Centrifugal blower improved to reduce vibration and noise

• US 5,601,400 A
• Filed: 09/15/1995
• Issued: 02/11/1997
• Est. Priority Date: 09/16/1994
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Ito, Koji, Kondo, Yasushi, Miyata, Manabu, Kameoka, Teruhiko
• Primary Examiner(s): Denion, Thomas E.
• Assistant Examiner(s): Lee, Michael S.
• Application Number:
  US08/529,133
• Time in Patent Office: 515 Days
• Field of Search: 415/119, 415/206, 415/204, 415/208.1, 415/211.1, 415/183
• US Class Current: 415/119
• CPC Class Codes: F04D 29/4226 Fan casings

Abstract

A centrifugal blower is provided with a casing which defines a spiral duct and a centrifugal fan which is rotationally provided within the casing. The centrifugal fan has a bottom plate and a plurality of blades which are equally spaced along the periphery of the bottom plate. The plurality of blades extends parallel to the rotational axis. The duct is arranged to reduce the size of a low velocity air flow zone which is generated in an upper radially outer region in the spiral duct. The low velocity air flow zone, which appears in an upper radially outer region in the air duct, is reduced to reduce surging in the blower.

Claims

1. A centrifugal blower comprising:

a casing having a top wall which has a spiral periphery, a bottom wall which has a spiral periphery, a side wall spirally extending along the periphery of the bottom wall, the side wall being connected to the bottom wall, and an intermediate wall spirally extending along the periphery of the top wall, the intermediate wall connecting the top and side walls and the intermediate wall substantially forming an L shape which has a substantially vertical wall connected to the top wall, and a substantially horizontal wall connected to the vertical wall and to the side wall;

a centrifugal fan rotationally provided within the casing, the centrifugal fan having a bottom plate and a plurality of blades separated along the periphery of the bottom plate, the plurality of blades extending substantially parallel to the rotational axis; and

the casing providing a spiral duct for the air flow, the duct having a substantially rectangular section, perpendicular to the flow direction, which has a cut out portion at the radially outer top corner by the intermediate wall.

2. A centrifugal blower comprising:

a casing having a top wall which has a spiral periphery, a bottom wall which has a spiral periphery, a side wall spirally extending along the periphery of the bottom wall, the side wall being connected to the bottom wall, and an intermediate wall spirally extending along the periphery of the top wall, the intermediate wall connecting the top and side walls and the intermediate wall substantially forming an outwardly concave wall which is connected to the top wall and to the side wall;

a centrifugal fan rotationally provided within the casing, the centrifugal fan having a bottom plate and a plurality of blades separated along the periphery of the bottom plate, the plurality of blades extending substantially parallel to the rotational axis; and

the casing providing a spiral duct for the air flow, the duct having a substantially rectangular section, perpendicular to the flow direction, which has a cut out portion at the radially outer top corner by the intermediate wall.