A fan apparatus may include a frame, a fan, and a drive mechanism. The fan may be supported for rotation relative to the frame and may include a fan shaft and a plurality of blades extending outward from the fan shaft. The drive mechanism may include a driven wheel, a drive shaft, a first drive wheel, a second drive wheel, and a torque-transmission loop. The driven wheel may be mounted on the fan shaft. The drive shaft may be supported for rotation relative to the frame. The first drive wheel may be mounted on the drive shaft. The second drive wheel may be mounted on the drive shaft. The torque-transmission loop may be engaged with the driven wheel and a selected one of the first and second drive wheels.

A fan apparatus may include a frame, a fan, and a drive mechanism. The fan may be supported for rotation relative to the frame and may include a fan shaft and a plurality of blades extending outward from the fan shaft. The drive mechanism may include a driven wheel, a drive shaft, a first drive wheel, a second drive wheel, and a torque-transmission loop. The driven wheel may be mounted on the fan shaft. The drive shaft may be supported for rotation relative to the frame. The first drive wheel may be mounted on the drive shaft. The second drive wheel may be mounted on the drive shaft. The torque-transmission loop may be engaged with the driven wheel and a selected one of the first and second drive wheels.

A wind wheel including a first air plate, a second air plate, and a plurality of blades disposed between the first air plate and the second air plate. The first air plate includes a central part and an air inlet disposed in the central part; each two adjacent blades form an air duct. The plurality of blades each includes an inlet section next to the air inlet, an intermediate section, and an outlet section. The thickness of the intermediate section is greater than the thickness of the inlet section and the thickness of the outlet section.

A rotating thrust-producing apparatus having a control system includes a rotatable foil having opposite first and second faces and a plurality of spaced apart fins occupying a periphery thereof. A pressure control assembly includes a first adjustable control surface disposed adjacent to a first face of the foil so as to be selectively movable over the fins of the foil. The pressure control assembly may include a second control surface disposed adjacent to the second face of the foil and which may be adjustable. As the foil is rotated, and the at least one adjustable control surface is moved over fins of the foil, a fluid pressure imbalance is created, causing a thrust in the direction of the pressure deficit.

A centrifugal compressor includes a casing. An impeller is arranged within the casing. The impeller is rotatable about an axis. A diffuser section is arranged within the casing. The diffuser section is positioned axially downstream from an outlet of the impeller and includes a forward portion fixed relative to the impeller and an aft portion distinct from the forward portion.

An impeller apparatus includes a housing, an impeller, and a heat generation member. The housing includes an air duct formed in the housing. The air duct includes a first air duct and a second air duct successively connected to each other. The second air duct has a non-blocking area. The impeller is arranged in the first air duct. The heat generation member is rotatably arranged in the second air duct and has a blocking state and a non-blocking state. In the blocking state, the heat generation member blocks the second air duct, in the non-blocking state, the heat generation member is accommodated in the non-blocking area and does not block the second air duct.

An impeller apparatus includes a housing, an impeller, and a heat generation member. The housing includes an air duct formed in the housing. The air duct includes a first air duct and a second air duct successively connected to each other. The second air duct has a non-blocking area. The impeller is arranged in the first air duct. The heat generation member is rotatably arranged in the second air duct and has a blocking state and a non-blocking state. In the blocking state, the heat generation member blocks the second air duct, in the non-blocking state, the heat generation member is accommodated in the non-blocking area and does not block the second air duct.

An airflow-doubling vane structure includes an axle, an inner vane unit, and an outer vane unit. The inner vane unit includes a plurality of vanes provided around a center defined by the axle and can be rotated along with the axle. The vanes of the inner vane unit are centrifugal vanes. The outer vane unit includes a plurality of vanes provided around the center defined by the axle and around the inner vane unit and can be rotated along with the axle. The vanes of the outer vane unit are axial-flow vanes and extend a certain radial distance from the vanes of the inner vane unit.

A heat exchanger arrangement includes a housing in which an air inlet opening is arranged on the circumference, a cover that covers the housing on an upper side and in which an air outlet opening is arranged, a reverse-operated radial fan being arranged inside the housing in such a way that it can generate an air flow between the air inlet opening and the air outlet opening, which air flow is directed radially inward with respect to the axis of rotation of the radial fan and which flows through at least one air heat exchanger arranged in the housing.

A heat exchanger arrangement includes a housing in which an air inlet opening is arranged on the circumference, a cover that covers the housing on an upper side and in which an air outlet opening is arranged, a reverse-operated radial fan being arranged inside the housing in such a way that it can generate an air flow between the air inlet opening and the air outlet opening, which air flow is directed radially inward with respect to the axis of rotation of the radial fan and which flows through at least one air heat exchanger arranged in the housing.