GAS/LIQUID CONTACT DEVICE

Abstract: A packing sheet for use in a device, e.g. a cooling tower wherein a film of liquid and a gas stream are brought into contact to effect heat exchange therebetween, the sheet be­ ing continuously corrugated to define a plurality of parallel depressions which are generally V-shaped in cross-section. Preferably the pair of walls which define each depression are disposed substantially at right angles with respect to one another and are disposed at an angle of around 45° with respect to the plane of the sheet. Preferably the sheet is formed with transverse ribs which project from the walls of the depressions and which extend substantially continuous­ ly between the depressions to form channels which commu­ nicate between the depressions. Advantageously the sheet is formed in the walls of the depressions with angled projec­ tions, which preferably extend continuously between two adjacent crests of the depressions. From another aspect the invention is a cooling tower pack for use in effecting contact between gas and a flowing liquid film, the pack comprising a plurality a packing sheets as described above assembled together to define a plurality of interconnected tubular cells each of which is of substan­ tially rectangular cross-section, the arrangement being such that the adjacent sheets are in line contact with one another at intervals so that substantially the whole surface of the sheets is available for use in effecting the gas/liquid contact.

Description: The invention relates to a gas-liquid contact packing device according to the preamble of claim 1. It is known to provide a pack for a cooling tower which pack comprises a plurality of similar sheets of a plastics material formed, e.g. by vacuum forming, with a series of corrugations so that when the sheets are assembled together they define a series of tubular cells through which liquid is intended to pass under gravity while gas is passed upwardly through the cells so that heat is transferred from one to the other. Such an arrangement which discloses the features of the preamble of claim 1 is described in GB-A-1351605. It is an object of the invention to provide a device for use in effecting contact between a gas and a flowing liquid film of the same general kind as described in GB-A-1351605 but which more efficiently utilizes the available area of the sheets of the pack for liquid/gas contact. The invention provides a gas-liquid contact packing device for enabling a film of liquid and a gaseous stream to be brought into contact to effect heat exchange therebetween, the pack comprising a plurality of sheets each of which is continuously corrugated to define a plurality of parallel depressions and is assembled with similar sheets to define a plurality of parallel tubular cells of substantially constant cross section, the cells being provided with angled projections arranged to impart rotary motion to the gas stream and the cells being formed with transverse ribs which form channels which interconnect adjacent cells to permit liquid flow between the cells, characterised in that the depressions in each sheet are V-shaped in cross section and have side walls which meet the side walls of adjoining depressions in the same sheet to provide rectilinear crests which meet the crests of adjacent sheets in substantially line contact, forming cells of substantially rectangular cross section. US-A-3485485 describes a cooling grid providing cells of rectangular cross section, but which is of very different construction from the device of the present invention. Preferably the angled projections extend continuously between two adjacent crests of the depressions, the angled projections being disposed on the sheet so that each of them has one end adjacent to a middle portion of an adjacent angled projection, and so that adjacent angled projections project from opposite sides of the sheet. The depressions preferably present a similar appearance on both sides of the sheet, the pair of walls which define each depression being disposed substantially at right angles with respect to one another and at an angle of around 45° with respect to the plane of the sheet. The transverse ribs may be of sinusoidal transverse cross-section so that they present a similar appearance on both sides of the packing sheet. The disposition of the angled projections on the packing sheet may be asymmetric. Angled projections are preferably formed in the walls of the depressions on both sides of the sheet. Preferably, two identical packing sheets can be assembled together by turning one through 180° with respect to the other, whereupon at least some of the angled projections on one sheet lie adjacent to at least some of the angled projections on the other sheet to form in each rectangular section tubular cell means for imparting a rotary motion to gas passing through the cell. An example of a gas/liquid contact packing device according to the invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a plan view of a packing sheet; Figure 2 is an end view of the packing sheet of Figure 1; Figure 3 is a scrap perspective view on an enlarged scale of part of the packing sheet of Figure 1; Figure 4 is a section taken on the line IV-IV of Figure 1; Figure 5 is a section taken on the line V-V of Figure 1; Figure 6 is a section taken on the line VI-VI of Figure 1; and Figure 7 shows a number of the packing sheets of Figures 1 to 6 assembled together to form a cooling tower pack. In the drawings there is shown a packing sheet 8 for an evaporative cooling tower, the sheet being vacuum formed from plastics material and being of same general kind as is described in GB-A-1351605. The sheets according to the present invention are continuously corrugated to form a plurlaity of parallel depressions or corrugations 9 which are V-shaped in cross-section as seen in the end view of Figure 2, the corrugations or depressions being mutually parallel and of equal size. The two flat walls 10 forming each corrugation or depression 9 are generally at right angles to one another and are such that they present the same appearance on both sides of the sheet. The sheet 8 is formed with cylindrical or conical projections 11 extending from the tops and from the bottoms of some of the corrugations 9 and these cylindrica and conical projections 11 form, on the other side of the sheet, correspondingly shaped recesses 17 (see Figure 3) whereby on assembly of a plurality of the sheets to form a pack the projections can be located in the recesses of adjacent sheets to hold the sheets mutually positioned with the tops or crests 12 of the corrugations of each sheet in contact with the tops of the corrugations of adjacent sheets to form a pack consisting of a series of tubular cells of substantially square cross-section as shown in Figure 7. Since the sheets meet in substantially line contact, virtually the whole surface of the sheets is available for liquid/gas contact. To ensure dispersal of the liquid evenly over the surface of the sheets they are formed with relatively small ribs 13 extending at right angles to the corrugations 9. The ribs are substantially sinusoidal in cross-section as best can be seen in Figure 4 and extend over substantially the whole of the surface of the sheet. Additionally the surfaces of the sheets are formed at intervals with elongate or angled projections 14 which extend along the corrugations at an acute angle thereto, e.g. around 30°. Each elongate or angled projection 14 extends from the crests 12 on one side of a depression 9 to the crest 12 on the other side of the same depression. The elongate, angled projections 14 are formed to extend from both sides of the sheet (the projections on one side of the sheet forming corresponding depressions 18 (see Figure 3) on the other side of the sheet) and are so arranged in relation to one another that each projection has one end adjacent to a middle portion of an adjacent depression, and the middle portion of each projection is disposed adjacent to one end of a depression. These elongate projections are intended to impart a helical motion to gas passing through the tubular cells formed by an assembly of the sheets to improve gas/liquid contact. In Figure 1 the elongate or angled projections 14 on the upper side of the sheet are indicated in full lines, while those on the underside of the sheet are indicated in dotted lines. It will be noted from Figure 4 that the crests 12 and valleys 15 of the sheets forming the tops and the bottoms of the saw-tooth corrugations, are castellated by reason of the presence of the small transverse sinusoidal ribs 13 so that on assembly of the sheets 8 to form a pack as shown in Figure 7, the tubular cells 16 of the pack are interconnected by substantially circular channels formed by pairs of the sinusoidal ribs 13 so that liquid overload of any cell 16 is prevented by transmission of the excess liquid to the adjacent cells. The invention thus provides a packing, e.g. for a cooling tower, of high efficiency due to the fact that virtually the whole of the surfaces of the packing sheets are used for liquid/gas contact.

Claims: A gas-liquid contact packing device for enabling a film of liquid and a gaseous stream to be brought into contact to effect heat exchange therebetween, the pack comprising a plurality of sheets (8) each of which is continuously corrugated to define a plurality of parallel depressions (9) and is assembled with similar sheets to define a plurality of parallel tubular cells (16) of substantially constant cross section, the cells (16) being provided with angled projections (14) arranged to impart rotary motion to the gas stream and the cells being formed with transverse ribs (13) which form channels which interconnect adjacent cells to permit liquid flow between the cells, characterised in that the depressions (9) in each sheet (8) are V-shaped in cross section and have side walls (10) which meet the side walls (10) of adjoining depressions (9) in the same sheet to provide rectilinear crests (12) which meet the crests (12) of adjacent sheets (8) in substantially line contact, forming cells (16) of substantially rectangular cross section. A gas-liquid contact packing device according to claim 1, characterised in that the angled projections (14) extend continuously between two adjacent crests (12) of the depressions (9), the angled projections being so disposed on the sheet that each angled projection has one end adjacent to a middle portion of an adjacent angled projection and so that adjacent projections project from opposite sides of the sheet. A gas-liquid contact packing device according to claim 1 or claim 2, characterised in that the depressions (9) present a similar appearance on both sides of the sheet (8), and in that the pair of the walls (10) defining each depression are disposed substantially at right angles with respect to one another and are disposed at an angle of around 45 degrees with respect to the plane of the sheet. A gas-liquid contact packing device according to any preceding claim, characterised in that the transverse ribs (13) are of sinusoidal transverse cross-section so that they present a similar appearance on both sides of their sheet (8). A gas-liquid contact packing device according to any preceding claim, characterised in that the angled projections (14) are asymmetrically disposed on their sheet (8). A gas-liquid contact packing device according to any preceding claim, characterised in that the angled projections (14) are formed in the walls (10) of the depressions (9) on both sides of the sheet (8).

Inventors: WIGLEY, ALBERT FREDERICK
Applicants: WIGLEY, ALBERT FREDERICK
Application year: 1984
Main classification: F28F25
IPC codes: B01J19, F28F25