Contact bodies for liquid and gas

A gas liquid contact body for use in a gas liquid contact apparatus is disclosed which consists of at least first and second sets of corrugated sheets with the sheets in the first set being disposed alternately with the sheets of the second set. The corrugations in the first set of sheets extend vertically in the contact body and the corrugations in the second set extend at an angle to the corrugations of the first set. The passageways formed between the inclined corrugations and the vertical corrugations serve to distribute air and water evenly through the contact body and avoid clogging thereof.

BACKGROUND OF THE INVENTION 
The present invention relates to an improved contact body for use in a 
liquid and gas contact apparatus and, in particular, to a contact body 
formed of alternating corrugated sheets of material. 
Contact bodies or packings for gas and liquid contact apparatus such as, 
for example, cooling towers, have been previously proposed in which the 
contact body is formed of adjacent corrugated sheets of material. 
Corrugated sheets are placed adjacent one another with their ridges or 
crests contacting each other so that channels or passageways are formed 
between the sheets to provide continuously varying width passages in the 
sheets which result in the flow direction of the gas and liquid being 
repeatedly changed during passage through the body. It has been found that 
contact bodies of this type are highly efficient in operation. One such 
contact body is shown in U.S. Pat. No. 3,262,682 to Bredberg. This type of 
cross fluted contact body is commonly used in cooling structures such as 
shown, for example, in U.S. Pat. No. 5,013,492. This Munters' type pack or 
contact body has been highly successful in use and generally accepted as a 
cooling tower medium where fairly large volumes of water are recirculated 
over it. 
In cooling towers in which the Munters', type of contact body has normally 
been used, a water recirculating system is typically provided. In such 
systems a certain amount of water is normally bled off from the system in 
order to keep salts and suspended solids in the water from exceeding 
certain concentrations due to evaporation. A source of makeup water 
provides fresh water to makeup for evaporation and bleed-off. However, due 
to restrictions on water usage, bleed-off levels have been reduced, 
raising the levels of salts and suspended solids in the recirculating 
water. As a result, the openings between the sheets become plugged by a 
combination of hardness salts, biological growth, silt, and other 
suspended materials in the water. The plugging is exacerbated by the fact 
that the amplitude heights of the corrugations in the pack are generally 
made relatively small and oriented angularly in the sheet in order to 
increase the retention time of the descending water and the cooling 
efficiency of the contact body. One solution to this problem has been to 
provide contact bodies with relatively large amplitude heights in their 
corrugations in order to increase the size of the passageways. However, 
this results in a reduction of the available contact surface for water and 
air and considerably less cooling. 
OBJECT OF THE INVENTION 
It is an object of the present invention to provide an improved contact 
body which has improved ability to maintain the passageways in the body 
clear while sacrificing little of the cooling efficiency. 
Another object of the invention is to provide a contact body which reduces 
the pressure drop of gas through the body to save on power requirements 
while sacrificing little of the efficiency. 
Yet another object of the invention is to provide a further improvement of 
contact bodies of the type described in the above-mentioned Bredberg and 
Munters patents. 
SUMMARY OF THE INVENTION 
In accordance with an aspect of the present invention, a contact body for 
use in a liquid gas contact apparatus such as a cooling tower is provided 
in which the gas and liquid flow in counter-current relationship to one 
another. The contact body is composed of at least first and second sets of 
corrugated sheets having corrugations disposed in a direction transversely 
of the horizontal plane of the contact body. The sheets of the first set 
are disposed alternately with the sheets of the second set, with the 
corrugations of the first set extending vertically and crossing the 
corrugations of the second set. The corrugations of the first set of 
sheets extend from the lower air inlet edge of the contact body to the 
upper air outlet edge thereof and cooperate with the corrugations of the 
second set to define passageways penetrating from end to end of the 
contact body. The corrugations of the corrugated sheets bear against one 
another so that the sheets touch where the crests of their respective 
corrugations cross whereby the passageways vary in width from zero at the 
places of contact between the sheets to a maximum width defined by the 
amplitude of the corrugations. The improvement provided by the present 
invention includes providing sheets in the fill pack whose corrugations 
extend vertically. By this arrangement the liquid will descend faster on 
the sheet with the vertical corrugations than on the adjacent sheets with 
slanted corrugations. This produces a flushing action which will prevent 
buildups of suspended solids such as silt and mud. 
In one embodiment the slanted corrugations of the sheets in one set are 
formed with a smaller amplitude than the vertical corrugations of the 
other set, thereby enlarging the passages and increasing the flushing 
action. 
The above and other objects, features and advantage of this invention will 
be apparent in the following detailed description of an illustrative 
embodiment thereof, which is to be read in connection with the 
accompanying drawings, wherein:

Referring now to the drawing in detail, and initially to FIGS. 1 and 2, a 
cooling tower T is disclosed which is similar to the cooling tower 
structure shown in U.S. Pat. No. 5,013,492. Cooling tower T contains a 
contact body 10 mounted in a housing or enclosure 12 whose bottom forms a 
water collecting basin 14. Housing 12 has openings 16 formed therein for 
admittance of air which passes in an upward direction through the contact 
body 10 and escapes through an outlet 18 within which a fan 20 with a 
motor 22 is provided. 
Water is supplied to the contact body 10 from above through a distributor 
24, or the like. For ease of illustration, distributor 24 has been shown 
as a stationary device or pipe with escape hole 26 on the lower side. 
However, a variety of different liquid distributing arrangements can be 
used in cooling towers as are known to those skilled in the art. 
Contact body 10 is formed of a plurality of individually formed packs or 
bodies. In the illustrative embodiment three layers 10a, 10b, and 10c of 
such packs 10.sup.1, 10.sup.11, 10.sup.111 are provided, stacked upon one 
another. Each pack is formed of a plurality of thin layers or sheets, 
which preferably are folded or corrugated and which are positioned 
vertically. The folds or corrugations cross one another and bear against 
one another at their points of contact where they are bonded together by 
means of a suitable bonding agent. The lines 28 denote the corrugations in 
every second sheet 31 and the dotted lines 30 denote the corrugations in 
the sheets 32 therebetween (in the left pack in FIG. 1 only one pair of 
lines is shown for ease of illustration). In FIG. 2, one of the sheets 31 
is broken away for illustrative purposes to illustrate the next adjacent 
sheet 32 having the corrugations 30 therein. 
The corrugated sheets 31 form channels or passageways with sheets 32 that 
penetrate from the lower end to the upper end of the contact body and 
produce both horizontal and vertical components of direction. The sheets 
32 form vertical passageways in the contact body helping to distribute 
liquid from one set of passageways to another. The passageways have a 
continuously varying width from zero at the points of contact 50 between 
the sheets up to the maximum sum of the amplitudes of the corrugations. 
The amplitudes h of the sheets in each set (See FIG. 5) may have same 
heights or amplitudes (e.g. 5 to 30 mm) so that the passageways have a 
maximum height of double the amplitudes of the corrugations. Preferably, 
the amplitudes of the corrugations in the two sets may be different. For 
example, the corrugations in sheets 32 may be larger than those of the 
sheets 31, or vice versa. These larger corrugations help prevent clogging 
in the contact body. 
Preferably, the corrugated sheets 31, 32 of the contact body are formed of 
a cellulosic material or a plastic material as is known in the art. 
The water distributed from above over the top of the contact body flows 
downwardly along both sides of the sheets forming the contact body as a 
film, following a winding path in order to obtain a very high rate of 
interaction between the fluids per unit of surface of the layers. When the 
water flows down in the form of a thin film along the layers in a 
substantially vertical direction of flow, gas, e.g., air, enters through 
the openings 16 in casing 12 as indicated by the arrows 42 into the casing 
and flows vertically through the passageways formed in the contact body 
countercurrent to the water. The air escapes through an outlet 18 within 
which the fan 20 is provided. The water is withdrawn from the collecting 
space 14 through conduit 34 controlled by a valve 36 to be recirculated in 
a known manner to the distributor 24. 
As is known in the art, some of the water may be bled off as it becomes 
contaminated and makeup water can be added to the circulatory flow as 
necessary. In addition, the level of water in the collector can be 
controlled by a float mechanism 38 causing fresh water to be supplied to 
replace losses due to evaporation within the contact body. 
Each contact body pack is turned 90.degree. with respect to the pack 
immediately therebelow. Thus the sheets in the packs 10.sup.1 of layer 10a 
extend transversely of the sheets in packs 10.sup.11 of layer l0b, while 
the sheets in pack 10.sup.11 of layer 10b extend transversely of the 
sheets in packs 10.sup.111 of layer 10c. As a result, the paths of travel 
of air and gas in the contact body changes at the interfaces between the 
packs. 
In another embodiment of the invention, the individual packs are formed of 
three sets of sheets, as illustrated in FIG. 3. In this embodiment, the 
third set of sheets 33 are corrugated like sheets 31, but the sheets are 
arranged with the corrugations extending in an opposite direction but at 
the same or different angles from the corrugations of sheets 31. 
Preferably, the three sets of sheets 31, 32 and 33 described above with 
respect to FIG. 3 are arranged in the order illustrated in FIG. 4, wherein 
sheet 31 is followed by the vertically corrugated sheet 32, which in turn 
is followed by the oppositely corrugated sheet 33 and then by another 
sheet 31. As a result, periodically through the contact body a sheet 31 is 
in contact with and engages the sheet 33. This arrangement and 
relationship of the sheets with the additional interspersing of vertically 
corrugated sheets aids in reducing the tendency of clogging of the fill 
material. 
Preferably, the angle of inclination of the corrugations relative to the 
horizontal plane may be from 45.degree. to 70.degree. for the 
corrugations, or 20.degree. to 45.degree. from the vertical. 
By arranging the contact body sheets in this manner, the film of water 
passing over the sheets will move downwardly faster on the sheets with the 
vertical corrugations than on the sheets with the slanted corrugations, 
thereby producing a flushing action which will prevent buildups of 
suspended solids in the passages. 
In the embodiments of FIGS. 3 and 4, as in previously described 
embodiments, the amplitudes or heights of the corrugations can be varied 
between the sheets. In particular, for example, the sheets 31, 33 can have 
corrugations of the same amplitude while the vertically corrugated sheets 
32 can have a greater amplitude. That amplitude can be varied as desired 
and may be twice that of sheets 31, 33. The enlarged passageways provided 
by this arrangement together with the vertical corrugations of sheets 32 
will serve to prevent clogging. 
Preferably, as illustrated for example in FIG. 2 and in the layer 10b in 
FIG. 1, the vertically corrugated sheets may be formed of a greater length 
than the cross-corrugated sheets so that they extend beyond the bottom 
edges of the cross-corrugated sheets. The vertically corrugated sheets 
therefore will provide support for the pack on the fill layer below it. 
The vertically corrugated sheets will also provide a dewatering edge for 
the sheets with the slanted corrugations. This enhances the flushing 
action of the water at the interface between fill layers where clogging is 
likely to occur. 
Although the present invention has been described herein in detail in 
connection with the accompanying drawings, it is to be understood that 
various changes and modifications may be affected therein by those skilled 
in the art without departing from the scope or spirit of this invention.