Pressure exchanger turbine

[krzys Mnich]

Hi,
Bruno Ogorelec wrote once, that wave rotors are one of the famous lost causes of aerospace industry, because no one knows what to make the pesky rotors out of. OK, but there were some ideas similar as wave rotors, possibly not as demanding. Look here:
http://www.google.com/patents/about?id= ... dq=2759660
The most elegant heat machine I've ever seen. Well, I actually thought out something like that several years ago, but that guy did it a half a century earlier.
When used as an engine, it can be reasonably efficient at small rotational speed. Looks simple. Doesn't seem to be any big problems (like sealing, cooling, centrifugal forces etc.). Can be small, lightweight, and very powerful.

So, why we haven't such engines yet? Where could be a problem? Or, may be someone can try to build it and check?

regards

krzys