Fog-generating device comprising: - at least one storage means of at least one fog-generating fluid; - at least one heat exchanger configured for quickly releasing thermal energy to said fog-generating fluid to produce steam (V) to diffuse in an external environment through one or more delivering means ; - pumping means of said fog-generating fluid from said storage means to said heat exchanger , said pumping means comprising at least one mechanical volumetric pump (20a; 20b) with continuous flow configured for receiving as input at least one flow of fog-generating fluid (FN) coming from said storage means and emitting at least one flow of said pressurized fog-generating fluid (FN') towards said heat exchanger , said mechanical volumetric pump with continuous flow comprising at least one compression chamber equipped with at least one inlet duct of said flow of fog-generating fluid (FN) coming from said storage means and at least one outlet duct configured for emitting said flow of pressurized fog-generating fluid (FN') towards said heat exchanger ; characterized in that said compression chamber is internally equipped with at least one rotor eccentric with respect to said compression chamber and rotating according to a rotation direction (R), said rotor being equipped with at least one radially moving blade configured for cyclically and progressively dividing, during said rotation (R), said compression chamber into at least one portion of depressurized chamber placed upstream of said blade with respect to said rotation direction (R) and at least one portion of pressurized chamber placed downstream of said blade with respect to said rotation direction (R); and in that the fog-generating device further comprises a motor supplied with direct current and configured to actuate said mechanical volumetric pump . - at least one storage means of at least one fog-generating fluid; - at least one heat exchanger configured for quickly releasing thermal energy to said fog-generating fluid to produce steam (V) to diffuse in an external environment through one or more delivering means ; - pumping means of said fog-generating fluid from said storage means to said heat exchanger , said pumping means comprising at least one mechanical volumetric pump (20a; 20b) with continuous flow configured for receiving as input at least one flow of fog-generating fluid (FN) coming from said storage means and emitting at least one flow of said pressurized fog-generating fluid (FN') towards said heat exchanger , said mechanical volumetric pump with continuous flow comprising at least one compression chamber equipped with at least one inlet duct of said flow of fog-generating fluid (FN) coming from said storage means and at least one outlet duct configured for emitting said flow of pressurized fog-generating fluid (FN') towards said heat exchanger ; characterized in that said compression chamber is internally equipped with at least one rotor eccentric with respect to said compression chamber and rotating according to a rotation direction (R), said rotor being equipped with at least one radially moving blade configured for cyclically and progressively dividing, during said rotation (R), said compression chamber into at least one portion of depressurized chamber placed upstream of said blade with respect to said rotation direction (R) and at least one portion of pressurized chamber placed downstream of said blade with respect to said rotation direction (R); <EOS>