U.S. patent application number 12/169378 was filed with the patent office on 2008-11-13 for blower exhaust backflow damper methods.
This patent application is currently assigned to International Business Machines Corporation. Invention is credited to Bruce E. Baker, Matthew S. Henry, David J. Jensen, Seth D. Lewis.
Application Number | 20080280552 12/169378 |
Document ID | / |
Family ID | 38472019 |
Filed Date | 2008-11-13 |
United States Patent
Application |
20080280552 |
Kind Code |
A1 |
Baker; Bruce E. ; et
al. |
November 13, 2008 |
BLOWER EXHAUST BACKFLOW DAMPER METHODS
Abstract
Methods for preventing exhaust backflow into a blower are
disclosed. Embodiments may include a blower system with an
invertible blower chassis having a blower exhaust to direct airflow
from the blower chassis at an airflow angle. The system may also
include a backflow damper frame attached to the blower chassis and
positioned to receive airflow from the blower chassis and one or
more vertical damper vanes rotatably attached to the backflow
damper frame. Each damper vane may freely rotate between a first,
closed position and a second, open position. The damper vanes may
block airflow into the blower exhaust when in the closed position
and may freely rotate to a position where the damper vanes are
substantially parallel to the airflow from the blower exhaust. The
damper vanes may each include a vane pin to rotatably attach to
frame holes of the backflow damper frame.
Inventors: |
Baker; Bruce E.; (Round
Rock, TX) ; Henry; Matthew S.; (Raleigh, NC) ;
Jensen; David J.; (Raleigh, NC) ; Lewis; Seth D.;
(Cary, NC) |
Correspondence
Address: |
IBM COPORATION (RTP);C/O SCHUBERT OSTERRIEDER & NICKELSON PLLC
6013 CANNON MOUNTAIN DRIVE, S14
AUSTIN
TX
78749
US
|
Assignee: |
International Business Machines
Corporation
Armonk
NY
|
Family ID: |
38472019 |
Appl. No.: |
12/169378 |
Filed: |
July 8, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11368778 |
Mar 6, 2006 |
7416481 |
|
|
12169378 |
|
|
|
|
Current U.S.
Class: |
454/229 ;
454/256; 454/259 |
Current CPC
Class: |
F04D 25/14 20130101;
H05K 7/20172 20130101; F24F 7/007 20130101; F04D 29/663
20130101 |
Class at
Publication: |
454/229 ;
454/256; 454/259 |
International
Class: |
F24F 11/00 20060101
F24F011/00; F24F 13/16 20060101 F24F013/16 |
Claims
1 A method for preventing exhaust backflow from a blower, the
method comprising: directing airflow through a blower intake fan
having a rotational axis to a blower exhaust substantially
perpendicular to the blower intake fan rotational axis, wherein the
airflow is directed through the blower intake fan substantially
along the rotational axis of the blower intake fan; receiving
angled exhaust airflow from a blower exhaust, the blower exhaust
airflow being angled at an airflow angle between an axis
perpendicular to the blower exhaust and an axis parallel to the
blower exhaust, wherein the airflow angle is at an acute non-zero
angle from the axis perpendicular to the airflow area and wherein
further the airflow angle is substantially large such that the
airflow angle is non-perpendicular to the airflow area; rotating
one or more damper vanes freely in the blower exhaust during
operation of the blower; and in the event of failure of the blower,
rotating the damper vanes to a closed position via a pressure force
applied to the damper vanes resulting from a lower pressure inside
the blower than ambient pressure outside the blower.
2. The method of claim 1, further comprising blocking rotation of
the one or more damper vanes past a vane centerline perpendicular
to the blower.
3. The method of claim 1, wherein rotating the one or more damper
vanes freely in the blower exhaust airflow comprises rotating the
one or more damper vanes freely about a vertical axis substantially
parallel to the gravitational axis.
4. The method of claim 1, wherein rotating the one or more damper
vanes freely in the blower exhaust comprises allowing the one or
more damper vanes to rotate to an angle parallel with the angled
blower exhaust airflow.
Description
CROSS-REFERENCES TO RELATED APPLICATION(S)
[0001] Pursuant to 35 USC .sctn. 120, this continuation application
claims priority to and benefit of U.S. patent application Ser. No.
11/368,778, entitled "BLOWER EXHAUST BACKFLOW DAMPER", attorney
docket number RPS920060032US1(4174), filed on Mar. 6, 2006, the
disclosure of which is incorporated herein in its entirety for all
purposes.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to the field of
blowers for cooling of computer servers, computer systems, or other
systems. More particularly, the present invention relates to
methods to prevent blower exhaust backflow, particularly for
blowers used for cooling of blade servers.
[0003] In today's environment, a server computer system often
includes several components, such as the server itself, hard
drives, or other peripheral devices. These components are generally
stored in racks. For a large organization, the storage racks can
number in the hundreds and occupy huge amounts of expensive floor
space. Also, because the components are generally free standing
components (i.e., they are not integrated), resources such as disk
drives, keyboards, and monitors cannot easily be shared. Blade
servers have been developed to bundle the server computer system
described above into a compact operating unit. A blade server may
be a high-density, rack-mounted packaging architecture for servers
that provides input/output (I/O), systems management, and power to
individual blades. Blades may include servers, processor nodes,
storage nodes, or other components and may each plug into and
operationally connect to the blade server to share in resources
such as power, cooling, network connectivity, management functions,
and access to other shared resources (such as a front-panel or
CD-ROM drive). One feature of blade servers is that individual
blades may be `hot swapped` without affecting the operation of
other blades in the system. An administrator or other user may
simply remove one blade (such as one that is inoperable or that
will be replaced) and place another in its place. An example blade
server is International Business Machines (IBM.RTM.) Corporation's
IBM eServer.TM. BladeCenter.RTM. system, a high-density,
rack-mounted packaging architecture for servers that provides I/O,
systems management, and power to inserted blades.
[0004] In server design, as in the design of many other types of
computer systems, there is a trend towards higher densities of
components. For example, it is often desirable to put a greater
number of server blades into a package of given size. Additionally,
server designers (similarly to designers of other computer systems)
continue to increase performance of server components in order to
meet customer needs. In combination, the higher component densities
and increased performance of components result in an increased need
for cooling of the servers and their components. Such increased
cooling needs are likely to continue to rise as component densities
and performance both increase. Accordingly, blade servers typically
cool their component blades by drawing air through the chassis of
the blade server and thus through each blade (or fillers) via the
use of blowers in a front-to-back blade cooling pattern. For many
blade server designs, the blowers are required to be invertible so
that the blower functions properly in both the standard and
inverted positions.
[0005] One problem with blowers is that, in the event of failure of
the blower fan, air may recirculate back into a blower through its
exhaust. While this problem can occur with blowers in any system,
this problem is exacerbated for blade server blowers because blower
air inlets typically face each other and hot exhaust air
recirculating through a failed blower will negatively impact the
performance of the other blower. In this situation, the remaining
functional blower draws air from the back of the system through the
failed blower and exhausts it out the back again, severely reducing
the flow of cooling air through the blade system as a whole.
Designers have provided one solution to this problem by providing a
backflow damper with a frame and several pivoting vanes that are
installed horizontally. In the event of blower failure, these
pivoting vanes utilize gravity to close when blower air no longer
keeps them open (i.e., after blower failure) and thus prevent
recirculation of air back into the blower. This solution, however,
greatly increases the impedance of the air exiting the blower as
the air exiting the blower must overcome the gravitational forces
on the vanes. Moreover, an extra vane must be added to the last
position to satisfy the inversion requirement, increasing the
cross-sectional `blockage` of the blower exhaust and thus
increasing the impedance.
[0006] Another solution to the problem of blower exhaust backflow
is to use a single large vane installed vertically on either side
of the frame that is spring-loaded to close when the blower fails.
This solution satisfies the inversion requirement but also greatly
increases the impedance of the backflow damper as the air exiting
the blower must overcome the spring force, which must be relatively
large to close the vane during failure and during shipping. There
is, therefore, a need for an effective and efficient system to
preventing exhaust backflow from a blower.
BRIEF SUMMARY OF THE INVENTION
[0007] The problems identified above are in large part addressed by
a system, method, and apparatus for preventing exhaust backflow
into a blower. Embodiments may include a blower system that
includes an invertible blower chassis having a blower exhaust to
direct an airflow from the blower chassis at an airflow angle from
an axis perpendicular to the chassis, where the blower chassis may
also be used with a first side and a second, opposite side being
substantially perpendicular to a vertical axis aligned with a
gravitational force. The system may also include a backflow damper
frame attached to the blower chassis and positioned to receive
airflow from the blower chassis and one or more vertical damper
vanes rotatably attached to the backflow damper frame. Each damper
vane may have a vane body and the damper vanes may freely rotate
between a first, closed position and a second, open position. The
damper vanes may block airflow into the blower exhaust when the
damper vanes are in the closed position and may freely rotate to a
position where the vane bodies are substantially parallel to the
airflow from the blower exhaust. In a further embodiment, the
damper vanes may each include a vane pin to rotatably attach to
frame holes of the backflow damper frame. In a further embodiment,
the damper vanes may be constrained to rotate within approximately
ninety (90) degrees or less from the closed position.
[0008] Another embodiment provides a backflow damper apparatus for
a blower having a backflow damper frame having a perimeter defining
an airflow area and one or more damper vanes rotatably attached to
the perimeter of the backflow damper frame. The backflow damper
frame may receive and pass airflow from a blower exhaust through
the airflow area where the airflow exhaust flows substantially at
an airflow angle from an axis perpendicular to the airflow area.
The one or more damper vanes may each have a vane body with a long
axis where the long axes of the vane bodies are adapted to be
vertically oriented when the backflow damper is attached to the
blower. The damper vanes may freely rotate between a first, closed
position and a second, open position, where the damper vanes block
airflow into the blower exhaust when the damper vanes are in the
closed position and where the damper vanes rotate to a position
where the vane bodies are substantially parallel to the airflow
from the blower exhaust during blower operation. In a further
embodiment, the damper vanes may be constrained to rotate within
approximately ninety (90) degrees or less from the closed
position.
[0009] Another embodiment provides a method for preventing exhaust
backflow from a blower. Embodiments of the method may include
receiving angled exhaust from a blower exhaust, where the blower
exhaust airflow is angled less than ninety (90) degrees from
perpendicular to the blower. The method may also include rotating
one or more damper vanes freely in the blower exhaust during
operation of the blower and, in the event of failure of the blower,
rotating the damper vanes to a closed position via a pressure force
applied to the damper vanes resulting from a lower pressure inside
the blower than the ambient pressure outside the blower.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0010] FIG. 1 depicts a front, top, and left side perspective view
of an invertible blower with a backflow damper with damper vanes
according to one embodiment;
[0011] FIG. 2 depicts a top cut-away view of the blower of FIG. 1
during normal operation according to one embodiment;
[0012] FIG. 3 depicts a top cut-away view of the blower of FIG. 1
immediately after blower failure according to one embodiment;
[0013] FIG. 4 depicts a top cut-away view of the blower of FIG. 1
after blower failure and closing of the backflow damper according
to one embodiment;
[0014] FIG. 5 depicts a front, top, and right side exploded
perspective view of a blade server with a chassis, blades, and an
enhanced blower module according to one embodiment;
[0015] FIG. 6 depicts a rear view of the blade server of FIG. 5
including two enhanced blower modules according to some
embodiments;
[0016] FIG. 7 depicts a front, top, and right perspective partial
view of a backflow damper with a stop according to some
embodiments;
[0017] FIG. 8 depicts a front, top, and right perspective exploded
view of a backflow damper with a stop according to some
embodiments; and
[0018] FIG. 9 depicts an example of a flow chart depicting closing
a backflow damper upon failure of a blower according to one
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The following is a detailed description of example
embodiments of the invention depicted in the accompanying drawings.
The example embodiments are in such detail as to clearly
communicate the invention. However, the amount of detail offered is
not intended to limit the anticipated variations of embodiments;
but, on the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the present invention as defined by the appended claims. The
detailed descriptions below are designed to make such embodiments
obvious to a person of ordinary skill in the art.
[0020] A system, method, and apparatus for preventing exhaust
backflow from a blower are disclosed. Embodiments may include a
blower system that includes an invertible blower chassis having a
blower exhaust to direct an airflow from the blower chassis at an
airflow angle from an axis perpendicular to the chassis, where the
blower chassis may also be used with a first side and a second,
opposite side being substantially perpendicular to a vertical axis
aligned with a gravitational force. The system may also include a
backflow damper frame attached to the blower chassis and positioned
to receive airflow from the blower chassis and one or more vertical
damper vanes rotatably attached to the backflow damper frame. Each
damper vane may have a vane body and the damper vanes may freely
rotate between a first, closed position and a second, open
position. The damper vanes may block airflow into the blower
exhaust when the damper vanes are in the closed position and may
freely rotate to a position where the vane bodies are substantially
parallel to the airflow from the blower exhaust. In a further
embodiment, the damper vanes may each include a vane pin to
rotatably attach to frame holes of the backflow damper frame.
[0021] As will be discussed in more detail subsequently, the
disclosed apparatus and system may provide for an efficient and
effective mechanism for preventing exhaust backflow upon failure of
a blower. The chassis architecture of the blower may provide an
angled exhaust flow that, when combined with the disclosed vanes,
provides for a lower impedance solution that may be particularly
useful for invertible blowers. When a blower failure occurs, the
configuration of the remaining air devices in the chassis may
create a sufficiently low pressure relative to ambient air to force
the damper vanes closed and prevent substantial exhaust backflow.
The disclosed vertical vanes may provide less impedance than the
previous horizontal vane design as gravitational forces need not be
overcome and cross-sectional impedance is reduced due to not
needing a vane in the last position. The disclosed vertical, freely
rotating vanes may also provide less impedance than previous
spring-loaded designs as the torsion springs need no longer be
overcome.
[0022] Turning now to the drawings, FIG. 1 depicts a front, top,
and left side perspective view of an invertible blower with a
backflow damper with damper vanes according to one embodiment. The
blower 102 may be invertible and able to operate in the depicted
orientation as well as an inverted orientation (flipped over with
respect to the vertical axis). The blower 102 may include a blower
chassis 106 and a blower intake fan 108. The blower intake fan 108
may draw air into the blower 102 and the internal architecture of
the blower 102 may direct air to the blower exhaust 104 for
ejection from the blower 102 into an ambient environment. The
internal chassis 106 design may provide for an angled exhaust
airflow that is at an acute angle from a perpendicular angle from
the front side of the blower 102. In the depicted embodiment of
FIG. 1, the exhaust airflow is directed outward and to the left
towards the side of the chassis 106 without the blower exhaust 104.
The blower exhaust 104 may also have an optional exhaust screen 110
to prevent foreign objects (e.g., debris, fingers) from entering
the blower chassis 106.
[0023] A backflow damper 120 may be installed at the blower exhaust
104 to assist in preventing substantial exhaust backflow in the
event of blower 102 failure. The backflow damper 120 may either be
integrated into the blower chassis 106 or attached to the blower
chassis 106 and may be positioned to receive and pass air from the
blower exhaust 104. The backflow damper 120 may include a backflow
damper frame 122 having a perimeter that substantially surrounds
the blower exhaust 104 exit to form an airflow area. One or more
damper vanes 124 may be installed or positioned within the backflow
damper frame 122 such that they are rotatably attached to the
backflow damper frame 122 and may rotate, or pivot, freely in the
airflow during blower 102 operation (with possible restrictions
described subsequently). The damper vanes 124 may be advantageously
aligned with the vertical axis so that they may rotate independent
of the gravitational force when the blower 102 is in its normal or
inverted positions, reducing the impedance of the backflow damper
120 when compared to horizontal vanes subject to gravitational
losses.
[0024] During normal operation of the blower 102 (and as will be
described in more detail in relation to FIG. 2), the airflow
exiting the blower exhaust 104 is at an angle from the
perpendicular and the damper vanes 124 may rotate so that they
become substantially parallel with the airflow. The damper vanes
124 may naturally rotate within the airflow to their lowest
impedance position by, in some embodiments, presenting their
thinnest edge to the airflow. In some embodiments, the airflow is
always at an acute angle and the damper vanes 124 accordingly
rotate within a ninety (90) degree maximum range. The damper vanes
124 of the disclosed system are not spring-loaded and thus the
spring force need not be overcome, reducing the impedance of the
damper vanes 124 when compared to spring-loaded vanes. While the
damper vanes 124 are described herein as freely rotating, they may
still be subject to nominal forces such as frictional forces from
their attachment to the backflow damper frame 122 and free rotation
shall refer to rotation absent from relatively large forces such as
spring forces or gravitational forces that impact rotation.
[0025] When the blower 102 fails (and as described in more detail
in relation to FIG. 3), the exhaust airflow stops and a lower than
ambient pressure may be created inside the blower chassis 106. The
pressure differential may rotate the damper vanes 124 shut to
prevent any substantial backflow into the blower exhaust 104 (a
nominal amount may enter during the rotation of the damper vanes
124), which may improve performance of other blowers 102 in a
system or prevent reduced cooling or other detrimental effects. As
will be described in more detail subsequently, the disclosed system
may accordingly provide a backflow damper system with reduced
impedance when compared to previous designs while still providing
the ability to be inverted and to substantially prevent exhaust
backflow.
[0026] One or more damper vanes 124 may be utilized in the backflow
damper 120. In one embodiment, a single damper vane 124 mounted at
one side and of sufficient size to cover the airflow area of the
backflow damper frame 122 may be utilized. In other embodiments, a
plurality of damper vanes 124 may be used. The depicted backflow
damper 120 includes four damper vanes 124 of substantially equal
size with the first damper vane 124 being attached at the outermost
edge of the blower 102. Cross-sectional impedance caused by the
damper vanes 124 may be minimized by using as few damper vanes 124
as possible and allowing them to self-orient with the exhaust flow.
Smaller damper vanes 124, however, may be more suitable for
transport. The optimal number of damper vanes 124 and their
relative sizes will depend on the damper vane 124 design, blower
102 design, and operational requirements.
[0027] FIG. 2 depicts a top cut-away view of the blower 102 of FIG.
1 during normal operation according to one embodiment. In FIG. 2,
an example path of airflow 202 during normal operation of blower
102 from the blower exhaust 104 and through the backflow damper 120
is depicted with directional arrows. The airflow 202 flows from
within the chassis 106 through the blower exhaust 104, through
optional exhaust screen 110, and then through the area formed by
the backflow damper frame 122. The damper vanes 124 may rotate to a
position substantially parallel with airflow 202 at an angle `A`
from a vane centerline 204. Vane centerline 204 may be an axis
coincident with an axis perpendicular from the side surface of the
blower chassis 106.
[0028] The precise angle to which a damper vane 124 will rotate in
an airflow with a steady direction will be depend on the design,
including aerodynamic design, of the damper vane 124 but may be
generally such that a low cross-sectional area side of the damper
vane 124 is presented to the airflow with the flow passing over the
surface of both sides of the main vane body. The damper vanes 124
thus follow the trajectory of the exhaust and impede the airflow
202 only by their cross-sectional area. The damper vanes 124 may
advantageously never rotate past the vane centerline 204 during
normal operation assuming airflow 202 remains angled in the same
direction. Since the damper vanes 124 will close in the direction
they are already angled upon blower failure because of the pressure
differential, the direction of the damper vanes 124 impacts the
closing of the backflow damper 120 as a whole. Because the damper
vanes 124 of the disclosed embodiments do not pass the vane
centerline 204, the additional vane (and additional impedance)
required of prior art designs to accommodate inverted blowers 102
is not required. As will be described in more detail in relation to
FIGS. 7 and 8, a stop or other means may optionally be added to the
damper vane 124 and/or backflow damper frame 122 to physically
prevent rotation of the damper vane 124 past the vane centerline
204 to prevent problems due to user error, during shipping,
etc.
[0029] FIG. 3 depicts a top cut-away view of the blower 102 of FIG.
1 immediately after blower 102 failure according to one embodiment.
As can be seen in FIG. 3, a lower pressure region 302 may form
within the blower chassis 106 after failure of the blower 102. The
lower pressure region 302 may be created by, for example, the
continued operation of other blowers 102 in a system such as a
blade server with multiple blowers. As the pressure in the lower
pressure region 302 begins to drop and the airflow stops, the
damper vanes 124 each begin rotation toward a closed position.
Because each damper vane 124 is at an acute angle with respect to
vane centerlines 204, the damper vanes 124 will each rotate closed
in the same direction, allowing for the backflow damper 120 to
close completely (as shown subsequently in FIG. 4).
[0030] FIG. 4 depicts a top cut-away view of the blower 102 of FIG.
1 after blower 102 failure and closing of the backflow damper 120
according to one embodiment. The embodiment of FIG. 4 represents
the closed position for the damper vanes 124 after they have
rotated from their positions shown in FIG. 3 immediately after
failure of the blower 102. As can be seen in FIG. 4, the lower
pressure region 302 within the blower chassis 106 remains as long
as the blower 102 remains inoperable. As a result of the damper
vanes 124 rotating in their designed direction (by starting the
rotation at an acute angle to the perpendicular), the closed damper
vanes 124 effectively close off the airflow area of the backflow
damper frame 122 and prevent additional backflow into the blower
exhaust 104. The damper vanes 124 may stay in a closed position as
long as the lower pressure region 302 has a lower or equal pressure
to the outside ambient pressure.
[0031] FIG. 5 depicts a front, top, and right side exploded
perspective view of a blade server with a chassis, blades, and an
enhanced blower module according to one embodiment. The blade
server 500 of the depicted embodiment may represent one application
of the blowers 102 with backflow dampers 120 as described herein.
In the depicted embodiment, the blade server 500 includes a chassis
504 partially enclosing a cavity 530 with an open front side (air
inlet 532) that may receive one or more blades 502 to form a blade
server 500. The blade server chassis 504 may include a plurality of
blade slots 536 to receive inserted blades 502. The embodiment of
FIG. 5 includes fourteen blades 502 that may be hot-pluggable into
the fourteen blade slots 536 in the front of the blade server
chassis 504. The blades 502 and modules (except the midplane
circuit board) of the blade server 500 may be hot-pluggable so that
if one fails it may be replaced without shutting down system power.
An example blade server 500 may be a modified International
Business Machines (IBM) Corporation's IBM eServer.TM.
BladeCenter.RTM. system, a high-density, rack-mounted packaging
architecture for servers that provides input/output (I/O), systems
management, and power to blades 502. One of ordinary skill in the
art will recognize, however, that other types of blower
applications besides blade servers 500 may be utilized within the
scope of the invention.
[0032] A media tray 508 may also be included within blade server
chassis 504. The media tray 508 may include a floppy disk drive
and/or CD-ROM drive and may couple to any of the attached blades
502. The media tray 508 may also house an interface board on which
is mounted interface light emitting diodes (LEDs), a thermistor for
measuring air inlet temperature, and a USB controller hub. Each
blade 502 may have one or more rear connectors 522 to operably
connect to the chassis 504 by insertion into the midplane circuit
board 506 located at the rear of the chassis 504. Blades 502 may
interface with other components of the blade server 500 via the
midplane circuit board 506 via interfaces such as a power
interface, communications or network interface (e.g., Ethernet,
Fibre Channel), a management module serial link, a VGA analog video
link, a keyboard/mouse USB link, a CD-ROM and floppy disk drive USB
link, control signal link, or other interface. These interfaces may
provide the ability to communicate to other components in the blade
server 500 such as management modules, switch modules, the CD-ROM,
etc. These interfaces may also be duplicated to provide redundancy.
One or more power modules 514 may also be included within blade
server chassis 504 in some embodiments. The power modules 514 may
provide DC operating voltages for the blades 502 and other
components by, for example, converting power from an AC source.
[0033] The blade server 500 may also include a rear blade server
chassis 508 that contains a plurality of hot-swappable modules. The
rear chassis 508 may attach to the rear of the blade server chassis
504 for forming the structure of the blade server 500.
Hot-swappable modules may include one or more enhanced blower
modules 510 as well as other modules such as switch modules and
management modules. Enhanced blower modules 510 may include one or
more variable-speed blowers 102 to draw air from the front of the
blade server 500 and exhaust it to the rear in order to cool its
components.
[0034] Other types of modules may include switch modules and
management modules. Switch modules may provide network and/or
switch functions to the blades 502. An Inter-Integrated Circuit
(I2C) Serial Bus Interface may be used by a management module 516
to configure, monitor and control the switch modules. Switch
modules may provide Ethernet connectivity in some embodiments, but
may also provide Fibre Channel or other connectivity. Management
modules may provide basic management functions such as controlling,
monitoring, alerting, restarting, and diagnostics to the blade
server 500, including the chassis 504, blades 502, modules, and
shared resources. The management module may consist of a processor
and keyboard, video, and mouse (KVM) switch function and may be
operably connected to other modules, the midplane circuit board
506, or other components. Management modules may also work in
conjunction with a baseboard management controller (BMC) of a blade
502 to provide management functions.
[0035] Blades 502 (which may also be known as server blades or
processor blades) may not only perform processor or server
functions but may also perform other functions, such as a storage
blade that includes hard disk drives and whose primary function is
data storage. Blades 502 may provide the processor, memory, hard
disk storage and firmware of an industry standard server. In some
embodiments, blades 502 may be general- or specific-purpose servers
that contain components such as processors, memory, optional local
integrated drive electronics (IDE) or Small Computer System
Interface (SCSI) disk drives, Ethernet or other network
controllers, the BMC, and power conversion circuitry to convert a
12 V DC input to the various voltages required by blade 502
electronics components. In addition, they may include KVM selection
via a control panel, an onboard service processor, and access to
the floppy and CD-ROM drives in the media tray 508. Each blade 502
may have a control panel with light-emitting diodes (LEDs) to
indicate current status plus switches for power on/off, selection
of server blade, reset, nonmaskable interrupt reset (NMI) for core
dumps, or other functions. A daughter card (not shown) may be
connected to a blade 502 via an onboard bus, connector or other
interface to provide additional high-speed links to the switch
modules.
[0036] Blades 502 may be hot-swapped without affecting the
operation of other blades 502 in the blade server 500. A blade 502
may typically be implemented as a single slot card but may, in some
cases, require two or more slots. A blade 502 may use any
microprocessor technology (i.e., be from any microprocessor family)
as long as it is compliant with the mechanical and electrical
interfaces (and is desirably consistent with the power and cooling
requirements of the blade server 500). Blades 502 may also contain
a baseboard management controller (BMC) (not shown) to work in
conjunction with the management module 516 to manage the blade 502.
BMCs (which may also be known as local service processors) may
support blade server 500 functions, such as communication with the
management modules 516, with the control panels and LEDs, with the
control panel buttons for power on/off, etc., and with inventory,
error reporting, and environmental monitoring and reporting. The
BMCs may also support other functions such as serial over LAN (SOL)
and wake on LAN (WOL).
[0037] Blades 502 may include server or processor blades as well as
expansion blades. An expansion blade 502, also known as a
`sidecar`, can be added to a base, or parent, blade 502 to expand
its functionality by connecting the expansion blade 502 to bus,
connector, or other interface bus of the parent. Sidecars may
include blade storage expansion (BSE) units with hard drives, a PCI
I/O expansion unit that can support a variety of PCI adapters,
special function add-ons (e.g., a daughter card or a specialized
processing unit), an expansion unit that may support additional I/O
daughter cards, or any other expansion blade known now or later
developed. Sidecars may also be an actual blade 502 in some
embodiments. Sidecars may be stacked in layers (i.e., sidecar
attached to sidecar attached to parent blade 502) and may be
attached to any external surface of the blade 502 besides the front
or rear. Other types of blades 502 may also be used, whether now in
use or later developed, as one of ordinary skill in the art will
recognize. Blades 502 may be physically connected, or attached,
either when physically external or internal to the chassis 504. For
example, a sidecar may mate with an already installed blade 502 by
being inserted next to blade 502 until clicking into place. The
same sidecar may have a release mechanism that may be depressed so
that an operator may remove the sidecar from the chassis 504
without removing the blade 502 to which it was connected.
[0038] Cooling of blades 502 may be accomplished by the enhanced
blower modules 510 drawing air from the front of the blade server
500 through air inlet 532 and exhausting the air to the rear so
that the air passes through and cools the blades 502. The enhanced
blower modules 510 may each have one or more blowers 102 (not
shown), and each blower 102 may have a backflow damper 120 (not
shown). If a blower 102 of one of the enhanced blower modules 510
fails, the backflow damper 120 may advantageously close in response
to the lower pressures generated by other, still operational
blowers 120 or other sources of low pressure. The enhanced blower
module 510 with the inoperable blower 102 may then be hot-swapped
with a fully-operational enhanced blower module 510.
[0039] FIG. 6 depicts a rear view of the blade server of FIG. 5
including two enhanced blower modules according to some
embodiments. In the depicted embodiment, blade server 500 includes
two enhanced blower modules 510 docked in the rear blade server
chassis 508, each with an integrated blower 102 and blower exhaust
104. In one embodiment, an enhanced blower module 510 includes one
or more blowers 102 within it along with docking and other
functionality, while in other embodiments the enhanced blower
module 510 and blower 102 may be considered interchangeable. The
blade server 500 and rear blade server chassis 508 may also include
switch modules 602 or other interchangeable modules.
[0040] Each blower exhaust 104 may have a backflow damper 120 to
minimize exhaust backflow upon failure of a blower 102. In the
depicted embodiment, the two blower exhausts 104 direct airflow at
an angle towards the center of the blade server 500 and away from
the edges. Accordingly, the damper vanes 124 of the disclosed
enhanced blower modules 510 will also point inward during normal
operation.
[0041] FIG. 7 depicts a front, top, and right perspective partial
view of a backflow damper 120 with a stop according to some
embodiments. The backflow damper frame 122 of FIG. 7 includes a
plurality of frame holes 704 for attaching the damper vanes 124.
The frame holes 704 may be positioned in opposite pairs (only top
pair shown in FIG. 7) to hold each end of the damper vanes 124. The
backflow damper 120 of FIG. 7 includes a stop for each damper vane
124 that physically prevents the damper vanes 124 from rotating
past the vane centerline 204. The keyed pin stops 702 of FIG. 7 are
accomplished by the profile of the frame hole 704 and damper vane
124 ends that permit only ninety (90) degrees of rotation. Each
frame hole 704 includes a notch 706 that interacts with the end of
the damper vane 124 to prevent excessive rotation.
[0042] One of ordinary skill in the art will recognize that many
different types of stops are possible and that the use of stops is
not necessary. The keyed pin stops 702 may be positioned on either
one side of the backflow damper frame 122 or both sides (i.e., on
opposing frame holes 704). The keyed pin stops 702 may also
restrain movement to a total angle of less than ninety (90)
degrees, such as by providing a notch 706/damper vane 124
combination that results in an angle `B` less than ninety (90)
degrees. Alternatively, other types of stops may also be used, such
as a protrusion attached to the backflow damper frame that
similarly restrains movement. Stops such as the keyed pin stops 702
may be particularly advantageous when the blowers 102 are being
transported as they may be handled in many different directions,
requiring a user to manually reconfigure the damper vanes 124
before initial usage unless stops are used.
[0043] FIG. 8 depicts a front, top, and right perspective exploded
view of a backflow damper 120 with a stop according to some
embodiments. The damper vanes 124 may be installed in the backflow
damper frame 122 vertically (parallel with an axis pointing to the
top of a blower 102) via a vane pin 808 that inserts into the frame
holes 704 of the backflow damper frame 122. The damper vanes 124
may be positioned within the airflow area 812 formed by the
backflow damper frame 122. The disclosed damper vanes 124 include
the vane pin having a long axis that will also be aligned
vertically once installed. The vane body 806 is attached or
integrated with the vane pin 808. Forces applied to the vane body
806 (i.e., pressure forces or airflow forces) may be transmitted to
the vane pin 808 and cause rotation about the vane pin 808. In this
fashion, the damper vanes 124 may rotate freely once the vane pin
808 is inserted into the frame holes 704.
[0044] The disclosed backflow damper 120 also has the keyed pin
stop 702 of FIG. 7. Each vane pin 808 has a keyed end 810 (on
either or both of its ends) which interacts with notches 706 of the
frame holes 704 to restrain movement of the damper vanes 124 beyond
a certain point. The damper vanes 124 may either be permanently
attached to the backflow damper frame 122 or replaceably attached
to the backflow damper frame 122. In an alternative embodiment,
other attachment means may be used to rotatably attach the damper
vanes 124 to the backflow damper frame 122, such as a pin and
receiver, an axle, or any other design.
[0045] FIG. 9 depicts an example of a flow chart depicting closing
a backflow damper 120 upon failure of a blower 102 according to one
embodiment. Components or combinations of components of the
backflow damper 120 may perform the elements of flow chart 900
while on a blower 102 in one embodiment. Flow chart 900 begins with
element 902, where the backflow damper 120 receives an angled
exhaust airflow from a blower exhaust 104. The backflow damper 120
may receive the airflow through an airflow area 812 formed by the
backflow damper frame 122. As described previously, the exhaust
airflow may advantageously be angled and not directly perpendicular
from the side of the blower 102. While the blower 102 is
operational and exhaust airflow is being received, the damper vanes
124 may freely rotate in the exhaust airflow at element 904. The
damper vanes 124 may automatically rotate to a position based on
their aerodynamic design with, generally speaking, a lower
cross-sectional area facing the airflow and with the airflow
passing over both sides of the damper vane 124.
[0046] The backflow damper 120 may have optional stops to prevent
the damper vanes 124 from passing a vane centerline 204. If stops
are included, the method of flow chart 900 performs decision block
906, where it is determined if the damper vane 124 has rotated such
that it is reaching the vane centerline 204 (or other specified
angle). If the damper vane 124 does reach the vane centerline 204,
the stop may at element 908 block the rotation of the damper vanes
124 past the vane centerline 204 via keyed pin stop 702 or other
means.
[0047] Until the blower fails and during normal operation, elements
904 through 908 may be repeated. Upon blower failure at decision
block 910, the method of flow chart 900 may continue to element
912, rotating the damper vanes 124 to a closed position, after
which the method terminates. The damper vanes 124 may rotate
because of the pressure differential caused by the failure of the
blower 102 as the pressure inside the blower 102 drops relative to
ambient pressure and causes a pressure force to rotate the damper
doors 124 closed.
[0048] It will be apparent to those skilled in the art having the
benefit of this disclosure that the present invention contemplates
a system, method, and apparatus for preventing exhaust backflow for
a blower. It is understood that the form of the invention shown and
described in the detailed description and the drawings are to be
taken merely as examples. It is intended that the following claims
be interpreted broadly to embrace all the variations of the example
embodiments disclosed.
[0049] While certain operations have been described herein relative
to a direction such as "above" or "below" it will be understood
that the descriptors are relative and that they may be reversed or
otherwise changed if the relevant structure(s) were inverted or
moved. Therefore, these terms are not intended to be limiting.
[0050] Although the present invention and some of its advantages
have been described in detail for some embodiments, it should be
understood that various changes, substitutions and alterations can
be made herein without departing from the spirit and scope of the
invention as defined by the appended claims. Although an embodiment
of the invention may achieve multiple objectives, not every
embodiment falling within the scope of the attached claims will
achieve every objective. Moreover, the scope of the present
application is not intended to be limited to the particular
embodiments of the process, machine, manufacture, composition of
matter, means, methods and steps described in the specification. As
one of ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes, machines,
manufacture, compositions of matter, means, methods, or steps,
presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes, machines, manufacture, compositions of matter, means,
methods, or steps.
* * * * *