Fan

• US 4,750,860 A
• Filed: 01/20/1987
• Issued: 06/14/1988
• Est. Priority Date: 06/30/1986
• Status: Expired due to Fees

• Current Assignee: Tandem Computers Incorporated (HP Inc.)
• Original Assignee: Tandem Computers Incorporated (HP Inc.)
• Inventors: Kelley, Francis E.
• Primary Examiner(s): Garrett, Robert E.
• Assistant Examiner(s): KWON, JOHN
• Application Number:
  US07/005,057
• Time in Patent Office: 511 Days
• Field of Search: 415/119, 181/225, 181/202, 181/204, 181/205, 181/277
• US Class Current: 415/119
• CPC Class Codes: F04D 29/545 Ducts
• CPC Class Codes: F04D 29/664 by means of sound absorbing material

Abstract

An improved fan, for mounting adjacent an opening in a mounting plate, includes blades rotatable about an axis and within a cylindrical housing. The fan blades move air through the opening in the mounting plate. A cylindrical, open-cell foam collar encircles the fan housing. The collar is sized so that the collar extends a substantial distance upstream past the edge of the collar. The foam collar reduces the acoustic noise from the fan by damping the housing vibration and also by acting as a barrier to muffle sound waves in the air. In addition, the foam collar straightens out the air flow prior to entering the fan blades making it more laminar and less turbulent to increase the efficiency of the fan.

Claims

1. An improved fan assembly comprising:

a fan including blades rotatable about an axis, the fan operable to move air in a downstream direction along the axis;

a cylindrical fan housing mounted about the fan blades coaxially with the axis so to surround the fan blades, the fan housing being a chosen axial length with a downstream edge and an upstream edge; and

a tubular foam collar sized to fit over the fan housing, the collar having a first portion, extending over the housing a first length in the downstream direction from the upstream edge, and a second portion, extending a second length from the upstream edge in an upstream direction opposite the downstream direction, the second length being at least a substantial portion of the first length;

whereby the foam collar reduces the noise from the fan assembly, by damping vibration of the fan housing and by muffling sound waves, and increases the air flow rate through the fan assembly.

2. The fan assembly of claim 1 further comprising a mounting plate having first and second sides and an air flow opening formed therein, the fan being mounted to the first side of the mounting plate at the air flow opening so that air flows from the first mounting plate side, through the opening and to the first mounting plate side, and wherein the downstream edge of the housing is adjacent the mounting plate.

3. The fan assembly of claim 2 wherein the fan housing is mounted directly to the mounting plate.

4. The fan assembly of claim 1 wherein the foam collar is cylindrical.

5. The fan assembly of claim 1 wherein the foam collar has a radial thickness of at least 1/2 inch.

6. The fan assembly of claim 1 wherein the foam collar is an open-cell foam collar.

7. The fan assembly of claim 6 wherein the foam collar has about 60-90 pores per inch.

8. The fan assembly of claim 1 wherein the first length of the foam collar is substantially equal to the chosen axial length of the fan housing.

9. The fan assembly of claim 1 wherein the fan has a diameter of about 6 inches, the fan housing has a chosen axial length of about 11/2 inches, the first and second lengths of the collar are each about 11/2 inches and the collar has a radial dimension of about 3/4 inch.

10. An improved fan assembly comprising:

a mounting plate having first and second sides and an air flow opening formed therein;

a fan, including blades rotatable about an axis, mounted to the first side of the mounting plate at the air flow opening, the fan operable to blow air in a forward direction along the axis from the first side, through the opening and to the second side;

a cylindrical fan housing mounted about the fan blades coaxially with the axis so as to surround the fan blades and on the first side of the mounting plate, the fan housing being a chosen axial length with a downstream edge adjacent the mounting plate and an upstream edge spaced apart from the mounting plate; and

a cylindrical, open-cell foam collar sized to fit over the fan housing, the collar having a first portion, housing a first length, covering the housing and a second portion extending in an upstream direction opposite the downstream direction, the second length being generally equal to the first length;

whereby the foam collar reduces the noise from the fan assembly, by damping vibration of the fan housing and by muffling sound waves, and increases the air flow rate through the fan assembly.

11. A method for improving the performance of a fan of the type mounted to a mounting structure adjacent an opening in the mounting structure so to blow air through the opening, the fan having blades surrounded by a cylindrical fan housing having upstream and downstream edges, the method comprising:

selecting a foam collar having an inside dimension sized for snug placement over the fan housing and having a chosen axial length; and

mounting the foam collar over the fan housing with a substantial portion of the foam collar extending on either side of the upstream edge so the foam collar both reduces noise and aids flow through the fan.

12. The method of claim 11 wherein the selecting step includes the step of selecting a foam collar with a chosen axial length being substantially greater than the axial length of the fan housing.

13. The method of claim 12 wherein the chosen axial length is about twice the axial length of the fan housing.