An impeller of metal for ventilators, pumps, fans for internal combustion engines and fans for air-conditioning equipment composed of root portions formed on the blades to form a closed ring which is engaged by the rim of a hub.
A fan comprises a flat disc sandwiched between two hub members, together with two or more blades, ech blade having a boss with a slit so that the boss straddles the peripheral portion of the disc and is gripped by the hub members. Fans can readily be assembled with any required number of blades and the blades can be set at any required angle by cutting the slits at the appropriate angle.
In an axial guide blade assembly for a compressor stator, the root end of each guide blade is attached in a ring gap of a preferably axially split, i.e. split along a normal plane, compressor housing made of a fiber reinforced synthetic material. The root of each blade is received in the ring gap or circumferential groove formed between two adjacent housing sections joined together along the axial separating plane. The guide blades hang on fiber rings with which the blade roots are clamped into the circumferential groove.
A fan rotor has a hub having a peripheral rim, a plurality of segments assembled together in the rim to form a ring, at least some of the segments having a base portion which forms a segment of the ring and a blade integral with the base and extending outwardly therefrom, slots in the segments and a U-shaped clamping member having its legs in slots of adjacent segments which hold the segments together.
A turbomachinery rotor blade for disposition within a fluid flow path in cooperation with a rotatable disc is provided with a platform for partially defining the flow path of the fluid. The platform is disposed between the airfoil of the blade and preselected means for mounting the blade to a rotatable disc. The platform is provided with means for resisting circumferential and radial vibratory displacement by the action of frictional damping. The damping is supplied by frictional engagement with platforms of laterally adjacent blades. To enhance this function, the circumferential extremities of the platforms are provided with two diagonal edges axially spaced from one another along the same axial line, the edges having predetermined angular offsets from the radial direction. The two edges along each circumferential extremity have anuglar offsets of opposite senses, and adjacent platforms effectively interlock with one another.
The present invention provides a fan having a molded, substantially non-metallic hub and a plurality of fan blades attached thereto. The fan blades can be rotationally indexable relative to the hub, so that a pitch angle may be adjusted. Further, the fan blades can be formed with an airfoil cross section and with a twist in the blades from a root end to a tip end so that the pitch angle varies along the length of the blade. In at least one embodiment, the fan is designed to be a high performance fan approaching the performance of metal fans with a performance of at least about 20 CFM per input watt at a static pressure of about 0.00 inches of water.
