Abstract: An impeller for wind turbines comprises a rear ring having a central axis. The impeller comprises a front ring having an inner peripheral surface. The front ring is arranged coaxially and is slidably associated with the rear ring. The front ring is movable along the central axis and switches between a close configuration and a spaced apart configuration, with respect to the rear ring. The impeller comprises a plurality of blades connected to the front ring and defining a variable-pitch propeller. The blades being adjustable between a minimum pitch when the front ring is in the close configuration and a maximum pitch when the front ring is in the spaced apart configuration.

Abstract: An impeller for wind turbines comprises a rear ring having a central axis. The impeller comprises a front ring having an inner peripheral surface. The front ring is arranged coaxially and is slidably associated with the rear ring. The front ring is movable along the central axis and switches between a close configuration and a spaced apart configuration, with respect to the rear ring. The impeller comprises a plurality of blades connected to the front ring and defining a variable-pitch propeller. The blades being adjustable between a minimum pitch when the front ring is in the close configuration and a maximum pitch when the front ring is in the spaced apart configuration.

Abstract: System to control a biogas collection plant having a manifold and a plurality of collection units connecting respective capturing wells to the manifold and having respective biogas flow rate regulation valves; the system having a control board with a pressure sensor, a methane sensor, an oxygen sensor, a biogas pressure monitoring network connecting the pressure sensor to the collection units by means of respective control valves, and a chemical biogas monitoring network connecting the methane sensor and the oxygen sensor to the collection units by means of as many control valves; the control board selectively controlling the control valves to measure pressure, methane concentration and oxygen concentration of the biogas in the collection units and controlling the regulation valves as a function of the pressure and methane and oxygen concentration values measured.

Abstract: System to control a biogas collection plant having a manifold and a plurality of collection units connecting respective capturing wells to the manifold and having respective biogas flow rate regulation valves; the system having a control board with a pressure sensor, a methane sensor, an oxygen sensor, a biogas pressure monitoring network connecting the pressure sensor to the collection units by means of respective control valves, and a chemical biogas monitoring network connecting the methane sensor and the oxygen sensor to the collection units by means of as many control valves; the control board selectively controlling the control valves to measure pressure, methane concentration and oxygen concentration of the biogas in the collection units and controlling the regulation valves as a function of the pressure and methane and oxygen concentration values measured.