Abstract: There is provided a centrifugal fan including an upper casing which has an air suction opening, a lower casing, and an impeller which is disposed between the upper casing and the lower casing. The impeller includes an upper shroud which is provided on an upper casing side, and a plurality of blades which are arranged along a circumference direction below the upper shroud, and is rotatable around a rotary shaft. A pressure surface of each of the plurality of blades has a convex shape in a rotation direction and is formed with a plurality of protrusions which extend in parallel with the rotary shaft.

Abstract: An impeller includes: a main plate; a shroud; and a plurality of blades provided between the main plate and the shroud and arranged circumferentially; wherein the impeller is configured to rotated about a rotation axis; wherein the plurality of blades include a pressure surface and a negative pressure surface; and the pressure surface has a shape, in which at least three types of circular arcs are connected, as viewed from a rotation axial direction. A centrifugal fan includes the above-described impeller; and three or more pillars, wherein an interval between one adjacent pillars of the three or more pillars is different from an interval between the other adjacent pillars of the three or more pillars.

Abstract: In a centrifugal fan, a casing includes: a top plate; a motor base configured to serve as a bottom plate; and a plurality of support members provided between the top plate and the motor base, wherein an opening functioning as an air outlet opening is formed at each side of the casing so as to be surrounded by adjacent support members, the top plate and the motor base, and an impeller, which is housed between the top plate and the motor base of the casing, includes: an annular shroud; and a plurality of blades arranged in the circumferential direction and provided under the shroud, wherein at least one part of each blade opposes directly the motor base of the casing, and wherein the motor base opposes the lower parts of the blades in the direction of a rotary shaft of the impeller with a predetermined air gap provided therebetween.

Abstract: There is provided a centrifugal fan including an upper casing which has an air suction opening, a lower casing, and an impeller which is disposed between the upper casing and the lower casing. The impeller includes an upper shroud which is provided on an upper casing side, and a plurality of blades which are arranged along a circumference direction below the upper shroud, and is rotatable around a rotary shaft. The upper casing and the lower casing configure an open-type casing. A surface of the upper shroud facing the upper casing includes a first portion which becomes closer to the lower casing as separating further from the rotary shaft. A surface of the upper casing facing the upper shroud includes a second portion which faces the first portion of the upper shroud and becomes closer to the lower casing as separating further from the rotary shaft.

Abstract: An impeller and a centrifugal fan having the same are provided. The impeller includes a lower shroud, an upper shroud, and a plurality of blades which are arranged along a circumference direction between the lower shroud and the upper shroud. The impeller is rotatable around a rotary shaft. An outside diameter of the lower shroud is equal to or smaller than an inside diameter of the upper shroud. An inside portion of each of the blades has an inclined portion which connects an inside circle portion of the upper shroud and an inside circle portion of the lower shroud.

Abstract: A centrifugal fan is provided. The centrifugal fan is configured such that an impeller having a plurality of blades along a circumferential direction and disposed between a disk-shaped main plate and an annular shroud is housed in a casing configured by an upper casing and a lower casing, and that an air suctioned from a suction opening is discharged outward in a radial direction of the impeller by a centrifugal force due to a rotation of the impeller. The shroud has a curved surface formed from an outer edge portion toward a center thereof. The shroud has a plurality of protrusions which are formed on the surface of the shroud such that a gap is formed between each of the protrusion portions and the upper casing.

Abstract: A centrifugal fan is provided. The centrifugal fan is configured such that an impeller having a plural blades disposed between a disk-shaped main plate and an annular shroud along a circumferential direction is accommodated in a casing, and that an air suctioned from a suction opening is discharged outward in a radial direction of the impeller by a centrifugal force due to a rotation of the impeller, and thereby discharging the air from the casing. The casing includes an upper plate, a lower plate, and a plural supporting struts interposed between the upper plate and the lower plate, and lateral sides of the casing have only the supporting struts to form a discharge opening.

Abstract: A motor mounting plate, composed of a metallic plate, includes: a disc-shaped plate body having a mounting portion to which a motor is mounted, and at least three flanges formed at a circumferential edge of the plate body, the flanges mounted at predetermined locations, an angle between adjacent flanges around the center of the plate body is 140° to 180°.

Abstract: An axial fan is provided. The axial fan includes a hub, an impeller having a plurality of blades mounted on an outer peripheral surface of the hub, and a housing surrounding the impeller. Each of the blades has a front edge angle (?) within a range of ?8° to ?20°, a mounting angle (?) within a range of 36° to 50°, and a twisted angle (?) within a range of 10°±2°.

Abstract: A motor includes a rotor with interior permanent magnets and a stator with teeth wound by concentrated windings. Each permanent magnet is split along a plane oriented towards the stator, and an electrically insulating section is set between the split magnet pieces. This structure allows each permanent magnet to be electrically split, thereby restraining the production of an eddy current. As a result, heat-production is dampened thereby preventing heat demagnetization of the permanent magnets.

Abstract: A motor includes a rotor with interior permanent magnets and a stator with teeth wound by concentrated windings. Each permanent magnet is split along a plane oriented towards the stator, and an electrically insulating section is set between the split magnet pieces. This structure allows each permanent magnet to be electrically split, thereby restraining the production of an eddy current. As a result, heat-production is dampened thereby preventing heat demagnetization of the permanent magnets.

Abstract: A motor includes a rotor with interior permanent magnets and a stator with teeth wound by concentrated windings. Each permanent magnet is split along a plane oriented towards the stator, and an electrically insulating section is set between the spilt magnet pieces. This structure allows each permanent magnet to be electrically split, thereby restraining the production of an eddy current. As a result, heat-production is dampened thereby preventing heat demagnetization of the permanent magnets.

Abstract: A motor includes a rotor with interior permanent magnets and a stator with teeth wound by concentrated windings. The permanent magnet is split along a plane oriented to the stator, and an electrically insulating section is set between the spilt magnet pieces. This structure allows the permanent magnet to be electrically split thereby restraining the production of eddy current. As a result, heat-production is damped thereby preventing heat demagnetization of the permanent magnet.

Abstract: An electric arc melting furnace includes a furnace shell (1) with an electrode (3) for melting scrap by heat of arc, an air blasting port (20) for blasting air, oxygen or oxygen-enriched air into the furnace shell (1) through an air control valve (19), a carbon blasted quantity indicator (CI) for measuring quantity of carbon to be charged into the furnace shell (1), a scrap charged quantity indicator (SI) for measuring quantity of the scrap charged into the furnace shell (1), an oxygen blasted quantity indicator (OI) for measuring quantity of oxygen blasted into the furnace shell (1) and an arithmetic processor (7) for computing quantity of air required for complete combustion of carbon monoxide (23) in the furnace shell (1) in response to measured value from the indicators (CI)(SI)(OI) to control a degree of opening of the air control valve (19).

Abstract: An electric arc melting furnace comprises a furnace shell (1) with an electrode (3) for melting scrap by heat of arc, an air blasting port (20) for blasting air, oxygen or oxygen-enriched air into the furnace shell (1) through an air control valve (19), a carbon blasted quantity indicator (CI) for measuring quantity of carbon to be charged into the furnace shell (1), a scrap charged quantity indicator (SI) for measuring quantity of the scrap charged into the furnace shell (1), an oxygen blasted quantity indicator (OI) for measuring quantity of oxygen blasted into the furnace shell (1) and an arithmetic processor (7) for computing quantity of air required for complete combustion of carbon monoxide (23) in the furnace shell (1) in response to measured value from the indicators (CI)(SI)(OI) to control a degree of opening of the air control valve (19).

Abstract: An apparatus for preheating and charging scrap material includes a throat section (38) having at one end thereof a material charging inlet (37) connected to a furnace shell (2), the throat section extending laterally and upwardly obliquely, a heat exchanger section (39) connected to the other end of the throat section (38) and extending upwardly, a sealing section (42) above the heat exchanger section (39), a material supply (43) for supplying the scrap material into the sealing section (42), an exhaust duct (53) formed at the heat exchanger section (39) just below the sealing section (42) and connected to an exhaust system (58) and a material delivery device (46) disposed at the other end of the throat section (38) for delivering the scrap material (13) from the heat exchanger section (39) to the material charging inlet (37). The scrap material (13) is substantially continuously charged into the furnace shell (2) while preheated by the high-temperature exhaust gases from the furnace shell (2).