Abstract:
An enclosure containing and operating electronic equipment is envisioned. The enclosure alleviates sound energy emanating from the enclosure. The enclosure is made from a plurality of exterior walls. An aperture is disposed in one of the exterior walls, where the aperture is operable to draw an airflow into the enclosure. A structure is disposed adjacent to the aperture interior to the enclosure. The interior structure is made of a first wall disposed in the enclosure to block the aperture from a line of sight to a noise source emanating from within the enclosure. The interior structure also has a lower wall, an upper wall, and a side wall all connected to the first wall. The interior structure forms an open-ended cage about the aperture.

Description:
FIELD OF THE INVENTION  
       [0001]    The invention is directed towards a sound suppression system for a computer enclosure. More specifically, the invention is directed towards intake vents that suppress sound generated within an enclosure. 
       BACKGROUND OF THE ART 
       [0002]    Many computer systems have venting systems to allow a fan or other environmental mechanism to output heated air to an external environment. Typically, a fan will draw air from an external environment through intake vents disposed in the housing of the enclosure. This air is then drawn across electronic components found within the enclosure for the computer system. The heated electronic components transfer heat to the air as an airflow passes across the electronic components. A fan or other environmental outlet mechanism draws the heated air to an aperture or vent disposed in the enclosure. The fan then directs the heated air through the vent into the external environment. 
         [0003]    In many systems, the sounds generated within the casing can be strong. These sounds can pass through the input vent essentially unimpeded. Accordingly, the sound of such systems can cause sonic discomfort to the users of the system. 
       BRIEF DESCRIPTION OF INVENTION 
       [0004]    An enclosure containing and operating electronic equipment is envisioned. The enclosure alleviates sound energy emanating from the enclosure. The enclosure is made from a plurality of exterior walls. An aperture is disposed in one of the exterior walls, where the aperture is operable to draw an airflow into the enclosure. A structure is disposed adjacent to the aperture interior to the enclosure. The interior structure is made of a first wall disposed in the enclosure to block the aperture from a line of sight to a noise source emanating from within the enclosure. The interior structure also has a lower wall, an upper wall, and a side wall all connected to the first wall. The interior structure forms an open-ended cage about the aperture. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more embodiments of the present invention and, together with the detailed description, serve to explain the principles and implementations of the invention. 
           [0006]    In the drawings: 
           [0007]      FIG. 1  is perspective view of an enclosure in accordance with the prior art. 
           [0008]      FIG. 2  is a cutaway diagram of the enclosure of  FIG. 1  detailing a sound dispersal structure disposed within the enclosure according to the invention. 
           [0009]      FIG. 3  is a sectional view of an alternative embodiment of a sound reducing enclosure according to the invention. 
           [0010]      FIG. 4  is a slice view from the top of the structure of  FIG. 3  according to the invention. 
           [0011]      FIG. 5  is a cutaway diagram of yet another alternative embodiment of a sound reducing enclosure according to the invention. 
           [0012]      FIGS. 6   a  and  6   b  are planar cutaway diagrams detailing possible constructions of walls making up the interior structure according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Embodiments of a system and method for suppressing noise generated from a computer casing are described herein in the context of an enclosure for the storage and operation of electronic components. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts. 
         [0014]    In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer&#39;s specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure. In accordance with the present invention, the components or structures may be implemented using various types of items. 
         [0015]      FIG. 1  is perspective view of an enclosure in accordance with the prior art. An enclosure  4  is made from several walls, including a top wall, a bottom wall, and side walls that connect them. The enclosure  4  is designed to house electronic components. The electronic components generate heat, and as such, need to be cooled. To effectuate this, a fan or other type of device that creates a flow of air is disposed within the enclosure  4 . The fan or other type of device draws air from the external environment into the enclosure  4 , and draws such air around the components to cool them. 
         [0016]    In particular, air is drawn into the enclosure  4  through openings  8  in the walls of the enclosure  4 . In many typical systems, the openings  8  allow the sounds from within the enclosure  4  to escape to the external environment. 
         [0017]    The openings  8  typically allow a free path from noise produced by a noise source  6  disposed within the enclosure  4  to the external environment. Sound waves are pressure waves that travel in a compressional fashion through the air. The sounds produced from within the enclosure  4  typically include the sounds of fans and other such devices employed to circulate air within the enclosure  4  to alleviate heating within the enclosure  4 . Thus, the pressure wavefronts emanating from within the enclosure  4  may be dispersed through any openings in the enclosure  4 . Thus, sounds corresponding to operating the electronic devices within the enclosure  4  are free to escape into the environment surrounding the enclosure  4 , and cause annoyance and possible disruption of work being performed in the area. 
         [0018]      FIG. 2  is a cutaway diagram of the enclosure of  FIG. 1  detailing a sound dispersal structure disposed within the enclosure according to the invention.  FIG. 2  is a cutaway diagram of the enclosure  10  through a plane running parallel to a top of the enclosure  10 . The side wall  12  contains several openings  8  to allow an airflow through the enclosure  10 . Disposed within the enclosure  10  is an internal mechanism  6  producing sound waves. Coupled to the side wall  12  and disposed generally about the opening  8  is a structure  14 . The structure  14  contains a back wall  16  that shields the opening  8  from the noise source(s)  6  disposed inside the enclosure  10 . Pressure waves emanating from the noise source impinge upon the back wall  16  and either diffract around the back wall  16  or are reflected back into the interior of the enclosure  10 . 
         [0019]    Noise energy containing components at higher frequencies tend not to diffract around line of sight obstacles, such as the structure  14  or the back wall  16 . Thus, the higher frequency components mainly are directed away from the openings  8  present in the wall  12  of the enclosure  10 . 
         [0020]      FIG. 3  is a sectional view of an alternative embodiment of a sound reducing enclosure according to the invention. In this aspect, a top wall  20 , a bottom wall  18 , and a side wall  22  supplement the back wall  16 . In this aspect of the invention, the structure  14  forms a baffle about the opening  8  present in the exterior side wall  12 . 
         [0021]      FIG. 4  is a slice view from the top of the structure of  FIG. 3  according to the invention.  FIG. 4  shows the wave paths from the sound source are cut off from the opening  8  by the structure  14 . High frequency components are highly directional, and as such, do not diffract easily around the structure  14 . Thus, high frequency component of sound emanating from the interior of the enclosure is impinged dramatically by the structure  14  disposed about the opening  8 . Additional noise abatement may also be effected on lower frequency components as well, since the sound waves that tend to diffract around the structure  14  will tend to interfere with reflections emanating off the wall  22  of the structure. 
         [0022]    In particular noise generated within the enclosure is represented by an arrow  24 . High frequency components are directional, and do not diffract around the wall  16 . Thus, they are represented as the arrow  26 , which indicates that the high frequency portions do not escape from within the enclosure through the opening  8 . 
         [0023]    Lower frequency components are not directional, and can diffract around the wall  16 . Thus, they are represented as the waves  28 . A portion of this sound energy is directed onto the wall  22 , from where they are reflected back into the plenum formed by the exterior wall  12 , and the wall  16 , the wall  22 , and the top and bottom portions of the cage-like structure that is disposed about the opening  8 . These reflected waves then interfere with the newly diffracted waves. 
         [0024]      FIG. 5  is a cutaway diagram of yet another alternative embodiment of a sound reducing enclosure according to the invention. In this aspect of the invention, a structure is formed about the airways, and this structure serves a dual function. In addition to the line of site abatement shown in the examples previously described, the shape of the structure may be formed to make a sonic reflector or resonator. For example, an inner wall  32  may be disposed within the inner volume or plenum defined by the structure  14  described previously. The inner wall  32  can be formed with an aperture in it. 
         [0025]    The combination of the inner wall  32  with the rest of the structure produces a back wave emanating out of a chamber  34  defined by the back wall  22 , the inner wall  32 , the wall  16 , the top and bottom walls, and the exterior wall  12 . This backwave then exits the aperture in the inner wall  32  and meets the now oncoming sound waves. The volume and dimensions of the chamber  34  may be designed to provide a reflective-type muffler for incoming sound waves to the structure. In this manner, further abatement may be obtained from the structure. 
         [0026]      FIG. 5  may be used to demonstrate the muffler effect of the structure depicted therein. A sound wave emanates at the entrance of the structure. This may be a diffracted wave from the edge of the structure, or reflected sound from another interior surface of the enclosure. The sound wave comes to the entrance of the inner wall  32 , and the aperture in the inner wall  32  provides a point source for sound to emanate into the chamber  34 . The sound wave in the chamber  34  is reflected off the inner surfaces of the chamber  34 . The chamber&#39;s volume and dimensions are “tuned” to produce a reflected inverted wave at the aperture in the inner wall  32  making up the chamber  34  for a particular frequency. The now inverted sound wave now interferes destructively with the any new incoming sound waves, thus abating the noise emanating from the aperture  8 . 
         [0027]      FIGS. 6   a  and  6   b  are diagrams detailing possible constructions of walls making up the interior structure according to the invention. The interior structure may be made of two or more differing materials. 
         [0028]    First, a rigid material having a fairly heavy weight makes up a first portion  36  of the wall. A second portion  38  of the wall is made of a sound absorptive layer. In this manner, the construction and composition of the wall allows further sound suppressive effects to occur. Energy in sound waves striking the absorptive layer  38  may end up with three different outcomes. First, the sound may be reflected. For highly sound absorbent material, very little of the impinging sound is reflected. In a second outcome, the absorptive material  38  absorbs some of the energy associated with the sound wave. The remaining energy in the impinging sound wave is transmitted. 
         [0029]    Turning now to the effect of the first portion  36  on sound wave energy, most sound energy striking the first portion  36  is mainly reflected. Thus, very little energy in the wall is transmitted outwards. Typically, the mass of the first portion  36  tends to attenuate transmission. On the “return, outward bound” trip, again some of the sound is absorbed by the absorptive material making up the second portion  38 . 
         [0030]    Walls of this type may be used both on the inner and outer portions of the structures described above relative to  FIGS. 1-4 . In particular, a triple layer wall, such as that shown in  FIG. 6   b , can work acoustic effects on sound within the enclosure and sound energy leaving the enclosure through the exterior aperture. In this case, the non-transmissive layer is sandwiched between two layers of absorptive layers, providing acoustic abatement for sound waves on both sides. In this case, both sound waves striking the outward facing surfaces and those that are diffracted into the exit plenum are attenuated prior to their exit from the enclosure through interaction with the walls making up the plenum. 
         [0031]    Thus, a system and method for suppressing noise generated from a computer casing is described and illustrated. Those skilled in the art will recognize that many modifications and variations of the present invention are possible without departing from the invention. Of course, the various features depicted in each of the figures and the accompanying text may be combined together. Accordingly, it should be clearly understood that the present invention is not intended to be limited by the particular features specifically described and illustrated in the drawings, but the concept of the present invention is to be measured by the scope of the appended claims. It should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention as described by the appended claims that follow.