Abstract: A turbine 400 has a central duct 410 which accelerates fluid passing through it and a blade configuration which retards the flow of fluid near the tips of the turbine. This structure results in a vortex having a higher fluid pressure behind the tips of the turbine blades 408 and a lower fluid pressure behind the duct. In the present invention, this vortex is enhanced by (1) an increased acceleration of the fluid passing through the duct 410 and a deceleration of the fluid passing through the blades 408; and/or (2) by a fluid redirection device 850 for directing the fluid passing through the duct towards the outer diameter of the turbine.

Abstract: A centrifugal blower wheel having an indivisible prime number of peripherally spaced blades projecting upwardly from the top surface of a generally annular-shaped base plate. Each blade includes a tapered portion extending along an inside edge of the blade to approximately 1/3 to 1/2 the length of the blade. A hub is centrally located on the top surface of the base plate and surrounded by the inside edges of the blades, the hub curving upwardly from the top surface of the base plate to form a smoothly contoured curve.

Abstract: A transverse fan includes a pair of end plates each having an annular shape, a plurality of blades annularly disposed between the end plates and a plurality of partition plates each having an annular shape and disposed at intermediate portions of the blades. Each of the partition plates has one side surface to which base ends of the blades are integrally secured to extend forward with a predetermined inclination and form a multi-blade impeller. A plurality of the multi-blade impeller are stacked axially so that each of the partition plates has another one side surface to which leading ends of the blades of adjacent multi-blade impeller are connected, and one of the end plate has one surface to which the leading ends of the blades of a leading end side one of the stacked multi-blade impellers are connected and another one of the end plates has one surface to which the base ends of the blades of a base end side one of the stacked multi-blade impellers is secured.

Abstract: A transverse fan in which a plurality of blades are disposed between disk- or ring-shaped end plates in a circumferential arrangement at fixed mounting pitches in a ring-shaped configuration. Partitions plates are disposed at intermediate portions in the longitudinal direction of the blades such that each of the blades is inclined at fixed angles with respect to a fan axis and mounted at unequal pitches. The transverse fan includes a plurality of multi-bladed impeller units disposed between the disk-shaped end plates. Each of the multi-bladed impeller units has one disk-shaped partition plate having one surface on which a plurality of blades are integrally disposed along a circumferential direction thereof at unequal pitches and inclined at predetermined angles so as to extend along the axial direction of the transverse fan. A plurality of the multi-bladed impeller units are integrally stacked coaxially with each other to form the transverse-fan.

Abstract: A high specific speed fan propeller is provided which has a hub, at least two main blades and at least two auxiliary blades. The hub has an attachment device for connecting the propeller to a turning part. The at least two main blades are attached to the hub and extend radially a first distance therefrom. The at least two auxiliary blades are also attached to the hub and extend radially a second distance therefrom. The first distance is greater than the second distance.

Abstract: A fan assembly has a fan motor and first and second generally identical and spaced apart fans each rotationally attached to the fan motor to turn at the same rotational speed. Each fan has an equal number of generally identical fan blades and produces noise including a tone having a frequency equal to its rotational speed times its number of fan blades. The fan blades of one fan are angularly offset at a relative phase angle with respect to the fan blades of the second fan such that the tones of each fan generally cancel each other out. An equation is provided for a ducted fan assembly relating the relative phase angle to the rotational speed of the fans, the number of fan blades of each fan, the geometry of the duct, and the speed of sound in air within the duct.

Abstract: A transverse fan impeller (30) having at least two modules (32). Each module is defined by an adjacent pair of partition disks (34) each perpendicularly centered on the rotational axis of the impeller. Blades (31) extend longitudinally between pairs of partition disks. The angular spacing of blades in a module is nonuniform but also not random, being determined by application of certain formulae disclosed. The angular blade spacing within each module of the impeller is the same, but the modules are angularly offset so that a blade in one module is offset from the corresponding blade in an adjacent module by a predetermined value. The module and blade configurations reduce both the blade rate tonal noise and overall radiated noise produced as compared to an impeller having uniformly spaced blades.

Abstract: A water pump including a rotating impeller is located between the two filter chambers, and pumps water from the aquarium tank, via the inlet conduit, into a corridor which communicates with the two filter chambers. The impeller is constructed with relatively closely spaced radially extending blades, each of which is formed of a circular disk. A base edge, or chord, of each blade is inclined upon a frustoconical surface of a central hub of the impeller.

Abstract: A propeller for an aircraft or fan comprises an even number of propeller blades, at least six in number, which are unsymmetrically arranged around the axis of roation of the propeller in two circumferentially equidistantly spaced groups of at least three blades each. Each blade of each group is paired and longitudinally aligned with a respective blade of another group at the opposite side of the axis of rotation of the propeller, and each two next adjacent blades in each group are offset relative to each other by a spacing angle of between about 15.degree. and 40.degree.. For a selected speed of rotation of the propeller corresponding to a particular blade-tip Mach number, the magnitude of the spacing angle is inversely related to the magnitude of that blade-tip Mach number, for effecting a reduction of the level of the rotational sound harmonics by interference.

Abstract: A propeller for an aircraft or a blower or fan, wherein the propeller blades are intended for operation at speeds characterized by blade tip Mach numbers in the range of about 0.4 to 0.8, comprises at least two pairs of diametrically opposed blades, the blade pairs being arranged at a spacing angle .epsilon. of between about 15.degree. and 50.degree. between them, and the magnitude of the spacing angle being inversely related to the magnitude of the blade tip Mach numbers, thereby to effect a reduction in the level of the rotational sound harmonics by interference. The pairs of blades may be axially spaced from one another, i.e., arranged in respective spaced parallel planes of rotation, shifted, with the rear one of two adjacent blades leading in the direction of rotation.

Abstract: Directly driven propeller whose propeller blades are provided with slats and which is designed for a lower blade tip Mach number in order to reduce the propeller noise. The slats are rigidly connected to the propeller blades and the slat tips lie on a diameter given by the equation ##EQU1## where LTLP=lower transonic limit of the particular blade configuration including slata.sub.o =velocity of sound in airv.sub..infin. =flight speedn=propeller rotational speed.

Abstract: In an axial fan whose fan wheel is retained in a tubular member by spokes, the blade edges of the individual fan blades which face the spokes are constructed geometrically different from one another.

Abstract: A device and method for reducing the flow resistance of air foils utilizes one or more flow compressors on the leading edge of the foil. The gas flowing in front of the leading edge is compressed and is expanded on the upper surface of the wing so that through induction of the expanded gas, gas from the area of the lower surface of the wing is admixed to increase the flow on the upper surface of the wing. The direction of the admixed gases is such that the velocity of the gas flowing out at the trailing edge of the wing is identical over the entire wing length. The separation point of the flow is displaced towards the trailing edge of the wind and, in the direction of the tip of the wing, the pressure of the gas flowing over the upper surface of the wing is increased.

Abstract: A boat propeller drive with double, counter-rotating propellers is distinguished by the after propeller having one more blade than the fore propeller as well as a smaller diameter than the fore propeller.

Abstract: In a propeller for use in a ship of the type comprising 4 or more even number blades, at least one of two adjacent blades is inclined forwardly or rearwardly or one inclined forwardly and the other rearwardly so as to make different the rake angles of the two blades. The pitch angle of the rearwardly inclined blade is made larger than that of the forwardly inclined blade. With this construction the mutual interference between adjacent blades is efficiently utilized to prevent decrease in the efficiency even when operating conditions and the diameter of the propeller vary.

Abstract: The action of upstream and downstream foil sets rotating on a common shaft within a fluid is enhanced by fixing certain interrelations of the foils such as the axial distance between the foils, the radial index between foils and pitch of one foil relative to the other so that the foil stages are fixedly mounted with the foils of each stage being symmetrically and equidistantly spaced from one another and from the foils of the next adjacent foil stage so that the interacting uniform adjacent foil pressures and the upstream foil wake beneficially interacts optimally with at least one of the surfaces or boundary layers of the foils of the next adjacent downstream foil stage.

Abstract: Axial flow impeller having at least two rows, preferably three rows, of a plurality of blades secured substantially radially to a rotor for rotation in a plane about the axis of the rotor. The blades have the same pitch throughout their lengths with the blades of the first row having a pitch angle less than the stall angle of the blades, preferably about 22.degree., the blades of the second row having a pitch angle greater than the pitch angle of the blades of the first row and less than the stall angle of the blades, preferably about 13.degree. greater than the pitch angle of the first row of blades, and the blades of a third row of blades having a pitch angle greater than the pitch angle of the blades of the second row and less than the stall angle of the blades, preferably about 13.degree. greater than the pitch angle of the second row of blades.

Abstract: A high speed turbine handpiece includes a housing with a turbine wheel chamber and a flow passage for air terminating in a nozzle opening on the periphery of the turbine wheel chamber as well as a discharge passage from the chamber to the exterior of the housing. An integrally formed turbine wheel in the chamber has a hub with two axially spaced sets of vanes extending about its circumference with the blades of one set circumferentially offset from the blades of the other set. The nozzle is aligned with the axial spacing or channel between the sets of vanes and is dimensioned to overlap the adjacent edge portions of the vanes so that air entering through the nozzle impinges on both sets of vanes.

Abstract: This invention is directed to an improved tandem marine propeller having sets of radially extending blades which are connected at their roots to a hub in tandem arrangement for minimizing drag adjacent the hub and having the blades configured by skewing one set forward and the other set backward and raking the blades of the two sets toward each other so that outer portions of the blades are equispaced radially about the hub and lie substantially in a common plane of rotation whereby loading on the blades of both sets is substantially equalized for increased efficiency.

Abstract: A boat propeller includes an elongated shaft and three vanes which extend outwardly from the shaft at axially spaced positions there along. The vanes lie approximately along a helix on the shaft, and the vanes are spaced about 120.degree. apart around the circumference of the shaft.