Vortex flow blower having blades each formed by curved surface and method of manufacturing the same

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein the curved surface is formed such that at least an inner portion of each of said blades is formed such that the fluid is introduced at an angle more inclined at a central portion of each of said blades than at an inner end of each of said blades, and wherein another portion of each of said blades is substantially perpendicular to a shroud surface of said shroud and a further portion of each of the blades is arched shaped from the shroud surface to an inlet of each of the blades.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein each of said blades includes a curved surface having a front edge, said curved surface being formed such that an axial angle of the front edge is progressively decreased from said inner end toward a central portion of each of the blades, and the axial angle is progressively increased from said central portion to an outer portion of each of the blades, and wherein another portion of each of said blades is substantially perpendicular to a shroud surface of said shroud and a further portion of each of the blades is arched shaped from the shroud surface to an inlet of each of the blades.

A vortex flow blower comprising:

• a casing having an annular passage of a semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein each of said blades is three dimensionally formed such that each of said blades is retracted with respect to a direction of rotation of said impeller, and an axial exit angle of each of said blades is progressively increased from a central portion of each of said blades to an outer end of each of said blades, and wherein another portion of each of said blades is substantially perpendicular to a shroud surface of said shroud and a further portion of each of the blades is arched shaped from the shroud surface to an inlet of each of the blades.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein each of said blades has a shape such that a side of each of the blades opposite to said casing is formed such that the relationships of .gamma..sub.c <.gamma..sub.0 and .gamma..sub.c <.gamma..sub.i are met, where .gamma..sub.c, .gamma..sub.0 and .gamma..sub.i represent axial angles at a central portion of each of said blades, at a first intermediate portion of each of said blades between said central portion and an outer end of each of said blades and at a second intermediate portion between said central portion and an inner end of each of said blades, respectively, and wherein another portion of each of said blades is substantially perpendicular to a shroud surface of said shroud and a further portion of each of the blades is arched shaped from the shroud surface to an inlet of each of the blades.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval and a motor for rotating said rotatable impeller, wherein each of said blades includes a curved surface having a front edge, said curved surface spaced from an inner end of each of the blades to a central portion of each of the blades such that both .gamma..sub.1 and .gamma..sub.c are less than 90 degrees and such that .gamma..sub.1 >.gamma..sub.c, where .gamma..sub.1 and .gamma..sub.c represent axial inlet angles of said front edge at said inner end and at said central portion, respectively, and wherein said blade is formed so as to extend in a direction of rotation of said rotatable impeller from the central portion to the outer portion, and wherein the central portion of each of said blades has an intermediate portion retracted with respect to the direction of rotation of said rotatable impeller.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein said blades are arranged in the shroud across said shroud passage having a semicircular cross-section, and wherein each two adjacent ones of said plurality of blades form an inflow passage portion inclined along an inflow direction of said swirling fluid flow and a middle flow passage portion having a surface which is substantially perpendicular to a circumferential direction, and wherein each of said plurality of blades has a middle portion in a front edge of the blade which is retracted with respect to a rotational direction of the impeller.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section, which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein said blades are arranged in said shroud across a passage having a semicircular cross-section, wherein each of said blades is inclined to a circumferential direction from an end opposing said casing to a side of a wall of said shroud in at least a fluid inflow side and a fluid discharge side, and wherein each of said blades is formed by a member different from said shroud, and wherein each of said blades is fixed to said shroud at plural fixed portions, and wherein each of said fixed portions has another portion perpendicular to said shroud.

A vortex flow blower comprising:

• a casing having an annular passage of semicircular cross-section, and an inlet port and an outlet port respectively communicating with said annular passage;
• a rotatable impeller having an annular shroud wall surface of semicircular cross-section which is opposed to said annular passage and has substantially the same shape as said annular passage, and a plurality of blades provided in said shroud wall surface with a constant interval;
• and a motor for rotating said rotatable impeller, wherein said blades are arranged in said shroud across a passage having a semicircular cross-section, wherein each of said blades is inclined to a circumferential direction from an end opposing said casing to a side of a wall of said shroud in at least a fluid inflow side of said blades and a fluid discharge side of said blades, and wherein each of said blades is formed by a member different from said shroud, and wherein each of said blades is fixed to said shroud at plural fixed portions, and wherein each of said blades has in at least a wall surface portion of said passage another portion perpendicular to said shroud.