This stydy present the constructive solution and the functioning principle for a new type of machinery (N.T.M.) which can be used as a working machine (i.e. pump, fan compressor) or as a prime mover (i.e. heat engine, pneumatic motor, hydrostatic motor). The study shows how the theoretical power of the machine can be calculated; it also analyses the influence of the constructive and functioning parameters on the latter. The paper makes a comparison between the N.T.M. and the roots compressor and points out the N.T.M. constructive and operating advantages.