ps; I'm so used to my old textbooks that sometimes I forget there's google! ...lol...

Which I just tried...and found that anyone who wants to be sure of their facts can do so in less than 5 seconds.

A google of "centrifugal turbine expander heat engine", and variations on those terms, instantly provided the following facts; among thousands of others.....

(underlines are mine)

Brayton cycle: Definition from Answers.com
1791 - John Barber received the first patent for a heat engine in which a bellows (compressor) and a turbine (expander) were connected...
www.answers.com/topic/brayton-cycle

Heat engine - Patent 6336316
6134876, Gas turbine engine with exhaust expander and compressor, Hines et al. ..... 4 comprises, as an example, a centrifugal turbine T 32 ,

(turbo-turbines are heat-engine turboexpanders)

"Elliott Company • Products • Steam Turbines/Expanders
The TH power recovery expander turbine is available to utilize the energy in high temperature, low pressure gas streams to drive..."

http://en.wikipedia.org/wiki/Steam_turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical work.

(it's the heat, not the pressure, producing the majority of the shaft-power)

etc. etc..

__________________
WANT to BUY: 3.0L diesel engine.

My other diesel is a....

1962 Cat D9-19A, 2,000 cu-in TD
1961 Cat 966B, D333 TD, powershift
1985 Mack MS300P 8.8L TDI, intercooled, crane-truck
1991 F350 4x4 5spd 7.3 IDI NA
1988 Dodge D50 4x4 5spd 2.4 Mitsu TD
1961 Lister-Petter 14hp/6kw Marine Corp genset weekly charging 5400 lbs of forklift batt for the off-grid homestead.
1965 Perkins 4-108 Fire/water Pump
1960 Deutz 20hp/8kw genset