solving the problem of toxic coolant leaks common in 1920s refrigerators.
Filed
December 16, 1927
Granted
November 11, 1930
Market context
Who's building on this
Companies in this space
Modern research into electromagnetic pumps continues in specialized fields like nuclear reactor cooling and liquid metal battery technology, where moving parts are undesirable.
Market impact
The patent did not trigger a mass-market shift, as the industry moved toward vapor-compression technology. However, it remains a significant historical example of how fundamental physics can be applied to solve common household mechanical reliability issues.
Claim 1 — Plain English
What this patent covers
The patent describes an absorption refrigerator system that eliminates the need for moving parts like pistons or electric motors, which were prone to failure and leaks in early refrigeration technology. It uses an electromagnetic pump to circulate a refrigerant fluid through a closed loop. By leveraging the interaction between an electric current and a magnetic field, the system moves the liquid coolant without any mechanical wear, aiming for a design that is silent and durable.
The clever bit
The innovation lies in using an electromagnetic pump to move liquid metal or other fluids, completely removing the need for mechanical seals that were the primary point of failure for early home refrigerators.
What it does not cover
- Does not cover standard vapor-compression refrigerators that use traditional electric compressors.
- Does not cover refrigerators using chemical refrigerants like Freon or modern hydrofluorocarbons.
- Does not cover systems that rely on mechanical pumps or rotating fans to move coolant.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
27/40
Moderately cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$14K – $46K
Midpoint $29K · expired or expiring · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
Albert, E., & Leo, S. (1930). How Albert Einstein and Leo Szilard Designed a Silent Refrigerator (U.S. Patent No. 1,781,541). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1781541/einstein-szilard-refrigerator
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Albert Einstein and Leo Szilard Designed a Silent Refrigerator cover?
A 1930 patent by Albert Einstein and Leo Szilard for a refrigerator that uses electromagnetic pumps instead of moving mechanical parts to circulate coolant.
Who owns patent US 1781541?
Electrolux Servel Corp owns this patent, granted in 1930.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 1781541 cited by?
This patent has been cited by 22 later patents that build on its ideas.
What problem does this patent solve?
This patent represents a rare intersection of theoretical physics and household appliance engineering. While the specific Einstein-Szilard design did not become a commercial standard due to the emergence of safer, more efficient compressor-based systems, it highlights the inventors' focus on solving the problem of toxic coolant leaks common in 1920s refrigerators.
What does this patent NOT cover?
Does not cover standard vapor-compression refrigerators that use traditional electric compressors.
Patent monitoring