Filling Sheets For Liquid-gas Contact Apparatus

Abstract

Corrugated sheet type filling for liquid-gas contact apparatus is provided with a plurality of ramp-like deformations which reduce liquid channeling particularly in the trough portions of the corrugations.

Description

Related subject matter is disclosed and claimed in my patent application entitled Filling Sheet Forming Apparatus filed even date herewith, Ser. No. 251,645.

BACKGROUND OF THE INVENTION

The present invention relates to means for the interphase contact of a liquid and a gas and the invention has particular utility in the liquid-gas heat exchange art.

It is known in the art to provide liquid-gas contact apparatus of the type wherein a liquid to be cooled or heated, by a cooler or warmer stream of air or gas, is sprayed from a plurality of outlet nozzles positioned above packing or filling within a tower through which passes in cross-flow manner or in counter-current manner a stream of gas.

It is also known to use filling units in such liquid-gas contact apparatus consisting of units of sheets of polyvinyl chloride or other plastic material wherein the units consist of alternate series of corrugated sheets and flat sheets with the corrugations running in a generally vertical direction. It is also known in the art to provide such devices wherein multiple units of such sheet-like filling are stacked within a cooling tower, preferably with the planes of the flat sheets being alternately directed 90.degree. to each other.

It has been found that such prior art sheet-like filling has not functioned satisfactorily due to the tendency of the liquid to form into streams and not to flow uniformly over the entire surface areas of the flat and corrugated sheets. This action is caused in part by capillary action of the liquid and is accentuated by non-vertical positioning of the sheet-like filling.

The result is a substantial reduction in the interphase contact between the liquid and the gases and a consequent reduction in heat transfer between the gas and the liquid. It has been proposed to remedy the channeling of the liquid in such sheet-like filling by perforating the corrugated and flat sheets to interrupt liquid flow. Improved liquid-gas contact has also been attempted by increasing the number of filling units and by reducing the vertical length of the contact sheets in each unit. Increasing the number of units requires an increase in the number of unit supports and consequentially materially complicates installation and increases material costs.

Increasing the number of units, perforating the sheets and arranging the units at 90.degree. with respect to adjacent units have improved the interphase contact in sheet filled liquid-gas contact apparatus but not to a significant amount.

It has also been proposed to provide stacked units of corrugated and flat sheets with "warped" surfaces so that the orientation of the corrugation troughs vary in a continuous path from the upper end to the lower end of the filling sheets. It has been found that the costs of manufacturing, assembling and installing such warped sheet filling units has been prohibitive.

THE PRESENT INVENTION

It is a primary object of the present invention to provide filling sheets for liquid-gas contact apparatus constructed of deformable material such as polyvinyl chloride plastics which materially reduce or eliminate the disadvantages encountered in the use of plastic filling sheets in prior art apparatus.

It is an object of the invention to provide corrugated filling sheets of filling units composed of alternate corrugated and flat elements provided with a plurality of ramp-like deformed areas adapted to bring about deviation of the streams of cooling liquid whereby the liquid traverses a greater area of the filling sheets and thus increases the interphase surfaces thereof.

It is another object to provide such filling sheets wherein the deformations which reduce liquid channeling are provided along edges of the corrugations thereof and to provide such ramps in zones where the corrugated sheets are joined to flat sheets that is to provide such deformed areas along the lines of intersection between the corrugated sheets and flat sheets.

The invention will be more particularly described in reference to the accompanying drawings wherein:

FIG. 1 is a fragmentary diagrammatic prospective view of a liquid-gas contact apparatus including the improved filling sheets of the present invention;

FIG. 2 is an enlarged detailed prospective view of a corrugated filling sheet having one form of deformations along the fold lines thereof;

FIG. 3 is a view similar to that shown in FIG. 2 of a modified filling sheet unit of the invention;

FIG. 4 is a view of a filling sheet unit similar to that illustrated in FIG. 3 of a further form of the present invention;

FIG. 5 is an enlarged fragmentary prospective view of another form of a filling sheet within the scope of the present invention; and

FIG. 6 is a section substantially on line 6--6 of the corrugated filling sheet shown in FIG. 5 in conjunction with a pair of flat sheets.

Referring to the drawing and in particular to FIG. 1 thereof, 10 generally designates a liquid and gas contact apparatus which includes a housing 12 having a lower gas inlet and an upper gas outlet with the flow path of the gas stream indicated by arrows A. Within the walls of the contact apparatus and between the gas inlet and gas outlet are arranged a plurality of stacked units of filling sheet structures generally designated 14.

Positioned above the uppermost unit are a plurality of liquid distribution conduits 16 connected to a source of liquid to be cooled generally represented by the arrow S. The conduits 16 are provided with a plurality of outlet nozzles 18 which direct streams of liquid to be cooled to the upper surfaces of the filling sheet units 14 as shown at 20.

Each unit 14 is composed of a number of spaced apart corrugated filling sheets generally designated 22 and where desired a number of flat sheets 24 alternately spaced in respect to the corrugated sheets 22.

The sheets 22 and 24 may be formed of various plastic materials, plastic coated or plastic filled fabrics or paper, sheet metal, or the like. While a number of materials may be used in the construction of the filling sheets, particularly advantageous are the polyvinyl chloride plastics which are heat deformable, relatively inexpensive and relatively inert.

The flat sheets 24 are heat welded, cemented or otherwise attached to the corrugated sheets 22 along the apices of the resulting dihedrans identified by arrows 26, 28 and 30. The corrugated sheets 22 are provided with ramp-like deformations or protrusions 32, which are more clearly shown and will be described in reference to FIG. 2.

It will also be noted that the corrugated sheets 22 in FIG. 1 of the drawing have their top edges formed to promote splashing of the liquid issuing from the nozzles 18 by alternately bending a short lip in one direction as at 34 and then in the opposite direction as at 36 for each surface face of the corrugated structure. The ramp-like deformations 32 will be more particularly described in reference to FIG. 2.

In FIG. 2 the corrugated sheet 22 has front edges 42 and rear edges 40 between which lie plane surfaces 44a to 44h. Further, in FIG. 2, the ramp-like deformations 32, while of the same general configuration, differ and for purposes of illustration, there are provided internal ramps between dihedran 26 designated 32a and oppositely directed ramps 32b. The outer edges 42 are also provided with oppositely directed ramp-like protrusions specifically designated 32c and 32d. It will also be noted in considering, for example, FIG. 2, the edges 40 and 42 are flattened or truncated, as at 41, to provide extended surfaces to which flat sheets such as flat sheets 24 of FIG. 1 may be welded or otherwise secured. Thus, the term "edge" as used herein is meant to include a narrow line at the apex of the V-sections or broader surfaces as hereinbefore set forth.

Referring specifically to internal ramps 32a, which are deformed to define dihedrans each having an edge 46 which is an outward projection of the internal line formed by rear edge 40 of the corrugated sheet, the edge being arranged obliquely with respect to the direction of the corrugation. Thus, a stream of liquid flowing down the internal edge 40 would be divided at point A.sub.2 and a portion of the stream would be directed toward point C.sub.2 and a portion would be directed toward point B.sub.2. Counterpart dihedral deformations 32b are directed from surfaces 44a, c, e, and g whereas the previouslydescribed dihedrans 32a were primarily directed from surfaces 44b, d, f, and h. Thus, a stream of liquid flowing down the internal surface of edge 40 would be diverted at point D.sub.2 with a portion of the stream directed to point E.sub.2 and a portion to point F.sub.2. The other dihedrans 32c and 32d correspond to dihedrans 32a and b except they are deformed adjacent edges 42.

Referring to FIG. 3 of the drawings, a modified filling sheet unit generally designated 22a is illustrated including one plane sheet 24. The corrugated sheet has front edges 42a and rear edges 40a. The deformations of this form of the invention are provided alternately on faces 50a, b, c, d, e, etc. and such deformations are designated 52a, 52b, 52c and 52d. Referring particularly to deformations 52b, on face 50c, it will be seen that the deformation is in the form of a triangular pyramid and has faces A.sub.3, B.sub.3 and C.sub.3. Face C.sub.3 is enclosed in the plane tangent to the corrugation including the edge E.sub.3, D.sub.3. Liquid channeling down the edge 42a of the corrugated sheet or at the intersection of face 50c and a front plain sheet, not shown, would be diverted at point E.sub.3 toward point B.sub.4 and toward point C.sub.4. Similar divergence of the flowing liquid would occur at deformations 52a, only in the opposite direction, that is, toward faces 50b and 50d of the corrugated structure.

In respect to deformations 52c and 52d, which are formed adjacent the rear edges 40a, they would also bring about more uniform spreading of the liquid to be cooled. Referring, for example, to deformation 52c on face 50c, the deformation has faces 60a, 60b, and 60c. Liquid flowing down the channel 40a at the apex of faces 50b and 50c would be diverted at point 60d causing a portion of the liquid to flow toward point 60e and internal point 60f.

The alternate internal deformation 52d would cause redirection of liquid from the channel 40a onto the face 50b. It will be particularly noted that the deformations alternate on one face and then on the other change the flow pattern of the two dihedrons 28 and 30. Such deformations would also modify the flow defined by the surfaces forming dihedron 26.

Referring now to FIG. 4, a form of the invention is shown containing deformations which are composites of the deformations shown in FIGS. 2 and 3. These deformations may be provided in the front edges 42b or the rear edges 40b of corrugated sheet 22b and in each instance each deformation is adapted to cause liquid flowing in the channels formed by edges 40b and 42b to spread onto the plane faces of the dihedrons having the edges as their apices. Thus, a single deformation brings about deviation of the liquid streams to two of the three dihedrons defined by one corrugated sheet and one plane sheet. In FIG. 4 the outer edge deformations are designated 70 while the inner deformations are designated 72 and the three dihedrons defined by the corrugated sheet 22b are designated 74, 76, and 78. By way of example, referring to deformation 72 formed in surfaces 80 and 82, the deformation is formed by moving a point 84 originally lying along edge 40b between surfaces 80 and 82 along a plane bisecting dihedron 76 and in a plane tangent to the corrugation and including the edge 40b which results in the first ramp-like projection 86 similar in form to the ramp-like projections shown and described in FIG. 2 and a second projection 88 similar to deformations 52a of the FIG. 3 form of the invention in dihedron 78.

Now referring to FIGS. 5 and 6, a complex series of deformations are illustrated which will bring about the deviation of liquid of a single stream into each of the three dihedrons defined by a corrugation and a plane sheet. In FIGS. 5 and 6, the corrugated sheet is designated 22c and the pair of plane sheets are designated 24c and 24c'. The forward edges of the corrugations are designated 42c while the rearward edges are designated 40c. It will be also noted that the corrugated sheet 22c, shown in perspective in FIG. 5, clearly illustrates the use of flattened edges and the alternate bending of the leading edges 34c and 36c previously referred to in the description of FIG. 1. In this form of the invention the outer edge deformations are generally designated 100 and the corresponding rearward edge deformations are designated 100a. The three dihedrons defined by plane sheet 24c or 24c' and the corrugated surfaces are designated 103, 104, and 105. The deformations 100 are defined by a protrusion or ramp having triangular surfaces 151 and 152 having a common edge 156 located in the bisecting plane of the angle between faces 101 and 102. The protrusion also includes a pair of protrusions 153 and 154 corresponding to the protrusions 52c and 52d respectively of the form of the protrusion shown in FIG. 3 and a further plane surface 155 formed therebetween. The plane surface 155 is positioned in the plane tangent to the corrugation including the edge 42c to thereby insure large surface contact with plane sheet 24c' or 24c. Diversion of a single stream of liquid flowing down edge 42c would be toward point A.sub.5 in dihedron 104, B.sub.5 in dihedron 103, C.sub.5 in dihedron 103, and D.sub.5 in dihedron 105. Thus, diversions occur in each of the three dihedrons and on the internal and external surfaces of the corrugation and the plane wall forming such dihedrons.

From the foregoing description it will be seen that the aims and objectives hereinbefore set forth, and others, are fully accomplished and in addition it will be seen that none of the disclosed deformations includes an undercut portion, thus the protrusions may be simply formed during manufacture of the filling sheets.

It will be recognized by those skilled in the art that the spacing between successive deformations would be chosen to eliminate re-formation of liquid streams and that a single unit may include deformations of the forms shown in FIGS. 2, 3, 4, 5, and 6, and that such deformations may be used in conjunction with perforations or holes which are known in the art as liquid spreading means. It will be further recognized that protrusions which assist in more uniform liquid distribution on the surfaces of the sheet-like fillings also aid in heat transfer by creating turbulance in the gas or air flowing through the liquid contact apparatus.

As more fully disclosed in my co-pending application, Ser. No. 251,645 filed even date herewith, manufacturing the corrugated filling sheets with protrusions may be simply carried out in continuous sheet corrugation forming apparatus, thus the cost of manufacture of the improved filling piece is not materially increased.

Claims

I claim:

1. A filling sheet for liquid gas-contact apparatus comprising an extended surface member corrugated to provide laterally spaced inner and outer edges and a plurality of protrusions formed in selected zones of the edges formed between dihedral surfaces of the corrugations; wherein each of said protrusions form ramps on at least one face of the sheet, in the vicinity of the edge of a corrugation; and wherein each of said ramps is triangle-shaped and has two of its sides extending from a point of the edge and enclosed in the planes of the corrugation sides, the third side extending transversally between said faces.

2. The invention defined in claim 1 wherein at least the corrugated sheet comprises plastic.

3. The invention defined in claim 2 wherein the plastic comprises polyvinylchloride.

4. A filling sheet as defined in claim 1 wherein each of said ramps is triangle-shaped and projects over one face of the corrugation and this ramp being limited laterally by a plane face enclosed in the plane tangent to the corrugation along the edge.

5. A filling sheet as defined in claim 1 wherein each of the protrusions is formed by moving laterally one point of a corrugation edge, to form two ramps, one on each side of the corrugation, and projecting respectively on the concave side and on the convex side thereof.

6. A filling sheet as defined in claim 1 wherein a ramp is formed on each face of the two sides of each corrugation.

7. A filling sheet as defined in claim 6 wherein the ramps located in the concave part of each of the corrugations have a common edge enclosed in the symmetry plane of the corrugation, which symmetry plane also forms a symmetry plane for the entire protrusion.

8. A filling sheet as defined in claim 6 wherein the ramps which project over the convex part of the corrugation are arranged symmetrically with respect to each other, on both sides of the symmetry plane of the corrugation and are limited by a common plane face enclosed in the plane tangent to the corrugation along the edge.

9. A filling device defined in claim 1 wherein the upper edges of the corrugated sheets are bent half on one side and half on the other side of the sheet.

10. The invention defined in claim 1 including plane filling sheets secured to the edges of the corrugated sheets; and wherein the upper edges of the corrugated and plane sheets are bent half on one side and half on the other side of the sheets.