Fans

A fan arrangement for a duct, the fan arrangement including a housing having an inlet and an outlet adapted to communicate air with the duct and an axially rotatably driven impeller supported within the housing between the inlet and the outlet, the impeller including a hub carrying a plurality of blades that span in a radial direction outwardly of the hub, the plurality of blades being shaped to urge air between the inlet and the outlet,

• wherein the plurality of blades have a tip solidity ratio in the range of about 0.8 to 1.55, and
• wherein each of the plurality of blades has a substantially constant thickness across a chord thereof and a chord length toward the tip is relatively longer than a chord length toward the root, and
• wherein, when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.

A fan arrangement for a duct, the fan arrangement including a housing having an inlet and an outlet adapted to communicate air with the duct and an axially rotatably driven impeller supported within the housing between the inlet and the outlet, the impeller including a hub carrying a plurality of blades that span in a radial direction outwardly of the hub, the plurality of blades being shaped to urge air between the inlet and the outlet,

• wherein the plurality of blades have a tip solidity ratio in the range of about 0.8 to 1.55,
• wherein each of the plurality of blades has-a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees, and a length of the chord toward the tip that is relatively longer than the chord toward the root,
• wherein, when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.

An impeller for a ducted fan arrangement having an inlet and an outlet, the impeller including a hub carrying a plurality of blades that span in a radial direction outwardly of the hub, the plurality of blades being shaped to urge air between the inlet and the outlet, wherein the plurality of blades have a tip solidity ratio in the range of about 0.8 to 1.55,

• wherein each of the plurality of blades has a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees and a substantially constant thickness across a chord thereof, and
• wherein, when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.

A method of forming a fan arrangement for a duct, the method including the steps of:

• forming a housing having an outer housing and an inner housing so as to form a passageway therebetween, the inner housing supporting a rotatable axially arranged impeller and the housing being shaped such that a pre-impeller section of the passageway is relatively larger in cross section to a post impeller section of the passageway;
• forming the impeller so as to have a tapered hub between the pre and post impeller sections with the tapered hub carrying a plurality of blades that substantially span in a radial direction between the hub and an internal surface of the outer housing, the plurality of blades being shaped to urge air between an inlet and an outlet of the housing and,
• forming the plurality of blades so as to have a tip solidity ratio in the range of about 0.8 to 1.55, and so that each of the plurality of blades has a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees and a substantially constant thickness across a chord thereof, and that when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.

A method of forming an impeller for a ducted fan arrangement having an inlet and an outlet, the method including:

• forming a hub arranged to taper outwardly in a direction between the inlet and outlet;
• forming a plurality of blades to fit with the hub from a material having a substantially constant thickness across a chord thereof and having a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees;
• forming the impellor by coupling the plurality of blades to the hub such that the plurality of blades span in a radial direction outwardly of the hub to urge air between the inlet and the outlet and have a tip solidity ratio in the range of about 0.8 to 1.55, and that when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.

A fan arrangement for a duct, the fan arrangement including a housing having an inlet and an outlet adapted to communicate air with the duct and an axially rotatably driven impeller supported within the housing between the inlet and the outlet, the impeller including a hub carrying a plurality of blades that span in a radial direction outwardly of the hub, the plurality of blades being shaped to urge air between the inlet and the outlet,

• wherein the plurality of blades have a tip solidity ratio in the range of about 0.8 to 1.55, and
• wherein each of the plurality of blades has a twist angle between a root and a tip thereof in the range of about 15 to 30 degrees and a substantially constant thickness thereby being non-aerofoil shaped, and
• wherein, when viewed in front plan form, leading edges and trailing edges of adjacent ones of the plurality of blades are parallel in a radial direction.