Cooling systems and heat exchangers for cooling computer components

Information

  • Patent Grant
  • 9596789
  • Patent Number
    9,596,789
  • Date Filed
    Monday, July 28, 2014
    10 years ago
  • Date Issued
    Tuesday, March 14, 2017
    7 years ago
Abstract
Computer systems having heat exchangers for cooling computer components are disclosed herein. The computer systems include a computer cabinet having an air inlet, an air outlet spaced apart from the air inlet, and a plurality of computer module compartments positioned between the air inlet and the air outlet. The air inlet, the air outlet, and the computer module compartments define an air flow path through the computer cabinet. The computer systems also include a heat exchanger positioned between two adjacent computer module compartments. The heat exchanger includes a plurality of heat exchange elements canted relative to the air flow path.
Description
TECHNICAL FIELD

The present disclosure relates generally to cooling systems and heat exchangers for cooling electronic components in computer systems.


BACKGROUND

Supercomputers and other large computer systems typically include a large number of computer modules housed in cabinets arranged in banks. The computer modules are typically positioned in close proximity to each other. During operation, the close proximity can make dissipating heat generated by the modules difficult. If not dissipated, the heat can damage the modules or significantly reduce system performance.


One conventional technique for computer module cooling includes drawing air into the cabinet to cool the computer modules and discharging the heated air to the room. One shortcoming of this technique, however, is that the heat capacity of the cooling air can quickly become saturated. As a result, some of the computer modules may not be adequately cooled. Accordingly, there is a need to effectively dissipate heat generated by computer modules during operation.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1A is a partially schematic elevation view of a computer system having internal heat exchangers configured in accordance with an embodiment of the invention.



FIG. 1B is an enlarged perspective view of a heat exchanger having canted heat exchange elements configured in accordance with an embodiment of the invention.



FIG. 1C is an enlarged, cross-sectional side view of two heat exchange elements from the heat exchanger of FIG. 1B, configured in accordance with an embodiment of the invention.



FIG. 2 is a cross-sectional side view of a heat exchange element having non-identical internal channels configured in accordance with another embodiment of the invention.



FIG. 3 is a front view of a heat exchange element having a plurality of fin configurations positioned along an air flow path in accordance with another embodiment of the invention.



FIG. 4 is a perspective view of a heat exchanger having partitioned inlet and/or outlet manifolds configured in accordance with another embodiment of the invention and suitable for use in the computer system of FIG. 1A.



FIG. 5 is a top view of a heat exchanger having counter-flowing working fluids configured in accordance with a further embodiment of the invention and suitable for use in the computer system of FIG. 1A.





DETAILED DESCRIPTION

The following disclosure describes several embodiments of cooling systems for use with supercomputers and/or other computer systems. Persons of ordinary skill in the art will understand, however, that the invention can have other embodiments with additional features, or without several of the features shown and described below with reference to FIGS. 1-5. In the Figures, identical reference numbers identify structurally and/or functionally identical, or at least generally similar, elements.



FIG. 1A is a partially schematic elevation view of a computer system 100 having a plurality of internal heat exchangers 118 (identified individually as heat exchangers 118a-d) configured in accordance with an embodiment of the invention. The computer system 100 can include a computer cabinet 102 in a room 101. Working fluid lines 106 (identified individually as a supply line 106a and a return line 106b) connect the computer cabinet 102 to a heat removal system 104. In the illustrated embodiment, the heat removal system 104 is situated in the room 101 and spaced apart from the computer cabinet 102. In other embodiments, however, the heat removal system 104 can be integrated into the computer cabinet 102, positioned outside the room 101, or situated in other suitable places.


The computer cabinet 102 can include an air inlet 114 for receiving cooling air from the room 101 or a floor plenum (not shown), an air outlet 116 for discharging air to the room 101, and a plurality of computer module compartments 120 (identified individually as first, second, and third computer module compartments 120a-c, respectively) arranged vertically between the air inlet 114 and the air outlet 116 in a chassis 110. Individual computer module compartments 120 hold a plurality of computer modules 112 oriented edgewise with respect to the flow of cooling air through the chassis 110.


The computer cabinet 102 can also hold a plurality of heat exchangers 118 in the chassis 110. As described in greater detail below with reference to FIGS. 1B-4, the individual heat exchangers 118 can be configured to receive a working fluid (not shown) from the heat removal system 104 via the supply line 106a. After flowing through the heat exchangers 118, the working fluid returns to the heat removal system 104 via the return line 106b. The working fluid can include hydrofluorocarbons, hydrochlorofluorocarbons, chlorofluorocarbons, ammonia, and/or other suitable refrigerants known in the art. The working fluid can include a vapor phase fluid, a liquid phase fluid, or a two-phase fluid when flowing through the heat exchangers 118.


The computer cabinet 102 can additionally include an air mover 130 (e.g., a fan) positioned proximate to the air inlet 114 to facilitate movement of the cooling air through the chassis 110 along a flow path 117. The air mover 130 can draw air from the room 101 or a floor plenum into the chassis 110 through the air inlet 114. The air then flows through the chassis 110 past the computer modules 112, and exits the chassis 110 via the air outlet 116.


The heat removal system 104 can include a pump 124 in fluid communication with a condenser 122. The condenser 122 can be a shell-and-tube type heat exchanger, a plate-and-frame type heat exchanger, or other suitable type of heat exchanger known in the art. The condenser 122 can include a working fluid inlet 126a for receiving heated working fluid returning from the computer cabinet 102, and a working fluid outlet 126b for supplying cooled working fluid to the pump 124. The condenser 122 can also include a coolant inlet 128a and a coolant outlet 128b for circulating chilled water, cooling water, or other suitable coolant (not shown) to cool the working fluid. The pump 124 can include a positive displacement pump, a centrifugal pump, or other suitable type of pump for circulating the working fluid back to the heat exchangers 118 via the supply line 106a.


During operation of the computer system 100, the air mover 130 draws air into the chassis 110 through the air inlet 114. The first heat exchanger 118a cools the air before it flows into the first compartment 120a. As the air flows through the first compartment 120a, the computer modules 112 in the first compartment 120a transfer heat to the air. The second heat exchanger 118b then cools the air before the air passes into the second compartment 120b by absorbing heat from the air into the working fluid. The air is similarly cooled by the third heat exchanger 118c before flowing into the third compartment 120c. The fourth heat exchanger 118d then cools the heated air leaving the third compartment 120c before the air is discharged to the room 101 via the air outlet 116.


In one embodiment, the working fluid is in phase transition between liquid and vapor as the working fluid leaves the heat exchangers 118. In other embodiments, the working fluid can have other phase conditions at this time. The heated working fluid from the heat exchangers 118 returns to the condenser 122 via the return line 106b. The coolant in the condenser 122 cools the working fluid before the pump 124 circulates the working fluid back to the heat exchangers 118.


Only a single computer cabinet 102 is shown in FIG. 1A for purposes of illustration and ease of reference. In other embodiments, however, supercomputers and other large computer systems can include a plurality of computer cabinets arranged in banks or other configurations. In such embodiments, the heat removal system 104 can provide working fluid to one or more of the computer cabinets 102 via an appropriately configured piping circuit. Further, although the heat exchangers 118 have been described above in the context of working fluid-type heat exchangers, in other embodiments, other types of heat exchangers can be used to inter-cool the air moving through the compartments 120 without departing from the spirit or scope of the present invention.



FIG. 1B is an enlarged perspective view of one of the heat exchangers 118 configured in accordance with an embodiment of the invention. The heat exchanger 118 can include a plurality of heat exchange elements 132 extending between and in fluid communication with an inlet manifold 134 and an outlet manifold 135. Although four heat exchange elements 132 are shown in FIG. 1B, in other embodiments, the heat exchanger 118 can include more or fewer heat exchange elements 132 depending on a number of factors including heat load, cost, manufacturability, etc.


The inlet manifold 134 can include a distribution section 137c extending between an inlet port 137a and a capped inlet end 137b. In the illustrated embodiment, the distribution section 137c includes a generally tubular structure (e.g., a section of a pipe or a tube) with a plurality of first slots 137d arranged along a length of the distribution section 137c. The first slots 137d are configured to receive first end portions of the heat exchange elements 132. In other embodiments, the distribution section 137c can have other configurations to accommodate other factors.


In the illustrated embodiment, the outlet manifold 135 is generally similar to the inlet manifold 134. For example, the outlet manifold 135 includes a collection section 139c extending between an outlet port 139a and a capped outlet end 139b. The collection section 139c includes a generally tubular structure with a plurality of second slots 139d arranged along a length of the collection section 139c in one-to-one correspondence with the first slots 137d. In other embodiments, the outlet manifold 135 can have other configurations, including others that differ from the inlet manifold 134. For example, the collection section 139c can have a different cross-sectional shape and/or a different size than the distribution section 137c.


The individual heat exchange elements 132 can include a plurality of fins 142 extending from a passage portion 140. A first end portion 132a of the passage portion 140 is coupled to the inlet manifold 134 via the first slots 137d, and a second end portion 132b of the passage portion 140 is coupled to the outlet manifold 135 via the second slots 139d. In the illustrated embodiment, the passage portion 140 extends into both the inlet manifold 134 and the outlet manifold 135. In other embodiments, however, the ends of the passage portion 140 can be generally flush with the first and/or second slots 137d, 139d. Further details of several embodiments of the passage portion 140 are described below with reference to FIG. 1C.



FIG. 1C is an enlarged side view of two of the heat exchange elements 132 of FIG. 1B, configured in accordance with one embodiment of the invention. As illustrated in FIG. 1C, the heat exchange elements 132 can be at least generally parallel to each other with a gap D (e.g., from about 1 cm to about 2 cm, or any other desired spacing) therebetween. In other embodiments, however, at least some of the heat exchange elements 132 can be nonparallel to the other heat exchange elements 132. The gap D can form an air passage 136 in fluid communication with the air flow path 117. The air passage 136 allows cooling air to flow past the heat exchange elements 132 during operation of the computer system 100.


In certain embodiments, individual heat exchange elements 132 can be canted relative to the incoming air flow path 117a. For example, as illustrated in FIG. 1C, the heat exchange elements 132 can form an angle A of from about 10° to about 45°, preferably from about 15° to about 40°, and more preferably about 20° to about 30° relative to the air flow path 117a. In other embodiments, the heat exchange elements 132 and the air flow path 117a can form other suitable angles. Each of the heat exchange elements 132 can form the same angle or different angles relative to the air flow path 117. For example, the angles can increase or decrease (e.g., linearly, exponentially, etc.) from one heat exchange element 132 to another.


The individual heat exchange elements 132 can include a plurality of internal fluid channels 144 (identified individually as first, second, third, and fourth internal channels 144a-d, respectively). In the illustrated embodiment, the internal channels 144 have generally the same cross-sectional shape, e.g., a generally rectangular shape, and generally the same cross-sectional area. In other embodiments, however, the internal channels 144 can have other cross-sectional shapes, such as triangular shapes, circular shapes, oval shapes, and/or other suitable shapes and/or cross-sectional areas. In further embodiments, the internal channels 144 can have non-identical configurations, as described in more detail below with reference to FIG. 2.


Referring to FIG. 1B and FIG. 1C together, in operation, a working fluid (not shown) flows into the inlet manifold 134 via the inlet port 137a, as indicated by the arrow 131a. The inlet manifold 134 distributes the working fluid to the internal channels 144 at the first end 132a of each of the heat exchange elements 132. The working fluid flows across the heat exchange elements 132 from the first end 132a toward the second end 132b. As the working fluid flows across the heat exchange elements 132, the working fluid absorbs heat from cooling air flowing through the air passage 136 and/or past the fins 142. As a result, in one embodiment, the working fluid can be at least partially vaporized (i.e., a two-phase fluid) at the outlet manifold 135. In other embodiments, the working fluid can be sub-cooled at the outlet manifold 135. In further embodiments, the working fluid can be substantially completely vaporized at the outlet manifold 135. In all these embodiments, the collection section 139c of the outlet manifold 135 collects the heated working fluid and returns the heated working fluid to the heat removal system 104 (FIG. 1A) via the outlet port 139a, as indicated by the arrow 131b.


Canting the heat exchange elements 132 can improve heat distribution along a length L (FIG. 1C) of the heat exchange elements 132. For example, as the cooling air flows past the heat exchange elements 132, the working fluid in one of the internal channels 144 (e.g., the fourth internal channel 144d) can absorb heat from air streams that have not been significantly cooled by working fluid flowing through other internal channels 144 (e.g., the first, second, and/or third internal channels 144a-c). As a result, heat distribution along the length L of the heat exchange element 132 can be more efficient than with heat exchange elements arranged parallel to the air flow. The canted heat exchange elements 132 can also increase the heat transfer area without significantly affecting the height of the heat exchanger 118. Furthermore, the canted heat exchange elements 132 can improve energy distribution in the computer cabinet 102 (FIG. 1A) because the canted heat exchange elements 132 can deflect cooling air to other parts of the computer cabinet 102 during operation, as indicated by the arrow 117.



FIG. 2 is a cross-sectional side view of a heat exchange element 232 having non-identical internal channels configured in accordance with another embodiment of the invention. As illustrated in FIG. 2, the heat exchange element 232 can include a plurality of internal channels 244 (identified individually as first, second, third, and fourth internal channel 244a-d, respectively), and at least one internal channel 244 has a different internal configuration than others. For example, the cross-sectional area of the internal channels 244 can sequentially decrease from the first internal channel 244a to the fourth internal channel 244d. In other embodiments, the first and second internal channels 244a-b can have a first cross-sectional area, and the third and fourth internal channels 244c-d can have a second cross-sectional area, smaller than the first cross-sectional area. As the foregoing illustrates, in further embodiments, the internal channels 244 can have different cross-sectional shapes and/or other arrangements.


In operation, the different internal configurations of the internal channels 244 can allow the working fluid to have different mass flow rates when flowing through the internal channels 244. For example, in the illustrated embodiment, the first internal channel 244a has a larger cross-sectional area than that of the second internal channel 244b. As a result, the mass flow rate of working fluid through the first internal channel 244a will be greater than the mass flow rate of the working fluid through the second internal channel 244b for a given fluid pressure.


Controlling the flow rate of the working fluid flowing through individual internal channels 244 can improve heat transfer performance of the heat exchange element 232. The inventor has recognized that, in certain situations, the working fluid flowing through the first internal channel 244a can be completely vaporized before and/or when it reaches the outlet manifold 135 (FIG. 1B). The completely vaporized working fluid typically cannot efficiently transfer heat because of a low heat capacity. By increasing the flow rate of the working fluid flowing through the first internal channel 244a, the working fluid can be at least a two-phase fluid when it reaches the outlet manifold 135, thus improving the heat transfer efficiency.


In other embodiments, the heat exchange element 232 can include other features that affect the mass flow rate of the working fluid in the internal channels 244. For example, individual internal channels 244 can include an orifice, a nozzle, and/or other flow restricting components. In another example, the heat exchange element 232 can include a barrier (not shown) that partially blocks the cross-section of at least one of the internal channels 244.



FIG. 3 is a front view of a heat exchange element 332 having a fin configuration configured in accordance with a further embodiment of the invention. In this embodiment, the heat exchange element 332 includes a first fin portion 342a and a second fin portion 342b arranged along the air flow path 117. The first fin portion 342a can include a plurality of first fins 343a, and the second fin portion 342b can include a plurality of second fins 343b, different than the first fins 343a. For example, in the illustrated embodiment, the second fin portion 342b can have a larger number of fins 343b than the first fin portion 342a. In another embodiment, the second fin portion 342b can include different types of fins than the first fin portion 342a (e.g., the second fins 343b can have different heights, thicknesses, etc). In a further embodiment, the second fins 343b can have a higher heat conductance than the first fins 343a. In any of these embodiments, the second fin portion 342b can have a higher heat transfer coefficient that the first fin portion 342a.


Having different fin configurations along the air flow path 117 can improve the heat transfer efficiency between the working fluid and the cooling air. The inventor has recognized that if the fins have the same configuration along the length L of the heat exchange element 332, the working fluid flowing through the fourth internal channel 144d (FIG. 1C) is likely to be mostly liquid when it reaches the outlet manifold 135 (FIG. 1B). Thus, the heat transfer between the working fluid and the cooling air is limited because the mostly liquid working fluid typically has a latent heat capacity much lower than its heat of vaporization. The inventor has further recognized that the limiting factor in the heat transfer between the working fluid and the cooling air is the heat transfer rate between the fins and the cooling air. Thus, by increasing the heat transfer efficiency and/or capability of the second fin portion 342b, the heat transfer between the working fluid in the fourth internal channel 144d and the cooling air can be improved.



FIG. 4 is a partially exploded perspective view of a heat exchanger 418 configured in accordance with another embodiment of the invention and suitable for use in the computer system 100 of FIG. 1A. Many features of the heat exchanger 418 can be at least generally similar in structure and function to the heat exchangers 118 describe above. For example, the heat exchanger 418 can include a plurality of heat exchange elements 432 extending between an inlet manifold 434 and an outlet manifold 435. The individual heat exchange elements 432 can include a plurality of fins 442 extending from a passage portion 440. The passage portion 440 can be generally similar to the passage portion 140 of FIGS. 1B and 1C, or the passage portion 240 of FIG. 2.


The inlet manifold 434 can include a distribution section 437c extending between an inlet opening 437a and a capped inlet end 437b. The inlet manifold 434 can also include an inlet divider 448 extending between the inlet opening 437a and the inlet end 437b. The inlet divider 448 separates the distribution section 437c into a first inlet volume 450a and a second inlet volume 450b. The inlet divider 448 also separates the inlet opening 437a into a first inlet port 452a and a second inlet port 452b.


In the illustrated embodiment, the outlet manifold 435 is generally similar to the inlet manifold 434. For example, the outlet manifold 435 includes a collection section 439c extending between an outlet opening 439a and a capped outlet end 439b. The outlet manifold 435 can also include an outlet divider 458 that separates the collection section 439c into a first outlet volume 460a and a second outlet volume 460b. The outlet divider 458 also separates the outlet opening 439a into a first outlet port 462a and a second outlet port 462b.


The inlet and outlet dividers 448, 458 cooperate to separate the internal channels 144 (FIG. 1C) of individual heat exchange elements 432 into a first channel portion 444a corresponding to the first inlet/outlet volumes 450a, 460a and a second channel portion 444b corresponding to the second inlet/outlet volumes 450b, 460b. Thus, the first inlet volume 450a, the first channel portion 444a, and the first outlet volume 460a form a first flow path of the heat exchanger 418. Similarly, the second inlet volume 450b, the second channel portion 444b, and the second outlet volume 460b form a second flow path of the heat exchanger 418. The first and second flow paths are isolated from each other and arranged along the air flow path 117.


In operation, the heat exchanger 418 can receive a first working fluid portion via the first inlet port 452a, as indicated by arrow 470a, and a second working fluid portion via the second inlet port 452b, as indicated by arrow 472a. The first and second inlet volumes 450a-b distribute the first and second working fluid portions to the first and second channel portions 444a-b, respectively. The first and second working fluid portions flow across the heat exchange elements 432, as indicated by arrows 470b and 472b, respectively. As the first and second working fluid portions flow across the heat exchange elements 432, they absorb heat from the cooling air flowing past the fins 442. The first and second outlet volumes 460a-b collect the heated first and second working fluid portions and returns them to the heat removal system 104 (FIG. 1A) via the first and second outlet ports 462a and 462b, respectively, as indicated by arrows 470c and 472c, respectively.


The first and second working fluid portions can have different physical characteristics. For example, in one embodiment, the first working fluid portion can have a mass flow rate that is less than the second working fluid portion. In another embodiment, the first working fluid portion can have a higher heat transfer coefficient than the second working fluid portion. In a further embodiment, the first working fluid portion can have a lower boiling point than the second working fluid portion. In yet another embodiment, the first working fluid portion can have a higher heat of vaporization than the second working fluid portion.


By controlling the physical characteristics of the first and second working fluid portions, the heat exchanger 418 can have improved heat transfer performance compared to conventional heat exchangers. The inventor has recognized that if the same working fluid is flowing through all the internal channels of the heat exchange elements 432, the working fluid in those channels proximate to the incoming cooling air is likely to be completely vaporized, while the working fluid in other channels spaced apart from the incoming cooling air may still be in liquid phase. Thus, by selecting appropriate heat transfer characteristics of the first and second working fluids, an operator can improve the heat transfer between the working fluid and the cooling air.


Although the inlet divider 448 and the outlet divider 458 are illustrated in FIG. 4 as being generally perpendicular to the air flow path 117, in other embodiments, at least one of the inlet divider 448 and the outlet divider 458 can be canted relative to the air flow path 117. In further embodiments, at least one of the inlet divider 448 and the outlet divider 458 can be omitted, and/or at least one of the first and second inlet/outlet volumes 450a-b, 460a-b can be standalone structures. For example, the first and second inlet volumes 450a-b can each include a generally tubular structure and spaced apart from each other.



FIG. 5 is a top view of a heat exchanger 518 configured in accordance with a further embodiment of the invention and suitable for use in the computer system 100 of FIG. 1A. Many features of the heat exchanger 518 can be at least generally similar in structure and function to the heat exchangers 118 describe above. For example, the heat exchanger 518 can include a plurality of heat exchange elements 532 (identified individually as first, second, third, and fourth heat exchange elements 532a-d, respectively) extending between a first manifold 534 and a second manifold 535. The individual heat exchange elements 532 can include a passage portion 540 and have a plurality of fins 542 extending from the passage portion 540. The passage portion 540 can be generally similar to the passage portion 140 of FIGS. 1B and 1C, or FIG. 2.


The first manifold 534 can include a first intermediate section 537c extending between a first opening 537a and a capped first end 537b. The first manifold 534 can also include a first divider 548 extending between the first opening 537a and the first end 537b. The first divider 548 separates the first intermediate section 537c into a first distribution volume 550a and a first collection volume 550b. The first divider 548 also separates the first opening 537a into a first inlet port 552a and a first outlet port 552b.


The first distribution volume 550a and the first collection volume 550b are in fluid communication with only a portion of the heat exchange elements 532. For example, in the illustrated embodiment, the first distribution volume 550a is in fluid communication with the second and fourth heat exchange elements 532b, 532d, and the first collection volume 550b is in fluid communication with the first and third heat exchange elements 532a, 532c. In other embodiments, the first manifold 534 can also have other flow configurations.


The second manifold 535 can include a second intermediate section 539c extending between a second opening 539a and a capped second end 539b. The second manifold 535 can also include a second divider 558 extending between the second opening 539a and the second end 539b. The second divider 558 separates the second intermediate section 539c into a second distribution volume 560a and a second collection volume 560b. The second divider 558 also separates the second opening 539a into a second inlet port 562a and a second outlet port 562b.


The second distribution volume 560a and the second collection volume 560b are in fluid communication with only a portion of the heat exchange elements 532. For example, in the illustrated embodiment, the second distribution volume 560a is in fluid communication with the first and third heat exchange elements 532a, 532c, and the second collection volume 560b is in fluid communication with the second and fourth heat exchange elements 532b, 532d. In other embodiments, the second manifold 535 can also have other flow configurations.


The heat exchanger 518 can thus have a first flow path from the first inlet port 552a to the second outlet port 562b via the first distribution volume 550a, the second and fourth heat exchange elements 532b, 532d, and the second collection volume 560b. The heat exchanger 518 can also have a second flow path from the second inlet port 562a to the first outlet port 552b via the second distribution volume 560a, the first and third heat exchange elements 532a, 532c, and the first collection volume 550b.


In operation, the heat exchanger 518 can receive a first working fluid portion via the first inlet port 552a, as indicated by arrow 570a, and a second working fluid portion via the second inlet port 562a, as indicated by arrow 572a. The first and second distribution volumes 550a, 560a distribute the first and second working fluid portions to corresponding heat exchange elements 532. The first working fluid portion then flows across the second and fourth heat exchange elements 532b, 532d in a first direction, as indicated by arrow 570b. The second working fluid portion then flows across the first and third heat exchange elements 532a, 532c in a second direction, as indicated by arrow 572b. In the illustrated embodiment, the second direction is generally opposite the first direction. In other embodiments, the first and second directions can form an angle of about 120° to about 180°. As the first and second working fluid portions flow across the heat exchange elements 532, the cooling air flowing past the fins 542 heats the first and second working fluid portions. The first and second collection volumes 550b, 560b collect the heated first and second working fluid portions and return them to the heat removal system 104 (FIG. 1A) via the first and second outlet ports 552b, 562b, as indicated by arrows 570c, 572c, respectively.


By flowing the first and second working fluid portions in generally opposite directions, the heat exchanger 518 can have improved heat transfer efficiency compared to conventional heat exchangers. The inventor has recognized that the heat transfer efficiency decreases as the first and/or second portions of working fluid flow across the heat exchange elements. Thus, if the first and second working fluid portions flow in the same direction, one side of the heat exchanger 518 may have insufficient heat transfer. However, by alternating the flow directions of the first and second working fluid portions, the heat transfer efficiency between the first and second working fluid portions and the cooling air can be improved.


From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. For example, the heat exchangers shown in FIGS. 4 and 5 can also incorporate the heat exchange elements shown in FIGS. 2 and 3. In another example, the heat exchanger shown in FIG. 1B can also incorporate the inlet/outlet manifolds of FIG. 4 or FIG. 5. Further, while advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims.

Claims
  • 1. A computer system, comprising: a computer cabinet having: an air inlet; an air outlet spaced apart from the air inlet; and a plurality of computer module compartments positioned between the air inlet and the air outlet, wherein the air inlet, the air outlet, and the computer module compartments define an air flow path through the computer cabinet; and a heat exchanger positioned between two adjacent computer module compartments, the heat exchanger including a plurality of heat exchange elements, wherein each of the heat exchange elements includes a passage portion having at least one internal channel configured to carry working fluid, wherein each of the passage portions is canted relative to the air flow path, and wherein each of the passage portions includes first and second fin portions extending therefrom, the first fin portion having a first configuration and the second fin portion having a second configuration, different than the first configuration.
  • 2. The computer system of claim 1 wherein the passage portions form an angle of from about 10° to about 45° relative to the air flow path.
  • 3. The computer system of claim 1 wherein the first and second fin portions are canted relative to the air flow path.
  • 4. The computer system of claim 1 wherein each of the passage portions includes a plurality of internal channels configured to carry working fluid between a first end and a second end.
  • 5. The computer system of claim 1 wherein the heat exchange elements include a first heat exchange element having a first passage portion and a second heat exchange element having a second passage portion, and wherein the first passage portion forms a first angle relative to the air flow path and the second passage portion forms a second angle relative to the air flow path, the first angle being different than the second angle.
  • 6. The computer system of claim 1 wherein at least the first fin portion includes a plurality of fins extending from the passage portion, wherein each of the fins includes a free edge extending parallel to the passage portion and canted relative to the air flow path.
  • 7. The computer system of claim 1 wherein the first fin portion is upstream of the second fin portion in the air flow path.
  • 8. The computer system of claim 1 wherein the first fin portion is upstream of the second fin portion along the air flow path, and wherein the second fin portion has a larger number of fins than the first fin portion.
  • 9. A computer system, comprising: a computer cabinet having a plurality of computer module compartments positioned between an air inlet and an air outlet, wherein the air inlet, the air outlet, and the computer module compartments define an air flow path through the computer cabinet; anda heat exchanger positioned between two adjacent computer module compartments, the heat exchanger including a plurality of heat exchange elements, wherein each of the heat exchange elements includes a passage portion having at least one internal channel configured to carry working fluid, and wherein each of the heat exchange elements further includes a plurality of first fins extending from the passage portion and a plurality of second fins, separate from the first fins, extending from the passage portion downstream of the first fins along the air flow path, wherein the plurality of first fins have a first configuration and the plurality of a second fins have a second configuration, different than the first configuration.
  • 10. The computer system of claim 9 wherein the plurality of first fins is spaced apart from the plurality of second fins by a gap therebetween.
  • 11. The computer system of claim 9 wherein the pluralities of first and second fins on each of the heat exchange elements are spaced apart from the pluralities of first and second fins on each of the other heat exchange elements.
  • 12. The computer system of claim 9 wherein each of the first fins has a first height and each of the second fins has a second height, different than the first height.
  • 13. The computer system of claim 9 wherein each of the first fins has a first thickness and each of the second fins has a second thickness, different than the first thickness.
  • 14. The computer system of claim 9 wherein the plurality of second fins have a higher heat transfer coefficient than the plurality of first fins.
  • 15. A computer system, comprising: a computer cabinet having a plurality of computer module compartments positioned between an air inlet and an air outlet; and a heat exchanger positioned between two adjacent computer module compartments, the heat exchanger including a plurality of heat exchange elements individually having a passage portion and a plurality of fins extending from the passage portion, wherein the plurality of fins include a first fin portion having a first configuration and a second fin portion having a second configuration, different than the first configuration, wherein the first fin portion is upstream of the second fin portion along an air flow path, and wherein the second fin portion has a larger number of fins than the first fin portion.
  • 16. The computer system of claim 15 wherein the first fin portion is spaced apart from the second fin portion by a gap therebetween.
  • 17. The computer system of claim 15 wherein the first and second fin portions on each of the heat exchange elements are disconnected from the first and second fin portions on each of the other heat exchange elements.
  • 18. The computer system of claim 15 wherein the second fin portion has a higher heat transfer coefficient than the first fin portion.
  • 19. A computer system, comprising: a computer cabinet having a plurality of computer module compartments positioned between an air inlet and an air outlet; and a heat exchanger positioned between two adjacent computer module compartments, the heat exchanger including a plurality of heat exchange elements individually having a passage portion and a plurality of fins extending from the passage portion, wherein the plurality of fins include a first fin portion having a first configuration and a second fin portion having a second configuration, different than the first configuration, wherein the first fin portion is upstream of the second fin portion along an air flow path, and wherein the second fin portion has a higher heat conductance than the first fin portion.
CROSS-REFERENCE TO APPLICATION(S) INCORPORATED BY REFERENCE

The present application is a divisional of U.S. patent application Ser. No. 12/862,002 filed Aug. 24, 2010, and entitled “COOLING SYSTEMS AND HEAT EXCHANGERS FOR COOLING COMPUTER COMPONENTS,” which is a divisional of U.S. patent application Ser. No. 11/958,114 filed Dec. 17, 2007, and entitled “COOLING SYSTEMS AND HEAT EXCHANGERS FOR COOLING COMPUTER COMPONENTS,” each of which is incorporated herein in its entirety by reference.

US Referenced Citations (316)
Number Name Date Kind
2628018 Koch Feb 1953 A
2673721 Dickinson Mar 1954 A
2661782 Swartz Nov 1958 A
3120166 Lyman Feb 1964 A
3192306 Skonnord Jun 1965 A
3236296 Dubin Feb 1966 A
3317798 Chu et al. May 1967 A
3348609 Dubin et al. Oct 1967 A
3525385 Liebert Aug 1970 A
3559728 Lyman et al. Feb 1971 A
3648754 Sephton Mar 1972 A
3903404 Beall et al. Sep 1975 A
3942426 Binks et al. Mar 1976 A
4016357 Abrahamsen Apr 1977 A
4158875 Tajima et al. Jun 1979 A
4261519 Ester Apr 1981 A
4270362 Lancia et al. Jun 1981 A
4271678 Liebert Jun 1981 A
4306613 Christopher Dec 1981 A
4313310 Kobayashi et al. Feb 1982 A
4315300 Parmerlee et al. Feb 1982 A
4386651 Reinhard Jun 1983 A
4449579 Miyazaki et al. May 1984 A
4458296 Bryant et al. Jul 1984 A
4473382 Cheslock Sep 1984 A
4513351 Davis et al. Apr 1985 A
4528614 Shariff et al. Jul 1985 A
4535386 Frey, Jr. et al. Aug 1985 A
4600050 Noren Jul 1986 A
4642715 Ende Feb 1987 A
4644443 Swensen et al. Feb 1987 A
4691274 Matouk et al. Sep 1987 A
4702154 Dodson Oct 1987 A
4728160 Mondor et al. Mar 1988 A
4767262 Simon Aug 1988 A
4774631 Okuyama et al. Sep 1988 A
4797783 Kohmoto et al. Jan 1989 A
4798238 Ghiraldi Jan 1989 A
4802060 Immel Jan 1989 A
4860163 Sarath Aug 1989 A
4874127 Collier Oct 1989 A
4901200 Mazura Feb 1990 A
4911231 Horne et al. Mar 1990 A
4993482 Dolbear et al. Feb 1991 A
5000079 Mardis Mar 1991 A
5019880 Higgins, III. May 1991 A
5035628 Casciotti et al. Jul 1991 A
5060716 Heine Oct 1991 A
5090476 Immel Feb 1992 A
5101320 Bhargava et al. Mar 1992 A
5131233 Cray et al. Jul 1992 A
5150277 Bainbridge et al. Sep 1992 A
5161087 Frankeny et al. Nov 1992 A
5165466 Arbabian Nov 1992 A
5168925 Suzumura et al. Dec 1992 A
5174373 Shinmura Dec 1992 A
5196989 Zsolnay Mar 1993 A
5263538 Amidieu et al. Nov 1993 A
5273438 Bradley et al. Dec 1993 A
5297990 Renz et al. Mar 1994 A
5323847 Koizumi et al. Jun 1994 A
5326317 Ishizu et al. Jul 1994 A
5329425 Leyssens et al. Jul 1994 A
5339214 Nelson Aug 1994 A
5345779 Feeney Sep 1994 A
5365402 Hatada et al. Nov 1994 A
5376008 Rodriguez Dec 1994 A
5395251 Rodriguez et al. Mar 1995 A
5402313 Casperson et al. Mar 1995 A
5410448 Barker, III et al. Apr 1995 A
5414591 Kimura et al. May 1995 A
5467250 Howard et al. Nov 1995 A
5467609 Feeney Nov 1995 A
5471850 Cowans Dec 1995 A
5491310 Jen Feb 1996 A
5493474 Schkrohowsky et al. Feb 1996 A
5501270 Young Mar 1996 A
5547272 Paterson et al. Aug 1996 A
5570740 Flores et al. Nov 1996 A
5572403 Mills Nov 1996 A
5603375 Salt Feb 1997 A
5603376 Hendrix Feb 1997 A
5684671 Hobbs et al. Nov 1997 A
5685363 Orihira et al. Nov 1997 A
5707205 Otsuka et al. Jan 1998 A
5709100 Baer et al. Jan 1998 A
5718628 Nakazato et al. Feb 1998 A
5749702 Datta et al. May 1998 A
5782546 Iwatare Jul 1998 A
5793610 Schmitt et al. Aug 1998 A
5829676 Ban et al. Nov 1998 A
5849076 Gaylord et al. Dec 1998 A
5880931 Tilton et al. Mar 1999 A
5927386 Lin Jul 1999 A
5941303 Gowan et al. Aug 1999 A
5979541 Saito et al. Nov 1999 A
6021047 Lopez et al. Feb 2000 A
6024165 Melane et al. Feb 2000 A
6026565 Giannatto et al. Feb 2000 A
6034870 Osborn et al. Mar 2000 A
6039414 Melane et al. Mar 2000 A
6046908 Feng Apr 2000 A
6052278 Tanzer et al. Apr 2000 A
6104608 Casinelli et al. Aug 2000 A
6115242 Lambrecht Sep 2000 A
6132171 Fujinaka et al. Oct 2000 A
6135875 French Oct 2000 A
6158502 Thomas Dec 2000 A
6164369 Stoller Dec 2000 A
6167948 Thomas Jan 2001 B1
6182787 Kraft et al. Feb 2001 B1
6183196 Fujinaka Feb 2001 B1
6185098 Benavides Feb 2001 B1
6205796 Chu et al. Mar 2001 B1
6208510 Trudeau et al. Mar 2001 B1
6223812 Gough May 2001 B1
6236564 Fan May 2001 B1
6272012 Medin et al. Aug 2001 B1
6305180 Miller et al. Oct 2001 B1
6310773 Yusuf et al. Oct 2001 B1
6328100 Haussmann Dec 2001 B1
6332946 Emmett et al. Dec 2001 B1
6351381 Bilski et al. Feb 2002 B1
6359779 Frank, Jr. et al. Mar 2002 B1
6361892 Ruhl et al. Mar 2002 B1
6396684 Lee May 2002 B2
6416330 Yatskov et al. Jul 2002 B1
6421240 Patel Jul 2002 B1
6435266 Wu Aug 2002 B1
6439340 Shirvan Aug 2002 B1
6462944 Lin Oct 2002 B1
6481527 French et al. Nov 2002 B1
6501652 Katsui Dec 2002 B2
6515862 Wong et al. Feb 2003 B1
6519955 Marsala Feb 2003 B2
6524064 Chou et al. Feb 2003 B2
6536510 Khrustalev et al. Mar 2003 B2
6542362 Lajara et al. Apr 2003 B2
6546998 Oh Apr 2003 B2
6550530 Bilski Apr 2003 B1
6554697 Koplin Apr 2003 B1
6557357 Spinazzola et al. May 2003 B2
6557624 Stahl et al. May 2003 B1
6564571 Feeney May 2003 B2
6564858 Stahl et al. May 2003 B1
6582192 Tseng et al. Jun 2003 B2
6587340 Grouell et al. Jul 2003 B2
6609592 Wilson Aug 2003 B2
6621698 Chang Sep 2003 B2
6628520 Patel et al. Sep 2003 B2
6631078 Alcoe et al. Oct 2003 B2
6644384 Stahl Nov 2003 B2
6646879 Pautsch Nov 2003 B2
6661660 Prasher et al. Dec 2003 B2
6679081 Marsala Jan 2004 B2
6684457 Holt Feb 2004 B2
6690576 Clements et al. Feb 2004 B2
6695041 Lai et al. Feb 2004 B2
6705625 Holt et al. Mar 2004 B2
6714412 Chu et al. Mar 2004 B1
6724617 Amaike et al. Apr 2004 B2
6725912 Moll et al. Apr 2004 B1
6742068 Gallagher et al. May 2004 B2
6742583 Tikka Jun 2004 B2
6745579 Spinazzola et al. Jun 2004 B2
6755280 Porte et al. Jun 2004 B2
6761212 DiPaolo Jul 2004 B2
6772604 Bash et al. Aug 2004 B2
6775137 Chu et al. Aug 2004 B2
6776707 Koplin Aug 2004 B2
6789613 Ozaki et al. Sep 2004 B1
6796372 Bear Sep 2004 B2
6801428 Smith et al. Oct 2004 B2
6819563 Chu et al. Nov 2004 B1
6836407 Faneuf et al. Dec 2004 B2
6854287 Patel et al. Feb 2005 B2
6854659 Stahl et al. Feb 2005 B2
6860713 Hoover Mar 2005 B2
6867966 Smith et al. Mar 2005 B2
6875101 Chien Apr 2005 B1
6876549 Beitelmal et al. Apr 2005 B2
6881898 Baker et al. Apr 2005 B2
6882531 Modica Apr 2005 B2
6896095 Shah et al. May 2005 B2
6904968 Beitelmal et al. Jun 2005 B2
6909611 Smith et al. Jun 2005 B2
6914780 Shanker et al. Jul 2005 B1
6932443 Kaplan et al. Aug 2005 B1
6952667 Kempe Oct 2005 B2
6964296 Memory et al. Nov 2005 B2
6975510 Robbins et al. Dec 2005 B1
6992889 Kashiwagi et al. Jan 2006 B1
6997245 Lindemuth et al. Feb 2006 B2
6997741 Doll et al. Feb 2006 B2
6999316 Hamman Feb 2006 B2
7016191 Miyamoto et al. Mar 2006 B2
7046513 Nishiyama et al. May 2006 B2
7051802 Baer May 2006 B2
7051946 Bash et al. May 2006 B2
7059899 Doll et al. Jun 2006 B2
7114555 Patel et al. Oct 2006 B2
7120017 Shieh Oct 2006 B2
7120027 Yatskov et al. Oct 2006 B2
7123477 Coglitore et al. Oct 2006 B2
7133285 Nishimura Nov 2006 B2
7144320 Turek et al. Dec 2006 B2
7152418 Alappat et al. Dec 2006 B2
7152668 Hoffmann et al. Dec 2006 B2
7154748 Yamada Dec 2006 B2
7177156 Yatskov et al. Feb 2007 B2
7182208 Tachibana Feb 2007 B2
7185696 Schaper Mar 2007 B2
7187549 Teneketges et al. Mar 2007 B2
7193846 Davis et al. Mar 2007 B1
7193851 Yatskov Mar 2007 B2
7209351 Wei Apr 2007 B2
7215552 Shipley et al. May 2007 B2
7218516 Yu et al. May 2007 B2
7222660 Giacoma et al. May 2007 B2
7226353 Bettridge et al. Jun 2007 B2
7227751 Robbins et al. Jun 2007 B2
7242579 Fernandez et al. Jul 2007 B2
7255640 Aldag et al. Aug 2007 B2
7259963 Germagian et al. Aug 2007 B2
7286351 Campbell et al. Oct 2007 B2
7304842 Yatskov Dec 2007 B2
7312985 Lee et al. Dec 2007 B2
7314113 Doll Jan 2008 B2
7315448 Bash et al. Jan 2008 B1
7318322 Ota et al. Jan 2008 B2
7319596 Fujiya et al. Jan 2008 B2
7330350 Hellriegel et al. Feb 2008 B2
7362571 Kelley et al. Apr 2008 B2
7365976 Fujiya et al. Apr 2008 B2
7367384 Madara et al. May 2008 B2
7382613 Vinson et al. Jun 2008 B2
7385810 Chu et al. Jun 2008 B2
7397661 Campbell et al. Jul 2008 B2
7411785 Doll Aug 2008 B2
7418825 Bean, Jr. Sep 2008 B1
7420805 Smith et al. Sep 2008 B2
7430118 Noteboom et al. Sep 2008 B1
7508663 Coglitore Mar 2009 B2
7513923 Lewis et al. Apr 2009 B1
7534167 Day May 2009 B2
7542287 Lewis et al. Jun 2009 B2
7554803 Artman et al. Jun 2009 B2
7630198 Doll Dec 2009 B2
7641101 Campbell et al. Jan 2010 B2
7657347 Campbell et al. Feb 2010 B2
7679909 Spearing et al. Mar 2010 B2
7707880 Campbell et al. May 2010 B2
7710720 Fuke et al. May 2010 B2
7788940 Madara et al. Sep 2010 B2
7830658 Van Andel Nov 2010 B2
7895854 Bash et al. Mar 2011 B2
7898799 Doll Mar 2011 B2
7903403 Doll et al. Mar 2011 B2
8081459 Doll et al. Dec 2011 B2
8156970 Farese et al. Apr 2012 B2
8170724 Kelley et al. May 2012 B2
8261565 Borror et al. Sep 2012 B2
8335081 Weiss et al. Dec 2012 B2
8472181 Doll Jun 2013 B2
8485248 Coyle et al. Jul 2013 B2
8537539 Doll et al. Sep 2013 B2
20020072809 Zuraw Jun 2002 A1
20030053928 Takano Mar 2003 A1
20040008491 Chen Jan 2004 A1
20040020225 Patel et al. Feb 2004 A1
20040052052 Rivera Mar 2004 A1
20050161205 Ashe et al. Jul 2005 A1
20050168948 Cader et al. Aug 2005 A1
20050186070 Zeng et al. Aug 2005 A1
20050207116 Yatskov Sep 2005 A1
20050217837 Kudija Oct 2005 A1
20050241810 Malone et al. Nov 2005 A1
20060002086 Teneketges et al. Jan 2006 A1
20060011326 Yuval et al. Jan 2006 A1
20060044758 Spangberg Mar 2006 A1
20060096738 Kang et al. May 2006 A1
20060180301 Baer Aug 2006 A1
20060213645 Wintersteen et al. Sep 2006 A1
20060262502 Chang et al. Nov 2006 A1
20070002536 Hall et al. Jan 2007 A1
20070034356 Kenny et al. Feb 2007 A1
20070062673 Olesen et al. Mar 2007 A1
20070070601 Vos et al. Mar 2007 A1
20070163750 Bhatti et al. Jul 2007 A1
20070165377 Rasmussen et al. Jul 2007 A1
20070224084 Holmes et al. Sep 2007 A1
20070279861 Doll et al. Dec 2007 A1
20080030956 Silverstein et al. Feb 2008 A1
20080078202 Luo Apr 2008 A1
20080098763 Yamaoka May 2008 A1
20080112128 Holland May 2008 A1
20080158814 Hattori Jul 2008 A1
20080190586 Robinson et al. Aug 2008 A1
20080212282 Hall et al. Sep 2008 A1
20080216493 Lin et al. Sep 2008 A1
20090154091 Yatskov Jun 2009 A1
20090260384 Champion et al. Oct 2009 A1
20100097752 Doll Apr 2010 A1
20100277870 Agostini et al. Nov 2010 A1
20100309630 Jones et al. Dec 2010 A1
20100315781 Agostini et al. Dec 2010 A1
20100317279 Yatskov Dec 2010 A1
20110026225 Ostwald et al. Feb 2011 A1
20110112694 Bash et al. May 2011 A1
20120020022 Peterson et al. Jan 2012 A1
20120026691 Campbell et al. Feb 2012 A1
20120188706 Kelley et al. Jul 2012 A1
20120212907 Dede et al. Aug 2012 A1
20120281161 Hubbard et al. Nov 2012 A1
20130107447 Campbell et al. May 2013 A1
20130107455 Cottet et al. May 2013 A1
Foreign Referenced Citations (7)
Number Date Country
2197195 Aug 1990 JP
07-030275 Jan 1995 JP
2002026548 Jan 2002 JP
2002237692 Aug 2002 JP
2004079754 Mar 2004 JP
WO-01-86217 Nov 2001 WO
WO-2005027609 Mar 2005 WO
Non-Patent Literature Citations (21)
Entry
U.S. Appl. No. 14/283,299, Yatskov.
“Box/Blade Cooling System,” Thermal Form & Function LLC, Manchester, MA, 2005 [online], Retrieved from the Internet May 10, 2006: URL: http://www.thermalformandfunction.com/boxsystem.html, Manchester, MA, 2005, 1 page.
“Frequently Asked Questions about Heat Pipes,” Thermacore International, Inc., [online], Retrieved from the Internet Jun. 14, 2004: URL: http://www.thermacore.com/hpt—faqs.htm, 3 pages.
“Heat Spreaders,” Novel Concepts, Inc., http://www.novelconceptsinc.com/heat-spreaders.htm, 2 pages [accessed Jun. 14, 2004].
“Managing Extreme Heat Cooling Strategies for High-Density Computer Systems,” Liebert Corporation, Dec. 7, 2003, Columbus, OH, 16 pages.
“Thermacore-base-Heat Sink,” Thermacore Thermal Management Solutions, pp. 1-3, [accessed Jun. 14, 2005].
“Thermal Form & Function—Rack Cooling System (RCS),” Thermal Form & Function LLC, 2005, Manchester, MA, one page,; http://www.thermalformandfunction.com/racksystem.html, [accessed May 11, 2006].
Baer D.B., “Emerging Cooling Requirements & Systems in Telecommunications Spaces,” Telecommunications Energy Conference 2001, Oct. 14-18, 2001, pp. 95-100.
Bleier, F. P., “FAN Handbook, Selection, Application and Design,” McGraw Hill, 1998, pp. 7.50-7.51.
Final Office Action for U.S. Appl. No. 11/958,114, Mail Date Apr. 9, 2010, 28 pages.
Final Office Action for U.S. Appl. No. 12/862,002, Mail Date Dec. 9, 2013, 12 pages.
Hannemann, R. et al., “Pumped Liquid Multiphase Cooling,” ASME, 2004, IMECE 2004, Paper IMECE2004-60669, Anaheim, CA, 5 pages.
JAMSTEC/Earth Simulator Center, “Processor Node (PN) Cabinet,” http://www.es.jamstec.go.jp/esc/eng/Hardware/pnc.html, 1 page, [accessed Mar. 5, 2004].
Marsala, J., “Pumped Liquid/Two Phase Cooling for High Performance Systems,” Thermal Form & Function LLC, May 13, 2003, Scottsdale, AZ, 19 pages.
Non-Final Office Action for U.S. Appl. No. 11/958,114, Mail Date Aug. 25, 2009, 22 pages.
Non-Final Office Action for U.S. Appl. No. 12/862,002, Mail Date Feb. 21, 2012, 16 pages.
Pitasi, M. “Thermal Mangement System Using Pumped Liquid R-134a with Two Phase Heat Transfer,” Thermal Form & Function LLC, Manchester, MA, Mar. 2002, pp. 1-9, http:/www.coolingzone.com/Guest/News/NL—MAR—2002/TFF/Tff.html.
Vogel, M. et al., “Low Profile Heat Sink Cooling Technologies for Next Generation CPU Thermal Designs,” Electronic Cooling Online, Feb. 17, 2005, 11 pages.
Webb, W., “Take the heat: Cool that hot embedded design,” EDN, May 13, 2004, 5 pages.
Notice of Allowance for U.S. Appl. No. 12/862,002, Mail Date May 22, 2014, 9 pages.
Notice of Allowance for U.S. Appl. No. 14/283,299, Mail Date Jan. 6, 2016, 12 pages.
Related Publications (1)
Number Date Country
20140333187 A1 Nov 2014 US
Divisions (2)
Number Date Country
Parent 12862002 Aug 2010 US
Child 14444985 US
Parent 11958114 Dec 2007 US
Child 12862002 US