Low noise centrifugal blower

• US 4,419,049 A
• Filed: 10/19/1981
• Issued: 12/06/1983
• Est. Priority Date: 07/19/1979
• Status: Expired due to Fees

• Current Assignee: SGM Company Incorporated
• Original Assignee: SGM Company Incorporated
• Inventors: Gerboth, Patrick L., Jozwiak, Stanley E. Jr.
• Primary Examiner(s): Hornsby, Harvey C.
• Assistant Examiner(s): Peterson, Christine A.
• Application Number:
  US06/312,884
• Time in Patent Office: 778 Days
• Field of Search: 415/203, 415/119, 415/204, 415/206, 415/207, 415/219 A, 415/219 B, 415/219 C
• US Class Current: 415/212.1
• CPC Class Codes: F04D 17/04 of transverse-flow type
• CPC Class Codes: F04D 29/403 especially adapted for elastic fluid pumps

Abstract

It has been discovered that by eliminating the cutoff in a centrifugal blower the tone or whistle-like noise usually produced by such blower may be eliminated without unreasonably affecting the performance of the centrifugal blower and in many instances without having any significant effect on such performance. Briefly, the invention is directed to a centrifugal blower and to a particular type of blower housing therefor, in which there is no such cutoff or like impediment to provide the allegedly required transition in the involute wall portion of the blower relatively proximate the blower outlet. Rather, in the present invention an extension wall portion extends from the end of the involute wall portion in a direction toward the blower outlet, preferably terminating at the latter so as to eliminate the conventional blower throat which leads to the blower outlet, with such extension wall portion, or at least a major part thereof, traveling therealong in a direction toward such blower outlet having an increasing radial spacing from the spiral center of the spiral shape housing and/or the radial center of the fan wheel.

Claims

1. A centrifugal blower, comprising generally cylindrical fan wheel means rotatable about its axis for blowing air;

housing means for collecting air blown by said fan wheel means, said housing means having a generally spiral shape to direct such collected blown air in a spiral flow path therein, outlet means for receiving such spiral flow of air and for discharging the same from said housing means in a generally straight-line direction, said outlet means comprising a generally planar plate-like member haing a planar cross-section outlet opening therethrough, said housing means having one wall portion terminating relatively far from the spiral center of said housing means, leading to said outlet means, and terminating at said outlet means in generally perpendicular relation thereto, an involute wall portion terminating relatively proximate such spiral center, and an extension wall portion extending from said involute wall portion toward said outlet means, said extension wall portion comprising a linear wall, having an increasing radial spacing from such spiral center in a direction toward said outlet means from at least one of the juncture of said extension wall portion and said involute wall portion and of a location on said extension wall portion otherwise most proximate such spiral center, not having a spiral extending cut-off, having an end terminating at said plate-like member opening in nearly parallel relation to the plane of said plate-like member, whereby said outlet opening is substantially fully open and unimpeded by a throat-like passage, having a major portion positioned with respect to said fan wheel means and said outlet means so as to avoid impeding air flow in said housing means and exiting the latter and said extension wall portion being generally tangential to said involute wall portion at a juncture of said involute and extension wall portions.

2. In a housing for centrifugal blower in which a fan wheel is rotated to blow air, the housing being generally spiral shape having an air inlet, said housing functioning to collect air blown by the fan wheel, the improvement comprising substantially unimpeded outlet means in said housing for discharging at least some of the blown air from said housing, said housing having one wall portion relatively remote from the spiral center and leading toward said outlet means, an involute wall portion relatively proximate such spiral center, and an extension wall portion leading from said involute wall portion to said outlet means, said extension wall portion comprising a generally linear wall positioned with respect to the fan wheel to avoid substantially impeding the blowing of air in said housing, said linear wall having one end coupled to said involute wall portion and a second end opposite said one end, and said outlet means comprising an opening in a plate-like wall exposed directly to the exterior of the blower, and said second end of said linear wall terminating at said plate-like wall, whereby said outlet means is fully open and unimpeded by a throat-like passage and said second end being substantially directionally parallel with the major cross-sectional directional extent of said outlet means.