ANTI-REVERSE FLOW COOLING FAN ASSEMBLY

A cooling fan assembly is provided which includes a fan housing and an axial fan. The fan housing has a shroud panel with cutout portions along the airflow path of the axial fan. Fixed members separate the cutout portions. Flap members are attached to the fixed members so that the flap members can pivot between an open position and a closed position. The flap members are pushed by airflow from the axial fan into an open position when the fan is operational. When the fan is non-operational or when air begins to enter the fan in the reverse direction of the axial fan's airflow path, the flap members are configured to move to a closed position. In the closed position, air cannot flow through the reverse direction of the axial fan's airflow path.

FIELD OF THE INVENTION

The present invention relates to cooling fan assemblies, and more specifically to cooling fan assemblies with anti-reverse flow features.

BACKGROUND

Computer systems typically include a large number of computer components, such as processors, graphic cards, power supplies, and memory modules. Typically, most of these components produce heat while being operated, and need to be kept within a certain temperature range in order to prevent over-heating. Consequently, computer systems typically incorporate cooling fans that circulate air over the components. In most computer systems, the cooling fans and the components are arranged so that the air circulating in the computer system carries heat away from the components and out of the computer system.

In some computer system designs, multiple fans can be provided to cool the computer system. For example, the multiple fans can be placed side-by-side across the width of the computer system to provide a uniform airflow through the computer system. However, if one of the fans fails or stops rotating for any reason, then the airflow through the computer system will no longer be uniform. This can lead to overheating of one or more components.

Some computer systems rely on the placement of louvers or shutters next to each fan in order to maintain a uniform airflow even when one or more fans are non-operational. The shutters can also be closed when the fan is non-operational. However, such louvers or shutters typically require additional space next to the fan. This additional space for the louvers or shutters takes up valuable physical storage space and adds unfavorable bulk to computer systems. Moreover, such shutters or louvers can also obstruct the flow of cooling air from the fan to the hardware components. Even worse, reverse airflow through the non-operational fan can occur, further reducing the amount of airflow being provided to downstream components.

What is needed is a cooling fan that minimally obstructs the air current over hardware components and that can quickly and easily be covered when the fan is non-operational, thereby preventing the flow of air through the fan in the reverse direction.

SUMMARY

The various examples of the present disclosure are directed towards a cooling fan assembly which prevents the reverse flow of air through the fan. In a first embodiment, the assembly includes a housing for the cooling fan that contains an inlet and an outlet. The housing is comprised of a shroud panel disposed at the outlet. An axial fan is disposed in the housing and configured to draw air from the inlet to the outlet. The shroud panel comprises a plurality of cutout portions disposed along an airflow of the axial fan. A plurality of fixed members separates the cutout portions. Flap members are pivotably attached to each of the fixed members. Each flap member is configured to alternate between at least two possible positions. In the first position, a flap member extends away from the shroud panel. In the second position, a flap member lies within one of the plurality of cutout portions. When in the second position, the flap members are configured to extend substantially across an associated cutout portion.

In a second embodiment, each of the plurality of flap members are pivotably attached to an associated fixed member using at least one biasing element. This biasing element can be configured to maintain an associated flap member in the second position when the axial fan fails to supply a threshold amount of airflow.

In another embodiment, each of the plurality of flap members and associated fixed members can be configured to define a static blade in the shroud panel. In this embodiment, the axial fan can further comprise a plurality of fan blades with a fan blade angle. Each of the static blades has a static blade angle. The fan blade angle and the static blade angle are offset by at least 90 degrees.

In another embodiment, the plurality of cutout portions extends along the shroud panel in an annular path.

In another embodiment, at least one of the plurality of flap members or an associated one of the plurality cutout portions includes one or more sealing elements.

In another embodiment, each of the plurality of flap members can be configured to alternate from the first position to the second position, in response to airflow from the inlet to the outlet. The flap members can alternate from the second position to the first position in response to airflow from the outlet to the inlet.

Throughout the present disclosure, the terms “personal computer”, “server system”, “laptop computer”, “computer system”, and “tablet” can be used interchangeably to identify any electronic computing system which can use a fan to cool overheating electronic components.

DETAILED DESCRIPTION

The present disclosure is directed to an assembly for a cooling fan that allows air to flow through the cooling fan in substantially only the intended direction. The cooling fan can be placed in a personal computer, a server system, a laptop computer, a tablet, or any other electronic computing system. As discussed above, current cooling fans do not provide an assembly sufficient to maintain uniform airflow without additional parts, a bulky design, or allowing air to flow through the reverse direction of the cooling fan.

In view of limitations of present cooling fans, the present disclosure provides a cooling fan designed with anti-reverse flow features. In particular, the cooling fan can include anti-reverse flow members. These anti-reverse flow members can be lifted into a first position by the positive pressure of the fan when the fan is in operation, thereby allowing airflow through the fan. If the fan is not operational, the anti-reverse flow members are configured to move into a second position and block a reverse airflow through the non-operational fan.

FIG. 1A-1Cshow a cooling fan assembly100according to a conventional design which includes a fan housing102with an inlet102aand an outlet102b; a shroud panel104; an axial fan106; fan blades108; cutout portions110; and static blades112. In particular,FIG. 1Ashows a schematic side view of fan assembly100.FIG. 1Bshows a schematic view of the inlet side of fan assembly100.FIG. 1Cshows a schematic view of the outlet side of fan assembly100.

The shroud panel104contains the outlet102bthrough which air passes on its way out of the fan assembly100. As shown inFIGS. 1A and 1C, the shroud panel104is comprised of static blades112and cutout portions110; and is located on the exterior of the cooling fan assembly100. An axial fan106directs air through the fan assembly100from the inlet102ato the outlet102b. The axial fan106includes a number of fan blades108. In operation, the axial fan106rotates the fan blades, which in turn pulls air through the inlet102aand pushes air through the outlet102b. At the outlet102b, the air flowing through the fan assembly100goes through the cutout portions110of the shroud panel104, and is further directed by the static blades112. The static blades112can be angled, relative to the fan blades108. For example, as shown by the dotted lines inFIG. 1A, the static blades112can be angled at 90 degrees with respect to the fan blades108.

One of the issues with the fan assembly100is that in the event that axial fan106stops rotating, there is no mechanism in the fan assembly100to prevent reverse airflow, i.e., airflow from the outlet102bback into the inlet102a. This issue is resolved with the new fan assembly design discussed below.

FIG. 2AandFIG. 2Bshows a fan assembly200according to an exemplary embodiment of the present disclosure. The fan assembly200includes a fan housing202with an inlet202aand an outlet202b, a shroud panel204, an axial fan206, fan blades208, cutout portions210, fixed members214, flap members216, and biasing elements218. In operation, the flap members216are configured to alternate between an extended or open position (as shown inFIG. 2A), and a retracted or closed position (as shown inFIG. 2B). In the extended or open position ofFIG. 2A, air is able to flow through the fan assembly200. In the retracted or closed position ofFIG. 2B, the flap members216are configured to block airflow through the fan assembly200, including any reverse airflow from the outlet202bto the inlet202a. This is discussed in greater detail below.

Like fan assembly100inFIGS. 1A-1C, the fan housing202inFIGS. 2A-2Bhas an inlet202awhere air passes into the fan assembly200, and an outlet202bwhere air passes out of the fan assembly200. In particular, the rotation of the fan blades208pulls air through the inlet202a; and pushes air through the shroud panel204and out of the fan assembly200through the outlet202b. As shown inFIGS. 2A and 2B, the shroud panel204contains a structure including cutout portions210, fixed members214, and flap members216.

Like the shroud panel104ofFIGS. 1A-1C, the shroud panel204ofFIGS. 2A and 2Bincludes fixed members214that are stationary and separated by a series of cutout portions210. Thus, the position of the fixed members214remains unchanged regardless of the direction of airflow through the fan assembly200. However, as shown inFIGS. 2A and 2B, fixed members214can have attached thereto flap members216. However, in some implementations, some flap members216may not have corresponding fixed members214. For example, a flap member216without a corresponding fixed member214is shown by the flap member216at the top of FIG.2A and the top ofFIG. 2B. In operation, the flap members216can alternate between the extended or open position (as shown inFIG. 2A), and a retracted or closed position (as shown inFIG. 2B). In the configuration ofFIGS. 2A and 2B, each of the flap members216is associated with at least one of the cutout portions210. In particular, each of the flap members216can be configured to block one of the cutout portions210in the retracted or closed position. In this manner, airflow, including reverse airflow, through the fan assembly200is blocked in the retracted or closed position.

As shown inFIGS. 2A and 2B, biasing elements218can be provided on the flap members216, and can be used to attach the flap member216to the fixed member214. Biasing elements218can be configured to serve as a pivot so that flap members216can rotate between the open position shown inFIG. 2Aand the closed position shown inFIG. 2B. In the various embodiments, biasing elements218can be configured in a variety of ways. For example, in some implementations, the biasing elements218can be spring-type or spring-loaded structure, and configured to respond to positive airflow (from the inlet202ato the outlet202b) through the fan assembly200. In such configurations, the spring-type or spring-loaded structure of the biasing elements218can be configured to bias the flap members216towards their respective cutout portions. In other implementations, the biasing elements218can be a gravity or weight driven structure configured to respond to positive airflow through the fan assembly200. In such configurations, select portions of the flap members216can be configured to have weighted portions so that in the absence of positive airflow, the weighted portions cause the flap members216to be biased towards their respective cutout portions. Any other types of biasing elements218can also be used without limitation.

In some implementations, the shape of the fixed members214and the flap members216can be selected so that in the open position, a fixed member214and an associated flap member216define a static blade portion, similar to the static blade112in fan assembly100.

In some implementations, sealing elements can also be provided. That is, the flap members216, the cutout portions210, or both, can include sealing elements to further reduce airflow in the closed position. For example, a flap member216can include a flexible edge around its perimeter so that when the flap member216is in the closed position, the airflow is more effectively blocked. Similarly, the cutout portions210can include similar features.

Although the implementations herein show one flap member216associated with one cutout portion210, the various embodiments are not limited in this regard. In some implementations, the multiple flap members216can be associated with the same cutout portion210. Thus, blocking of airflow through the one cutout portion210is provided when the associated flap members216are all in the closed position.

InFIG. 2A, the flap members216and their corresponding fixed members214are separated at regular intervals by cutout portions210. However, the various embodiments are not limited in this regard, and the fixed members214can separate the cutout portions210at irregular intervals.

FIGS. 3A-3Dshow a fan assembly300according to an exemplary embodiment of the present disclosure where the fan is configured to allow airflow across electronic components. The fan assembly300is shown only for illustrative purposes and not by way of limitation.

The fan assembly300includes a fan housing302with an inlet302aand an outlet302b; a shroud panel304; an axial fan306; fan blades308; cutout portions310; fixed members314; flap members316; and biasing elements318. The fan housing302holds the components for the fan assembly300. The axial fan306includes fan blades308that rotate and pull air in through the inlet302a, and push air through the outlet302b. The shroud panel304provides a window for air to be pushed through the outlet302b, and provides the attachment between the axial fan306and the flap members316, fixed members, and biasing elements318. Flap members316are attached to fixed members314via a biasing element318. The biasing element318is configured to allow the flap members316to pivot between an open position (shown inFIG. 3AandFIG. 3C) and a closed position (shown inFIG. 3BandFIG. 3D). When the axial fan306powers the rotation of the fan blades308, the air pressure flowing through the fan assembly300causes the flap members316to open outwards (as shown inFIG. 3AandFIG. 3C). If the axial fan306is not powered for some reason, the biasing element318can cause the flap members316to rotate into a closed position preventing the flow of air into or out of the fan assembly300(as shown inFIG. 3BandFIG. 3D).

In greater detail,FIG. 3Ashows the flap members316extending outwards from the pressure of air flowing through the fan assembly300. In this embodiment, there are nine flap members316, but there can be more or fewer flap members316so long as there is at least one. In this embodiment, the flap members316are arranged in a circular or annular pattern around the axial fan306in the same pattern as the fan blades308(shown in greater detail inFIG. 3C).

Referring toFIG. 3B, the fan assembly300is shown at the same angle as the fan assembly300inFIG. 3A, butFIG. 3Bshows the flap members316in the closed position. When there is no airflow out of the fan assembly300, the flap members316can pivot to a closed position via the biasing elements318. Alternatively, or in addition, the biasing elements318can contain a spring component, which causes the flap members316to snap shut when the axial fan306is not operational, or when the axial fan fails to provide a threshold amount of airflow. The flap members316can also fall shut in response to airflow from the outlet302bto the inlet302a. The biasing elements318can be configured to maintain the flap members316in the closed position until the axial fan306provides a threshold amount of airflow.

In this closed position, the flap members316can be configured to cover cutout portions310on the shroud panel304. This blocks air from passing through the fan assembly300. Additionally, as discussed above, either the flap members316or the fan housing302can contain sealing elements which provide an airtight cover for the fan assembly300. For example, a sealing element could be placed on the outside of each flap member316; on the interior perimeter of the shroud panel304; on the exterior perimeter of the axial fan306; or on some combination of the preceding locations. The sealing element can provide additional protection from air flowing in the reverse direction through the fan assembly300. The sealing element does not need to be completely airtight, and can still allow some air to flow through the reverse direction. However, the sealing element will not allow enough air to flow through so that the axial fan306begins to turn in the reverse direction.

Referring now toFIG. 3C, a side perspective view of the fan assembly300in the extended or open position is shown. From this angle, it is clear that the fan blades308and the flap members316can be offset by at least 90 degrees in the open position. This allows the direction of airflow to pass directly through the cutout portions310with minimum obstruction from the flap members316. Therefore, airflow occurs with great efficiency when the flap members316are in the open position.

FIG. 3Dshows a side perspective of the fan assembly300when the flap members316are in the closed position. When the flap members316are in the closed position, the flap members316lie flush with the fan housing302to block cutout portions310.

Fan System in Servers

In server systems or other electronic computing systems, more than one cooling fan may be needed to cool all the system's components. Cooling fans can be placed in parallel structures in a computing system to blow across different components. This allows more system cooling to occur than with individual fans. However, one of the cooling fans in a row of fans can become non-operational. The air current and airflow coming from the other fans can cause a reverse air current through the non-operational fan. This decreases the cooling ability of the fan system and can lead to overheating of electronic components, since the hot air from the overheating components is sucked back into the computing system.

A cooling fan according to an embodiment of the present disclosure does not allow reverse air current through a non-operational fan. As soon as a cooling fan becomes non-operational, the flap members316close, forming a static blade and a seal so that air cannot flow in the reverse direction. Cooling fans according to an embodiment of the present disclosure can therefore be used in a server system where more than one cooling fan is needed to cool the electronic components. Whenever a cooling fan becomes non-operational, the closed flap members will prevent the creation of a reverse air current and continue to allow maximum cooling of components. Even with one or more cooling fans non-operational, all air will continue to flow in the proper direction and continue to cool off over-heating components.

FIG. 4shows an exemplary configuration of cooling fans in a computer system400. The computer system400includes disk storage units402; cooling fan assemblies404; memory modules406; processing units408; power supplies410; and internet connections412. The processing units408and memory modules406can have a greater need for cooling than other computer components because these components generate high amounts of heat due to the high volumes of electric signals passing through them. Therefore, the cooling fan assemblies404can be placed in a row spanning the width of the computer system400, and move air in the direction of the memory modules406and processing units408. The airflow can exit the computer system400by flowing over any remaining computer components such as power supplies410and internet connections412. The closing of flap members when any of the cooling fan assemblies404become non-operational can prevent the flow of hot air in the reverse direction back towards the disk storage units402.

While various examples of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the disclosed examples can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described examples. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.