Laminar flow duct cooling system

• US 6,343,984 B1
• Filed: 11/30/1998
• Issued: 02/05/2002
• Est. Priority Date: 11/30/1998
• Status: Expired due to Term

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Robbins, Robert, Langdon, Daryl J.
• Primary Examiner(s): Joyce, Harold
• Application Number:
  US09/203,220
• Time in Patent Office: 1,163 Days
• Field of Search: 454/184, 361/695, 165/80.3, 165/122
• US Class Current: 454/184
• CPC Class Codes: F04D 25/0613 the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
• CPC Class Codes: F04D 25/166 using fans
• CPC Class Codes: F04D 29/545 Ducts
• CPC Class Codes: G06F 1/20 Cooling means

Abstract

The invention provides a redundant cooling system with abatement of noise from cooling fans used primarily in computer equipment and other boxes housing electronic equipment. Typically either the computer system or box housing electronic components has two parallel side panels, a front panel, and a back panel upon which cooling fans are mounted to draw air across various electronic components and through the box for heat dissipation. The cooling system includes an airflow grille attached to one end of a laminar flow duct and two adjacent cooling fans mounted to the other end of a laminar flow duct which includes a Venturi opening on the top panel of the laminar flow duct to facilitate laminar flow through the laminar flow duct at a distance before the cooling fans and at a distance after the cooling fans.

Claims

1. A cooling system which reduces aerodynamic and electromagnetic noise comprising:

one or more cooling fans in a housing, each fan having a toroidal fan opening and disposed for providing positive airflow over a first planar region, along a first linear axis substantially parallel to the first planar region;

an airflow grille, defining a second planar region substantially perpendicular to said first linear axis, said airflow grille defining a set of through-holes substantially parallel to said first linear axis wherein said grille opening is equal to or greater than said toroidal fan opening such that aerodynamic and electromagnetic noise are minimized; and

a first laminar flow region disposed between said cooling fans and said airflow grille, said first laminar flow region defined by a laminar flow duct wherein said laminar flow duct has a geometry of a rectangular solid such that said laminar flow duct defines a Venturi opening, said Venturi opening being operative in conjunction with said one or more cooling fans to provide airflow through said Venturi opening from a region both upstream and above a region of said laminar flow duct containing said Venturi opening wherein airflow is parallel to said first laminar flow region, said laminar flow duct being coupled on a first end to a housing for said one or more cooling fans and on a second end to said airflow grille, and said laminar flow duct being substantially parallel to said first linear axis, wherein said laminar flow duct acts as an RF collimator to reduce electromagnetic noise.

2. A method for cooling electronics and minimizing aerodynamic and electromagnetic noise, including steps for:

cooling incoming air with one or more cooling fans in a housing, disposed for providing positive airflow over a first planar region, along a first linear axis substantially parallel to the first planar region;

receiving air through an airflow grille which defines a second planar region substantially perpendicular to said first linear axis, said airflow grille defining a set of through-holes substantially parallel to said first linear axis; and

receiving air through a first laminar flow region disposed between said cooling fans and said airflow grille, said first laminar flow region defined by a laminar flow duct, said laminar flow duct being coupled on a first end to a housing for said one or more cooling fans and on a second end to said airflow grille, and said laminar flow duct being substantially parallel to said first linear axis.

3. A method for cooling electronics and minimizing aerodynamic and electromagnetic noise, including steps for:

cooling incoming air with one or more cooling fans in a housing, each fan having a toroidal fan opening and disposed for providing positive airflow over a first planar region, along a first linear axis substantially parallel to the first planar region;

receiving air through an airflow grille which defines a second planar region substantially perpendicular to said first linear axis, said airflow grille defining a set of through-holes substantially parallel to said first linear axis wherein said grille opening is equal to or greater than said toroidal fan opening such that aerodynamic and electromagnetic noise are minimized; and

receiving air through a first laminar flow region disposed between said cooling fans and said airflow grille, said first laminar flow region defined by a laminar flow duct wherein said laminar flow duct has a geometry of a rectangular solid such that said laminar flow duct defines a Venturi opening, said Venturi opening being operative in conjunction with said one or more cooling fans to provide airflow through said Venturi opening from a region both upstream and above a region of said laminar flow duct containing said Venturi opening wherein airflow is parallel to said first laminar flow region, said laminar flow duct being coupled on a first end to a housing for said one or more cooling fans and on a second end to said airflow grille, and said laminar flow duct being substantially parallel to said first linear axis wherein said laminar flow duct acts as an RF collimator to reduce electromagnetic noise.