Abstract:
A cooling system for use with compact PCI circuit cards in a computer, where the system includes an array of removable individual airflow-restricting panels disposed beneath the circuit cards. The panels having airflow characteristics which are matched to the circuit cards disposed immediately above, so as to control the volume of airflow across a particular circuit card, depending upon its individual cooling needs.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to computers, and more particularly relates to cooling systems and methods for use in personal computers, and even more particularly relates to a system and method for controlling airflow over compact PCI cards in a computer. 
     BACKGROUND OF THE INVENTION 
     In the past, designers of computing systems have endeavored to provide systems with increased reliability. One successful approach has been to include fans in the PC chassis to move air across the circuit cards therein. It has been a common practice in the industry to respond to higher heat-producing circuit cards by including higher powered fans which are capable of moving a larger overall volume of air through the chassis. 
     While these systems and methods have many advantages, they also have significant drawbacks. 
     First of all, the use of high-power fans often results in an undesirable increase in ambient sound levels, especially when numerous computers are in close proximity to each other, such as in a rack. 
     Secondly, high-powered fans typically consume valuable space inside the computer; this is especially troublesome when a compact computer design is desired. 
     Thirdly, larger and larger electric motors to drive the high-powered fans often generate an increased level of electrical noise on the computer&#39;s power bus, such that additional remedial measures are required. 
     Consequently, there exists a need for improvement in systems and methods for controlling airflow over circuit boards in personal computers. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide enhanced reliability of personal computers. 
     It is a feature of the present invention to include a relatively small cooling fan in association with airflow-controlling members in the personal computer. 
     It is an advantage of the present invention to eliminate the undesirable requirement that larger cooling fans are needed to effectively cool a personal computer, which has at least one high density and high heat-generating circuit card therein. 
     The present invention is an apparatus and method for controlling airflow through a personal computer, which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out with a “large fan-less” system, in a sense that the requirement for an increased volume of cooling air when a computer includes at least one higher heat-generating circuit board therein, is greatly reduced. 
     Accordingly, the present invention is a system and method for controlling airflow over circuit boards in a personal computer by including a parallel array of airflow-restricting plates beneath the circuit cards. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein: 
     FIG. 1 is a front elevation view of a computer of the present invention. 
     FIG. 2 is a rear elevation view of a computer of the present invention. 
     FIG. 3 is a cross-sectional plan view of the airflow metering apparatus taken along line  3 — 3  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings, wherein like numerals refer to like matter throughout, and more particularly to FIG. 1, there is shown a system of the present invention, having a front side generally designated  100 , which includes a front side air intake opening  102 , a PCI circuit card receiving area  104 , having a plurality of circuit card receiving slots therein and a front removable access plate cover (not shown), a drive bay  106 , and an extraction/insertion handle  108 . 
     Now referring to FIG. 2, there is shown a back side generally designated  200  of the present invention, which includes a rear air intake opening  202  and a fan/air exhaust compartment  204 , which could include a fan that exhausts air upwardly or rearwardly. In a reverse flow alternative, the fan  204  is an intake which blows air through the chassis and out the intake openings  102  and  202 . Back side  200  includes a rear removable access plate cover (not shown) which is removed to allow access to the computer to insert circuit cards into circuit card receiving slots therein. The rear access plate cover, as well as the front access plate cover, are well known in the art and may be a single solid, non-air-permeable member or any other cover with differing characteristics, depending upon the particular requirements of a particular computer. 
     Now referring to FIG. 3, which is a cross-sectional plan view of the present invention, taken along a line  3 — 3  of FIG.  1  and looking down onto an array of a plurality of removable air-restricting panels, generally designated  300 . This array would normally be disposed below the circuit card slot area of the computer. Removable air-restricting panels  300  include a first panel  302  generally extending from front side  100  to rear side  200 . A first partial panel  304  and second partial panel  306  are also shown. Panel  304  has a series of relatively smaller air holes in comparison to those in second partial panel  306 . Typically, an arrangement such as panels  304  and  306  would be used below a circuit card that had relatively high heat-generating capabilities for the rear of the card and relatively low heat-generating capabilities for the front of the card. Panel  308  is a solid panel which permits no air penetration therethrough. This may be frequently used where no card is located in a circuit card receiving slot immediately above. Panel  310  is shown partially slid into a panel receiving slot  311 , to better demonstrate how these removable air-restricting panels may be inserted and removed. Panel  312  shows a dual line of air holes. Numerous other air hole configurations could be used as well for each of the panels. Panel  314  is partially slid into slot  315 . Third partial panel  316  is shown adjacent to fourth partial panel  318 . Slot  320  is shown with no panel therein, thereby providing maximum volume of airflow therethrough. Panels  322  and  324  are also shown. 
     In operation, and now referring to FIGS. 1-3, the present invention operates as follows: 
     The fan  204  expels air from within the chassis. This causes a reduction in pressure in the chassis, resulting in airflow into the chassis through front air intake opening  102  and rear air intake opening  202 . This presumably cooler air then passes through the array  300  of removable air-restricting panels. The airflow is metered or controlled by the character of the panel disposed within a particular panel-receiving slot. The larger the air hole in the panel, the more airflow for cooling. Preferably, the airflow is controlled so that more air is allowed to flow over and about the circuit cards and portions thereof which have the highest heat generation. The air passes through the panels, then over the cards, thereby cooling them, and finally, the warmer air is exhausted by fan  204 . 
     If a new card is placed in the computer, then a change in the array of removable air-restricting panels may be necessary, depending upon the heat generation characteristics of the new card with respect to the card which had occupied the card slot before; i.e. if a new card is exchanged into a circuit card slot where the new card has a higher heat-generation characteristic than the card previously disposed therein, then a new removable air-restricting panel should be used which has a larger open area through which cooling air may flow. This matching of airflow to heat generation would also be done preferably on a card segment-by-card segment basis, especially when areas of a particular card can have widely varying amounts of heat generation. 
     The circuit cards discussed herein are preferably compact PCI circuit cards, because it is believed that the benefits of the present invention will be readily appreciated when such cards are used. 
     It is thought that the method and apparatus of the present invention will be understood from the foregoing description, and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof.