Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-06-26
2003-09-23
Chervinsky, Boris (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S692000, C361S719000, C165S080300, C312S223200
Reexamination Certificate
active
06625018
ABSTRACT:
BACKGROUND OF THE INVENTION
Electronic systems, such as computers typically include a protective case, one or more circuit boards mounted inside the case, and one or more components such as a processor or a power supply mounted to each of the boards. In operation, the components generate heat that the system must remove from the case to prevent overheating and the damage it may cause.
To remove the heat, the system typically includes one or more fans that draw cool air into the case, circulate the drawn air within the case such that it absorbs the heat generated by the components, and expel the heated air from the case. The rate at which the heat is removed is typically proportional to the rate at which the air flows into and out of the case. The greater the flow rate, the greater the heat-removal rate and vice versa.
To prevent hot spots within the case, however, the system designer typically must consider the size, location, and orientation of the boards and components when designing the cooling system. The boards and components add resistance to the airflow paths within the case. Because the air will follow the paths of least resistance, components that lie along high-resistance paths may overheat if the cooling system is not designed to provide adequate flow rates along these high-resistance paths. Therefore, the designer analyzes the layout of the boards and components and determines the size, speed, and placement of the cooling fans that will provide adequate flow rates along all of the airflow paths for the lowest cost. Factors that affect the cost of the cooling system include the number of fans, the amount of power they consume, and how difficult it is to manufacture/install the cooling system.
Furthermore, to keep electromagnetic interference (EMI) to an acceptable level, the designer typically must consider the layout of the boards and components within the case when designating an EMI shielding system.
To take advantage of the economies of scale in mass production, most models of a system include the same cooling and shielding systems, but may include different circuit boards or components. For example, a high-end model of a data server may include a mother board with four processors mounted thereto, while a low-end model of the same server might include the same board with only one processor mounted thereto. To ensure that a system that includes all of the possible boards and components is properly cooled and shielded the cooling and shielding systems are typically designed for such a fully populated system. Consequently, when one or more of the components or boards are omitted from the system, the airflow and EMI footprint of the system may change such that the cooling system, shielding system, or both are no longer adequate.
FIGS. 1 and 2
illustrate the effect that an omitted component can have on the air flow within an electronic system.
FIG. 1
illustrates an electronic system
20
that includes components
22
and
24
attached to the circuit boards
26
,
28
and
30
. Air flows along paths
32
,
34
and
36
between the circuit boards
26
,
28
and
30
to remove heat from the components
22
and
24
. Because the cooling system (not shown in
FIGS. 1 and 2
) is designed for the fully populated system
20
, the air flow adequately cools the components
22
and
24
.
But, as
FIG. 2
illustrates, when the component
24
is removed from the circuit board
28
, the air flowing along the path
34
does not encounter the resistance of the omitted component
24
. Consequently, assuming the same overall air flow into the case as in
FIG. 1
, air flow along the path
34
increases and the air flow along the paths
32
and
36
decreases. Consequently, the components
22
on the boards
26
and
30
may overheat. One solution is to increase the overall air flow (e.g. by increasing the fan speed) to a level where the flow along the paths
32
and
34
is sufficient to cool the components
22
on the boards
26
and
30
. However, this often increases the amount of power consumed by the cooling system and may reduce the life of the cooling fans. It also may increase costs if a technician has to manually adjust the fan speed of each partially populated system.
Still referring to
FIGS. 1 and 2
, the omission of the component
24
from a circuit board of an electronics system can change the EMI footprint in a similar manner, and tailoring the EMI shielding for each different system can be prohibitively expensive.
SUMMARY OF THE INVENTION
In one aspect of the invention, a fluid-flow balancer for taking the place of a system component having an air-flow resistance includes a flow-resistance element and a mount. The flow-resistance element is operable to mimic the air-flow resistance of the component, and the mount is operable to mount the flow-resistance member within the system.
By mimicking the air-flow resistance of an omitted component, such a balancer can maintain the flow along the air paths within a system at proper levels without tweaking or redesigning the cooling system. In a related aspect of the invention, the balancer also mimics the EMI suppression provided by the omitted component.
REFERENCES:
patent: 4399485 (1983-08-01), Wright et al.
patent: 5684674 (1997-11-01), Yin
patent: 5690306 (1997-11-01), Roesner
patent: 5914858 (1999-06-01), McKeen et al.
patent: 5940266 (1999-08-01), Hamilton et al.
patent: 6018458 (2000-01-01), Delia et al.
patent: 6252161 (2001-06-01), Hailey et al.
patent: 6449150 (2002-09-01), Boone
patent: 6483700 (2002-11-01), Malone et al.
Augustin Thomas J.
Barsun Stephan Karl
Malone Christopher Gregory
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