Engines of Our Ingenuity
No. 145:

by John H. Lienhard

Click here for audio of Episode 145.

Today, we look at heat transfer and product innovation. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

George Wise talks about three ways innovation takes place in industry. The most obvious way is a response to a need. We've seen again and again in this series that things are seldom that straightforward. The second way is more common. That's when innovation is driven by some revolutionary discovery. The transistor, for example, triggered all sorts of new technology. But Wise is most interested in a third pattern. He calls it the product-driven innovation cycle.

An engineer works to improve an existing product. It needn't be anything fancy. Then he suddenly sees it in a new light. A radically different concept suddenly pops out of it. A butterfly is born of a caterpillar. Wise tells us that that sort of thing is far more common than we might think; and he gives several illustrations which all involve heat transfer. Here's one:

In 1908, General Electric hired a young man -- an American with a German Ph.D. in applied chemistry. His name was Irving Langmuir. His thesis had dealt with the way air carried heat away from small wires. He seemed to be just the person to work on heating elements.

Langmuir went to work on the G.E. line of stoves, flatirons, and other heaters. He used what he knew to improve their heating elements. Now G.E. had another product that also used heated wires -- that was the light bulb. G.E.'s bulbs were all evacuated to keep the filament from burning. Low-wattage bulbs did well enough at the time. But the tungsten wires in brighter bulbs began to evaporate. Tungsten vapor was gradually deposited on the inside of the bulbs. It eventually turned them black.

Then Langmuir realized that evaporation would be suppressed if the light bulb were be filled with a gas -- an inert gas, that wouldn't burn the filament. The trouble was that gas circulating in a light bulb removed too much heat -- the bulb wouldn't stay bright. But he knew from his research that a lot less heat would be shed if the filament were wound in a tight coil. By knowing about heat removal, Langmuir gave us the bright argon-filled bulbs we use today. And all because he was put to work on stoves and irons.

Wise traces other connections -- how refrigerators led to turbo-superchargers and how steam-turbines led to air conditioners. Of course he's pointing out a process common to invention. A good engineer makes one thing turn into another. He lets innovation be driven by whatever's in front of him. And Langmuir had the vision to do this. In 1932, by the way, he won the Nobel Prize for his work on the surface chemistry of metals.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Wise, G., Heat Transfer Research in General Electric, 1910-1960: Examples of the Product Driven Innovation Cycle, History of Heat Transfer: Essays in Honor of the 50th Anniversary of the ASME Heat Transfer Division. (E. Layton and J. H. Lienhard, eds.) New York: The American Society of Mechanical Engineers, 1988, pp. 189-211.

This episode has been greatly revised as Episode 1570.

The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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