Apparatus and Method for Restricting Air Flow Within an Electronic Equipment Enclosure

Abstract

An air flow restrictor panel adapted for use in an electronics equipment enclosure to block a gap existing between a midplane and an electronics module positioned adjacent the midplane. The air flow restrictor panel may incorporate a main panel portion and a plurality of flanges extending from the main panel portion. The main panel portion may have a footprint sufficiently large in area to block the gap.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional patent application Ser. No. 61/106,302, filed Oct. 17, 2008, the entire contents of which are hereby incorporated by reference.

FIELD

The present disclosure relates to systems and methods for managing air flow through an electronics equipment enclosure, and more particularly to systems and methods that block air from flowing through a selected internal area of an electronics equipment enclosure.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Open enclosure specifications targeting the communications equipment market, such as the PICMG AdvancedTCA specification, describe mechanical building practices utilizing Rear Transition Modules (RTMs). The RTMs are printed circuit board (PCB) modules, also referred to in the art as “blades”, that are contained with a rear (i.e. RTM) card cage area of a chassis. The RTMs are physically located behind a rear surface of a midplane that is positioned within the chassis RTM. On the opposite surface of the midplane is a front board card cage area. The front board card cage area has a plurality of card slots where one or more front boards, also sometimes referred to as “blades”, are electrically coupled to the midplane. The RTMs are electrically coupled to the front boards through a connector zone known in the art as the “Zone-3” area, which is located above the midplane when the RTMs and front boards are arranged in a vertical orientation.

The main purpose of the RTMs is to support the rear input/output (I/O) interfaces, thus decoupling such interfaces from the processing activities of front boards and increasing the available PCB area for performing various functions. Cooling of the RTM card cage area of an AdvancedTCA specification chassis has been traditionally accomplished through natural convection cooling, that is, without the need for electrically powered cooling fans. However, as the power dissipation of the RTMs has increased, this has necessitated a move to forced convection cooling systems for the RTM card cage area. The associated mechanical specifications of an AdvancedTCA chassis have not been optimized with the goal of implementing optimal efficiency for the forced convection cooling of the RTM cardcage. Since some degree of variability is required to allow for variations in the thickness of the midplane due to differing midplane connectivity requirements, this has resulted in the creation of a relatively large gap. Thus, with present building practices for an AdvancedTCA chassis, the gap will typically exist between the midplane and the rear edges of the RTMs installed in the RTM card cage area of an enclosure. FIG. 1 illustrates this gap 2 within an AdvancedTCA specification enclosure 8. The gap 2 can be seen to exist between a rear surface 4a of the midplane 4 and a rear edge 6a of an RTM 6 within the enclosure 8.

The gap 2 leaves unwanted low impedance, lateral air flow paths between the RTMs 6 and the midplane rear surface 4a. The gap 2 essentially acts like a low air flow impedance bypass path that allows a cooling air flow directed through the RTM card slots of the RTM card cage area to be diverted away from the RTMs 6. The existence of the gap 2 thus forms unwanted lateral flow paths that make the air flow distribution between the RTMs highly unpredictable. The air flow distribution through the RTM card cage area also becomes configuration specific, meaning that the configuration of the RTMs and their surface mounted components will play a significant role in determining the air flow distribution through the RTM card cage area. This is highly undesirable in an AdvancedTCA chassis where RTMs may be provided from multiple vendors, and therefore are not generally designed to take these effects into account. This can give rise to the need to independently verify each configuration of RTMs within the RTM card cage area, which is both time-consuming and costly, and which will need to be repeated for each subsequent configuration change. Existence of a low impedance air flow bypass path within the RTM card cage area also leads to wasted air flow and potentially to an insufficient volume of cooling air flow for the RTMs.

SUMMARY

In one aspect the present disclosure includes an air flow restrictor panel adapted for use in an electronics equipment enclosure to block a gap existing between a midplane and an electronics module positioned adjacent the midplane. The air flow restrictor panel may incorporate a main panel portion and a plurality of flanges extending from the main panel portion. The main panel portion may have a footprint sufficiently large in area to block the gap.

In another aspect the present disclosure includes an air flow restrictor panel adapted for use in an electronics equipment enclosure to block a gap existing between a midplane and an electronics module positioned adjacent the midplane. The air flow restrictor panel may include a main panel portion having a generally rectangular shape. A plurality of flanges may extend from the main panel portion. At least a subplurality of the flanges may each have a depth that is sufficient to substantially or entirely block a depth of the gap. The main panel portion may also have a footprint sufficiently large in length and height so as to block an area associated with the gap.

In another aspect the present disclosure includes a method for restricting a flow of air between a gap existing between a midplane and an electronics module within an electronics equipment enclosure. The method may involve providing an air flow restrictor panel having a planar main panel portion. A plurality of flanges may be formed on the main panel portion such that the plurality of flanges extend from the main panel portion. At least a subplurality of the flanges each have a depth that is sufficient to substantially or entirely block a depth of the gap. The main panel portion may be formed with a footprint that is sufficiently large in length and height so as to block an area associated with the gap when the air flow restrictor panel is installed in the gap.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1A is a simplified side view of a prior art electronics equipment enclosure, in this example an AdvancedTCA specification chassis, illustrating the gap that exists between a rear surface of the midplane and a rear edge of the RTM;

FIG. 1B is a more detailed perspective view of the equipment chassis shown in FIG. 1 further illustrating the gap, and also showing in greater detail the midplane of the chassis with a plurality of alignment pins projecting therefrom that engage with portions of each RTM when the RTMs are secured with the RTM card cage area;

FIG. 2 is a rear perspective view of an air flow blocking panel constructed to occupy the gap, and thus eliminate the lateral air flow paths that the gap would otherwise provide between the adjacently positioned RTMs and the midplane;

FIG. 3 is a front perspective view of the air flow blocking panel shown in FIG. 2, and also a perspective view of an electrically non-conductive insulating sheet that may be positioned on a front surface of the air flow blocking panel;

FIG. 4 is a simplified side view of the enclosure of FIG. 1A but with the air flow blocking panel installed to block the gap; and

FIG. 5 is a perspective view showing the RTM card cage area with just the air flow blocking panel (i.e., no RTMs installed) installed over the midplane to occupy the gap.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

Referring to FIG. 2, there is shown an air flow restrictor panel 10 in accordance with one embodiment of the present disclosure. For convenience, the air flow restrictor panel 10 will be referred to hereinafter simply as the “panel 10”. The panel 10 has a length “L” and height “H” that are sufficient to at least substantially, but more preferably completely, cover an area (i.e., length and height) associated with the gap, for example the gap 2 shown in FIGS. 1A and 1B.

The panel 10 may include a generally planar and generally rectangular shaped main panel portion 12 having a plurality of cutouts 14 along an upper area 16. The cutouts 14 in this example are each semi-circular in shape, but they could be of other shapes such as rectangular, square, elliptical, triangular, etc. The upper area 16 also includes flanges 18 that extend at approximately a ninety degree angle from the main panel portion 12 between the cutouts 14. Side areas 20 and 22 similarly include flanges 24 and 26 respectively that also extend at an angle of about ninety degrees from the main panel portion 12. Bottom area 28 likewise includes a flange 30 that extends at about a ninety degree angle from the main panel portion 12.

The side areas 20 and 22 each include pairs of tabs 32 and 34 having holes 32a and 34a, respectively, for enabling the panel 10 to be secured the sidewalls of an electronic equipment enclosure, such as for example an AdvancedTCA specification chassis (e.g., enclosure 8 in FIGS. 1A and 1B). The tabs 32 and 34 may be formed by punching out small sections of the main panel portion 12. The upper area 16 similarly may include holes 36 through which push-in type fasteners, rivets or threaded fasteners may extend to secure the panel 10 within the enclosure 8.

The flanges 18, 24, 26 and 30 may all have the same depth, denoted by reference numeral 38 in FIG. 2. The depth is further preferably equal to, or just slightly smaller (e.g., by 1-2 mm) than the depth of the gap 2, as indicated by dimensional arrows 40 in FIG. 1A. The panel 10 may be formed from steel, aluminum, plastic, rubber or any other material that is impervious to air flow. However, the use of metal provides specific benefits in terms of adding rigidity to the enclosure 8, enhancing overall structural integrity, enhancing fire resistance and limiting fire propagation.

Referring to FIG. 3, an electrically non-conductive, insulating sheet 42 may be positioned over a front surface 44 of the panel 10. The insulating sheet 42 has dimensions and cutouts 46 that match (or substantially match) the configuration of the panel 10. The insulating sheet 42 provides a non-conductive barrier between the rear edge 6a of each RTM 6 and the front surface 44 of the panel 10 that ensures that no unwanted electrical contact will be made between the rear edges 6a of the RTMs 6 and the panel 10. The insulating sheet 42 may be formed from plastic or any other suitable, non-conductive material such as rubber. The insulating sheet 42 may be secured to the panel 10 by adhesives or by independent fasteners, for example push-in type fasteners 48, that extend through the holes 50 in the insulating sheet and aligned holes 36 in the panel 10. The insulating sheet 42 has an area (i.e., footprint) preferably sufficient to cover the entire front surface 44 of the panel 10. Instead of the insulating sheet 42, the panel 10 front surface 44 may be coated with non-conductive paint or any other form of electrically non-conductive coating. However, if the panel 10 is constructed from an electrically non-conductive material, then the insulating sheet 42 would not be needed.

Referring to FIG. 4 the panel 10 can be seen installed against the midplane 4. The panel 10, with the help particularly of the flange 30, effectively fills the entire cross-sectional volume of the gap 2 so that the gap is eliminated. The installed panel 10 positioned in the enclosure 8, without any

RTMs installed in the enclosure, is also shown in FIG. 5. From FIG. 5 it can be seen that the cutouts 14 provide clearance for alignment pins 52 projecting from the rear surface 4a of the midplane 4. The alignment pins 52 aid in providing precise alignment of the RTMs 6 when the RTMs are being installed in the card slots in an RTM card cage area 54.

The panel 10 thus provides a structure and method for eliminating the gap 2, and thus ensuring that the cooling air flow directed into the RTM card cage area will flow through the RTM card slots in a predictable manner. A particular advantage of the panel 10 is that it eliminates the need to perform RTM configuration specific testing to ensure that the desired air flow through the RTM card slots is being achieved. Furthermore, if the RTM configuration should be changed at a later date, no re-testing of the air flow through the RTM card cage area is required. The panel 10 further does not add appreciable cost, weight or complexity to the construction of an AdvancedTCA specification chassis, and can even enhance the structural properties of the chassis such as its rigidity and fire worthiness.

While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.

Claims

1. An air flow restrictor panel adapted for use in an electronics equipment enclosure to block a gap existing between a midplane and an electronics module positioned adjacent the midplane, the air flow restrictor panel comprising:

a main panel portion;

a plurality of flanges extending from the main panel portion; and

the main panel portion having a footprint sufficiently large in area to block the gap.

2. The air flow restrictor panel of claim 1, wherein a bottom area of the main panel portion includes one of the flanges, and wherein said one of the flanges extends at least substantially along an entire length thereof and projects from the main panel portion at an approximate 90 degree angle.

3. The air flow restrictor panel of claim 1, wherein said main panel portion includes a plurality of spaced apart cutouts along a length thereof.

4. The air flow restrictor panel of claim 3, wherein the cutouts are semi-circular in shape.

5. The air flow restrictor panel of claim 4, wherein a subplurality of said flanges extends between adjacent ones of said cutouts and at an approximate ninety degree angle from said main panel portion.

6. The air flow restrictor panel of claim 1, wherein a subplurality of the flanges include tabs, and where each of the tabs have holes formed therein, for enabling the air flow restrictor panel to be secured to said electronics equipment enclosure.

7. The air flow restrictor panel of claim 1, further comprising an electrically non-conductive insulating sheet secured to one side of the main panel portion.

8. The air flow restrictor panel of claim 1, wherein the electrically non-conductive insulating sheet is comprised of one of plastic and rubber, and is of dimensions substantially similar to dimensions of the main panel portion.

9. The air flow restrictor panel of claim 1, wherein the main panel portion includes side areas that each include one of the flanges.

10. The air flow restrictor panel, wherein the main panel portion is rectangular in shape and the flanges extend from all four edges of the main panel portion.

11. The air flow restrictor panel of claim 3, further comprising an electrically non-conductive insulating sheet secured to one side of the main panel portion;

wherein the electrically non-conductive insulating sheet is comprised of one of plastic and rubber, and is of dimensions substantially similar to dimensions of the main panel portion; and

wherein the electrically non-conductive insulating sheet includes cutouts arranged to generally align with the cutouts in the main panel portion when the electrically non-conductive insulating sheet is secured adjacent to the main panel portion.

12. The air flow restrictor panel of claim 1, wherein the flanges each have a depth that is one of the same, or substantially the same, as a depth of the gap.

13. An air flow restrictor panel adapted for use in an electronics equipment enclosure to block a gap existing between a midplane and an electronics module positioned adjacent the midplane, the air flow restrictor panel comprising:

a main panel portion having a generally rectangular shape;

a plurality of flanges extending from the main panel portion, at least a subplurality of the flanges each having a depth that is sufficient to substantially or entirely block a depth of the gap; and

the main panel portion having a footprint sufficiently large in length and height so as to block an area associated with the gap.

14. The air flow restrictor panel of claim 13, wherein the flanges extend along all four side edges of the main panel portion.

15. The air flow restrictor panel of claim 14, wherein the flanges extend at an angle of about 90 degrees from the main panel portion and each have a depth that is at least substantially similar to a depth of the gap.

16. The air flow restrictor panel of claim 15, wherein the flanges include a plurality of tabs each having holes for enabling the air flow restrictor panel to be secured to the electronics equipment enclosure.

17. The air flow restrictor panel of claim 13, wherein the main panel portion includes a plurality of spaced apart cutout sections along one edge of the main panel portion.

18. A method for restricting a flow of air between a gap existing between a midplane and an electronics module within an electronics equipment enclosure, the method comprising:

providing an air flow restrictor panel having a planar main panel portion;

forming a plurality of flanges on the main panel portion such that the plurality of flanges extend from the main panel portion, at least a subplurality of the flanges each having a depth that is sufficient to substantially or entirely block a depth of the gap; and

forming the main panel portion with a footprint that is sufficiently large in length and height so as to block an area associated with the gap when the air flow restrictor panel is installed in the gap.

19. The method of claim 18, further comprising forming the plurality of flanges to extend at an angle of approximately ninety degrees from the planar main panel portion.

20. The method of claim 19, further forming at least one of the plurality of flanges to include a tab having a hole for assisting in securing said air flow restrictor panel within said electronics equipment enclosure.