# 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.

- **Patent:** US 1781541
- **Original title:** Refrigeration
- **Owner:** Electrolux Servel Corp
- **Granted:** 1930
- **Status:** Public domain (expired)
- **Times cited:** 22
- **Field:** mechanical, energy

## What it does

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.

## 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.

## 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.

## Real-world examples

1. Experimental absorption refrigeration prototypes
2. Early silent cooling systems for laboratory use

## Why it matters

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.

## 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.

**Full plain-English explainer:** https://patentbrief.org/patent/us/1781541/einstein-szilard-refrigerator

**Original patent:** https://patents.google.com/patent/US1781541

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How Early Electromagnetic Pumps Moved Liquid Metal Using Magnetic Fields](https://patentbrief.org/patent/us/1647147/sound-on-film-talking-pictures) — A 1927 patent for a pump that uses electromagnetic forces to move conductive liquids without needing moving mechanical parts like pistons or impellers.
- [John Gorrie's 1851 Patent for Artificial Ice Production](https://patentbrief.org/patent/us/8080/ice-machine-refrigeration-gorrie) — An 1851 patent by John Gorrie describing a mechanical process to create ice by compressing air and using it to cool water.
- [How Nikola Tesla Invented the Modern AC Electric Motor](https://patentbrief.org/patent/us/382280/tesla-ac-motor) — Nikola Tesla's 1888 patent for an induction motor that uses rotating magnetic fields to convert electricity into mechanical motion without needing physical brushes.
- [How Clarence Birdseye Invented Modern Frozen Food](https://patentbrief.org/patent/us/1773079/frozen-food-birdseye) — This 1930 patent describes the process of rapidly freezing food in small packages to prevent the formation of large ice crystals that ruin texture and flavor.
- [How Willis Carrier Invented the Modern Air Conditioner](https://patentbrief.org/patent/us/808897/air-conditioning-carrier) — Willis Carrier's 1906 patent for an apparatus to control humidity and temperature, forming the technical foundation for modern air conditioning systems.