Single-phase fluid with counter flow round and cooling system and method using flat tube heat exchanger

Abstract

To provide a cooling system and a method that cool multiple information technology (IT) racks.SOLUTION: A cooling system 100 includes a heat exchanger 116 having one or more rows of flat tubes forming a counterflow heat exchanger, louvered fins disposed between pairs of flat tubes, and special header tubes. The heat exchanger having multiple rows is installed near or adjacent to an IT rack 112 and is fluidly connected to an outdoor fluid cooler 140 having one or more rows. A single-phase fluid is pumped through a fluid circuit loop that includes the heat exchanger in the server rack and an outdoor heat exchanger 142, by a pump 120. The flat tubes are formed tubes having one or more flow paths or extruded tubes having multiple flow paths. The heat exchanger includes header tubes / connections that facilitate easy fabrication and connection between rows and inlet / outlet ports, and reduce pressure drop.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to cooling systems and methods.

Background Art

[0002] Over the past several years, manufacturers of computer equipment have been expanding the performance of their servers' data collection and storage devices. The expansion of server performance has led to an increase in the total power consumption and total heat output for each server and each server rack assembly within the data center. It has also led to an increase in the power and temperature control requirements for the data collection and storage devices of the computer. As a result, the data collection and storage device industry has been and is seeking new and innovative equipment, systems, and design strategies to cope with the tremendous and continuous growth in the performance of the data collection and storage devices of the computer.

[0003] Cooling systems for computer server racks have struggled to keep up with the ability to cool the constantly increasing computer server heat load within the data center. Due to the increase in the computer server heat load (measured in kilowatts (kW)), it has been required to allocate more space for the cooling base within the data room, or for the cooling system to be centralized at the heat source, that is, the computer server rack. Recently, cooling systems have been designed to concentrate cooling on the computer server rack. Such cooling systems include rear door heat exchangers and rack top coolers.

Summary of the Invention

[0004] In one aspect, the present disclosure features a system for cooling a plurality of information technology (IT) racks. The system includes a heat exchanger disposed in or near a hot aisle formed by the plurality of IT racks. The heat exchanger then includes a first row including a first plurality of flat tubes, and a second row including a second plurality of flat tubes in fluid communication with the first row. The system further includes a blower disposed in air communication with the heat exchanger. The blower moves air from the hot aisle, through the heat exchanger, and from the second row to the first row. The system further includes a single-phase fluid circuit coupled to and in fluid communication with the heat exchanger. The single-phase fluid circuit circulates a single-phase fluid from the first flat tubes through the heat exchanger to the second flat tubes.

[0005] In an aspect, each flat tube of the first and second pluralities of flat tubes includes one or more flow paths. Each flat tube of the first and second pluralities of flat tubes includes two flow paths, three flow paths, or five flow paths.

[0006] In an aspect, each flat tube of the first and second pluralities of flat tubes is an extruded or brazed aluminum tube.

[0007] In an aspect, the system includes a plurality of fins disposed between pairs of flat tubes of the first and second pluralities of flat tubes. In an embodiment, each of the plurality of fins may include a wave pattern in the direction of the air flow. In an embodiment, the plurality of fins are louvered fins.

[0008] In an aspect, the heat exchanger further includes a third row including a third plurality of flat tubes in fluid communication with the second row, and a fourth row including a fourth plurality of flat tubes in fluid communication with the third row. In an aspect, the blower moves hot air from the hot aisle, through the heat exchanger, and from the fourth row to the first row, and the single-phase fluid circuit circulates a single-phase fluid from the first row through the heat exchanger to the fourth row.

[0009] In an aspect, the first column and the second column are connected using an O-ring and one or more bolts or screws.

[0010] In an aspect, the single-phase fluid is a fluoroketone (FK) fluid. In an aspect, the FK fluid contains microencapsulated phase change material.

[0011] In an aspect, the system further includes a water circuit and a second heat exchanger connected between the single-phase fluid circuit and the water circuit.

[0012] In an aspect, the system further includes a third heat exchanger disposed within the outdoor fluid cooler and in fluid communication with the water circuit. The third heat exchanger includes one or more rows of a plurality of flat tubes.

[0013] In an aspect, the system further includes a second heat exchanger disposed within the outdoor fluid cooler and in fluid communication with the single-phase fluid circuit. The second heat exchanger includes one or more rows of a plurality of flat tubes.

[0014] In an aspect, the heat exchanger is disposed above the high-temperature passage.

[0015] In an aspect, the system further includes an air duct connected between the heat exchanger and the high-temperature passage.

[0016] In another aspect, the present disclosure features a method for cooling a plurality of information technology (IT) racks. The method involves moving air from a hot aisle formed by the plurality of IT racks across the entire first plurality of flat aluminum formed tubes of a first row of a first heat exchanger, and then across the entire second plurality of flat aluminum formed tubes of a second row of the heat exchanger, pumping a single-phase fluid from the second plurality of flat aluminum formed tubes to the first plurality of flat aluminum formed tubes through the heat exchanger to transfer heat from the air to the single-phase fluid and through a first flow path of a second heat exchanger, and circulating a cooling aqueous solution through a second flow path of the second heat exchanger.

[0017] In an aspect, the single-phase fluid is a fluoroketone (FK) fluid. In an aspect, the FK fluid includes a microencapsulated phase change material.

[0018] In yet another aspect, the present disclosure features a heat exchanger. The heat exchanger includes a first row including a first pair of header tubes and a first plurality of flat tubes connected between the first pair of header tubes such that the first plurality of flat tubes are in fluid communication with the first pair of header tubes. The heat exchanger also includes a second row including a second pair of header tubes and a second plurality of flat tubes connected between the second pair of header tubes such that the second plurality of flat tubes are in fluid communication with the second pair of header tubes. The header tube of the first pair of header tubes is connected to the header tube of the second pair of header tubes without using a brazing process. The heat exchanger also includes a plurality of fins disposed between each pair of the first and second plurality of flat tubes.

[0019] In an aspect, the first column and the second column are constructed separately using a brazing process. In an aspect, the plurality of first and second flat tubes each include two flow channels, three flow channels, or five flow channels. In an aspect, the plurality of first and second flat tubes are extruded or brazed aluminum tubes.

[0020] In an aspect, each of the plurality of fins includes a wave pattern in the direction of the air flow. In an aspect, the plurality of fins are louvered fins.

[0021] In an aspect, the present heat exchanger includes a fluid inlet connected to and in fluid communication with the first column, a fluid outlet connected to and in fluid communication with the second column, and one or more blowers configured to move hot air from the second column to the first column through the present heat exchanger.

[0022] In an aspect, the header tube of the first pair of header tubes is connected to the header tube of the second pair of header tubes by connecting the header connection of the header tube of the first pair of header tubes to the header connection of the header tube of the second pair of header tubes using an O-ring or gasket and one or more bolts or screws.

[0023] In yet another aspect, the present disclosure features a method of manufacturing a heat exchanger. The method includes connecting a first plurality of flat tubes between a first pair of header tubes through a brazing process such that the first plurality of flat tubes are in fluid communication with the first pair of header tubes, connecting a second plurality of flat tubes between a second pair of header tubes through a brazing process such that the second plurality of flat tubes are in fluid communication with the second pair of header tubes, and connecting the first header tube of the first pair of header tubes to the second header tube of the second pair of header tubes without using a brazing process.

[0024] In an aspect, the manufacturing method further includes connecting a first header tube to a second header tube by connecting a first header connection of the first header tube to a second header connection of the second header tube through an O-ring or gasket.

[0025] Various aspects and features of the present disclosure are described below with reference to the following drawings.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

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Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6

Figure 7A

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Figure 8A

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Figure 9A

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Figure 10A

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Figure 11A

Figure 11B

Figure 11C

Figure 11D

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present disclosure is directed to heat exchangers having a number of tube rows and special header tubes that maintain counterflow and facilitate easy connection between the rows and the inlets / outsets.

[0028] Embodiments of the present disclosure are described in detail herein with reference to the drawings, which designate identical or corresponding elements in each of several figures with similar reference numerals. In the drawings and in the following description, terms such as front, back, top, bottom, upper, lower, and similar directional terms are used merely for convenience of description and are not intended to limit the present disclosure. Additionally, in the following description, well-known functions and structures are not described in detail so as to avoid obscuring the present disclosure with unnecessary details.

[0029] Currently, computer servers generate high heat, and rear door heat exchangers and other similar cooling products on the market have difficulty handling the cooling requirements of such high-density computer servers. In addition, while traditional finned copper tube coils produce significant air-side and fluid-side pressure drops, single-row flat tubes or microchannel heat exchangers produce high temperature approaches for single-phase fluids, resulting in performance degradation.

[0030] The present disclosure relates to systems and methods for cooling a data center or other heat loads having a high temperature difference. Compared with existing R134a liquid refrigerant systems with pumps, the systems according to embodiments of the present disclosure utilize the low specific heat and high temperature difference of fluoro ketone (FK) fluids and counterflow heat exchangers to achieve higher energy efficiency. The heat exchangers and other parts of the cooling system are less likely to leak due to the low operating pressure and single-phase nature of the FK fluid. Also, while the FK fluid has only one global warming potential (GWP), R134a has a GWP of approximately 1400. Compared with water-based liquid cooling systems, the systems according to the present disclosure are safer because the FK fluid does not harm the server's electronic devices if leakage occurs, has no possibility of freezing under low-temperature outdoor ambient conditions, and has no concerns about corrosion compared with water-based systems.

[0031] The cooling system according to embodiments of the present disclosure uses a single-phase fluid. For example, the cooling system can use an FK fluid (e.g., Novec™ 649 made by 3M™), or a heat transfer fluid having similar properties. As another example, the cooling system can use a hydrofluoroether (FIFE) fluid, which is a non-ozone-depleting fluid. The single-phase fluid is pumped to a heat exchanger connected proximate to a computer server rack or another heat load to provide cooling. Thereafter, the single-phase fluid warmed by the computer server rack or another heat load is pumped to an outdoor fluid cooler to reject heat directly to the surroundings for “free cooling,” and further cooled (if necessary) to a supply temperature (e.g., 16.7° C.) required or desired through an evaporator of a cryogenic cooler. The cooled single-phase fluid is pumped back to the heat exchanger near the server rack to complete the cycle. The single-phase fluid can be any other liquid fluid that is non-conductive and inert.

[0032] Further, compared to a pumped liquid refrigerant system, the fluid system according to embodiments of the present disclosure does not use a fluid that changes from a liquid phase to a vapor phase and operates at a relatively low pressure, and thus is much more robust to operate. Also, the fluid cycle according to embodiments of the present disclosure maintains a high temperature change (e.g., between the temperature of the fluid exiting a heat exchanger in a server load and the temperature of the fluid supplied by a cryogenic cooler and / or an outdoor fluid cooler), and a low temperature approach that results in a lower fluid flow rate, higher energy efficiency, and more “free cooling” or partial “free cooling” time than other cooling loop systems.

[0033] FIG. 1 shows a schematic diagram of a cooling system 100. Hot air from the IT rack 112 is discharged into the hot air passage 114 and then drawn into the FK fluid heat exchanger 116 at the top of the hot air passage by the blower 118. The heat exchanger 116, described in more detail below, includes a number of rows of a number of flat tubes. For example, the heat exchanger 116 may include two or four rows of a number of flat tubes. The hot air is cooled on the tube side of the heat exchanger 116 by the FK fluid flowing through the heat exchanger 116 or another suitable single-phase fluid and discharged so as to return to the chamber, that is, the cold air passage. The warmed FK fluid from the heat exchanger 116 is pumped by the pump 120 to the fluid-to-air free-cooling heat exchanger 142 of the outdoor fluid cooler 140 where the FK fluid is cooled by the ambient air. The heat exchanger 142 includes one or more rows of flat tubes. For example, the heat exchanger 142 may include one or two rows of a number of flat tubes. If, for example, further cooling of the FK fluid is required due to the high temperature of the ambient air, the modular cryogenic cooler 130 can be operated.

[0034] In one example method, if the temperature of the FK fluid exiting fluid cooler 140, or another suitable single-phase fluid, reaches the supply temperature (e.g., 16.7°C) required when the ambient air is sufficiently cool (e.g., 13.3°C), the FK fluid is pumped back to the indoor hot aisle heat exchanger 116 to complete a cycle for full "free cooling" (where no operation of the compressor or cryocooler is required, e.g., no need to operate the modular cryocooler 130). If the FK fluid exiting fluid cooler 140 is greater than the required supply temperature (e.g., 16.7°C), the cryocooler 130 is operated to further cool the FK fluid flowing through the cryocooler 130 (e.g., flowing through the evaporator of the cryocooler 130) to the set point. The further cooled FK fluid is then pumped back to the indoor hot aisle heat exchanger 116 to complete the cycle as "partial free cooling". An adiabatic wet medium 144, in which water is distributed throughout by a media water distribution system 146, i.e., a water sprayer, is installed at the air inlet of the fluid cooler 140 to cool the temperature of the incoming air to near the wet bulb temperature, thereby increasing full free cooling or partial free cooling to conserve energy.

[0035] FIG. 2 illustrates a cooling system 200 according to another embodiment of the present disclosure. The intermediate plate heat exchanger 210 is used to thermally couple a FK fluid loop or circuit 205 near the server rack to a water loop or circuit 215 using cooling water (or a glycol / water mixture) to cool the FK fluid and reject heat to the outdoor fluid cooler 140 and / or the cryocooler 130 (when required). The advantage of this configuration is that the charge of the FK fluid can be significantly reduced.

[0036] Figure 3 illustrates a cooling system 300 according to yet another embodiment of the present disclosure. The intermediate plate heat exchanger 310 cools the FK fluid and transfers heat to the outdoor fluid cooler 140 and (when required) the cryogenic cooler 130 by thermally connecting the FK fluid loop 305 near the IT rack to a water loop 315 using cooling water (or a glycol / water mixture). The cooling system 300 uses a small secondary pump 308 to pump the FK fluid separately to each individual heat exchanger 116 in the hot path, thus avoiding large liquid supply and return pipes and preventing one heat exchanger from affecting the others in case of failure.

[0037] Figures 4A and 4B illustrate a cooling system 400 according to yet another embodiment of the present disclosure. Hot air from the hot path is drawn into the rooftop air handling unit 410, where it is cooled and returned to the room, i.e., the cold path. The cryogenic liquid (e.g., FK fluid or other similar fluid) is pumped through a single-phase fluid loop 405 that includes a heat exchanger 415 of the air handling unit 410 and a heat exchanger 420 that is in fluid communication with the outdoor fluid cooler 440 and the cryogenic cooler 430 (via the water circuit 425) to provide cooling to the air handling unit 410 and transfer heat to the fluid cooler 440 and the cryogenic cooler 430. The heat exchanger 415 can be a flat tube heat exchanger that includes a number of rows of a number of flat tubes according to the embodiments disclosed herein, e.g., in Figures 5A - 11D.

[0038] According to an embodiment of the cooling system, microencapsulated phase change material (MEPCM) can be added to the liquid FK fluid to increase the heat capacity (i.e., increase the heat mass / heat transfer) and reduce the flow rate / pumping force for all the cooling systems in Figures 1 - 4B. The MEPCM includes a number of different chemical compositions that are suitable for the operating temperature range for cooling of data centers or any other applications.

[0039] In an embodiment, the cooling system utilizes a multi-row flat aluminum tube counterflow heat exchanger for an indoor high-temperature passage heat exchanger (i.e., an air handling unit heat exchanger) and an outdoor fluid cooler. The highly efficient counterflow heat exchanger can bring the temperature of the fluid exiting the indoor heat exchanger close to the inlet temperature of the hot air and the exit temperature of the air from the outdoor fluid cooler close to the temperature of the incoming FK fluid. In other words, such heat exchangers have a very large number of transfer units (NTU) or a high effectiveness (e.g., 95% or higher). This improves the system energy efficiency over R134a pumped liquid systems or other competing technologies.

[0040] FIG. 5A shows a front view of the heat exchanger 500, and FIG. 5B shows a cross-sectional view of the heat exchanger 500 taken along the cut line 5A-5A of FIG. 5A. The heat exchanger 500 has four rows 501: a first row 501a, a second row 501b, a third row 501c, and a fourth row 501d. Alternatively, the heat exchanger 500 may have two rows or any number of rows depending on a particular application. Each of the rows 501 includes a number of tubes 502: the first row 501a includes a number of tubes including tube 502a, the second row 501b includes a number of tubes including tube 502b, the third row 501c includes a number of tubes including tube 502c, and the fourth row 501d includes a number of tubes including tube 502d.

[0041] The tube 502 can be a flat tube. The flat tube can be a flat aluminum-formed tube. Each tube 502 can have a single flow path, two flow paths, or multiple flow paths (not shown). The tube 502 can also be a multi-port extruded aluminum tube. Louver fins (not shown) are used on the air side 504 (the fins can be stacked with each component to cover all four columns 502a, 502b, 502c, 502d, and each column 502a, 502b, 502c, 502d has its own fins such that the fins are separated for each column 502a, 502b, 502c, 502d). The four columns 501a, 501b, 501c, 501d form a countercurrent circuit - the liquid fluid enters the fourth column 501d, then passes through the third column 501c, then through the second column 501b, and then exits from the first column 501a, while the air flow enters the first column 501a and exits from the fourth column 501d.

[0042] Compared with a traditional finned copper tube coil, the flat tube heat exchanger 500 has better heat transfer performance, but has a lower air flow pressure drop and a lower fluid side pressure drop. Compared with a conventional cross-flow heat exchanger with flat tubes, the multi-column and countercurrent circuit of the heat exchanger 500 results in a high heat transfer efficiency with a closer approach temperature between the liquid and the air. This is achieved by the inlet header tube 506a, the intermediate header tube 506b, and the outlet header tube 506c of the heat exchanger 500.

[0043] FIG. 5B shows the header tubes 506 at each end of the heat exchanger 500 that cover all four columns 501a, 501b, 501c, 501d of the flat tubes 502a, 502b, 502c, 502d to form an internal compartment and a countercurrent circuit.

[0044] FIG. 5C is a top view of the heat exchanger of FIG. 5A, and FIG. 5D is a cross-sectional view of the heat exchanger of FIG. 5A taken along the cut line 5D-5D of FIG. 5C. As shown in FIG. 5C, the fluid inlet tube 508a is connected to the fourth row 501d, whereby the fluid inlet tube 508a is in fluid communication with the flat tubes 502d of the fourth row 501d, and the fluid outlet tube 508b is connected to the first row 501a, whereby the fluid outlet tube 508b is in fluid communication with the flat tubes 502a of the first row 501a. In an embodiment of the present disclosure, the fluid inlet tube 508a and the fluid outlet tube 508b can be connected to a single-phase fluid circuit.

[0045] FIG. 5D illustrates a number of flat tubes 502a-502d in each of the rows 501a-501d, respectively. The fins 503a-503d are disposed between pairs of the flat tubes 502a-502d. In some embodiments, the fins 503a-503d are louvered fins.

[0046] FIGS. 6-7C show different embodiments of the rows 501 and the header tubes 506. FIG. 6 shows two two-row heat exchangers 600 stacked together to form a four-row heat exchanger 610. The connection between the second row 602b and the third row 602c is through two short connection tubes 612, and one connection 612 is at each end of a header tube (not shown), or one short connection 612 is at both ends of a header tube. The liquid fluid enters the fourth row 602d from one end of the header tube 606 of each row 602 and exits from the first row 602a.

[0047] Figures 7A - 7C show four separate columns 602 stacked together to form a single heat exchanger 610, and the liquid connections 614 between any two columns 602 and the inlets 614a and outlets 614b pass through a set of additional connection tubes 616 from the opposite side. Figure 7C is a left - side view showing the liquid inlet 614a, outlet 614b, and transition section 616 from the second column 602b to the third column 602c. The connections 614 between the first column 602a and the second column 602b, and between the third column 602c and the fourth column 602d are similar.

[0048] Generally, embodiments of the heat exchangers 500, 610 of the present disclosure can be used in any liquid - to - gas heat exchanger. For example, embodiments of the heat exchangers 500, 610 of the present disclosure can be used to closely couple a heat exchanger near a server rack during cooling of a data center and also for an outdoor fluid cooler for a data center.

[0049] Figures 8A and 8B illustrate a column of a heat exchanger according to another embodiment. The column includes a number of flat tubes 801 connected between header tubes 805a, 805b. The flat tubes 801 can be aluminum tubes, for example, extruded aluminum tubes. The column also includes header connectors 810a, 810b for connecting to one or more other columns. For example, header connector 810a can connect to a header connector on a first other column, and header connector 810b can connect to a header connector on a second other column. The header connectors 810a, 810b can be attached or connected to header connectors on other columns via an O - ring or gasket and one or more bolts or screws. Figure 8A illustrates a column having three header connectors 810a, 810b on each of the header tubes 805a, 805b, respectively. Other embodiments can include fewer or more header connectors. For example, more header connectors can be used to reduce the pressure difference.

[0050] FIG. 8C is a cross-sectional view of the flat tube 801 of the row of heat exchangers of FIGS. 8A and 8B taken along the cut line 8C-8C of FIG. 8B. The flat tube 801 includes five flow channels 820. Other embodiments of the flat tube 801 may include fewer or more flow channels 820. For example, the flat tube 801 may include one flow channel, two flow channels, three flow channels, or six flow channels.

[0051] FIGS. 9A and 9B illustrate a heat exchanger fin 905 provided according to some embodiments of this disclosure. The fin 905 is disposed between the flat tubes 801 illustrated in FIGS. 8A-8C to increase heat transfer between the air flowing through the row of heat exchangers and the fluid flowing through the heat exchanger, such as a single-phase fluid.

[0052] FIG. 10A is a detailed front view of the heat exchanger fin of FIGS. 9A and 9B according to some embodiments of this disclosure. FIG. 10B is a cross-sectional view of the heat exchanger fin of FIG. 10A taken along the cut line 10B-10B of FIG. 10A. The fin includes a straight portion 1005 and, in the illustrated embodiment, a wave portion 1010 having a sawtooth pattern or shape. In other embodiments, the wave portion 1010 may have a sine pattern or a triangular pattern.

[0053] Figures 11A-11D illustrate yet another heat exchanger provided in accordance with other embodiments of the present disclosure. As shown in Figure 11A, the heat exchanger 1100 includes four rows 1101-1104. Row 1101 includes, for example, header tubes 1111 and header connectors 1121 that are attached or connected together by, for example, a brazing process. Row 1102 includes a first header tube 1112a and a first header connector 1122a that are connected together, and a second header tube 1112b and a second header connector 1122b that are connected together. Row 1103 includes a first header tube 1113a and a first header connector 1123a that are connected together, and a second header tube 1113b and a second header connector 1123b that are connected together. Row 1104 includes header tubes 1114b and header connector 1124 that are connected together. Rows 1102 and 1103 are connected together by connecting header connectors 1122a and 1123a. For example, as illustrated in Figure 11B, header connector 1123a includes holes or openings 1143a, 1144a, and header connector 1122a includes corresponding holes through which bolts or other similar fasteners can be installed to connect header connectors 1122a, 1123a together. An O-ring or gasket 1105 can be installed between header connectors 1122a, 1123a to provide a seal against leakage from the inside of rows 1101-1104 to the air side. Similarly, header connectors 1121 and 1122b are connected together, and header connectors 1123b and 1124 are connected together.

[0054] Such header connectors that are not connected together have a spacer 1131 installed between them, such as between header connectors 1111a, 1121a, to allow for fluid communication between the corresponding rows. Spacer 1131 can include fasteners for attaching header connectors 1111a, 1121a to spacer 1131.

[0055] As shown in FIG. 11C, the first header tube 1111a of the first column 1101 includes an inlet fitting, i.e., a tube stub 1141, for connecting to a fluid supply line, and the fourth header tube 1114a of the fourth column 1104 includes an outlet fitting, i.e., a tube stub 1142, for connecting to a fluid return line.

[0056] Compared with a conventional finned copper tube coil, the heat exchanger embodiments of FIGS. 8A - 11D exhibit a lower pressure drop for both the air side and the liquid side. And its high effectiveness results in a small temperature approach between the air side and the liquid side.

[0057] Although some embodiments of the present disclosure have been shown in the drawings, the present disclosure is intended to be as broad in scope as the art will permit and the specification is to be read likewise, and thus the present disclosure is not intended to be limited thereto. Accordingly, the above description should be construed as illustrative of specific embodiments only and not as limiting. The embodiments of FIGS. 8C, 9, and 10 are contemplated to be applicable not only to the heat exchangers shown in FIGS. 8 or 11, but also to the embodiments shown in FIGS. 5, 6, and 7.

Claims

【Claim 1】 The invention described in the specification and / or the drawings.

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