Indirect heat exchanger

Abstract

A cartridge for use in a cartridge heat exchanger, the cartridge having an inlet and an outlet and comprising an upper plate and a lower plate. The upper and lower plates are sealed together around an edge region of the cartridge, thereby forming a flow path within the cartridge and between the inlet and the outlet. The plate is formed with a stamped pattern that increases the surface area of the plate compared to the flat plate surface. The stamping pattern includes a series of welding spots, thereby welding or bonding the upper plate and the lower plate together at spot locations.

Description

[0001] This application is a divisional application of the invention patent application with the invention name “Indirect Heat Exchanger”, the international application date is January 4, 2019, the international application number is PCT / US2019 / 012366, and the national application number is 201980013057.6. Technical Field

[0002] The present application generally relates to indirect heat exchangers, such as closed loop fluid coolers, fluid heaters, condensers, evaporators, thermal storage systems, air coolers, air heaters, etc. More specifically, the present application relates to cassette-type indirect evaporative heat exchangers. Background Art

[0003] Indirect evaporative heat exchangers are made of one or more bundles of individual boxes stacked and connected together. Each box is made of two generally flat plates formed of thin-walled conductive materials (e.g., copper, aluminum, steel, etc.), and the periphery of the plates is sealed together so that the internal fluid can flow through the box between the inlet and outlet without leaking through the outer edge. Outside the box, an external fluid (e.g., air, water, or a combination thereof) flows on the surface of the box. Through this process, heat is indirectly transferred from the high-temperature fluid to the low-temperature fluid through the box plates.

[0004] From a heat transfer perspective, it is more efficient for a box to use a relatively thin walled plate, as the thinner material will have a higher heat transfer rate than a thicker wall. However, from a structural perspective, thicker walls provide greater structural stability than thin walls, which may be important if the box is subject to relatively high levels of internal pressure.

[0005] In order to achieve the heat transfer benefits of thin-walled boxes while avoiding the associated structural problems, the boxes can be welded together at multiple points between the plates by weld lines. These weld lines help to hold the plates together and allow the box to withstand high internal pressures, but they also reduce heat transfer capabilities because the length of the lines tends to limit the flow rate of the fluid through the box. Moreover, these weld lines tend not to mix the external fluid over the surface area of ​​the box and the unwelded portions, thereby further inhibiting heat transfer performance. Summary of the invention

[0006] The present application describes a cassette for use in a cassette heat exchanger. The cassette has an inlet and an outlet and includes an upper plate and a lower plate. The upper plate and the lower plate are sealed together around an edge region of the cassette (i.e., at least a portion of the periphery excluding the inlet and the outlet), thereby forming a flow path within the cassette and between the inlet and the outlet. The plate is formed with a stamped pattern that increases the surface area of ​​the plate compared to a flat surface. The pattern includes a series of weld points, thereby welding or bonding the upper plate and the lower plate together at point locations.

[0007] The stamping patterns in the plates forming this construction can result in: (1) increased internal and external heat transfer rates; (2) reduced pressure drop to increase air flow rate; (3) an integral header at a lower manufacturing cost; and (4) improved structural rigidity to resist internal hydraulic pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a front view of a heat exchanger in a cooling tower according to an example described in the present application.

[0009] Figure 2 is a front view of another heat exchanger in a cooling tower according to examples described herein.

[0010] Figure 3A is an isometric view of a cassette for a heat exchanger according to examples described herein.

[0011] Figure 3B yes Figure 3A A cutaway isometric view of a box.

[0012] Figure 3C It is taken along line AA Figure 3A Cross-sectional view of the box.

[0013] Figure 4A is a front view of a cassette bundle for use in a heat exchanger according to examples described herein.

[0014] Figure 4B yes Figure 4A Side view of the box bundle.

[0015] Figure 4C yes Figure 4A and 4B Side view of a variation of the box bundle.

[0016] Figure 4D is a top view of a plurality of cassettes used to form a cassette bundle according to examples described herein.

[0017] Figure 4E is a top view of an additional plurality of cassettes used to form a cassette bundle according to examples described herein.

[0018] Figure 5A is a front view of another box bundle according to the examples described herein.

[0019] Figure 5B yes Figure 5A A top view of the box bundle.

[0020] Fig. 6A is a front view of a box plate used to form a box according to examples described herein.

[0021] Figures 6B to 6HTaken at different locations Fig. 6A A cross-sectional side view and an alternative cross-sectional side view of a box plate.

[0022] Fig. 7A is an isometric view of a box having a boxboard pattern according to examples described herein.

[0023] Figure 7B and 7C Is has Fig. 7A A side view of a box bundle with a box plate pattern of a box. DETAILED DESCRIPTION

[0024] The present application describes an indirect heat exchanger including a stacked box bundle. A separate box includes a pair of conductive plates that are sealed around the periphery and form an inlet and outlet that allow an internal fluid to pass through. The plate of the box is formed (e.g., stamped) to have a three-dimensional surface pattern that improves the internal fluid heat transfer rate without significantly increasing the pressure drop in the box. In some examples, the stamped pattern takes the form of two intersecting sinusoidal wave patterns. That is, the pattern can take the form of a first sinusoidal wave pattern extending on the box plate surface along a first direction and a second independent sinusoidal wave pattern extending on the box plate surface along a second direction different from the first direction. It should be noted that throughout the application, the term "sine" refers to an oscillation pattern of any waveform. The term "sine" represents a pattern that includes multiple independent crests and troughs in a specified oscillation, and should not be understood to represent a pattern that must be able to be drawn according to a mathematical equation based on "sine". The sinusoidal pattern is tilted overall because they have a generally smooth and circular or arc-shaped pattern without a sharp corner or vertex.

[0025] The pattern applied to the box helps to improve the heat transfer rate of external sensible heat and evaporation heat without significantly increasing the pressure drop. In addition, the pattern also helps to increase the structural stability of the box and resist the deformation that can be caused by high internal pressure without increasing the thickness of the box plate (and thus reducing the heat transfer efficiency). The surface pattern is adaptive so that it can adapt to various sizes, shapes and forms of boxes, fluid inlets and outlets. Various examples of surface patterns that embody these improvements are described and illustrated in this article. The box can be formed together to form a box bundle, which can be used in a heat exchanger device.

[0026] The box surface pattern can be used for a variety of purposes. For example, the pattern can promote mixing and acceleration of the internal fluid, thereby improving the convective heat transfer coefficient of the box. In addition, the pattern can be used to increase the heat transfer surface area from a generally flat surface for performing a large amount of heat transfer. In addition, the pattern can help control the mixing of the external fluid to increase the heat transfer rate of convection and evaporation. Therefore, compared to similar types of box heat exchangers with generally smooth and flat surface areas, the surface pattern can result in a combination of a significant improvement in heat transfer rate and a significant reduction in cost because much thinner materials can be used than typical stand-alone box heat exchangers without surface patterns.

[0027] As mentioned above, the box for heat exchanger is formed by two plates (i.e., upper plate and lower plate), which are sealed together to form a closed flow path between the box inlet allowing fluid to enter the box and the outlet through which the fluid is discharged from the box. The upper plate and the lower plate are all stamped or otherwise embossed with surface patterns. The surface patterns are roughly similar or even identical so that they form a roughly uniform thickness gap between the upper plate and the lower plate. The area near the outer edges of the two plates is tapered so that the outer edges of the plates form a contact surface that allows the two plates to be combined, welded or otherwise sealed together. The plate edges can also be sealed by brazing or by using gaskets, hems, seams or other sealing methods.

[0028] Typically, the center portions of the upper and lower panels (i.e., the portions significantly removed from the edges) are generally flat. Of course, this refers to the average center plane of the panels, not the surfaces of the panels, which are not necessarily flat due to the stamped surface pattern. However, in some examples, the panels may take a generally curved (e.g., convex) shape, thereby forming a pillow-shaped box.

[0029] In one example, the surface pattern of the plate includes two differently sized, generally sinusoidal surface shapes that cross each other. When viewed from a diagonal direction to the general direction of internal fluid flow, the pattern will have small, repeating, generally sinusoidal cross-sectional areas with secondary valleys and secondary ridges. The generally sinusoidal shapes can be composed entirely of curved surfaces, a combination of curved and flat surfaces, or entirely of flat surfaces. When viewed from a diagonal direction to an external fluid flow direction that may be generally perpendicular or parallel to the internal fluid flow direction, the pattern will have large, repeating, generally sinusoidal cross-sectional areas with primary valleys and primary ridges. Figure 3A and 3B Such an example pattern is shown in the illustrated embodiment.

[0030] The spacing or gap between the upper and lower plates is designed to be large enough to allow the internal fluid and some small particles to flow through and to keep the inside fluid pressure drop within reasonable design limits, while being small enough to keep the internal fluid velocity high and therefore the internal heat transfer coefficient high. The gaps between the boxes in the box bundle are selected so that a low-density fluid (such as air) with a large volume flow rate can be used as the external fluid, allowing a reasonable external pressure drop.

[0031] The pattern also includes dimples or flat areas where the two plates contact each other for spot welding or other forms of joining (including brazing, fastening, riveting, adhering, gluing, etc.), which can be distributed throughout the upper and lower plates. The spot welds can be evenly distributed or distributed in a geometric pattern. The spot welds can prevent the upper and lower plates from separating due to internal fluid pressure or other forces. The spot welds can be formed by multiple ridges or valleys so that the tension generated by the plates due to internal pressure is evenly applied to the spot welds.

[0032] Each box has at least one internal fluid inlet and at least one internal fluid outlet. In some examples, the internal fluid inlet and internal fluid outlet connections can be stamped directly into the plate or box, which can help reduce manufacturing costs, but in other examples, fittings or pipes can be added as independent inlets or outlets.

[0033] As mentioned above, the pattern on the plate of the box generally takes a sinusoidal pattern, which includes "waves" or deformations in the plate material, thereby obtaining a surface pattern of unevenness or texture. This pattern can be used for a variety of purposes, thereby providing a variety of benefits compared to other boxes that do not use a plate with such a pattern. The following describes in more detail how this generally multi-directional sinusoidal pattern design can be used for a variety of purposes. For example, this pattern can promote the mixing of the internal fluid in the box, because compared with the box without such a pattern, the sinusoidal pattern (for example, a looser or "lower frequency" wave pattern) produces a flow path with more intense flow. This helps to provide a more uniform temperature curve on the internal fluid. Specifically, compared with the unmixed internal fluid, it helps to distribute a uniform temperature curve on the cross-sectional area perpendicular to the direction of travel of the internal fluid. Having a more uniform internal temperature curve increases the temperature difference between the internal fluid near the plate and the plate itself, and a larger temperature difference increases the heat transfer rate. Outside the box, the same wider wave pattern also better mixes the cooling air sucked by the fan between the boxes by guiding the air in the cross direction. Moreover, a second sinusoidal pattern with smaller waves (e.g., a tighter or "higher frequency" wave pattern) can be used to better distribute the flow of an external fluid (e.g., a water spray from a nozzle), thereby enhancing heat transfer between the box and the external fluid. The same smaller wave pattern is also used to "disperse" the cooling air drawn in by the fan at the box surface to increase turbulence and thus improve the heat transfer rate.

[0034] Another benefit of the generally sinusoidal shaped pattern is that it provides a greater surface area for heat transfer for a given area than a generally smooth, flat free-standing box design. That is, the wavy pattern texture requires more material surface area than a simple flat surface, thereby allowing more area for heat transfer.

[0035] In addition, in some embodiments, the pattern can take a roughly sinusoidal shape in a direction generally parallel to the internal fluid flow and in a direction generally perpendicular to the external fluid flow. This configuration helps to resist the accumulation of internal pressure inside the box, which can cause surface expansion or expansion between the welds. This is because the roughly sinusoidal shape is used as a cold-worked structural member, thereby increasing the structural integrity or rigidity of the box wall and making them less likely to deform compared to unpatterned walls. For example, a sheet with a nominal thickness of 0.03 inches can withstand internal pressures up to hundreds of pounds per square inch, and the surface shape is not significantly deformed.

[0036] The patterned boxes also provide a way to improve mixing of the external fluid. For example, when two boxes are stacked together with an external fluid gap between the two boxes, the sinusoidal pattern will cause multiple valleys to form in a direction generally diagonal to the direction of external fluid flow, which serve as air paths for mixing the external fluid, thereby resulting in higher heat transfer rates. It should be understood that within the external fluid gap between the two boxes, the multiple valleys in one box can be oriented in the same direction as the valleys of the other box or in a cross direction in the gap. Examples of such a configuration are shown in FIG. Figure 5B Shown in.

[0037] Additionally, the pattern of small repeating shapes that are generally sinusoidal in the direction of the internal fluid flow helps mix the external fluid near the surface. And because the internal fluid gaps between the plates have narrow cross-sectional areas in the direction of the external fluid flow, the external fluid can flow easily without significant outside pressure drop.

[0038] The figures show various examples of heat exchangers and cassettes utilizing the generally sinusoidal plate patterns discussed above. Figure 1 1 is a front view of a heat exchanger having an indirect heat exchange section 10, and shows the interior of a closed loop cooling tower 3. A direct heat exchange section 4 (optional component) is located below the indirect heat exchanger 10, and may include a polyvinyl chloride fill sheet. The direct heat exchange section 4 receives air through an air inlet 6 near the bottom of the closed loop cooling tower 3, and the air is drawn generally upward through the direct heat exchange section 4 by a fan 5 rotated by a motor 6.

[0039] The indirect heat exchange section 10 includes an internal fluid inlet 11 and an internal fluid outlet 12 and is located above the direct heat exchange section 4. It should be understood that the internal fluid inlet 11 and the internal fluid outlet 12 can be reversed if desired, and the direct heat exchange section 4 can be placed on top of the indirect heat exchanger 10 if desired.

[0040] The evaporative fluid (e.g., water) flows downward from the water distribution assembly 9 so that the evaporative fluid falls onto and passes through the indirect heat exchange section 10 and then passes through the direct heat exchange section 4. While falling onto and passing through the indirect heat exchange section 10 and the direct heat exchange section 4, a small portion of the evaporative fluid evaporates by moving the air, and latent heat transfer occurs from the evaporative fluid to the air. It should be noted that in some applications, condensation from the air into the evaporative fluid occurs.

[0041] The evaporated fluid transmitted downward and passing through the indirect heat exchange section 10 and the direct heat exchange section 4 is collected in the sump 7 and pumped by the pump 5 to the water distribution assembly 9. The water distribution assembly 9 may include various pipes with openings, orifices or nozzles, or may be other water distribution assemblies known in the art.

[0042] exist Figure 1 In the embodiment of the invention, the indirect heat exchange section 10 includes a plurality of cassette heat exchangers 15. The fluid to be cooled, condensed, heated or evaporated passes within the cassette heat exchangers 15. A plurality of external gaps between the cassette heat exchangers 15 allow the evaporative fluid (usually water) to flow downward from the water distribution assembly 9 and allow air to flow through the cassettes.

[0043] While falling and passing through the indirect heat exchange section 10 and the direct heat exchange section 4, a small portion of the evaporative fluid is evaporated by the moving air and latent heat transfer from the evaporative cooling tower liquid to the air occurs. It should be noted that in some applications, condensation from the air into the cooling tower liquid occurs.

[0044] Each cassette heat exchanger 15 has a surface pattern 16 that, when placed in a closed loop circuit cooling tower 3, increases the heat transfer efficiency of both sensible and latent heat.

[0045] It should be noted that the indirect heat exchange section 10 can be operated in a closed loop cooling tower 3 without a direct heat exchange section 4. It should also be noted that when the ambient air becomes sufficiently cold, the indirect heat exchange section 10 can be operated without an evaporative fluid in a sensible heat transfer or drying mode. The surface pattern 16 increases the surface area and significantly improves the sensible cooling characteristics of the indirect heat exchange section 10 compared to a typical non-patterned smooth plate heat exchanger or a typical tubular heat exchanger.

[0046] Figure 2is a front view of another heat exchanger 22 having an indirect heat exchange section 20 and is shown positioned in a sump 29 and submerged below the level of evaporative fluid in a closed loop cooling tower 21 .

[0047] The direct heat exchange section 24 may include filler, which may include polyvinyl chloride sheets. The direct heat exchange section 24 receives air through an air inlet 26 near the bottom of the closed loop cooling tower 21, and is drawn generally upward through the direct heat exchange section 24 by a fan 27 rotated by a motor 28.

[0048] The indirect heat exchange section 20 has an internal fluid inlet 33 and an internal fluid outlet 34. It should be understood that the operation of the internal fluid inlet 33 and the internal fluid outlet 34 may be reversed if desired.

[0049] The evaporative fluid flows downward from the water distribution assembly 30 so that the evaporative fluid falls onto and passes through the direct heat exchange section 24. While falling and passing through the direct heat exchange section 24, a small portion of the evaporative fluid is evaporated by the moving air, and latent heat transfer occurs from the evaporative fluid to the air. It should be noted that in some applications, condensation from the air into the evaporative fluid occurs.

[0050] The evaporated liquid that passes down and through the direct heat exchange section 24 passes through the cassette heat exchanger 20, is then collected in a sump 29, and is pumped by a pump 31 to a water distribution assembly 30. The water distribution assembly 30 may include various tubes having openings, orifices, or nozzles, or may be other water distribution assemblies known in the art.

[0051] exist Figure 2 In the embodiment, the indirect heat exchange section 20 includes a plurality of cassette heat exchangers 25. The fluid to be cooled, condensed, heated or evaporated passes through the cassette heat exchangers 25. The plurality of external gaps between the cassette heat exchangers 25 allow the evaporation fluid (usually water) in the sump 29 to flow generally downward and laterally through the indirect heat exchange section 20, and indirect sensible heat transfer occurs between the fluid to be cooled, condensed, heated or evaporated passing through the cassette heat exchangers 25 and the evaporation fluid.

[0052] Each cassette heat exchanger 25 has a surface pattern 32 that increases surface area and improves heat transfer efficiency when placed in a closed loop circuit cooling tower 21 .

[0053] The overall dimensions of the cassette heat exchanger 25 may vary significantly depending on the internal pressure drop requirements, size requirements, air pressure drop requirements, and heat transfer rate requirements. Also, the locations of the internal fluid inlet 33 and the internal fluid outlet 34 may vary. The flow path within the cassette heat exchanger 25 may be as follows: Figure 2 As shown, it is generally straight, or it can be as Figure 1 Shown has a serpentine shape.

[0054] Figure 3A , 3B and 3C show an indirect heat exchanger 40 in the form of a cassette 41 . Figure 3B A cross-sectional view of a cassette 41 is shown. The cassette 41 includes an upper plate 45, a lower plate 46, an internal fluid inlet 42, and an internal fluid outlet 43. The cassette 41 has an internal fluid inlet 42 and an internal fluid outlet 43. It should be understood that for each cassette 41, there may be more than one internal fluid inlet 42 and more than one internal fluid outlet 43. Figure 3C is a cross-sectional view of cartridge 41 taken along line AA to help illustrate the double sine wave pattern of the cartridge.

[0055] The upper plate 45 and the lower plate 46 are thin stamped metal plates that, when assembled together, generally form a gap 47 between the two plates in the middle and contact each other at a perimeter 48 and a plurality of dimples 44. The perimeter 48 and the contact area of ​​the dimples 44 are used to weld the two plates together to form the box 41 and form a watertight seal around the box 41. It should be understood that the upper plate 45 and the lower plate 46 can also be made of thermoformed or injected plastic. It should also be understood that the upper plate 45 and the lower plate 46 can also be glued, brazed, riveted, bolted, stapled or fastened together, or assembled and sealed in any other way known in the art.

[0056] Inside the box 41 is a surface pattern 49 covering most of the surface of the box 41. Between the perimeter 48 and the pattern 49 is a transition area 58 that gradually transitions from the generally sinusoidal pattern 49 to the generally straight or flat surface of the perimeter 48. The box 41 has a plurality of valleys 50 for allowing an external fluid such as air, water, or air and water to travel as the external fluid generally travels in a direction from edge 51 to edge 52. By allowing the external fluid to travel in a direction slightly diagonal to the general flow direction from edge 51 to edge 52, the plurality of main valleys 50 facilitate mixing of the external fluid and improve the heat transfer rate of sensible heat and evaporation from the plate surface 49 to the external fluid. The plurality of main valleys 50 are generally aligned along the direction of the main valley direction 53.

[0057] It should be understood that the external fluid may also travel in a direction from fluid inlet 42 to fluid outlet 43 or from fluid outlet 43 to fluid inlet 42 , and the plurality of primary valleys 50 may still facilitate mixing of the external fluid and increase the heat transfer rate of cartridge 41 .

[0058] The dimples 44 are located adjacent to the major ridges 55 of the upper plate 45 and are generally evenly spaced across the upper plate 45. The vertices 56 between the dimples 44 are generally in the direction of the minor ridge directions 57, which will be discussed further in a later paragraph.

[0059] Figure 4A 6 is a front view of a box bundle 60, which includes a plurality of boxes constrained together, including box 61. Box 61 is made of two patterned plates put together to form an internal fluid channel between the two plates. When the internal fluid flows inside the channel between the top plate and the bottom plate, the temperature difference between the internal fluid of box 61 and the external fluid causes heat transfer through the thickness of the patterned plate.

[0060] The box 61 has an internal fluid inlet 63 and an internal fluid outlet 64. It should be understood that the internal fluid inlet 63 and the internal fluid outlet 64 can be reversed if desired. All peripheral edges of the box 61 are watertight and are typically welded. It should be understood that the peripheral edges can also be glued, brazed, sealed using gaskets or O-rings or any other method known in the art.

[0061] The weld 65 is used to control the flow direction of the internal fluid. The weld 65 effectively increases the distance the internal fluid needs to travel from the internal fluid inlet 63 to the internal fluid outlet 64, and increases the fluid flow rate for a specified flow rate, and thereby increases the convective heat transfer coefficient. More than one weld 65 may be provided alternating sides to form a more tortuous path, and this is not a limitation of the present invention.

[0062] Major valley direction line 66A represents a direction generally parallel to a line passing through the major valley locations on the wave of the pattern running generally upward (relative to the figure). At weld 65, the direction of the lines changes as shown by direction line 66B, which represents the major valley direction line on the upper portion of the box. Secondary ridge direction lines 68A and 68B represent a direction generally parallel to a line passing through the major valley locations on the wave of the pattern running generally horizontally (relative to the figure). Figure 4A )The line of the secondary ridges of the traveling wave is roughly parallel to the line. Although Figure 4A One example of a directional line is shown, but it will be appreciated that the lines may be opposite to the primary valley direction 66B within the box 61 to increase mixing of the air flowing over the outer surface of the box 61 and navigating through the plurality of primary valleys 67 .

[0063] Figure 3B A typical location of one of the vertices 56 is shown at Figure 4A 6A and 6B are shown as vertices 69. Multiple vertices 69 are located midway between a pair of dimples 70. The line of vertices 69 is generally aligned in the secondary ridge direction 68A. When the primary valley direction 66A changes to 66B at the weld 65, the secondary ridge direction 68A can change to 68B within the box. It should be understood that within the box 61, multiple sections of the pattern 71 can be provided, and therefore there can be multiple changes in direction and multiple angles of the secondary ridge directions 68A and 68B to the primary valley directions 66A and 66B.

[0064] In some examples, the angle between the vertical line and the main valley direction 66B is from about 15° to about 45°. The angle depends on the size requirements and the pressure drop requirements. Generally, a smaller angle is preferred for larger boxes and lower pressure requirements. It is also preferred that the angle between the secondary ridge direction 68B and the horizontal line is from about 0° to about 25°.

[0065] The secondary ridge line 73 represents the continuous highest points of the secondary ridge in the overall secondary ridge direction 68A. Similarly, the secondary valley line 74 represents the continuous lowest points of the secondary valley in the overall secondary ridge direction 68A. It should be noted that the secondary ridge line 73 and the secondary valley line 74 are not straight, but are somewhat sinusoidal in shape. The secondary ridge line 73 and the secondary valley line 74 will be discussed more later.

[0066] Figure 4B There is shown a side view of the box 61. When viewed from the side of the box 61, the box 61 is generally straight. Figure 4C A side view of a variation of the cassette 61 is shown, wherein the cassette 61 is generally curved when viewed from the side of the cassette 61 .

[0067] Figure 4D 6 is a top view of a box bundle 60 made of a plurality of boxes 61. When viewed from the top of the box bundle 60, the plurality of boxes 61 are stacked together with a plurality of gaps 72 between the boxes 61. The generally sinusoidal pattern on the boxes 61 forms a plurality of main valleys 67 that promote air mixing by causing some of the air to move somewhat sideways from the general direction of the airflow in the gaps 72.

[0068] Figure 4E is a top view of a modified box bundle 60A, wherein the modified box bundle is Figure 4D A variation of the embodiment of FIG. 60A is shown with a plurality of boxes 61A stacked together when viewed from the top of the heat exchanger 60A, with a plurality of gaps 72A between the boxes 61A. The generally sinusoidal pattern on the curved boxes 61A forms a plurality of major valleys 67A that promote air mixing by displacing some of the air somewhat sideways from the general direction of airflow in the gaps 72. Each box 61A can be curved in different ways to meet various geometric constraints that may be imposed by a closed loop cooling tower or any other structure in which the boxes 61A are located.

[0069] Figure 5A and 5B Another cassette bundle 80 is shown that includes another type of cassette 81. The cassette 81 is made of an upper plate 94 and a lower plate 95 that are welded together to form an internal fluid channel between the two plates. When the internal fluid flows inside the channel, the temperature difference between the internal fluid and the external fluid of the cassette 61 causes heat transfer through the thickness of the patterned plate.

[0070] The box 81 has an elevated internal fluid inlet 83 and an elevated internal fluid outlet 84. It should be understood that the internal fluid inlet 83 and the internal fluid outlet 84 can be reversed if desired. Figure 5B As shown in FIG, the fluid inlet 83 and the fluid outlet 84 can be welded to their adjacent fluid inlets and fluid outlets, respectively, so that these fluid inlets and fluid outlets form an inlet header 85 and an outlet header 86. An inlet connecting tube 97 and an outlet tube 98 can be welded or attached to the fluid inlet 83 and the fluid outlet 84, respectively, while a baffle plate 99 is welded to the opposite end to seal the last hot box in the box bundle.

[0071] When a plurality of cassettes 81 are placed together to form a cassette bundle 87 , every other cassette 81 may be rotated so that its main valley direction 88 may cross with respect to the main valley direction 88 of the non-rotating cassette 81 . Figure 5B A top view of the main valley direction 88 and the intersecting main valley direction 89 is shown. It should be understood that the fluid inlet 83 and the fluid outlet 84 can be positioned so that every other box can be oriented by flipping or a combination of flipping and rotating to cross the main valley direction 88 of the every other box relative to the main valley direction 89 of the non-oriented box 81.

[0072] exist Figure 5A 90 and a plurality of secondary valley lines 91 are shown. The secondary ridge lines 90 and the secondary valley lines 91 alternate due to the generally sinusoidal nature of the pattern 92 covering a majority of the box 81. Both the secondary ridge lines 90 and the secondary valley lines 91 are somewhat sinusoidal when viewed from the front of the box 81. The secondary ridge direction 93 shows that the overall inclination of both the plurality of secondary ridge lines 90 and the plurality of secondary valley lines 90 has a downward angle in the range of about 0° to about 25°.

[0073] Fig. 6A is a front view of a cassette plate 101 used to form a cassette 100 according to examples described herein.

[0074] Fig. 6A FIG. 1 is a front view of another heat exchanger device 100 in the form of a box segment 101. A plurality of secondary ridge lines 110 and a plurality of secondary valley lines 111 are shown. Figure 5A Compared to the fourth embodiment shown in FIG. 1 , both the secondary ridge line 110 and the secondary valley line 111 are substantially straight when viewed from the front of the box segment 101 .

[0075] The generally downwardly sloping secondary ridge direction 120 showing the plurality of secondary ridge lines 110 and the plurality of secondary valley lines 111 has a downward angle in the range of about 0° to about 25°. The transition zone 113 is located between the generally sinusoidal pattern 115 and the generally straight peripheral top edge 114. It should be understood that the top edge 114 may also be generally curved.

[0076] The plurality of dimples 112 are distributed throughout the pattern 115. The plurality of dimples 112 are upper plates 116 and lower plates 126 (not shown because they are Fig. 6A The middle is located behind the upper plate 116; Figure 5B A similar upper plate 94 and lower plate 95 are shown where they can be welded together so that the upper plate 116 and lower plate 126 forming the box 101 will not separate due to high internal pressure. The plurality of dimples 112 are generally evenly spaced apart so that no one of the plurality of dimples 112 needs to resist too much separation force caused by internal pressure.

[0077] The main valley lines 117 represent the consecutive lowest points along the main valleys, and the main ridge lines 118 represent the consecutive highest points along the main ridges. It should be understood that the main valley lines 117 and the main ridge lines 118 may also be curved or substantially sinusoidal.

[0078] Figure 6B and 6C Various cross-sectional areas of the box section 101 are shown. Specifically, Figure 6B and 6C Two different cross-sectional areas of the large sinusoidal pattern of pattern 115 are shown. Sections AA and BB of box segment 101 show the overall shape and position of the plurality of major valley lines 117 and the plurality of major ridge lines 118 relative to each other.

[0079] In addition, in section AA, the distance between the upper plate 116 and the lower plate 126 is roughly uniform. The gap 140 generated between the upper plate 116 and the lower plate 126 provides space for the flow of the internal fluid. The gap 140 is always maintained by the shallow groove 112, and when the internal fluid passes through the gap 140 in a circuitous manner, the internal fluid is both mixed and accelerated, which leads to a higher internal heat transfer coefficient. At a plurality of shallow grooves 112, the upper plate 116 and the lower plate 126 are welded together. It should be understood that, as known in the art, instead of welding, the upper plate 116 and the lower plate 126 can also be combined, glued, riveted, fastened together or attached together. It should also be understood that in the case where all boxes are compressed and held together by thick end plates, a plurality of shallow grooves 112 can be removed, in which case section BB looks very similar to section AA.

[0080] Even though the upper plate 116 and the lower plate 126 may be made of very thin plates, the plates may resist significant deformation due to internal pressure. The generally sinusoidal shape 119 between the pair of dimples 112 shown in section BB provides strength to the plates, which can withstand high internal pressures better than a generally straight or gently curved shape 119 between the pair of dimples 112. In such a case, a generally flat surface would be more likely to expand.

[0081] Fig.6D and6E An alternative configuration of the box plate pattern taken along lines AA and BB is shown. In this configuration, the overall design of having an upper plate 116, a lower plate 126, a plurality of generally evenly spaced dimples 112, and a plurality of major ridges 118 is maintained. The difference is that every other major valley line 117 becomes a super major ridge line 120.

[0082] Figures 6F to 6H Two different cross-sectional areas of the main sinusoidal pattern of pattern 115 are shown. Section CC and section DD of box segment 101 show the location of a plurality of secondary valley lines 111 and a plurality of secondary ridge lines 110. Fig. 6F A possible configuration is shown along section CC, and Figure 6G An alternative construction is shown taken along the same location (labeled as section CC-2).

[0083] The upper plate 116 and the lower plate 126 are welded together at the plurality of dimples 112. It should be understood that, instead of welding, the upper plate 116 and the lower plate 126 may be bonded, glued, riveted, fastened together, or attached together as is known in the art. Even though the upper plate 116 and the lower plate 126 are made of very thin plates, the generally sinusoidal shape 131 between a pair of dimples 112 shown in section BB resists significant deformation of the generally sinusoidal pattern 115 in the presence of high internal pressures better than a generally straight shape 131 that may expand.

[0084] In the case of very large boxes, or when the evaporative cooling water is dirty and may be prone to clogging, Fig. 6F Compared with the structure of Figure 6G The configuration shown in (section CC-2) may be preferred. In the configuration of this section CC-2, the overall design with the upper plate 116, the lower plate 126 and the plurality of generally evenly spaced dimples 112 is maintained. The change is that every other secondary ridge line 110 becomes a super secondary valley line 130.

[0085] Fig. 7A is an isometric view of a box 141 having a boxboard pattern 142. Box 141 is similar to Figure 3A The box 41 shown is different from the box 141 in that the box 141 does not have Figure 3A A plurality of dimples 44 are shown. Figure 7B and 7C Is has Fig. 7A A side view of a box bundle with a box plate pattern of a box.

[0086] In some examples, the box pattern does not include Fig. 7AThe plurality of dimples 44 shown may be effective. For example, when the internal fluid pressure is low enough that the generally sinusoidal structural pattern 142 alone is sufficient to resist deformation of the box 141. The second case is when a box or stack of boxes is restrained to prevent expansion by two relatively thick end plates held together by any available technique. In these cases, a large gap 146 between two adjacent boxes 141 can be maintained by a plurality of spacers 145 stamped into the structural pattern 142.

[0087] Likewise, in these cases, if Figure 7C As shown, if there is no need for a large gap 146 between the boxes, the multiple high points 150 and the multiple low points 151 of the structural pattern 142 can be used as spacers and provide multiple fluid paths. In order to prevent the nesting of the boxes in the stack of boxes, two different boxes, such as box 141 and box 143, can be used. Another way to prevent nesting without using box 143 is to rotate, flip, or rotate and flip every other box 141 in the stack of boxes 141 so that the structural patterns 142 of two adjacent boxes 141 are not aligned. In this way, two different box designs will not be needed.

[0088] The present application describes preferred embodiments and examples of heat exchangers and associated boxes, and therefore should be interpreted as illustrative rather than restrictive. It should be appreciated by those skilled in the art that the described examples may be modified and / or combined with one another without departing from the scope described herein. In addition, the features of an embodiment or example may be combined with the features of other embodiments or examples to provide additional embodiments or examples as required. All references cited, discussed, noted or mentioned in the present application are incorporated herein by reference in their entirety.

Claims

1. A cassette for a heat exchanger, the cassette comprising: -Entrance; -exit; - Upper board; as well as - Lower plate, wherein the upper plate is welded to the lower plate around an edge region of the box to form a flow path within the box and between the inlet and the outlet, the flow path extending along a longitudinal axis of the box, the longitudinal axis being perpendicular to a horizontal axis of the box, wherein both the upper plate and the lower plate are formed with at least one stamping pattern that increases the surface area of ​​the plates, wherein the at least one stamping pattern comprises a first sinusoidal wave pattern and a second sinusoidal wave pattern intersecting the first sinusoidal wave pattern, The first sine wave pattern and the second sine wave pattern are both curved portions, The first sinusoidal wave pattern has a first wavelength, the second sinusoidal wave pattern has a second wavelength, and the second wavelength is smaller than the first wavelength, The at least one punching pattern includes a welding portion that interrupts the first and second sinusoidal wave patterns and joins the upper plate and the lower plate together. 2 . The box according to claim 1 , wherein the at least one stamping pattern includes at least two stamping patterns and a weld separating the at least two stamping patterns.

3. The cartridge of claim 1, wherein the inlet comprises an elevated fluid inlet portion extending perpendicular to the upper plate and the lower plate, and wherein the outlet comprises an elevated fluid outlet portion extending perpendicular to the upper plate and the lower plate.

4. A box according to claim 3, wherein the elevated fluid inlet portion is configured to connect with the elevated fluid inlet portion of another box to form a fluid inlet manifold of the box bundle, and wherein the elevated fluid outlet portion is configured to connect with the elevated fluid outlet portion of another box to form a fluid outlet manifold of the box bundle.

5. A heat exchanger, comprising: an indirect heat exchange section; a evaporative fluid distribution assembly configured to distribute evaporative fluid downwardly toward the indirect heat exchange section; a sump configured to collect the evaporated fluid; a pump operable to pump evaporative fluid collected in the sump to the evaporative fluid distribution assembly; The indirect heat exchange section comprises a plurality of cassettes constrained together, an individual cassette comprising: -Entrance; -exit; -On the board; and - Lower plate; wherein the upper plate of each of the individual boxes is welded to the lower plate around an edge region of the box to form a flow path within the box and between the inlet and the outlet, the flow path extending along a longitudinal axis of the box, the longitudinal axis being perpendicular to a horizontal axis of the box, and wherein the upper plate and the lower plate of each of the individual boxes are formed with at least one pattern that increases the surface area of ​​the plates, and wherein the at least one pattern comprises a first sinusoidal wave pattern and a second sinusoidal wave pattern intersecting the first sinusoidal wave pattern; wherein the first sinusoidal wave pattern and the second sinusoidal wave pattern are both curved portions; The first sinusoidal wave pattern has a first wavelength, the second sinusoidal wave pattern has a second wavelength, and the second wavelength is smaller than the first wavelength, The at least one pattern includes a welding portion that interrupts the first and second sinusoidal wave patterns and joins the upper plate and the lower plate together. 6 . The heat exchanger according to claim 5 , wherein the at least one pattern includes at least two patterns and a weld separating the at least two patterns.

7. A heat exchanger according to claim 5, wherein the inlet of at least one individual box includes an elevated fluid inlet portion extending perpendicular to the upper plate and the lower plate, and wherein the outlet of at least one individual box includes an elevated fluid outlet portion extending perpendicular to the upper plate and the lower plate.

8. A heat exchanger according to claim 7, wherein the elevated fluid inlet portion of at least one individual box is connected to the elevated fluid inlet portion of another individual box to form a fluid inlet header of the box bundle, and wherein the elevated fluid outlet portion of at least one individual box is connected to the elevated fluid outlet portion of another individual box to form a fluid outlet header of the box bundle.

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