Axial fan

Claim 2

An axial fan whose fan blades are fixed to the rotor of an electrical driving motor and are mounted coaxially within a pipe section and extend over at least half the axial length of the said pipe section, whereby the flow channel formed by the pipe section is constricted from a wide suction side inlet to a necked-down portion in the flow direction and from this necked-down portion is widened to a wide pressure side outlet, wherein the said necked-down portion closely embraces the periphery of the blades and extends only over a small fraction of the suction side axial length of the blades and wherein the shaft of a rotor is mounted with axial clearance in bearing means and is supported on the suction side on a punctiform bearing arranged centrally in flange means and wherein the flange means is fixed with spokes to the suction side edge of the pipe section, the said spokes spanning the annular axial surface of projection of the blades hollowed out by the flange means in an inclined manner relative to the suction side edges of the blades and specifically with such an orientation of the inclined position that the axial projection of the intersection points of the spokes with the edges is displaced outwardly in operation; wherein the outlet of the flow channel is bounded by a polygonal contour, in whose corner areas the outlet end portion of the flow channel projects over the circular periphery circumscribed by the polygonal contour and the outlet cross-section of the flow channel is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 3

An axial fan whose fan blades are fixed to the rotor of an elecrical driving motor and are mounted coaxially within a pipe section and extend over at least half the axial length of the said pipe section, whereby the flow channel formed by the pipe section is constricted from a wide suction side inlet to a necked-down portion in the flow direction and from this necked-down portion is widened to a wide pressure side outlet, wherein the said necked-down portion closely embraces the periphery of the blades and extends only over a small fraction of the suction side axial length of the blades and wherein the shaft of a rotor is mounted with axial clearance in bearing means and is supported on the suction side on a punctiform bearing arranged centrally in flange means and wherein the flange means is fixed with spokes to the suction side edge of the pipe section, the said spokes spanning the annular axial surface of projection of the blades hollowed out by the flange means in an inclined manner relative to the suction side edges of the blades and specifically with such an orientation of the inclined position that the axial projection of the intersection points of the spokes with the edges is displaced outwardly in operation; wherein the outlet and inlet of the flow channel are bounded by the same polygonal contour, in whose corner areas the inlet side end portion and the outlet side end portion of the flow channel project beyond the circular periphery circumscribed by the polygonal contour and the outlet cross-section is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 4

An axial fan whose fan blades are fixed to the rotor of an elecrical driving motor and are mounted coaxially within a pipe section and extend over at least half the axial length of the said pipe section, whereby the flow channel formed by the pipe section is constricted from a wide suction side inlet to a necked-down portion in the flow direction and from this necked-down portion is widened to a wide pressure side outlet, wherein the said necked-down portion closely embraces the periphery of the blades and extends only over a small fraction of the suction side axial length of the blades and wherein the shaft of a rotor is mounted with axial clearance in bearing means and is supported on the suction side on a punctiform bearing arranged centrally in flange means and wherein the flange means is fixed with spokes to the suction side edge of the pipe section, the said spokes spanning the annular axial surface of projection of the blades hollowed out by the flange means in an inclined manner relative to the suction side edges of the blades and specifically with such an orientation of the inclined position that the axial projection of the intersection points of the spokes with the edges is displaced outwardly in operation; wherein the outlet and inlet of the flow channel are bounded by the same polygonal contour, in whose corner areas the inlet side end portion and the outlet side end portion of the flow channel project beyond the circular periphery circumscribed by the polygonal contour and the outlet cross-section is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 5

An axial fan comprising an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; and a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, said constricted portion being closely adjacent to said fan blades at only a small fractional portion of the suction side of the blades, the major portion of the fan blades being downstream of said constricted portion in the flow direction.

Claim 6

An axial fan comprising an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; and a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, said constricted portion being closely adjacent to said fan blades at only a small fractional portion of the suction side of the blades, the major portion of the fan blades being downstream of said constricted portion in the flow direction.

Claim 7

An axial fan according to claim 3, wherein said flow channel widens at the outlet end from said necked-down constricted portion into a first diffuser region and thereafter further widens into a second diffuser region, and wherein said fan blades extend downstream into said second diffuser region.

Claim 8

An axial fan comprising: an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, and wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by the polygonal contour of said corner areas, wherein said constricted portion and said widening portion are closely adjacent to said fan blades, said fan blades being of a greater radial length in said widening portion than in said constricted portion.

Claim 9

An axial fan comprising: an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, and wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by the polygonal contour of said corner areas, wherein said constricted portion and said widening portion are closely adjacent to said fan blades, said fan blades being of a greater radial length in said widening portion than in said constricted portion.

Claim 10

An axial fan according to claim 5, wherein said fan structure has an axial dimension which is compact relative to its radial dimensions.

Claim 11

An axial fan according to claim 5, wherein more than half of the fan blades are downstream of said constricted portion in the flow direction.

Claim 12

An axial fan according to claim 7, wherein said flow channel widens at the outlet end from said necked-down constricted portion into a first diffuser region and thereafter further widens into a second diffuser region, and wherein said fan blades extend downstream into said second diffuser region.

Claim 13

An axial fan comprising an elecrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, wherein said constricted portion is closely adjacent to said fan blades, and extends only over a small fractional portion of the suction side axial length of said blades, and wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by said polygonal contour at said corner areas.

Claim 14

An axial fan comprising an elecrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, wherein said constricted portion is closely adjacent to said fan blades, and extends only over a small fractional portion of the suction side axial length of said blades, and wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by said polygonal contour at said corner areas.

Claim 15

An axial fan according to claim 9, wherein flange means having spokes fixed at said flow channel are provided for mounting said motor.

Claim 16

An axial fan according to claim 10, wherein said spokes span the annular space of said flow channel, and said spokes are inclined relative to suction end edges of said fan blades at an orientation such that the axial projection of the intersection points of said spokes with the blade edges is displayed outwardly during operation of the fan.

Claim 17

An axial fan according to claim 9, wherein the outlet end and the inlet end of the flow channel are both bounded by the same polygonal contour with said corner areas, said suction inlet end and said pressure outlet end of the flow channel projecting beyond the circular periphery circumscribed by the polygonal contour at said corner areas.

Claim 18

An axial fan according to claim 9, wherein the pressure outlet end extension of the flow channel widens in the manner of a diffuser.

Claim 19

An axial fan according to claim 9, wherein said flow channel widens at the outlet end from said necked-down constricted portion into a first diffuser region and thereafter further widens into a second diffuser region, and wherein said fan blades extend downstream into said second diffuser region.

Claim 20

An axial fan comprising an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, said constricted portion being closely adjacent to said fan blades at only a small fractional portion of the suction side of the blades, the major portion of the fan blades being downstream of said constricted portion in the flow direction, and flange means for mounting said motor and having spokes fixed at said suction inlet end of said flow channel, said spokes spanning the annular space of said flow channel, and said spokes being inclined relative to suction end edges of the fan blades at an orientation such that the axial projection of the intersection points of said spokes with the blade edges is displaced outwardly during operation of fan; wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by said polygonal contour at said corner areas.

Claim 21

An axial fan comprising an electrical driving motor having a rotor; plurality of fan blades secured to said rotor; a channel section forming an axial flow channel, said motor and said fan blades being mounted within said channel section, said flow channel having a wide suction inlet end narrowing down to a necked-down constricted portion and thereafter widening from said constricted portion to a wide pressure outlet end along the entire inner periphery of said channel section, said constricted portion being closely adjacent to said fan blades at only a small fractional portion of the suction side of the blades, the major portion of the fan blades being downstream of said constricted portion in the flow direction, and flange means for mounting said motor and having spokes fixed at said suction inlet end of said flow channel, said spokes spanning the annular space of said flow channel, and said spokes being inclined relative to suction end edges of the fan blades at an orientation such that the axial projection of the intersection points of said spokes with the blade edges is displaced outwardly during operation of fan; wherein the outlet end of the flow channel is bounded by a polygonal contour with corner areas, said pressure outlet end projecting beyond the circular periphery circumscribed by said polygonal contour at said corner areas.

Claim 22

An axial fan according to claim 15, wherein the cross-section at the pressure outlet end of the flow channel is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 23

An axial fan according to claim 15, wherein the inlet end of the flow channel is bounded by said polygonal contour having said corner areas, said suction inlet end of the flow channel projecting beyond the circular periphery circumscribed by the polygonal contour at said corner areas.

Claim 24

An axial fan according to claim 15, wherein the outlet end and the inlet end of the flow channel are both bounded by the same polygonal contour with said corner areas, said suction inlet end and said pressure outlet end of the flow channel projecting beyond the circular periphery circumscribed by the polygonal contour at said corner areas.

Claim 25

An axial fan according to claim 15, wherein the outlet end and the inlet end of the flow channel are both bounded by the same polygonal contour with said corner areas, said suction inlet end and said pressure outlet end of the flow channel projecting beyond the circular periphery circumscribed by the polygonal contour at said corner areas, and wherein the cross-section at the pressure outlet end is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 26

An axial fan according to claim 15, wherein the inlet end of the flow channel is bounded by said polygonal contour with corner areas, said suction inlet end of the flow channel projecting beyond the circular periphery circumscribed by the polygonal contour at said corner areas, and wherein each spoke is arranged opposite an associated corner area with a peripheral end of the associated corner area being fixed to the edge of the channel section in the direction of rotation of said rotor.

Claim 27

An axial fan according to claim 15, wherein the constriction of the flow channel at the suction side of the fan blades has a pitch which continuously decreases in the flow direction.

Claim 28

An axial fan according to claim 15, wherein the pressure outlet end extension of the flow channel widens in the manner of a diffuser.

Claim 29

An axial fan according to claim 15, wherein the constriction of the flow channel at the suction side of the fan blades has a continuously decreasing pitch in the flow direction, and wherein the pressure outlet end extension of the flow channel widens in the manner of a diffuser.

Claim 30

An axial fan according to claim 15, wherein the rotor includes an external-type rotor surrounding the stator of the electric motor.

Claim 31

An axial fan according to claim 15, wherein said electric motor has a rotor shaft supported at the suction inlet end of the flow channel by a punctiform bearing arranged centrally in said flange means.

Claim 32

An axial fan according to claim 25, wherein the cross-section at the pressure outlet end of the flow channel is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 33

An axial fan according to claim 25, wherein the rotor includes an external-type rotor surrounding the stator of the electric motor.

Claim 34

An axial fan according to claim 25, wherein said rotor shaft is mounted with axial clearance in pivot bearings.

Claim 35

An axial fan according to claim 28, wherein the cross-section at the pressure outlet end of the flow channel is bounded in the corner areas by segments of a surface of revolution coaxial to the rotor axis.

Claim 36

An axial fan according to claim 28, wherein the rotor includes an external-type rotor surrounding the stator of the electric motor.