Abstract: A double suction impeller is disclosed. In at least one embodiment, the impeller is configured for centrifugal pumps and hydraulic power recovery turbines. The impeller's flow-path arrangement comprises inter-blade channels, intersecting each other at the impeller's outer diameter and defining a variable cross section shape, so that the equivalent number of blades is at least doubled with respect to a conventional configuration obtained by the coupling of two single suction impellers and an improved control over the velocity of the flow within the inter-blade channels is achieved.

Abstract: An active magnetic rotor-bearing assembly for conveying a fluid comprising a rotor assembly is disclosed and a bearing assembly for contactless bearing the rotor assembly, where the bearing assembly comprises an even number of electromagnetic units arranged around a central structure each comprising a first salient established by a magnetic material and a permanent magnet providing a first magnetic pole and a coil around the salient, further comprises an inter-yoke with inter-yoke portions connected to the first salient of each electromagnetic unit and being separated from each other by structure spacers, providing a closed first magnetic flux passing the rotor assembly applying a first attractive force further comprising a position stabilizing portion perpendicular to the first attractive force on the rotor-assembly and the coils providing an electromagnetic flux between each first salient and the rotor assembly for applying adaptable axial force and/or tilting torque to the rotor assembly.

Abstract: A double suction impeller is disclosed. In at least one embodiment, the impeller is configured for centrifugal pumps and hydraulic power recovery turbines. The impeller's flow-path arrangement comprises inter-blade channels, intersecting each other at the impeller's outer diameter and defining a variable cross section shape, so that the equivalent number of blades is at least doubled with respect to a conventional configuration obtained by the coupling of two single suction impellers and an improved control over the velocity of the flow within the inter-blade channels is achieved.

Abstract: A fan wheel disc has at least one region that extends in a curved manner, at least in some sections, from radially inside to radially outside. A blade attachment surface is formed at least in some sections. The blade attachment fixedly connects an axial end side of at least one fan wheel blade. The blade attachment surface extends, at least in some sections, within the curved region of the fan wheel disc within a two-dimensional connecting plane.

Abstract: A centrifugal fan includes a housing, a driving device, and a fan impeller. The housing has a hollow chamber which has a central axis. The driving device is located at the central axis of the hollow chamber. The fan impeller is disposed in the hollow chamber and includes a hub, several blades, and several fins. The hub is connected with the driving device. The blades are disposed around the hub. Each blade has a windward surface and a leeward surface. Each fin extends from the windward surface of one of the blades, outward by an arc surface from the windward surface starting from a location near the central axis, and further extends to the leeward surface of an adjacent blade.

Abstract: A diffuser divider shaped as disc with a central axis, a leading edge disposed at an inner radius about the central axis, a trailing edge disposed at an outer radius about the central axis, an upper surface disposed between the leading edge and the trailing edge, a lower surface disposed between the leading edge and the trailing edge and one or more mounting features configured to mount the disc in a diffuser section configured to receive air compressed by two compressor wheel faces and to direct the compressed air to a volute. Such a divider can define throats in a diffuser section of a compressor assembly. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.

Abstract: A method for forming an inclined-blade blower wheel is provided by arranging a plurality of blades about respective circumferences of first and second end caps. The plurality of blades extend longitudinally between the first and second end caps and parallel to an axis defined by respective centers of the first and second end caps. The first end cap is rotated with respect to the second end cap a predetermined amount, therein skewing the plurality of blades at a desired longitudinal pitch between the first end cap and second end cap. The first end cap and second end cap are then rotated in unison while crimping the circumferences of the first end cap and second end cap, therein securing the plurality of blades to the first and second end caps and fixing the desired longitudinal pitch of the plurality of blades from the first end cap to the second end cap.

Abstract: A pump having anti-airlock provisions. The pump is comprised of a volute comprised of a volute wall, and an impeller comprising back vanes on a side of the impeller that is proximate to the volute wall, with the back vanes having a length extending radially outwardly along the impeller. A bleed hole is formed in the volute wall in communication with the portion of the volute between the back vanes and the volute wall, and the exterior of the volute, such that the bleed hole is located midway along the length of the back vanes. When the pump is operating with air, liquid, or a combination of air and liquid in the volute, the bleed hole is under positive pressure with respect to the exterior of the volute. The bleed hole may be in communication with the exterior of the volute through a lateral tunnel formed in the pump.

Abstract: A centrifugal fan that includes an impeller having fan blades with notched tabs extending through slots in a pair of disc shaped base elements with the notches engaging the ends of the slots to secure the fan blades upon the impeller.

Abstract: A pet toy includes a noise making instrument. In a preferred embodiment, the noise making instrument is a squeaker incorporated within the pet toy by an internal holding pocket that is integrally molded when the pet toy is manufactured. The internal holding pocket frictionally engages the squeaker. The squeaker is located within the protected internal holding pocket such that it is very difficult for the animal to remove the squeaker. Optionally, a control element may be used to activate or deactivate the squeaker.

Abstract: A resin cross flow fan and a method for manufacturing a resin cross flow fan are provided in which an annealing step can be omitted and the number of circular disks can be reduced, and which provides improved fan strength and air blowing performance. A resin cross flow fan is disposed with a plurality of blades and a plurality of plates. The plurality of blades are annually disposed about a rotation axis. Insertion portions each constituted by a hole or a groove into which each blade is inserted and projecting portions that projects from the periphery of the insertion portions in a direction of the rotation axis are formed on each of the plurality of plates disposed spaced apart in the direction of the rotation axis. Each blade is fixed to the projecting portions by laser welding.

Abstract: A cooling fan (20) includes a housing (22) and an impeller (24). The housing has a base (221), a sidewall (222) extending from a periphery of the base with an air outlet (226) defined therein, and a cap (223) covering the sidewall. The impeller has a plurality of blades (242) rotatably received in the housing for generating an airflow. An air channel (225) is formed between tip portions of the blades and an inner face of the sidewall. The air outlet has a near section (226A) and a far section (226C). The airflow first reaches the near section and then the far section. The base of the housing has a protrusion (227) extending into the air outlet for guiding the airflow flowing towards the far section from the near section of the air outlet.

Abstract: The present invention is directed to a turbine comprising a pair of opposing end discs concentrically aligned with a central axis of the turbine and a plurality of blades extending between the end discs. At least one end discs is adapted for engaging with a generator for generating power. The plurality of blades rotates in a single direction when exposed to fluid flow and thereby rotates the pair of opposing end discs. The plurality of blades are interconnected by at least one faired ring oriented parallel to the pair of opposing end discs and intersecting the plurality of blades, wherein the at least one faired ring is in concentric alignment with the central axis. The present invention further comprises a method for generating power comprising engaging the turbine with a generator to create a turbine generator unit and deploying the turbine generator unit within a fluid flow.

Abstract: Each of blades of a multi-blade centrifugal blower is provided with a taper portion, which is arranged at an inside periphery at least at the side of one rotation-shaft-direction end of the blade and tapers from the side of other rotation-shaft-direction end of the blade toward the side of the one rotation-shaft-direction end. The taper portion is positioned at a rotation-direction front side with respect to a back portion disposed at the side of the other rotation-shaft-direction end of the blade. Each of inlet angles throughout the taper portion is set in a range from 55° to 74°. Therefore, air flowing speed at an outlet of an impeller wheel is uniformed throughout the blade width. Work capacity and efficiency of the impeller wheel are increased, while noise is reduced.

Abstract: A back-to-back double-flow bi-directional thrust-balanced micro-impeller for use in optimized compression cycles of small volumetric flow rates is provided. The back-to-back micro-impeller is a component of a compressor capable of generating a pressure head suitable for maintaining the flow rate needed for dissipating heat, such as produced by an electronic component. The back-to-back micro-impeller provides a fluid path on both sides of the micro-impeller, imparting an equal momentum (or velocity) to the fluid. The left and right compressor sections provide a balancing of forces generated by high-pressure fluid against the two sides of the micro-impeller. This reduces vibrational forces and provides a balancing force on the shaft which reduces the thrust on the shaft in a direction away from the gas flow path. Also, the approximately equally distributed mass about the rotation axis X, provides for a balanced impeller which is desirable when operated at high rotation speeds.

Abstract: A blower having an enclosure having side walls defining an internal chamber, an open end comprising a first inlet, a second inlet and an outlet. A flow separator plate extends across the internal chamber between the side walls defining a first scroll duct and a second scroll duct. The first scroll duct is in flow communication with the first inlet and the outlet, while the second scroll duct is in flow communication with the second inlet and the outlet. A blower wheel is rotatably mounted in the enclosure through an opening in the separator plate having a first wheel portion disposed in the first scroll duct and a second wheel portion disposed in the second scroll duct.

Abstract: Cross flow fan having a plurality of unit fans assembled in succession with the unit fans twisted from each other at sides, and an air conditioner fitted with the same. The unit fan includes an annular rim, and a plurality of impellers arranged on a side of the rim vertical to, and along a circumference of the rim. The present invention provides a cross flow fan extension lines from the impellers of the unit fan have a phase difference with the extension lines from the impellers of an adjacent unit fan.

Abstract: A connector sleeve 17 secured to the backing plate 7a of a wear-resistant liner 7 facilitates attachment of the liner 7 to the body9 of a rotor blade by virtue of welding of a thrust collar 20 to a portion of the connector sleeve 17 projecting past a bore 18 in the blade body 9. Removal of the liner later for replacement is possible by burning off the welds connecting the thrust collar to the connector sleeve. A clamping tool 22 comprising a tubular body 23 and a bolt 24 can be used to hold the thrust collar firmly against the back of the blade body 9 during the welding operation.

Abstract: Heat exchange devices are provided for use in ventilation and air conditioning systems where the heat carriers do not mix with one another. According to one embodiment, a heat exchanger type fan includes a casing having two inlets and two outlets, and a double-sided centrifugal impeller. The casing is divided into two isolated chambers, and the chambers together with the impeller form two isolated centrifugal fans. The impeller is made of a solid dividing disk, with backward curved blades located on both sides of the dividing disk, and intermediate blades placed between the backward curved blades and located over a periphery of the dividing disk. A ratio of a length of the backward curved blades to a distance between the intermediate blades over a mid-radius of the impeller is at least 10.

Abstract: The centrifugal fan of the present invention comprises a frame, a rotatory means and an impeller. Among these, the frame has a first intake, a second intake, at least one air outlet and a plurality of ribs crossing the second intake. The rotatory means mounted in the frame. The impeller further includes a hub, a partition, a plurality of first blades and a plurality of second blades. The hub is coupled to the motor. The partition separates the inlet air of the first intake and that of the second intake so as to reduce the noise caused by the disturbance. A plurality of first blades and second blades are formed on the first surface and the second of the impeller, respectively. Each of the first blades and second blades selectively include a cut corner formed thereon. The second blade and said rib forms an intersection angle of about 90 degrees as the second blade crosses the rib.

Abstract: An air-guiding impeller for a blower. The impeller includes a rotary shaft adaptable for a motor, an annular frame, blades formed on the annular frame, and air-guiding ribs interconnected between the annular frame and the rotary shaft and inclined with respect to the annular frame.

Abstract: A method for aerating waste water, wherein the interface area between air and waste water is enlarged by splashing the water by means of blades and wherein the sludge present in the waste water is kept in suspension by creating flows and/or turbulence in the water. The waste water is set in motion by moving a plurality of blades arranged in a circle through the waste water, in such a manner that the connecting parts interconnecting the blades substantially do not extend into the waste water. The device for aerating waste water is provided with a container for waste water and with a rotor being rotatable about a substantially vertical axis, whose portion pointing downwards may extend into the waste water. The rotor comprises blades having surfaces which are substantially radially and axially oriented, whereby the blade surfaces are at least partially located below the rotor parts interconnecting the blades so that the connecting parts substantially do not extend into the waste water.

Abstract: Method for mixing granulates, powders and liquids in a continuous process, whereby the material is placed in a mixing housing and is mixed therein with the aid of a rotor equipped with mixing arms. The material is thereby moved to and fro many times during one rotation of the rotor, towards the rotor axis and away from it. For that purpose the device with which the method is implemented has longitudinal stators, mounted principally in the axial direction of the rotor, between which the mixing arms move when in operation. The mixing housing consists preferably of two chambers situated behind one another seen in the direction of the axis of the rotor and separated from one another by the rotor disk. The material which is to be mixed enters the housing in the first chamber, where it is undergoes a preliminary mix, then flows into the second chamber and is mixed further there.

Abstract: A ventilation system for a car including an outside air channel, an interior air channel, and a radial fan having a suction side and an exhaust side. The fan is situated at junction between the outside air and interior air channels, so that the outside air and interior air channels are axially connected to the suction side of the fan. A partition wall is movable within an unrestricted cavity, so that the outside air and interior air channels are situated at different sides thereof.

Abstract: A centrifugal blower wheel is provided with forward-curved multi-blades comprising a pair of end rings, a plurality of blades and a disk. By separating the blades into "vane members" which assume the function of a fluid device and "vane attachment members" which assume the function of a high speed rotating device, there is a greater degree of freedom of design, so optimum materials and shapes can be assigned to these different functions. The end rings, vane attachment members and disk are therefore constructed of metal and provided with beads so as to give a highly rigid structure, while the vane members are constructed of non-metal. This makes it possible to provide a blower wheel which is more lightweight and quieter in operation than a conventional blower wheel.

Abstract: A blade wheel for a centrifugal pump has at least two blade discs spaced along an axis of rotation of the discs. At least one row of generally radial blades extends between the blade discs and is spaced successively in a circumferential direction of the blade discs with blade ends radially outermost at peripheries of the blade discs. The blade ends are at an angle to the axis of the rotation of the discs, whereby each blade end has a leading edge and a trailing edge in the circumferential direction. In order to reduce pressure variations caused by the blades in a discharge conduit of the pump, the leading edge of the blade end of a trailing blade in the circumferential direction is one of in axial alignment with the trailing edge of the blade end of a successively leading blade in the circumferential direction and ahead of the trailing edge in the circumferential direction.

Abstract: Poor inlet suction characteristics in regenerative pumps may be avoided in a construction including a housing (10) having an impeller receiving cavity (20) with a circular impeller (22) therein. Channel-like annular grooves (32, 34) are disposed in the housing (10) and open to the cavity (20) at sides (36, 38) of the impeller (22). An outlet seal (63) is located in each of the grooves (32, 34) and outlet ports (62) opening to the grooves (32, 34) are located just upstream of the outlet seal (63). Peripheral recesses (42, 44) are located in the impeller sides (36, 38) and have radially inner extremities (59) located radially inward of the channels (32, 34). A plurality of blades (52) are mounted to the impeller (22) within the recesses (42, 44) around the periphery thereof and have radially inner edges (54) spaced from the radially inner recess extremities (59) while being isolated from recirculation within the channels ( 32, 34).

Abstract: A centrifugal fan has blades the effective width of which are variable during fan operation through the actuation of modulation apparatus which rotates with the fan wheel and is driven thereby. The modulation apparatus isolates the blocked off and unused portions of the fan blades which prevents the interaction of the blocked off portion of the blades with air flowing through the fan housing in a manner which results in a highly efficient and extremely quiet fan.

Abstract: A modified centrifugal airfoil fan wheel having a plurality of radially extending blades, a spaced back plate and front plate that interconnect each blade along the lateral edges of each blade, a center plate and a plurality of stiffeners. The center plate is spaced intermediate and parallel to the back and front plates and interconnect each blade along an intermediate portion. The plurality of stiffeners encircle and are secured to each blade at the outermost portion of the blades. The back plate, front plate and center plate each have a central concentric opening and each may have a cutout spaced between each blade. This modified design results in reduced stress during operation and an extended fatique life.

Abstract: The mixing apparatus has a plurality of pump impellers having one common axis and extending parallel to each other. Immediately adjacent pump impellers have opposite directions of rotation. The blading of the pump impellers is such that the currents of the mediums exiting the pump impellers have an as large as possible peripheral component. The medium currents exiting the adjacent pump impellers and having opposite senses of rotation are guided together and generate at the mutual point of contact an extremely high turbulence because the peripheral components of the exiting rotating currents of the mediums are directed oppositely to each other and eliminate each other practically immediately.

Abstract: A motor-driven fan including a hub adapted to be driven by a motor, a plurality of fan blades provided on the hub to extend in radial directions, a shroud including a ring-shaped portion encircling the fan blades and stay members for supporting the ring-shaped portion, each of the fan blades being formed at a tip end thereof with a deflector which is bent in a direction of rotation of the fan by a width which increases from a leading edge to a trailing edge of the blade.

Abstract: A domestic electrical appliance for food preparation has a generally cylindrical bowl and a vertical shaft rotatably mounted in this bowl. A beating/emulsifying tool of the invention is arranged to be mounted on the shaft. The tool comprises a disc arranged to extend near the bottom of the bowl and to be rotated by the vertical shaft. A series of radially directed projections are formed on one or both of the faces of the disc which can be used alone in the appliance for the preparation of emulsions such as mayonnaise. A cage can additionally be mounted in the bowl to cooperate with the disc for the effective beating of foodstuffs such as egg whites and cream.

Abstract: A shaft and pulley assembly for a blower having a scroll housing containing an impeller utilizes a square section shaft having a pulley retained thereon, an impeller having a hub with inner surfaces which lie in face-to-face contiguity with the shaft, a pair of adaptors having inner surfaces which also lie in face-to-face contiguity with the shaft and having curved external surfaces which support the adaptors from bearings which are themselves carried in bearing housings which are fixed with respect to the scroll housing, at least one of the adaptors having latches thereon which retain its said bearing against displacement.

Abstract: A single-piece plastic fan wheel for a radial fan comprises a hub, a blade ring having fan blades and an intermediate piece interconnecting the hub and the blade ring. The hub comprises an inner hub ring attachable to the drive shaft of a motor and an outer hub ring connected to the inner hub ring by a plurality of axially and radially extending resilient strips which serve to damp tangential vibrations emanating from the motor owing to pulsations in the torque output thereof.

Abstract: A centrifugal blood pump has an impeller with a hub, a blade support ring and alternating long and short blades. A tapered seal between a pump housing wall and a hub of an impeller which provides a fluid tight seal interface surrounding a shaft. The long blades of the impeller have rear edges which are closer to the wall than is the seal interface and inner edges which extend from the rear edges to the hub. This provides high flow in the vicinity of the seal interface to enhance heat dissipation from the seal interface.

Abstract: An armoring system for use with an airfoil centrifugal fan for preventing erosion of the airfoil blades of the fan. The armoring system comprises an armor shield adapted to be releasably secured to at least a portion of the upper surface of the fan blades to prevent erosion thereof. The armoring system further includes mounting means cooperating with the armor shield for releasably securing the armor shield to the blades. The mounting means are positionable within the hollow space formed by the upper and lower surfaces of the blades to structurally reinforce the blades without altering their aerodynamic shape.

Abstract: The improved dual-entry radial compressor rotor of the present invention has two sets of alternating full length and partial length blades on a symmetrical hub, with the partial length blades on one hub side terminating at the rotor high velocity exit coincident with the full length blades on the other hub side, to smooth the gas velocity profile in the tangential direction. Aerodynamically shaped sawtooth-profiled reliefs are provided in the hub radial portion between the blade tips to allow induced pressure differentials between the flow paths to smooth the axial velocity profile.

Abstract: A radial fan has airfoil-like, backwardly curved blades placed between a support plate and a cover plate. The blades are so formed that the blade entry angle on the cover plate side is 4.degree. to 7.degree. smaller than the blade entry angle on the support plate side and the blade exit angle on the cover plate side is 3.degree. to 6.degree. smaller than the blade exit angle on the support plate side. The blade entry angle on the cover plate side is between 14.degree. and 20.degree. and the blade exit angle on the cover plate side is between 39.degree. and 45.degree.. This form is produced by twist of the blades or twist-free deformation thereof.

Abstract: A center plate-blade attachment configuration for a centrifugal blower wheel which gives improved high speed rupture strength and improved resistance to the center plate slipping circumferentially relative to blades. The inner edge of each blade is provided with a T-shaped notch and the edges of the two discs forming the center plate are forced axially into the slots forming the ends of the head of each T, a distance such that the edges of the disc and the base of the slot are plastically deformed.

Abstract: Shrink fit sleeves 30 interposed between the hub 21 and the shaft 10 of a large rotating apparatus adapted for operation in an environment subject to severe cyclical loading as occasioned by large thermal transients, are provided with the property of having greater axial shear flexibility than radial flexibility and/or greater axial flexibility than that of the shrunk on component 21.

Abstract: A radial blower, especially for heaters and/or air conditioning systems of motor vehicles. The radial blower including a housing having a front portion provided with an air intake opening and a back portion provided with discharge or exit openings. The housing is adapted to accommodate a drive motor for a fanwheel which is manufactured as a one piece plastic part. The fanwheel includes a fan ring with fan blades and a hub. A spacer is provided for connecting the fan ring with the fan blades. A spacer is provided with openings having spokes disposed therebetween. The spokes constitute a bundle of springs connected in parallel. Openings in a back portion of the housing and/or the drive motor have a limited cross section for drawing in a sufficient flow of cooling air.

Abstract: An impeller assembly for use in a blower structure including a blower wheel which defines a centrally located peripheral groove in which a special endless metallic pulley band is fixedly mounted and having a hub sleeve which is demountably carried on a tubular axle shaft which demountably carries a stub shaft in each of its opposite ends for rotatable journalling in the bearings of the blower structure.

Abstract: A regenerative pump apparatus has a housing and a substantially disc-shaped impeller rotatably housed by the housing. Circumferential rows of radial vane grooves are formed in the outer peripheral portions of both side surfaces of the impeller. Each circumferential row includes first vane grooves of an axial depth equal to or greater than a half of the impeller thickness and second vane grooves of an axial depth smaller than a half of the impeller thickness. The first and second vane grooves are arranged alternatingly in the circumferential direction in each row, such that the first vane grooves and the second vane grooves in one row are axially aligned with the second vane grooves and the first vane grooves in the other row.

Abstract: A fabricated, heavy duty centrifugal pump impeller wherein the relatively heavy gauge shrouds are formed by plastic deformation such as by metal spinning, stretch forming or hydroforming. The hub is similarly formed and a plurality or regularly circumferentially spaced spiral vanes extend axially therebetween so that when the hub, blades and shroud are joined by welding or brazing, there is formed a heavy duty impeller having an axially extending inlet and a radially extending annular outlet. Following the fabrication, the impeller is finished and metallized.

Abstract: A water wheel for providing both flotation and propelling forces. The water wheel includes a disc made up of a pair of side walls spaced apart in their center area and joined at their peripheries to define a cavity. Paddle members are fixed to the outside of the disc, and have a curved working surface for acting against water as the wheel rotates. The leading edge of the paddle members cuts into the water without creating turbulence, and water flow over the rest of the paddle member is smooth.

Abstract: An improved heat shield and thermal insulating arrangement for a hub 12 of a high temperature centrifugal fan includes a cover overlying thermal insulation 38, the cover including a circumferential portion comprising segments 42, 44, an end ring 52, and fasteners 54, 58 holding the cover to the hub and a locking collar 28, with the cover basically shielding the root portion 20 of the hub, and being remote from and unattached to the wheel plate 16.

Abstract: A hub assembly for a centrifugal fan subjected to large transient thermal stresses is provided in which a pair of opposed hubs sandwich the inner peripheral margin of a disc-shaped fan plate, with the inner peripheral margin of the plate including a thickened ring portion to provide oppositely projecting annular shoulders at the outer periphery of the thickened ring portion, with the opposing hubs having annular recesses to receive the thickened ring portion and with the outer peripheries of the recesses in closely abutting relation with the shoulders to provide a shoulder-recess bearing area and with a plurality of fastener means extending through the hubs and through the thickened ring portion so that the shoulder-recess bearing area, which is located radially outwardly from the bearing stress areas at the bolt holes, largely receives the transient thermal stresses and therefore reduces the stress in the bolts and plate.

Abstract: A fabricated, heavy duty centrifugal pump impeller wherein the relatively heavy gauge shrouds are formed by plastic deformation such as by metal spinning, stretch forming or hydroforming. The hub is similarly formed and a plurality or regularly circumferentially spaced spiral vanes extend axially therebetween so that when the hub, blades and shroud are joined by welding or brazing, there is formed a heavy duty impeller having an axially extending inlet and a radially extending annular outlet. Following the fabrication, the impeller is finished and metallized.

Abstract: An improved rotor for a side-channel compressor in which the ratio of the pressure of the compressor at zero output and the suction pressure of the compressor is greater than or equal to 1.79 and which rotor includes a plurality of spaced-apart blades having cells interposed therebetween. The improvement of the invention comprises the blades having a thickness dimension chosen so that the ratio of the blade cell volume to the sum of the blade cell volume and the blade volume is a maximum value of 0.72 and a minimum value of 0.45/(p.sub.max /p.sub.1 -1).sup.2.

Abstract: A martensitic stainless steel to be used for the impellers of turbo-blowers, compressors and the like consisting essentially, based on weight of 0.04 - 0.15% C, up to 2.0% Si, 0.2 - 2.0% Mn, 3.5 - 6.0% Ni, 10 - 16% Cr, and at least one element selected from the group consisting of 0.5 - 3.0% Mo, 0.01 - 0.8% Nb, and the balance being Fe. The amounts of .delta.-ferrite therein is not more than 10%. The steel may further contain up to 0.2% additional element or elements, i.e., N, Al, Ti, Ca, and/or a rare-earth element or elements. The steel of this composition offers high strength, great toughness, and good weldability and, when annealed after welding, it will display the same properties as after quenching and tempering. Impellers made of this steel are for heavy-duty, high-efficiency applications.