Minto wheel
Encyclopedia
The Minto wheel is a heat engine
developed by Wally Minto.
The engine consists of a set of sealed chambers arranged in a circle, with each chamber connected to the chamber opposite it. One chamber in each connected pair is filled with a liquid with a low boiling point (propane
and R-12
are listed in the Mother Earth News articles). As the lower chamber in each pair is heated, the liquid begins to vaporize, forcing the remaining liquid to travel to the upper chamber. This fluid transfer causes a weight imbalance, which causes the wheel to rotate. Minto's pamphlet also suggests obtaining a pressure differential with a dissolved gas instead of a boiling gas. Soda water or propane dissolved in kerosene are suggested.
The Minto wheel operates on a small temperature gradient, and produces a large amount of torque, but at very low rotational speed. The speed of rotation is directly proportional to the surface area of the containers used, the volume, and the height of the wheel. The higher the ratio of surface area to volume, the greater the rate of revolution.
A working example of a wheel was first published in a series of articles in The Mother Earth News
, Issues #38 March, #39 May and #40 July 1976.
Test units constructed by Mother Earth News (Issue 40, July 1976) and the MythBusters (Episode 24, December 5, 2004 – "Ming Dynasty Astronaut") did work to convert temperature difference into torque; however not as well as overenthusiastic boosters claimed.
Heat engine
In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...
developed by Wally Minto.
The engine consists of a set of sealed chambers arranged in a circle, with each chamber connected to the chamber opposite it. One chamber in each connected pair is filled with a liquid with a low boiling point (propane
Propane
Propane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
and R-12
Dichlorodifluoromethane
Dichlorodifluoromethane , is a colorless gas, and usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane , used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other...
are listed in the Mother Earth News articles). As the lower chamber in each pair is heated, the liquid begins to vaporize, forcing the remaining liquid to travel to the upper chamber. This fluid transfer causes a weight imbalance, which causes the wheel to rotate. Minto's pamphlet also suggests obtaining a pressure differential with a dissolved gas instead of a boiling gas. Soda water or propane dissolved in kerosene are suggested.
The Minto wheel operates on a small temperature gradient, and produces a large amount of torque, but at very low rotational speed. The speed of rotation is directly proportional to the surface area of the containers used, the volume, and the height of the wheel. The higher the ratio of surface area to volume, the greater the rate of revolution.
A working example of a wheel was first published in a series of articles in The Mother Earth News
Mother Earth News
Mother Earth News is a bi-monthly American magazine that has a circulation of 475,000. It is based in Topeka, Kansas.Approaching environmental problems from a down-to-earth, practical, how-to standpoint, Mother Earth News has, since the magazine’s founding in 1970, been a pioneer in the promotion...
, Issues #38 March, #39 May and #40 July 1976.
Test units constructed by Mother Earth News (Issue 40, July 1976) and the MythBusters (Episode 24, December 5, 2004 – "Ming Dynasty Astronaut") did work to convert temperature difference into torque; however not as well as overenthusiastic boosters claimed.