DIRECT HEAT EXCHANGE FILL

Abstract

A fill sheet and a fill pack manufactured from a plurality of fill sheets for cooling a cooling medium in a cooling tower, each fill sheet optionally having microstructures, the fill sheet's having pairs of elliptically-shaped projections and depressions that act as spacers when the sheets are stacked on one-another to form a fill pack; and/or a fill sheet defining a continuous wave parallel to the longitudinal axes of the flutes.

Claims

1. A fill sheet for cooling a cooling medium in a cooling tower, the fill sheet comprising: a first end; a second end; a first side; a second side; said second end extending substantially parallel to the first end and generally perpendicularly relative to a vertical axis (with respect to water travel), the first and second ends extending substantially parallel to a lateral axis of the fill sheet; said first second side extending substantially parallel to the first side and generally parallel to said vertical axis, said first and second sides connecting said first and second ends; said first end, second end, first side and second side defining a first face and a second face, said first and second faces mirror images of one-another; said first face of said fill sheet comprising a plurality of first-face elliptically-shaped projections and depressions arranged in a plurality of rows across said fill sheet, each of said first-face elliptically shaped projections corresponding to a second-face elliptically shaped depression on said second face, each of said first-face elliptically shaped depressions corresponding to a second-face elliptically shaped projection on said second face.

2. A fill sheet according to claim 1, wherein said first-face elliptically-shaped projections and depressions are arranged in pairs, each of said pairs having a single first-face elliptically shaped projection and a single first-face elliptically shaped depression.

3. A fill sheet according to claim 1, wherein each of said first-face elliptically-shaped projections and depressions has a major axis that is parallel to a direction of air travel across said fill sheet.

4. A fill sheet according to claim 1, wherein all of said first-face elliptically-shaped projections and depressions have a major axis that is aligned at a same angle that is equal to or less than +15 degrees from horizontal.

5. A fill sheet according to claim 1, wherein all of said first-face elliptically-shaped projections and depressions have a major axis that is aligned at a same angle that is equal to or less than −15 degrees from horizontal.

6. A fill sheet according to claim 2, wherein each first-face elliptically-shaped projection is oriented in an opposite direction, up or down, to horizontal compared to its paired first-face elliptically-shaped depression, and to each horizontally and vertically adjacent first-face elliptically-shaped projection.

7. A fill sheet according to claim 1, wherein all of said first-face elliptically-shaped projections have a major axis that is aligned at a same angle that is equal to or less than +15 degrees from horizontal, and all of said first-face elliptically-shaped depressions have a major axis that is aligned at a same angle that is equal or less than negative 15 degrees from horizontal.

8. A fill pack assembly for cooling a fluid flowing through the pack with a gas flowing through the pack in a substantially horizontal direction, the fill pack assembly comprising a plurality of identical fill sheets according to claim 1, wherein said plurality of fill sheets are arranged so that elliptically-shaped projections on adjacent faces of adjacent sheets contact one-another.

9. A fill sheet for cooling a cooling medium in a cooling tower, the fill sheet comprising: a first end; a second end; a first side; a second side; said second end extending substantially parallel to the first end and generally perpendicularly relative to a vertical axis (with respect to water travel), the first and second ends extending substantially parallel to a lateral axis of the fill sheet; said first second side extending substantially parallel to the first side and generally parallel to said vertical axis, said first and second sides connecting said first and second ends; said first end, second end, first side and second side defining a first face and a second face, said first and second faces mirror images of one-another; said fill sheet further defining a continuous wave extending in a direction parallel to a direction of air flow.

10. A fill sheet according to claim 9, wherein said continuous wave has a period of 3 inches to 6 inches and an amplitude of 0.05 inches to 0.5 inches.

11. A fill sheet according to claim 9, wherein said continuous wave has a period of 4 inches to 5.5 inches and an amplitude of 0.1 inches to 0.35 inches

12. A fill sheet according to claim 9, wherein said continuous wave has a period of 4.7 inches and an amplitude of 0.2 inches.

13. A fill sheet according to claim 9 having elliptically-shaped spacers formed thereon.

14. A fill pack for cooling a fluid flowing through the pack with a gas flowing through the pack in a substantially horizontal direction, the fill pack assembly comprising a plurality of identical fill sheets according to claim 9.

15. A fill pack according to claim 14, wherein said plurality of fill sheets are arranged so that elliptically-shaped projections on adjacent faces of adjacent sheets contact one-another.

16. A cross-flow cooling tower comprising a plurality of fill sheets according to claim 1 wherein said plurality of fill sheets are individually hanging in a direct heat exchange section, are hanging in said direct heat exchange section in the form of fill packs, or supported from below by cooling tower structure in said direct heat exchange section in the form of fill packs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a side schematic view of a cross flow cooling tower.

[0028] FIG. 2 is an elevational front view of a single fill sheet according to an embodiment of the invention.

[0029] FIG. 3 is a perspective view of a single fill sheet according to an embodiment of the invention.

[0030] FIG. 4 is a closeup perspective view of the embodiment of FIG. 3.

[0031] FIG. 5 is a further closeup perspective view of the embodiment of FIG. 3.

[0032] FIG. 6 is a perspective view of the top left corner of a stack of fill sheets according to an embodiment of the invention.

[0033] FIG. 7 is a perspective view of the top right corner of the stack of fill sheets shown in FIG. 6.

[0034] FIG. 8 is a perspective view of a stack of fill sheets according to an embodiment of the invention.

[0035] FIG. 9 is a close-up perspective view of the embodiment of FIG. 8.

[0036] FIG. 10 is a further closeup perspective view of the embodiment of FIG. 8.

[0037] FIG. 11 is a schematic representing a first embodiment of the invention in which the spacers are all oriented horizontally and parallel to the air flow.

[0038] FIG. 12 is a schematic representing a second embodiment of the invention.

[0039] FIG. 13 is a schematic representing a third embodiment of the invention.

[0040] FIG. 14 is a schematic representing a fourth embodiment of the invention.

[0041] FIG. 15 is a schematic representing a fifth embodiment of the invention.

[0042] FIG. 16 is a front elevational view of a single fill sheet according to another invention.

[0043] FIG. 17 is a perspective view of the top left corner of a single fill sheet according to the invention of FIG. 16.

[0044] FIG. 18 is a side view of the embodiment of FIG. 17.

[0045] FIG. 19 is a perspective view of a stack of fill sheets according to the invention of FIG. 16.

[0046] FIG. 20 is a side view of the embodiment of FIG. 19.

[0047] Features in the attached drawings are numbered with the following reference numerals:

TABLE-US-00001 200 Fill Pack 210 Surface features 202 Fill Sheet 212 Spacer 204 Vertical Axis 212a Female Spacer 206 Horizontal Axis 212b Male Spacer 208a First End 214 Wave Shape 208b Second End 216 Air Inlet Louvers 208c First Side 218 Drift Eliminators 208d Second Side

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] Referring to FIGS. 2-10, for example, the invention is directed to a cross flow water dispersion media in the form of individually hanging fill sheets 202, or fill pack 200 comprised of a plurality of identical stacked and engaged fill sheets 202. Each of the sheets 202 defines a vertical axis 204 extending generally vertically and a horizontal axis 206 extending generally horizontally relative to the fill sheets 202. It will be understood that use of the terms “vertical” and “horizontal” with respect to the axes 204 and 206 is arbitrary for the purposes of description of the structure of the invention and are not intended to limit the orientation of the invention hereof in use. That said, and without limiting the invention or the use thereof, the fill pack 200 of the invention would generally be oriented in a standard cross-flow cooling tower so that vertical axis 204 is generally parallel to the direction of the water travel in a standard cross-flow cooling tower and horizontal axis is generally parallel to the direction of air travel.

[0049] Continuing the description of the invention from the standpoint a standard cross-flow cooling tower, the water flows through the fill pack 200 generally along the vertical axis 204 between first and second ends 208a, 208b of the sheets 202. First and second ends 208a and 208b of the fill sheets 202 are joined by first and second sides 208c and 208d. The air passes through the fill pack 200 generally along the horizontal axis 206 between the first and second sides 208c and 208d. The first end 208a extends substantially parallel to the second end 208b and generally perpendicular relative to the longitudinal axis 204. The first and second ends 208a, 208b extend substantially parallel to the lateral axis 206. Each fill sheet is preferably manufactured from thermoplastic material, for example, PVC, CPVC, HPVC or polypropylene, and preferably has a thickness of 0.010 to 0.025 inches (10 mils to 25 mils) and more preferably of 0.012 to 0.020 inches (12 mils to 20 mils).

[0050] The surface of the fill sheets may be smooth and/or featureless, or it may include surface feature 210 such as micro-ridges and valleys extending in a zigzag (e.g., herringbone) pattern across the surface of the sheet. By way of non-limiting example, the embodiments shown in the figures have microstructures in the form of alternating diagonal mini-corrugations that traverse the faces of the sheets. The fill sheets of the invention may include integrally formed air inlet louvers 216 on the air inlet side and/or integrally formed drift eliminators 218 at the air outlet side.

[0051] Each fill sheet 202 has formed thereon a plurality of integrally formed spacers 212 in the form of elliptically-shaped protrusions extending out of the primary plane of the sheet (the plane defined by first end 208a, second end 208b, first side 208c and second side 208d). The elliptically shaped spacers are preferably arranged in pairs, with pairs spaced across the fill sheet in a plurality of rows. Each pair of elliptically shaped spacers includes one spacer formed in one direction perpendicular to the plane of the fill sheet, and the other spacer of a pair formed in the opposite direction perpendicular to the plane of the fill sheet, with the result that no matter the perspective, one spacer of a pair is pressed into the fill sheet, “the female spacer” (212a) and the other spacer of the pair extends out of the fill sheet, the “male spacer” (212b). Each male spacer, viewed from the perspective of one side of a fill sheet, is a female spacer when viewed from the perspective of the opposite side of the same sheet. Conversely, each female spacer, when viewed from the perspective of one side of a fill sheet, is a male spacer when viewed from the perspective of the opposite side of the same sheet.

[0052] The preferred aspect ratio of the elliptical shapes of the spacers 212 (ratio of the length of the major axis to the length of the minor axis) is 2:1, although any aspect ratio between 4:1 and 1.5:1 would be understood to provide similar benefits and is therefore considered to be within the scope of the invention.

[0053] When the “A” and “B” fill sheets 202 are stacked against one-another with their tops aligned, the male spacers 212b of facing surfaces of adjacent “A” and “B” sheets align with and contact one-another to create a space between the fill sheets that is equivalent to the height of two male spacers.

[0054] According to various embodiments of the elliptical spacer invention, a) the major axes of the elliptically shaped spacers may all be arranged horizontally, in which case the air passes generally straight through the sheets of fill. See, e.g., FIG. 11, in which the two sets of spacers on the first three rows of spacers on a single fill sheet are represented (similar to the field of view of FIG. 4). In FIG. 11, as well as FIGS. 12-15, the blue ellipses represent the male spacers on one side of a fill sheet (extending out of the plane of the sheet, toward the reader), and the red ellipses represent the female spacers (that is, the male spacers on the reverse side of the same fill sheet, extending into the plane of the fill sheet, away from the reader). According to another embodiment, b) the major axes of the elliptically shaped spacers on one side of a fill sheet may alternate in upwardly tilting and downwardly tilting directions, see, e.g., FIG. 12. According to this embodiment, the air on one side of a fill sheet is forced up, then down, then up, then down, and so on, and air on the opposite side of the same fill sheet is alternatively forced down, then up, then down, then up, and so on. According to a further embodiment, c) the major axes of the elliptically shaped male spacers on one side of a fill sheet may all be tilted upwardly, and the major axes of the elliptically shaped male spacers on the opposite side of fill sheet may all be tilted downwardly, see, e.g., FIG. 13, in which the blue ellipses represent the elliptically-shaped spacers on one side of a fill sheet, and the red ellipses represent the elliptically-shaped spacers on the reverse side of the same fill sheet. According to yet another embodiment, d), the major axes of all of the elliptically shaped male spacers on both sides of a fill sheet may be tilted upwardly, in which case the air is continuously forced upward as it crosses the fill sheet, see, e.g., FIG. 14. According to yet another embodiment, e), the major axes of all of the elliptically shaped male spacers on both sides of a fill sheet may be tilted downwardly; in which case the air is continuously forced downward as it crosses the fill sheet, see, e.g., FIG. 15.

[0055] According to the above-described invention, the aerodynamic shape of the elliptical-shaped spacers 212 reduces the drag coefficient and associated pressure drop relative to typical round spacers. The reduced pressure drop results in higher thermal capability.

[0056] According to the embodiment in which the elliptically-shaped spacers 212 are all aligned parallel to the horizontal axis of the fill sheet, the fill pack may be aligned so that the major axes of the elliptical-shaped spacers are essentially parallel to the airflow when installed in cooling tower. According to the other embodiments in which the elliptically-shaped spacers are arranged at an angle relative to the horizontal in order to enhance mixing of the airflow through the fill pack, it is preferred that the major axes of the spacers be arranged so that the major axes of the spacers do not exceed fifteen (15) degrees relative to horizontal in order to minimize drag coefficient.

[0057] According to preferred embodiments, facing male spacers 212b on adjacent sheets may be bonded together according to various known methods, e.g., solvent adhesives, ultrasonic welding, etc.

[0058] The first invention having been described above, the second invention presented herein will now be described. The second invention presented herein is a fill sheet 202 and fill pack 200 where each fill sheet 202 defines a continuous wave 214 having a wavelength that is parallel to the direction of air flow, see, e.g., FIGS. 16-20. The fill sheet 202 may include elliptically-shaped spacers 212 as described with respect to the first invention herein; the fill sheet 202 may include round spacers, or spacers of other shapes. In any event, the spacers may be formed in pairs, pressed in first and second directions perpendicular to the plane of the sheet as described above, with the pairs distributed across and down the sheet in a series of rows.

[0059] The wavy fill sheets of this invention increase the structural performance of a mechanically bonded pack when supported from the bottom. Compared to a cross-flow fill sheet made from a flat sheet, the wavy fill sheets of the invention enhance the bending stiffness and buckling load of the fill sheet. The wave-shaped sheets maintain a constant spacing between adjacent sheets via spacers, which may be prior art spacers or the elliptical spacers according to the first invention herein, but the wavy shape induces turbulence to increase air water contact and thermal efficiency. The period and the amplitude of the wave shape may be optimized to balance increased pressure drop vs. increased thermal efficiency. According to a preferred embodiment the period of the wave form is 3 inches to 6 inches, preferably 4 inches to 5.5 inches, and more preferably 4.7 inches and the amplitude is 0.05 inches to 0.5 inches, preferably 0.1 inches-0.35 inches, and more preferably 0.2 inches.

[0060] It will be appreciated by those skilled in the art that changes could be made to the preferred embodiments described above without departing from the inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as outlined in the present disclosure and defined according to the broadest reasonable reading of the claims that follow, read in light of the present specification.