Abstract: An impeller is for separating a conveyed stream of material. The impeller has a central rotatable hub with a plurality of blades extending radially therefrom. The hub and blades form a number of generally wedge-shaped material receiving spaces within the impeller. One set of spaces has a baffle arrangement which is configured to direct material in this set outwardly from the impeller on the upstream side of the baffle arrangement. Another set of spaces has a guide arrangement which is configured to guide the material in this set of spaces outwardly from the impeller on the downstream side of the baffle arrangement. The impeller is particularly useful for separating streams of particulates, such as wood chips, compressed shavings, or the like.

Abstract: An alternator has front and rear cooling fans to effectively cool the stator windings and field coil of the alternator. The front cooling fan has a first number (e.g. six) of diagonal-flow type blades for cooling mainly the field coil and a second number (e.g. five) of centrifugal-flow-type blade for cooling the stator windings which are disposed between the diagonal-flow-type blades. The combination of the first and second numbers is designed to suppress noise level caused by the cooling fan.

Abstract: An axially compact axial flow fan with improved air-moving properties has a first array of fan blades that extend radially from a fan hub to a circumferential blade support member, a second array of fan blades extend from the first support member to a radially outward second circumferential blade support member. The fan blades in the second array each enjoy pitch angles that decrease from the second circumferential blade support radially along only a portion of each blade length. Thereafter, the pitch angles for the blades in the second array remains constant to the second circumferentially extending blade support member.

Abstract: A Variable Diameter Rotor (VDR) system (4) having telescoping odd and even blade assemblies (O.sub.b, E.sub.b) wherein the odd blade assemblies define a radial length R.sub.O and the even blade assemblies define a radial length R.sub.E. Each blade assembly (O.sub.b, E.sub.b) defines an internal chamber (64) for accepting a positioning means (70) operative to effect telescopic translation of the blade assemblies (O.sub.b, E.sub.b) such that the radial length R.sub.E of the even blade assemblies (E.sub.b) is equal to the radial length R.sub.O of the odd blade assemblies (O.sub.b) in a first operating mode, and such that the radial length R.sub.E is between about 70% to about 95% of the length R.sub.O in a second operating mode. The positioning means (70) includes a centrifugal restraint assembly (80) disposed within each internal chamber (64) of the rotor blade assemblies (O.sub.b, E.sub.

Abstract: An impeller for a submersible radial pump has an impeller disk which is formed with a pair of blades on a side thereof opposite the boss. The leading end of one of the blades is thicker than the leading end of the other blade to reduce the possibility that pieces of fabric or the like will hang up on the blades in operation of the pump.

Abstract: A vehicle engine-cooling fan assembly for circulating air to cool an engine. The fan assembly has a central hub with a plurality of blades extending radially outward from the central hub. Each blade has a root joined to the central hub, a tip, and a span formed between the root and the tip. The blades are spaced circumferentially from each other, by unequal spacing angles, around the central hub. The unequal spacing angles minimize noise produced by the fan assembly. The blades are positioned at a radial location along a blade span by unequal setting angles which increase the efficiency of the fan assembly. The blades can have either a straight or a curved planform. Mechanical energy is imparted to the fan assembly from an electric motor, a hydraulic motor, or some other source. Also disclosed is a process for designing a vehicle fan assembly combining unequal fan blade spacing angles and unequal fan blade setting angles.

Abstract: An array (32) of flow directing elements such as fan blades (20) for a turbine engine (10) is disclosed. Each blade in the array has a set of circumferentially shrouds (42, 44) whose contact edges (46, 48) abut each other during engine operation. A shroud angle .sigma. establishes the running chord angle .alpha. of the airfoil (30) portion of the array. Slight differences in the shroud angles of adjacent blades cause corresponding differences in the running chord angles so that the array is detuned and airfoil flutter is precluded.

Abstract: A rotor system (4) having odd and even blade assemblies (O.sub.b, E.sub.b) mounting to and rotating with a rotor hub assembly (6) wherein the odd blade assemblies (O.sub.b) define a radial length R.sub.O, and the even blade assemblies (E.sub.b) define a radial length R.sub.E and wherein the radial length R.sub.E is between about 70% to about 95% of the radial length R.sub.O. Other embodiments of the invention are directed to a Variable Diameter Rotor system (4) which may be configured for operating in various operating modes for optimizing aerodynamic and acoustic performance. The Variable Diameter Rotor system (4) includes odd and even blade assemblies (O.sub.b, E.sub.b) having inboard and outboard blade sections (10, 12) wherein the outboard blade sections (12) telescopically mount to the inboard blade sections (10). The outboard blade sections (12) are positioned with respect to the inboard blade sections (10 such that the radial length R.sub.E of the even blade assemblies (E.sub.

Abstract: A Variable Diameter Rotor (VDR) system (4) having telescoping odd and even blade assemblies (O.sub.b, E.sub.b) wherein the odd blade assemblies define a radial length R.sub.O and the even blade assemblies define a radial length R.sub.E. Each blade assembly (O.sub.b, E.sub.b) defines an internal chamber (64) for accepting a positioning mechanism (70) operative to effect telescopic translation of the blade assemblies (O.sub.b, E.sub.b) such that the radial length R.sub.E of the even blade assemblies (E.sub.b) is equal to the radial length R.sub.O of the odd blade assemblies (O.sub.b) in a first operating mode, and such that the radial length R.sub.E is between about 70% to about 95% of the length R.sub.O in a second operating mode.

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: An impeller of a centrifugal pump for transporting dirty liquids has transport elements, for example back-vanes or grooves disposed on the pressure side of a cover disk. The transport elements are arranged asymmetrically and are limited to one arc sector of the cover disk to create a transverse stream that rotates with the impeller. Solids which have penetrated into the space to the side of the wheel are carried out by this stream in the direction of the transport elements.

Abstract: In a propeller for a boat, a plurality of stationary blades and a plurality of variable blades are alternately disposed around an outer periphery of a propeller boss. Exhaust passages are formed in the propeller boss to axially pass through the propeller boss at location corresponding to the stationary blades. Despite the provision of the variable blade which is variable in diameter or pitch, the exhaust passage can be formed into a large sectional area in the blade boss without being obstructed by a blade shaft for the variable blade.

Abstract: A flow-straightener with stationary vanes and aerodynamic profile is mounted downstream of the rotor with blades in the transverse duct passing through the fairing at the tail of the helicopter. The blades of the rotor are distributed angularly about the axis of the rotor with uneven azimuth modulation, such that any angle between two arbitrary blades of the rotor is different from any angle between two arbitrary vanes of the flow-straightener.

Abstract: An apparatus is provided that includes a bladed device having a hub which is rotatable about an axis and one or more blades attached to the hub by self-energizing, self-locking, insertion and retention features which are formed integrally with the blade and hub. The insertion and retention features include a locking tang formed integrally with the root of the blade, and detent features which are part of the locking tang and hub. As the blade is inserted axially into the hub, the locking tang deflects radially inward and then snaps radially outward by spring action of the tang to engage the detent feature of the hub, and thereby lock the blade against further axially or radially movement with respect to the hub. The locking tang is oriented and configured in such a manner that the locking tang is self-energizing, thereby causing the tang to grip the hub more tightly as rotational speed of the bladed device increases.

Abstract: An impeller structure of a closed type centrifugal pump suitable for inelastic fluids such as an engine coolant, comprises front and rear shrouds having a driven connection with a pump drive shaft, and a series of blades provided between the front and rear shrouds for pressurizing an incoming fluid. An inner edge (17a) of a first blade of two adjacent blades is formed to be up-sloped from its inside corner to its outside corner, whereas an inner edge (17c) of a second blade of the two adjacent blades is formed to be down-sloped from its outside corner to its inside corner, so as to enhance an efficiency of the pump, suppressing occurrence of cavitation at or near the pump inlet.

Abstract: A fuel pump for supplying diesel fuel to an engine includes a pump housing, a motor mounted within the housing, a shaft extending from the motor, an impeller slidably attached to the shaft which has a prime number of vanes spaced unevenly about its circumference, a chamber body, and a chamber cover with a bleed orifice. The chamber body and cover form a chamber for the impeller and are held together by the housing. The chamber body and cover have pump channels of constant depth and are made of phenolic with fiberglass fill. The impeller is made of phenolic with fiberglass fill and granular fill.

Abstract: Vibration in the blade of a turbo-machine is suppressed by the incorporation of both inner and outer restraints that inhibit deflections of the blade foils. The outer restraint comprises shroud, welded lugs or tie wires that divide the row of blades into a plurality of blade groups by connecting the blades in each group together. The number of blades in each group can be equal to the number of blades in the row divided by the harmonic of the rotor rotational frequency that is closest to the blade resonant frequency of concern. The inner restraint comprises welded lugs or tie wires disposed radially inward from the outer restraint that divide each blade group into a plurality of sub-groups, thereby further suppressing blade vibration. Since the length of the inner restraints is less than that associated with harmonic shrouds, the stresses in the inner restraint, as well as in the blades, due to radial growth of the rotor are maintained within acceptable levels.

Abstract: An improved torque converter assembly utilizing or making use of the same or similar composite materials for each component of the torque converter to result in a high strength yet light weight torque converter assembly which may be easily recycled. Further, the torque converter includes a unique hub member having integral fingers radially extending therefrom for use in bonding hub member to a multi-bladed body such as a turbine, wherein the fingers are circumferentially spaced about an outer circumferential surface on the hub member such that the spacing between a common finger and adjacent fingers on each side thereof is not equal. Such a hub member distributes the loads and stresses onto different planes extending radially and transverse the longitudinal axis of the hub member.

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: An inlet orifice structure and impeller assembly for a centrifugal flow fan. The inlet orifice has an elliptical cross section in a plane passing through the axis of rotation of the fan. The impeller is shrouded and also has a similarly elliptical cross section. The impeller is sized so that, when assembled together, the shroud overlaps and rotates around the stationary inlet orifice. In a preferred embodiment, there are 13 impeller blades nonuniformly spaced around a hub plate. A particular blade spacing is disclosed and claimed. The inner surface of the hub plate is arcuately curved to guide the air flow through the fan from its entering axial direction to its radial exiting direction. The contour of the hub plate allows for the fan drive motor to be partially recessed into the plate.

Abstract: A transverse fan impeller (10) having blades (31) that extend longitudinally parallel to the rotational axis of the impeller. Each blade has an airfoil cross section, defined by a chord line (Ch) and a camber line (Ca), and is positioned in the impeller at a setting angle (.GAMMA.). The outermost edge (Eo) of each blade is located at a distance (Rmax) from the rotational axis (Ar, Ar'). The angular spacing (.SIGMA.) between blades in the fan is uniform. Among the blades of the impeller, the values of at least one of the parameters distance from outermost edge to rotational axis (Rmax), length of chord line (Ch), maximum deviation of camber line from chord line (Dmax) and setting angle of blades vary randomly from reference values of these parameters. The random parametric variations reduce the blade rate tonal noise produced by a fan having such an impeller as compared to a fan having an impeller with uniform blade parameters.

Abstract: In the rotor of a turbomachine, especially the turbine of a gas turbine engine, each rotor blade is mounted in the rotor disk rim by a blade root having a serrated profile that engages a correspondingly formed axial groove in the rotor disk rim. A shroud band is constructed so that at a predetermined operating point of the turbine, adjacent blades are supported against one another so as to damp vibrations. Light weight and heavy weight rotor blades are mounted alternatingly around the circumference of the rotor disk. The blade root and corresponding axial groove associated with each light weight or heavy weight blade are differently dimensioned or shaped to correspond to the differing loads associated with the heavy weight blades and the light weight blades respectively. Different materials, having different densities, are used for the heavy weight blades and the light weight blades.

Abstract: A high output fan assembly for cooling the radiator of a motor vehicle. The fan assembly comprises a shaft, first and second fans, and a motor. The first fan includes a plurality of first blades, each of which has an inner portion attached to the shaft, while an outer hub is attached to an outer portion of at least one of the first blades. The second fan includes a plurality of second blades, each of which has an inner portion attached to the outer hub. The motor is drivingly connected to the shaft to drive the first and second fans at the same number of revolutions per minute. The fan assembly is situated either for pulling or for pushing air across the radiator and an air conditioning condenser of the motor vehicle.

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 device for linking a blade to the hub comprising a laminate attachment at the end of the rooting part with torsion bars of the blade, the laminate attachment being in abutment against the pins for holding on the hub. The opposite blades of the rotor may be arranged angularly offset with respect to the other blades.

Abstract: An auger-tube pump mixing device for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided.

Abstract: A static efficiency enhancer for an axial fan having a hub and a plurality of blades extending radially outward from the hub, the enhancer comprising a plurality of airfoils connected to the hub and extending outwardly therefrom to provide additional air velocity at the periphery of the hub.

Abstract: A ducted fan-type tail rotor of a rotor craft in which the tail rotor is surrounded by a tubular duct is provided which includes at least six rotor blades, and pitch horns, each mounted to the respective rotor blades. Each pitch horn is swingable to change a pitch angle of the rotor blade. Some of the pitch horns, the number of which is about a half of the total number of the pitch horns, are mounted to a first type of the rotor blades at a mounting angle larger than a reference mounting angle required to obtain a predetermined thrust, and the remainder of the pitch horns are mounted to a second type of the rotor blades at a mounting angle smaller than the reference mounting angle.

Abstract: A regenerative toric pump in which undesirable noise generation and leakage through clearance gaps between the impeller and housing is minimized includes an impeller having vanes lying in general planes radiating from the impeller axis disposed at variable spacings from each other in a geometrically balanced pattern. Recesses in one of opposed side surfaces on the impeller and housing are arranged in a pattern such as to minimize leakage through the clearance gap between those surfaces from points in the pump chamber which are at different pressures.

Abstract: A turbofan gas turbine engine fan stage having alternating relatively rugged, preferably hollow titanium, blades and staggered relatively less rugged, preferably composite, blades. The blades are staggered such that the leading edges of the rugged titanium blades are positioned forward of the leading edges of the less rugged composite blades. One embodiment provides that all fan blades have trailing edges at the same axial position while another embodiment provides that all fan blades are of the same size and shape.

Abstract: Freestanding rotor blades are mixed tuned by varying the dimensions of the blades at two locations. First, a profiled tip includes a machined-out strip, having a height which can be varied to achieve the desired tuning effect. The longer or deeper the profile, the higher the frequency will become. This tuning technique is used in conjunction with a broadened base section. Blades having a shorter profile tip are machined beginning at the base section, so as to remove enough mass from between the base section and a next upper section to provide the desired tuning effect. The lower frequency blade has a thinner base section and a shorter profile tip.

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 regenerative toric pump in which undesirable noise generation and leakage through the clearance gaps between the impeller and housing is minimized includes an impeller having vanes lying in general planes radiating from the impeller axis disposed at variable spacings from each other in a geometrically balanced pattern. Recesses in one of opposed side surfaces on the impeller and housing are arranged in a pattern such as to minimize leakage through the clearance gap between those surfaces from points in the pump chamber which are at different pressures.

Abstract: A freestanding mixed tuned taper-twisted steam turbine blade having an X-X axis parallel to a rotor axis, includes a root portion having a root center line defined by a root center line radius, a platform portion connected to the root portion; and an airfoil portion connected to the platform portion and having a leading edge, a trailing edge, a convex section-side surface, a concave pressure-side surface and a profiled tip, the platform portion having a concave edge, a convex edge, a first end in vertical proximity to the leading edge of the airfoil portion and a second end in vertical proximity to the trailing edge of the airfoil portion, the concave edge being sloped towards the root center line radius at a predetermined angle of slope to define an arcuate sloped surface, and having a sloped flat cut-out surface formed at the second end of the platform portion, the flat cut-out surface having the same predetermined angle of slope as the concave edge and sloping towards the X-X axis.

Abstract: Impellers and impeller systems are described which enable liquids and liquid suspensions to be mixed and blended where the size of the impeller and the viscosity of the liquid may require operation in the turbulent and laminar flow regimes, as well as in the transitional flow regime therebetween. The impellers have a plurality of fluidfoil blades and have camber and twist. The angle at the tip of two diametrically disposed blades of a four blade impeller may have a different blade angle at the tip than the other pair of blades. A pair of impellers may be used. These impellers may be of different diameter and disposed in close proximity so that they are in dependent relationship (preferably spaced apart by less than the diameter of the larger impeller).

Abstract: An integral shroud blade comprising a root portion for mounting the blade in a row on a turbine rotor; a platform portion; an airfoil portion extending upwardly from the platform portion and having a leading edge, a trailing edge, and a tip; a shroud formed on the tip of the airfoil portion and having two opposite tangential side surfaces and a top surface; and at least one pair of holes extending into the shroud, each of the two tangential sides having one hole of each pair being formed therein.

Abstract: A vehicular AC generator comprising a magnetic pole core secured to a shaft and excited by an excitation coil, the magnetic pole core having opposite end faces, a stationary core surrounding the magnetic pole core and having mounted thereon a stationary coil, and a front and a rear bracket supporting the stationary core and rotatably supporting the shaft through bearings. The front and rear brackets having ventilation openings defined therein, and a fan mounted to each of the opposite end faces of the magnetic pole core is provided for generating flows of cooling air through the ventilation openings in the front and rear brackets, An inlet opening side end portion of a blade of the fan that overlaps the inlet opening has a radially length dimension which is equal to or less than 50% of radial legnth dimension of the inlet opening side end portion.

Abstract: An improved compact automobile fan unit of the type including a turbofan fixedly mounted on the drive shaft of a motor and having a plurality of backwardly curved blades, and a generally cup-shaped housing having intake openings in its end wall and discharge openings in its side wall and secured to a yoke of the motor for containing therein the turbofan, wherein the backwardly curved blades are circumferentially spaced at different angular intervals and the turbofan has a center of gravity located at an axis of the drive shaft. With the blades thus arranged, the fan unit is capable of operating at high speeds with large capacity without generating unpleasant noise.

Abstract: An axial flow fan comprising: a cental hub rotatable on an axis; and a plurality of blades extending from the hub, each of the blades comprising a root portion adjacent to the hub, and terminating in a tip portion, the root portions of the blades being approximately evenly spaced around the hub; wherein each of the blades exhibits a curvature from the root portion of the blade to the blade's tip portion, the curvature being in a plane that is perpendicular to the axis on which the fan rotates; and wherein the curvature differs between at least two of the blades, such that the distance between the tip portions of at least wo sets of adjacent blades is unequal. The invention therefore achieves the advantage of having uneven blade spacing near the tips while maintaining high solidity near the hub, where the blade spacing is even. Uneven blade spacing near the tips reduces noise. Having high solidity near the hub, where non-dimensional loading is highest, maintains higher dynamic performance.

Abstract: An impeller comprises a central hub part, and a plurality of vanes extending from the central hb part, the plurality of vanes including two first neighboring vanes having a predetermined construction and at least one second vane located between the first vanes and having a construction which is different from the construction of the first vanes.

Abstract: The invention concerns a peripheral pump with an impeller, housing and conveyance channel beginning at a suction aperture and passing through at least one flow duct in the housing and impeller blade cells therein to a discharge orifice, the spacing between at least two impeller blades being larger or smaller than the spacing between the other impeller blades.

Abstract: Within a rotor blade row of a steam turbine, rotor blades having one resonant frequency alternate with rotor blades having a second, different resonant frequency. The two different resonant frequencies are achieved by profiling the tips of every other rotor blade.

Abstract: A fan having a plurality of blades where a selected number of the blades are arranged with their leading faces disposed parallel to the axis of rotation of the fan. The remaining blades are arranged with their leading faces at angles to the axis of rotation such that the air streams from the two types of blades intersect to create turbulent flow. The fan's heat transfer ability is increased and the air flow from the fan is dispersed over a wider area than with conventional fans.

Abstract: An airscrew for propelling an aircraft has a hub, a jacket and a plurality of propeller blades secured by blade necks to the hub. These blade necks are secured to the hub with symmetric or equal angular spacings around the hub between neighboring radial blade neck axes. Each propeller blade has a longitudinal axis. At least certain of these longitudinal blade axes extend at different sweep angles relative to the respective radial blade neck axis. When the sweep angle is positive the respective sweep of the blade is a positive sweepback with a trailing sweep of the respective blade relative to a rotational direction of the airscrew. When the sweep angle is negative the respective sweep of the blade is a negative sweep forward with a leading sweep of the respective blade relative to a rotational direction of the airscrew. These differing sweep angles achieve a substantial noise reduction compared to conventional airscrews having a completely symmetrical construction.

Abstract: The uncovering of the opening of the oil pickup tube is avoided by preventing the formation of a stable vortex. The prevention of the formation of a stable vortex is achieved by making the paddles of the impeller axially asymmetrical by at least a minimum critical value.

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 heat exchanger is disclosed having a coil positioned between an outer casing member with a bottom having a sump formed therein and an inner casing member containing a rotatable shaft to which a fan is mounted. The fan has a first stage or set of blades which pushes air from the outside down over the coils and a second stage or set of blades having a pitch opposite the first set for pulling the air up through the inner casing member to exhaust. A distributor having a pump which operates on centrifugal force is also provided which draws a liquid heat transfer medium preferably water from the sump and rotates with the fan blades to effectively "sling" the medium over the coils as the fan rotates.

Abstract: A mill with an impeller in which blades are mounted between two disks, and each blade has a leading edge projecting into the cross-section of the inlet. The leading edge of every other one of the blades is perpendicular to the axis of the impeller, and the leading edge of the remaining blades on the impeller are skewed. The blades on the impeller alternate in sequence along the circumference of the impeller so that each blade with leading edge perpendicular to the impeller axis is adjacently neighbored on each side with blades having skewed leading edges. The alternative sequence of the blades reduce wear on the blades by a predetermined amount for increasing the operating life of the blades.

Abstract: An impeller for a centrifugal impeller comprising a disc portion, a coaxial hub portion having a longitudinal through-bore by which the impeller is mounted on a rotatable shaft, and a plurality of blades in any one of several forms. The tip of each blade is curved in a direction opposite to the rotation of the impeller more than the rest of the blade. The radius of the tip curve decreases uniformly toward the radially outer end of the blade. This tip treatment produces improved isentropic efficiency.

Abstract: An impeller for a cross-flow fan, including a plurality of impeller sections. Each impeller sections includes a pair of plate members and a number of blades extending between and circumferentially of the plate members such that the blades are circumferentially spaced at random pitch angles without periodicity.