A device usable as an impeller has a plurality of vanes rotating eccentrically about a shaft. Eccentric rotation is enabled by a cam mounted on the shaft. The vanes are received within slots in a rotor which surrounds the shaft and rotates about an axis coaxial with the shaft. The rotor rotates within a housing having a cylindrical surface facing the rotor. The surface is eccentric to the shaft. The vanes execute reciprocal motion upon rotation of the rotor. The vane motion is constrained so that the edges of the vanes remain proximate to the cylindrical surface during rotation.

An energy-saving device with functions of air feeding and power generation includes an air feeder, an actuator unit, an air-operated device, a generator, and a power storage unit. The actuator unit includes a mounting base, a cylindrical body received in the mounting base, and an axle body rotatably received in the cylindrical body. The mounting base is connected to the air feeder through an air duct for introduction of gases from the air feeder to the cylindrical body. When the air feeder is activated, the axle body of the actuator unit is rotated to supply high-pressure gases to the air-operated device and simultaneously drive the generator to generate electricity, which is stored in the power storage unit for the air-operated device and/or a power-consuming end, for fullest use of electricity and energy sufficiency.

A pneumatic motor has a housing, an axle, and multiple blades. The axle is rotatably mounted in the housing and has multiple blade recesses. The blades are mounted respectively and moveably in the blade recesses. Each blade has an inner side edge. The inner side edge is mounted in a corresponding one of the blade recesses. The inner side edge of each one of at least half of the multiple blades has a straight segment and a rectangular tab. Each one of the blade recesses which holds the blade having the straight segment and the rectangular tab has a bottom having a straight segment and a tab hole.

A rotary vane air motor comprises a rotor, stator and vanes. The rotor has slots for the vanes, and the vanes may move between a retracted position and a contact position in which the vanes contact the cylinder. Each vane may have a longitudinal portion whose shape conforms generally to the slot, and a transverse portion that is radially outside of the slot and extends at least in part in a direction that is transverse to the longitudinal portion and that may be tangential to the perimeter of the rotor at the slot. The shape of the perimeter may be a polygon with rounded corners. The vanes may also include a magnetic portion or a rotating portion.

A device usable as an impeller has a plurality of vanes rotating eccentrically about a shaft. Eccentric rotation is enabled by a cam mounted on the shaft. The vanes are received within slots in a rotor which surrounds the shaft and rotates about an axis coaxial with the shaft. The rotor rotates within a housing having a cylindrical surface facing the rotor. The surface is eccentric to the shaft. The vanes execute reciprocal motion upon rotation of the rotor. The vane motion is constrained so that the edges of the vanes remain proximate to the cylindrical surface during rotation.

A bladed expander for recovery of thermal energy from a working fluid, comprising a stator provided with an inlet port and an outlet port for the working fluid, a rotor housed within the stator, and a plurality of blades set between the rotor and the stator so as to delimit between them a plurality of compartments with variable volume that increases between the inlet port and the outlet port. The stator and the rotor are subjected to a heat exchange with a hot fluid so as to carry out a transformation of expansion during which the working fluid receives thermal energy from outside.