Impeller for transverse fan

• US 5,478,205 A
• Filed: 03/07/1994
• Issued: 12/26/1995
• Est. Priority Date: 03/07/1994
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Bushnell, Peter R., Chou, Rudy S. T.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): LARSON, JAMES
• Application Number:
  US08/206,702
• Time in Patent Office: 659 Days
• Field of Search: 416/203, 416/178, 416/187, 415/119, 415/53.1
• US Class Current: 416/178
• CPC Class Codes: F04D 29/283 rotors of the squirrel-cage type
• CPC Class Codes: F04D 29/666 by means of rotor construction or layout, e.g. unequal distribution of blades or vanes

Abstract

A transverse fan impeller (10) having blades (31) that extend longitudinally parallel to the rotational axis of the impeller. Each blade has an airfoil cross section, defined by a chord line (Ch) and a camber line (Ca), and is positioned in the impeller at a setting angle (Γ). The outermost edge (Eo) of each blade is located at a distance (Rmax) from the rotational axis (Ar, Ar'"'"'). The angular spacing (Σ) between blades in the fan is uniform. Among the blades of the impeller, the values of at least one of the parameters distance from outermost edge to rotational axis (Rmax), length of chord line (Ch), maximum deviation of camber line from chord line (Dmax) and setting angle of blades vary randomly from reference values of these parameters. The random parametric variations reduce the blade rate tonal noise produced by a fan having such an impeller as compared to a fan having an impeller with uniform blade parameters.

Claims

1. An improved impeller (30) for a transverse fan (10) of the type having

a plurality of blades (31) longitudinally aligned parallel to and extending generally radially outward from the rotational axis (Ar) of said impeller, the improvement comprising

each of said blades having a chord (Ch), a camber (Ca), a setting angle (Γ

) and an outer edge (Eo) that is at a distance (Rmax) from the rotational axis; and

among said plurality of blades, at least one of the values of maximum deviation of chord to camber (Dmax) or setting angle varies randomly with respect to a reference set of parameters, said reference set of parameters being

a camber in which the maximum deviation between said camber and said chord is equal to the average of the maximum deviations of all blades in said plurality of blades,

a setting angle of zero and

a distance of outer edge from rotational axis equal to the largest of said distances among all blades in said plurality of blades.

2. The impeller of claim 1 in which maximum deviation from chord to camber is the value that varies.

3. The impeller of claim 2 in which the value of said maximum deviation varies from 0.5 to 1.5 time said reference maximum deviation.

4. The impeller of claim 1 in which setting angle is the value that varies.

5. The impeller of claim 4 in which said setting angle varies within ±

15 degrees of said reference setting angle.

6. The impeller of claim 1 in which said distance of outer edge from rotational axis varies from 0.9 to 1.0 times said reference distance of outer edge from rotational axis.