77469657
May 8, 2008
Mar 19, 2013
Positive displacement rotary pumps having three dimensional engagement surfaces to displace fluid for use in the natural gas industry in natural gas transmission lines; positive displacement rotary compressors having three dimensional engagement surfaces to displace air for use in the natural gas industry in natural gas transmission lines; continuous turbine-like rotational positive displacement rotary gas expanding engines, not for land vehicles, having three dimensional engagement surfaces for use in the natural gas industry
Machinery