U.S. patent number 3,862,280 [Application Number 05/396,984] was granted by the patent office on 1975-01-21 for apparatus for gas-liquid contact.
This patent grant is currently assigned to AB Carl Munters. Invention is credited to Walter Polovina.
United States Patent |
3,862,280 |
Polovina |
January 21, 1975 |
APPARATUS FOR GAS-LIQUID CONTACT
Abstract
Apparatus for gas-liquid contact having a contact body mounted
in a housing, said contact body being formed from a plurality of
corrugated sheets of a fibrous web material impregnated with a
polyepoxy-cross-linked plasticized rubber composition.
Inventors: |
Polovina; Walter (Princeton,
NJ) |
Assignee: |
AB Carl Munters (Sollentuna,
SW)
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Family
ID: |
26882385 |
Appl.
No.: |
05/396,984 |
Filed: |
September 13, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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330101 |
Feb 6, 1923 |
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186768 |
Oct 5, 1971 |
3798057 |
Mar 19, 1974 |
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Current U.S.
Class: |
261/112.2;
428/178 |
Current CPC
Class: |
D21H
17/74 (20130101); C03C 25/47 (20180101); F28C
1/02 (20130101); F28F 25/087 (20130101); D21H
5/0002 (20130101); D21H 21/34 (20130101); C03C
25/26 (20130101); F28C 1/04 (20130101); D06M
15/55 (20130101); C03C 25/27 (20180101); B01J
19/32 (20130101); D21H 27/40 (20130101); D06M
15/227 (20130101); C04B 41/4838 (20130101); Y02B
30/70 (20130101); Y10T 428/24661 (20150115); B01J
2219/32227 (20130101); B01J 2219/3221 (20130101); B01J
2219/3222 (20130101); B01J 2219/32425 (20130101); B01J
2219/32483 (20130101); B01J 2219/32441 (20130101) |
Current International
Class: |
B01J
19/32 (20060101); D06M 15/37 (20060101); D06M
15/55 (20060101); D06M 15/227 (20060101); F28F
25/08 (20060101); F28F 25/00 (20060101); D04H
1/64 (20060101); C04B 41/48 (20060101); C04B
41/45 (20060101); C03C 25/26 (20060101); D06M
15/21 (20060101); C03C 25/24 (20060101); C03C
25/10 (20060101); B01f 003/04 () |
Field of
Search: |
;117/126AB,126R,136,161A
;260/3.3,837R ;261/96,98,112,DIG.11 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Miles; Tim R.
Attorney, Agent or Firm: Curtis, Morris & Safford
Parent Case Text
This is a continuation of application S.N. 330,101, filed Feb. 6,
1973 and now abandoned, which is a continuation-in-part of
application S.N. 186,768, filed Oct. 5, 1971 and now U.S. Pat. No.
3,798,057 granted Mar. 19, 1974.
Claims
What is claimed is:
1. Apparatus for gas-liquid contact having means for mounting a
contact body therein and a contact body comprising a plurality of
facially opposed corrugated sheets with the corrugations in
adjacent sheets being disposed at an angle to each other and the
corrugations in alternate sheets being disposed parallel to form a
plurality of criss-crossing channels for gas and liquid, said
corrugated sheets being a fibrous web impregnated with from 10 to
30 percent, by weight of the impregnated web, of a mixture
comprising a chlorinated polymeric C.sub.3 or C.sub.5 hydrocarbon,
about 5 to about 100 percent, by weight of said polymer, of a
chlorinated terphenyl or chlorinated paraffin; and about 0.5 to
about 10 percent, by weight of said polymer, of a polyglycidyl
ether of a polyphenol.
2. Apparatus as in claim 1 wherein said contact body comprises
sheets impregnated with a mixture which additionally comprises up
to 2 percent of carbon black and up to 50 percent of mineral
fillers, by weight of said polymer.
3. Apparatus for gas-liquid contact having means for mounting a
contact body therein and a contact body comprising a plurality of
facially opposed corrugated sheets with the corrugations in
adjacent sheets being disposed at an angle to each other and the
corrugations in alternate sheets being disposed in parallel to form
a plurality of criss-crossing channels for gas and liquid, said
corrugated sheets being a non-flammable web of mineral fibers
impregnated with from 10 to 30 percent, by weight of the
impregnated web, of a mixture comprising: (1) a chlorinated rubber
or chlorinated polypropylene comprising about 65 percent by weight
of chlorine; (2) about 5 to about 100 percent, by weight of said
chlorinated rubber or chlorinated polypropylene, or a chlorinated
terphenyl or chlorinated paraffin comprising about 40 to 70 percent
by weight of chlorine; (3) about 0.5 to about 10 percent, by weight
of said chlorinated rubber or chlorinated polypropylene, of a
polyglycidyl ether of a bisphenol.
4. Apparatus as in claim 3 wherein said contact body comprises
sheets impregnated with a mixture which additionally comprises from
0 - 2 percent, by weight of said chlorinated rubber or chlorinated
polypropylene, of finely divided carbon black.
5. Apparatus for gas-liquid contact having means for mounting a
contact body therein; said contact body comprising a plurality of
facially opposed operatively interconnected sheets of an
impregnated fibrous web defining a plurality of channels in said
contact body through which gas and liquid are passed; said sheets
being impregnated with from 10 to 30 percent by weight of the
impregnated web, of a mixture comprising a chlorinated polymeric
C.sub.3 or C.sub.5 hydrocarbon, about 5 to 100 percent, by weight
of said polymer, of a chlorinated terphenyl or chlorinated
paraffin; and about 0.5 to 10 percent, by weight of said polymer,
of a polyglycidyl ether of polyphenol.
6. Apparatus as in claim 5 wherein said plurality of facially
opposed operatively interconnected sheets includes corrugated
sheets operatively connected to adjacent sheets in said contact
body thereby to form said channels and to allow liquid to flow
through said contact body.
Description
The present invention relates to cooling towers for gas-liquid
contact. More in particular, the present invention relates to
cooling towers having a contact body mounted in a housing, said
contact body being formed from a plurality of sheets of an
impregnated fibrous web defining a plurality of channels or ducts
in said contact body through which gas and liquid are passed.
A better understanding of the present invention and of its many
advantages will be had by referring to the accompanying drawings,
in which:
FIG. 1 is a vertical longitudinal section through one embodiment of
a cooling tower according to the present invention;
FIG. 2 is a vertical longitudinal section of a further embodiment
of a cooling tower according to the invention; and
FIG. 3 is a perspective view, partially in section, of a contact
body adaptable to use in the cooling towers of the invention.
FIG. 1 shows one embodiment of a cooling tower comprising casing 10
in which is mounted contact body 11. The base of casing 10 is
formed into sump 12 having float 19 and drainage line 20. A liquid,
such as water, is introduced through liquid supply line 17 and
passes over contact body 10 after discharge from perforations 18 in
supply line 17. A gas, such as air, is introduced in cross-current
or counter-current to the liquid flow through openings 13 in
portions of casing 10 beneath the contact body. Air may be pulled
in an upward direction by fan 15, driven by motor 16, both mounted
in gas outlet 14 above contact body 11 in casing 10 or the fan may
be eliminated in a natural draft system. When the water or other
liquid in sump 12 reaches a pre-determined minimum level, float 19
activates valve and/or pump means (not shown) to introduce
additional liquid into the circulating liquid system. Within the
contact body, the gas and liquid introduced thereinto are in a
heat-exchange relationship.
FIG. 2 shows a further embodiment of a cooling tower having casing
21 in which one or more contact bodies 22 are mounted. The base of
the casing is formed into sump 23 having float 24 and drainage line
25. In this embodiment, a gas such as air enters channels or ducts
within the contact bodies at uncovered portions thereof 26 and may
be drawn upwardly, within the apparatus to outlet 29 equipped with
fan 30 and motor 31 therefor. A liquid, such as water, is
introduced into the cooling tower through liquid supply line 27 and
escapes from the line through perforations 28. Conveniently, the
liquid escaping perforations 28 is passed through pad 32 which more
evenly distributes the liquid to the channels or ducts within
contact bodies 22.
FIG. 3 shows a contact body suitable for use in the cooling towers
of FIGS. 1 and 2. The body comprises a plurality of corrugated
sheets 33, 34, 35, 36 with the corrugations in adjacent sheets,
such as 33 and 34, being disposed at an angle to each other and the
corrugations in alternate sheets, such as 33 and 35, or 34 and 36,
being disposed in parallel, whereby a plurality of criss-crossing
is formed within said contact body. When the contact body is
mounted in a cooling tower, the corrugations are generally at an
angle relative to the horizontal so as to permit the gravity flow
of liquid therethrough. The angle at which adjacent corrugated
sheets are disposed is not critical, and it is evident from FIGS. 1
and 2 that the angular disposition of the alternate sheets, as
suggested by the crossing solid and dashed lines in contact bodies
11 and 22 in these Figures, may vary from apparatus to apparatus
depending on a particular construction or particular function to be
performed thereby.
The corrugations in the corrugated sheets of contact bodies like
that shown in FIG. 3 are conveniently from 5 to 40 or 60
millimeters in height from trough to peak, and are usually from 10
to 30 millimeters. The corrugated sheets may be adhered one to
another at points of contact within the contact body or may be held
in fixed position by suitable spacing and retaining means at their
edges.
Heretofore, contact bodies like that shown in FIG. 3 have been
comprised of corrugated plastic sheets or, more conventionally, of
sheets of a fibrous woven or non-woven web. (Webs of mineral fibers
such as of glass or asbestos are preferred as being
non-inflammable.) Such fibrous webs are impregnated with a resin,
conventionally a phenolic resin or melamine-formaldehyde resin, to
impart greater rigidity and wet strength thereto.
It has been found that the impregnated sheet materials used to form
bodies in cooling towers in the prior art, while often satisfactory
at pH values surrounding the neutral point (pH 7), degrade rapidly
when in contact with water at higher or lower pH values.
Melamine-formaldehyde resins, for instance, hydrolyze fairly
rapidly at alkaline pHs. This is particularly undesirable because
the acid chromates heretofore widely used as additives in
water-cooled refrigeration and air conditioning systems are more
and more being replaced by alkaline additives. In general, the
contact bodies in prior art cooling towers are most useful at pHs
between 6 and 9 and at temperatures below 110.degree.F. At pH
values above or below these values and at temperatures above
110.degree.F., there is a strong tendency for the impregnating
resin therein to be attached and removed from the sheets, resulting
in weakening of the sheets and eventual destruction and collapse of
the contact bodies.
Further, where the liquids employed in the gas-liquid interchange
contain corrosive contaminants, for example organic solvents, a
rapid attack of the resins employed in the prior art contact
bodies, and subsequent rapid destruction of these bodies, has been
experienced.
The cooling towers of the present invention employ contact bodies
comprising a plurality of facially opposed corrugated sheets, as
shown in FIG. 3, wherein the sheets are impregnated and coated with
a mixture principally comprising a chlorinated hydrocarbon resin, a
chlorinated additive thereto which functions as a plasticizer
and/or film-forming agent, and a polyepoxy compound believed to
function as a cross-linking agent. Optionally, the coating mixtures
may contain pigments, particularly carbon black, and mineral
fillers such as clays or powdered silica.
The webs forming the contact bodies employed in the cooling towers
of the invention suitably may vary in thickness from 0.1 to 2 mm,
generally from 0.1 to 1 mm. Such webs are conveniently impregnated
by immersion thereof in an impregnating solution containing the
aforementioned impregnating mixture in an organic solvent such as
toluene for a time sufficient to saturate the web. Excess
impregnating solution is removed, and the damp sheet is then formed
(for example by vacuum forming) into corrugated sheets. Any
remaining solvent is removed from the sheets by evaporation,
generally at a temperature above room temperature and preferably at
a temperature above about 100.degree.C. In commercial production,
brief heating at 250.degree. - 300.degree.C. (30 - 60 seconds) is
employed. The sheets are then formed into contact bodies as
described above, either with the use of adhesive at points of
contact between adjacent corrugated sheets or by spacing and
supporting means at their edges.
The compositions used to impregnate the fibrous webs which form the
sheets of the contact bodies of the cooling towers of the present
invention principally comprise a chlorinated polymeric hydrocarbon,
specifically a chlorinated polypropylene (hereinafter "chlorinated
C.sub.3 polymeric hydrocarbon") or chlorinated rubber. The
chlorinated rubbers are preferred, and may be either natural
rubbers or synthetic rubbers. Both the natural and synthetic
rubbers principally comprise isoprene (C.sub.5) units, and will be
referred to hereinafter as "chlorinated C.sub.5 polymeric
hydrocarbons."
The rubbers contained varying amounts of chlorine. Suitable
commercially available materials (e.g. "Parlon") contain about 65
percent by weight of chlorine, for example, which insures good fire
resistance. The rubbers are available in a variety of grades and
molecular weights, for example between about 30,000 and 120,000
(weight average molecular weight).
Alternatively, chlorinated polypropylene resins, also commercially
available (e.g., "Parlon") with about the same degree of
chlorination (about 65 percent ), can be obtained in the same
variety of grades as the chlorinated rubbers.
A plasticizer and/or film-forming agent is employed with these
chlorinated C.sub.3 and C.sub.5 polymeric hydrocarbons.
Particularly suitable agents include the chlorinated terphenyls and
chlorinated paraffins, i.e., chlorinated higher aliphatic
hydrocarbons having 20 - 30 carbon atoms.
These chlorinated terphenyls and paraffin hydrocarbons are
available commercially (e.g., "Aroclor," "Chlorowax," "Chlorafin")
containing different amounts of chlorine. Materials containing
between about 40 percent and about 70 percent by weight of chlorine
are particularly useful.
The plasticizing and/or film-forming ingredients described above
are combined with the chlorinated polymeric hydrocarbon in amounts
from about 5 to 100 percent by weight of the polymeric hydrocarbon,
preferably in amounts from 5 to 50 or 5 to 25 percent by
weight.
The polyepoxy compound which imparts particular rigidity and
resistance to softening by heat to the compositions of the
invention is believed, because of its polyfunctionality, to behave
as a cross-linking agent in the compositions. The polyepoxy
compounds are glycidyl ethers of polyphenols, specifically
diglycidyl or polyglycidyl eithers of bisphenols such as bisphenol
A and bisphenol F.
In general, the amount by weight of such a polyepoxy compound in
the compositions of the invention may be between about 0.5 and 10
percent, by weight of the chlorinated polymeric hydrocarbon forming
the principal ingredient.
Finally, the compositions present in the contact bodies used in the
cooling towers of the present invention may optionally contain
pigments and/or fillers. In particular, the compositions may
contain up to about 2 percent, by weight of the chlorinated
polymeric hydrocarbon, of a pigment such as finely divided carbon
black which serves not only to color the composition but also
affords some degree of ultraviolet protection to the resinous
impregnant when the contact bodies are in cooling towers exposed
outdoors.
Other fillers and extenders which may optionally be present in
amounts up to 50 percent by weight of the chlorinated hydrocarbon
resin components include minerals such as finely divided clays,
amorphous silica, or aluminum oxide powders. The materials are used
in finely divided form, generally with an average particle size of
less than 2 microns in diameter, preferably less than 1 micron.
After impregnation of a fibrous web by the method described earlier
herein, or by alternative methods, the dried web generally
comprises from 10 - 30 percent of impregnant therein, by weight of
the treated product. This amount of impregnant can be applied from
solutions having a solids content of from 20 - 35 percent by
weight, for example.
Cooling towers according to the present invention employing contact
bodies formed from sheets of fibrous webs impregnated with a
composition as described above have shown unusually long lifetimes
for the contact bodies therein under circumstances in which
conventional contact bodies disintegrate rapidly and would require
replacement. The cooling towers of the invention are thus more
trouble-free, require less maintenance, and can be employed for
gas-liquid contact with liquids, such as those at high or low pH
values or containing corrosive contaminants, under conditions in
which cooling towers employing contact bodies of the type
conventional in the prior art would be unusable or would require
expensive maintenance for frequent replacement of the contact
bodies.
Further, the towers of the present invention can be used to cool
liquids from temperatures as high as 180.degree.F. without the same
loss of contact body structural strength observed in towers
employing contact bodies treated with prior art impregnants.
Finally, contact bodies comprising a web of mineral fibers treated
with the impregnants described herein are substantially
non-combustible and will not support flames.
* * * * *