CA2083118A1 - Heat exchanger - Google Patents
Heat exchangerInfo
- Publication number
- CA2083118A1 CA2083118A1 CA 2083118 CA2083118A CA2083118A1 CA 2083118 A1 CA2083118 A1 CA 2083118A1 CA 2083118 CA2083118 CA 2083118 CA 2083118 A CA2083118 A CA 2083118A CA 2083118 A1 CA2083118 A1 CA 2083118A1
- Authority
- CA
- Canada
- Prior art keywords
- recited
- layer
- heat exchanger
- microns
- metal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 46
- 239000002184 metal Substances 0.000 claims abstract description 46
- 239000004033 plastic Substances 0.000 claims abstract description 44
- 229920003023 plastic Polymers 0.000 claims abstract description 44
- 239000011888 foil Substances 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 14
- 239000002650 laminated plastic Substances 0.000 claims abstract description 13
- 239000007788 liquid Substances 0.000 claims abstract description 12
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000011552 falling film Substances 0.000 claims abstract description 6
- 229920002678 cellulose Polymers 0.000 claims abstract description 5
- 239000001913 cellulose Substances 0.000 claims abstract description 5
- 229920000728 polyester Polymers 0.000 claims abstract description 5
- 229920000098 polyolefin Polymers 0.000 claims abstract description 5
- 229910001369 Brass Inorganic materials 0.000 claims abstract description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000010951 brass Substances 0.000 claims abstract description 4
- 229910052802 copper Inorganic materials 0.000 claims abstract description 4
- 239000010949 copper Substances 0.000 claims abstract description 4
- 238000001704 evaporation Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 9
- 238000005260 corrosion Methods 0.000 claims description 5
- 230000007797 corrosion Effects 0.000 claims description 5
- 239000000853 adhesive Substances 0.000 claims description 4
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 239000012530 fluid Substances 0.000 claims 1
- 150000002739 metals Chemical class 0.000 abstract 1
- 241000446313 Lamella Species 0.000 description 20
- 239000010408 film Substances 0.000 description 9
- 230000008020 evaporation Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- GLGNXYJARSMNGJ-VKTIVEEGSA-N (1s,2s,3r,4r)-3-[[5-chloro-2-[(1-ethyl-6-methoxy-2-oxo-4,5-dihydro-3h-1-benzazepin-7-yl)amino]pyrimidin-4-yl]amino]bicyclo[2.2.1]hept-5-ene-2-carboxamide Chemical compound CCN1C(=O)CCCC2=C(OC)C(NC=3N=C(C(=CN=3)Cl)N[C@H]3[C@H]([C@@]4([H])C[C@@]3(C=C4)[H])C(N)=O)=CC=C21 GLGNXYJARSMNGJ-VKTIVEEGSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229940125758 compound 15 Drugs 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
- F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
- F28F19/04—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of rubber; of plastics material; of varnish
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
- F28F3/12—Elements constructed in the shape of a hollow panel, e.g. with channels
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Laminated Bodies (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A heat exchanger, evaporator made from the heat exchanger, and method of utilization thereof, take advantage of the thin yet strong and good heat exchange surface that is provided by a metal-plastic laminate. A laminate is typically either one plastic layer and a metal layer, or two plastic layers sandwiching a metal layer between them. The laminate normally has a thickness of less than about 200 microns, for example the metal foil layer having a thickness of about 5-40 microns and the plastic layer a thickness of about 12-25 microns. Aluminum, copper, and brass are good metals, while polyester and polyolefins are good plastics. Cellulose pulp mill plant liquid effluents may be passed in a falling film over the laminates to evaporate them, while steam is passed in the interior chamber between two laminates forming an evaporator.
A heat exchanger, evaporator made from the heat exchanger, and method of utilization thereof, take advantage of the thin yet strong and good heat exchange surface that is provided by a metal-plastic laminate. A laminate is typically either one plastic layer and a metal layer, or two plastic layers sandwiching a metal layer between them. The laminate normally has a thickness of less than about 200 microns, for example the metal foil layer having a thickness of about 5-40 microns and the plastic layer a thickness of about 12-25 microns. Aluminum, copper, and brass are good metals, while polyester and polyolefins are good plastics. Cellulose pulp mill plant liquid effluents may be passed in a falling film over the laminates to evaporate them, while steam is passed in the interior chamber between two laminates forming an evaporator.
Description
A HEAT EXCHANGER
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a heat exchanger, in which a new kind of an extremely thin, but yet strong heat exchange su~ace is utilized, and a method of5 evaporating an effluent from a cellulose pulp mill utilizing such a heat exchanger as a falling film evaporator.
Heat exchange devices, such as lamella heat exchangers, are conventionally manufactured of metal, e.g. of stainless steel. Lamellas have been manufactured of 1-1.5 mm thick metal plates to act as heat exchange elements, for example, in10 evaporators. Such a construction allows considerable pressure differences, but on the other hand it is heavy and rather expensive. If acid solutions are treated, the problem of corrosion arises, which again leads to the necessity of using specialsteel or titaniurn as the material of heat exchange surface, which considerably incraases the price of the equipmen~.
15 Heat exchangers of light, corrosion-r0sistant and inexpensive construction have been manufactured by utilizing a thin plastic fllm as a heat exchancje surface, whereby the heat exchange elements may, for example, be bag-like. Such heat exchangers are known, for example, from patent publications EP 34920 and DE
2511144. Plastics have, however, the disadvantage of poor heat conductivity and 20 poor physical properties when in a thin filrn configuration.
EP 2864~0 discloses a plate-type heat exchanger in which the heat exchanger element is rnanufactureci by combining two polymer panels of the thickness of 0.12-0.7 mm under heat and pressure to form flow channels th~rebetween. A first surface of one of the panels is coated with a particular material at a ciesired 25 channel pattern. A second surface of the other panei facing the first surface is treated with a material such that, when the two surfaces are combined, it attaches to the first panel surface, except at the flow channeis. The polymer used is preferably a polyamide, which may be coated by a metal film to improve i~s heat exchange proper~ies.
,.. ~
According to the present invention, the above mentioned problems are eliminated or minimi~ed. A heat exchanger applicable for differ0nt purposes is provided which is simple to manufacture, and the heat exchange surface of which conduets heat well, is thin and light, but yet at the same time strong.
5 A characteristic feature of the heat exchanger in accordanoe with the present invention is that the heat exchange surface of ~he heat exchange elements is formed of a laminate, which comprises at least two layers of different materials, a metal film layer and a plastics layer.
The laminate is manufactured preferably by combining a plastics layer to a thin 10 metal foil layer. The heat exchange surface thus generated is light and the strength thbreof is decisively better than that of a mere metal foil, and its heat transfer capabilities are greater than those of plastic. Also the manufacture of such a heat exchanger is less expensive than its metal counterpart.
Accordin~ to a preferred embodiment a laminate comprises three layers, i.e. two 15 plastics layers and a metal layer sandwiched therebetween.
The invention also contemplates use of the heat exchanger in a method of evaporating a liquid effluent (e.g. from a cellulose pulp mill) utiiizing an ev~porator surface comprising a metal-plastic laminate having a thickness of less than about 200 microns, comprising the step of passing pulp mill liquid effluellt in a falling film 20 over the metal-pla~ic laminate surface. This step may be further practiced bypassing the pulp mill effluent in contact with the plastic layer of the metal-plastic laminate. Steam may pass interiorly of the laminate to provide heat for the evaporation o7 ~he liquid effluent.
The invention is described more in detail below, by way of examplel with reference 25 to the accompanying drawings illustrating some embodiments in accordance withthe present inven~ion, in which a lamella is formed by using a laminate as a heat exchange surface.
. .
BRIEF DESCRIPTION OF THE DRAWINGS
Fl5URES 1 and 2 are fragmentary cross-sectional views of exemplary lamella according to the present invention; and FIGURE 3 is a side schernatic view illustrating use of the lamelia of FIGURE 1 as 5 an evaporator.
DETAILED DESCRIPTION OF THE DRAWINGS
It is possible, according to Fig. 1, to form a lamella, capable of use as a heattransfer eiement~ from a laminate. The laminate 3 comprises a rnetal foil 1 and a plastics film 2. It is manufactured by means of methods known per se, for 10 example, ~y gluing the metal foil 1 and the plastics film 2 to each other, or by extruding the plastics film 2 onto the metal foil 1. The lamella 4 is preferablymanufac~ured by attaching two rectangular laminate strips 3 to each other along the opposite edges thereo~, for example, by an adhesive joint 5 ~r the like. An opening is left on one side for the supply of the heat exchange medium and 15 another opening on the opposite side for the discharge thereof. The plastics layer Z in ~he laminate strip 3 may be longer ~han the metal layer 1, whereby the outer layers of plastics 2 are also at~ached to each other by adhesive joint 5, as seen in Fig 1.
It is normally not necessary to protect the interior surface of the interior layer --20 metal layer 1 in Fig. 1 (e.g. the steam space) -- of the lamella 4. However, if required the interior surface of metal layer 1 may be coated, as seen at 6 in Fig.
1, so that corrosion protection is provided for both the outer (by layer 2) and the inner surfaces of the metal foils 1. The protective coating 6 rnay comprise a film or paint.
~5 No additional supporting structure within the lamella 4 is required for maintaining the laminates 3 separate, although an interior support 7 could be provided if necessary. The inner pressure of the lamella 4 is slightly greater than the pressure of the outside, whereby the laminate walls 3 are maintained at a distance from each other due to a pressure difference so that a passage for th~ heat exchang~
medium is formed between the walls. The laminates 3 may also be ~ttach0d to each other by means of do~-like junction points (not shown) instead of spacers 7, for example by attachment with adhesive so as to limit ths changes of form 5 caused by the pressure of the heat exchange medium such as s~eam flowing between them.
In the embodiment in accordance with Fig. 2 a laminate 3' comprises three different layers, whereby a metal film layer 1' is set between two plastics layers 2'.
The laminate strips forming a lamella 4' are attached to each other, as described 10 in connection with Fig. 1, for example by a glue joint 5'.
The inner layer 1, 1' of the lamella illustrated in Figs. 1 and 2 is preferably the metal layer, and the outer layer 2, 2' the plastics layer. The metal layer 1, 1 ' may alternatively be on the outer surface of the lamella 4, 4'.
The metal layer 1, 1~ of the laminate may contain any known metal or a compound 15 or alloy thereof, such as aluminum, brass or copper. The most appropriate metal is believed to be aluminum due to its inexpensiveness. The ~hickness of the metal f~il layer 1, 1' may be very small, but it must provide the laminatc 3 with sufficient rigidity. Normally a thickness of layer 1, 1' less than about 100 microns is sufficient, but also thicker films (e.g. 200 microns) are possible and utili~ed, if the 20 attaching method of the laminate layers and the construc~ion of the heat exchanger require them. When aluminum is used usually a thickness of about 5-40 microns, preferably about 9-18 microns, is sufficient.
Applicable materials for the plastic layer 2, 2' may vary widely. Various plastiss may be chosen, for example, according to the application purpose of the particular 25 heat exchanger. The plastic material of the layer 2, ~' must provide a sufficient mechanical strength and corrosion resistance given the operation conditions of the heat exchanger. Preferably the thickness o~ each plastics film 2, 2' is less than about 100 microns. In most cases applicablc plastics are polyester and polyolefins, such as polyethylene and polypropylene, whereby the thickness of a 30 plastics layer is preferably about 12-25 microns.
A
,.
It must ba noted that the heat transfer efficiency of a laminate d~pends inversely directly on the thickness of the plastic layer 2, 2', whereas the good heat conductivity of the metal 1, 1' allows the free use of metal foils of diFferent thicknesses without the heat transfer efficiency cor,siderably decreasing. Thus the 5 thickness of the plastic layer 2, 2' must be adjusted so that ~t provides sufficient strength to ~he laminate 3, 3', but is not excessiveiy thick thus decreasing theconduct3vity of the laminate 3, 3'. The ~otal thickness of the laminate 3, 3' istypically less than about 200 microns.
Heat exchange units 8 may be formed by means known per se from lamellas 4, 10 4 in accordance with the drawings to provide units of differen~ sizes for different purposes. Lamellas 4, 4' may be attached one a~ter another in a supporting frameto form a lamella cassette, as is known per se. A desired nurrlber of cassettes m~y be set within the same casing to form an evaporator.
Thus it is possible to manufacture a rather rigid, but yet flexible heat exchange 15 lamella 4, which is corrosion resistant yet of sufficiently strong construction so as to ba used as an evaporator, e.g. for evaporating waste iiquids in a cellulose pulp mill. It operates, for example with respect to Fig. 3, as a falling film evaporator 8 in such a way that the condensing stearn is supplied into the intarior of the lamella 4 at inlet 10, and the liquid being evaporated (e.g. waste water) is caused to flow 20 over the outer surface of the lamella 4, as indicated at 9 in Fig. 3. Vapour obtained in the evaporation is withdrawn from the space betw0en the lamellas 4 at 11. Thetreated liquid (concentrate) is withdrawn at 12 and the condensate formed in theinterior of the lamella is withdrawn at 13. The condensate 13 (clean water) is recycled back to the process.
25 By causing a pressure difference between the heat surfaces the condensing temperature is brought higher than ~he evaporation temperature. Thus it is possible to transfer the condensing temperature through the laminates 3 for evaporation (temperature differenoe T is a function of the pressure difference and the boiling point elevation of the liquid being evaporated).
The above description illustrates the use of a laminate 3 formed by combining atleast two different materials for the manufacture of evaporators, but the use of the laminates is not limited for this. Instead it may be used as a heat transfer surface also in many other applications, such as in effecting heat transfer betw0en two 5 liquids.
While the invention has been dsscribed in connection with what is presently considered to b2 the most practical and preferred ernbodiment, it is to be understood that the invention is not to be lirnited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent 10 arrangements inciuded within the spirit and scope of the appended claims.
.. ~,.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a heat exchanger, in which a new kind of an extremely thin, but yet strong heat exchange su~ace is utilized, and a method of5 evaporating an effluent from a cellulose pulp mill utilizing such a heat exchanger as a falling film evaporator.
Heat exchange devices, such as lamella heat exchangers, are conventionally manufactured of metal, e.g. of stainless steel. Lamellas have been manufactured of 1-1.5 mm thick metal plates to act as heat exchange elements, for example, in10 evaporators. Such a construction allows considerable pressure differences, but on the other hand it is heavy and rather expensive. If acid solutions are treated, the problem of corrosion arises, which again leads to the necessity of using specialsteel or titaniurn as the material of heat exchange surface, which considerably incraases the price of the equipmen~.
15 Heat exchangers of light, corrosion-r0sistant and inexpensive construction have been manufactured by utilizing a thin plastic fllm as a heat exchancje surface, whereby the heat exchange elements may, for example, be bag-like. Such heat exchangers are known, for example, from patent publications EP 34920 and DE
2511144. Plastics have, however, the disadvantage of poor heat conductivity and 20 poor physical properties when in a thin filrn configuration.
EP 2864~0 discloses a plate-type heat exchanger in which the heat exchanger element is rnanufactureci by combining two polymer panels of the thickness of 0.12-0.7 mm under heat and pressure to form flow channels th~rebetween. A first surface of one of the panels is coated with a particular material at a ciesired 25 channel pattern. A second surface of the other panei facing the first surface is treated with a material such that, when the two surfaces are combined, it attaches to the first panel surface, except at the flow channeis. The polymer used is preferably a polyamide, which may be coated by a metal film to improve i~s heat exchange proper~ies.
,.. ~
According to the present invention, the above mentioned problems are eliminated or minimi~ed. A heat exchanger applicable for differ0nt purposes is provided which is simple to manufacture, and the heat exchange surface of which conduets heat well, is thin and light, but yet at the same time strong.
5 A characteristic feature of the heat exchanger in accordanoe with the present invention is that the heat exchange surface of ~he heat exchange elements is formed of a laminate, which comprises at least two layers of different materials, a metal film layer and a plastics layer.
The laminate is manufactured preferably by combining a plastics layer to a thin 10 metal foil layer. The heat exchange surface thus generated is light and the strength thbreof is decisively better than that of a mere metal foil, and its heat transfer capabilities are greater than those of plastic. Also the manufacture of such a heat exchanger is less expensive than its metal counterpart.
Accordin~ to a preferred embodiment a laminate comprises three layers, i.e. two 15 plastics layers and a metal layer sandwiched therebetween.
The invention also contemplates use of the heat exchanger in a method of evaporating a liquid effluent (e.g. from a cellulose pulp mill) utiiizing an ev~porator surface comprising a metal-plastic laminate having a thickness of less than about 200 microns, comprising the step of passing pulp mill liquid effluellt in a falling film 20 over the metal-pla~ic laminate surface. This step may be further practiced bypassing the pulp mill effluent in contact with the plastic layer of the metal-plastic laminate. Steam may pass interiorly of the laminate to provide heat for the evaporation o7 ~he liquid effluent.
The invention is described more in detail below, by way of examplel with reference 25 to the accompanying drawings illustrating some embodiments in accordance withthe present inven~ion, in which a lamella is formed by using a laminate as a heat exchange surface.
. .
BRIEF DESCRIPTION OF THE DRAWINGS
Fl5URES 1 and 2 are fragmentary cross-sectional views of exemplary lamella according to the present invention; and FIGURE 3 is a side schernatic view illustrating use of the lamelia of FIGURE 1 as 5 an evaporator.
DETAILED DESCRIPTION OF THE DRAWINGS
It is possible, according to Fig. 1, to form a lamella, capable of use as a heattransfer eiement~ from a laminate. The laminate 3 comprises a rnetal foil 1 and a plastics film 2. It is manufactured by means of methods known per se, for 10 example, ~y gluing the metal foil 1 and the plastics film 2 to each other, or by extruding the plastics film 2 onto the metal foil 1. The lamella 4 is preferablymanufac~ured by attaching two rectangular laminate strips 3 to each other along the opposite edges thereo~, for example, by an adhesive joint 5 ~r the like. An opening is left on one side for the supply of the heat exchange medium and 15 another opening on the opposite side for the discharge thereof. The plastics layer Z in ~he laminate strip 3 may be longer ~han the metal layer 1, whereby the outer layers of plastics 2 are also at~ached to each other by adhesive joint 5, as seen in Fig 1.
It is normally not necessary to protect the interior surface of the interior layer --20 metal layer 1 in Fig. 1 (e.g. the steam space) -- of the lamella 4. However, if required the interior surface of metal layer 1 may be coated, as seen at 6 in Fig.
1, so that corrosion protection is provided for both the outer (by layer 2) and the inner surfaces of the metal foils 1. The protective coating 6 rnay comprise a film or paint.
~5 No additional supporting structure within the lamella 4 is required for maintaining the laminates 3 separate, although an interior support 7 could be provided if necessary. The inner pressure of the lamella 4 is slightly greater than the pressure of the outside, whereby the laminate walls 3 are maintained at a distance from each other due to a pressure difference so that a passage for th~ heat exchang~
medium is formed between the walls. The laminates 3 may also be ~ttach0d to each other by means of do~-like junction points (not shown) instead of spacers 7, for example by attachment with adhesive so as to limit ths changes of form 5 caused by the pressure of the heat exchange medium such as s~eam flowing between them.
In the embodiment in accordance with Fig. 2 a laminate 3' comprises three different layers, whereby a metal film layer 1' is set between two plastics layers 2'.
The laminate strips forming a lamella 4' are attached to each other, as described 10 in connection with Fig. 1, for example by a glue joint 5'.
The inner layer 1, 1' of the lamella illustrated in Figs. 1 and 2 is preferably the metal layer, and the outer layer 2, 2' the plastics layer. The metal layer 1, 1 ' may alternatively be on the outer surface of the lamella 4, 4'.
The metal layer 1, 1~ of the laminate may contain any known metal or a compound 15 or alloy thereof, such as aluminum, brass or copper. The most appropriate metal is believed to be aluminum due to its inexpensiveness. The ~hickness of the metal f~il layer 1, 1' may be very small, but it must provide the laminatc 3 with sufficient rigidity. Normally a thickness of layer 1, 1' less than about 100 microns is sufficient, but also thicker films (e.g. 200 microns) are possible and utili~ed, if the 20 attaching method of the laminate layers and the construc~ion of the heat exchanger require them. When aluminum is used usually a thickness of about 5-40 microns, preferably about 9-18 microns, is sufficient.
Applicable materials for the plastic layer 2, 2' may vary widely. Various plastiss may be chosen, for example, according to the application purpose of the particular 25 heat exchanger. The plastic material of the layer 2, ~' must provide a sufficient mechanical strength and corrosion resistance given the operation conditions of the heat exchanger. Preferably the thickness o~ each plastics film 2, 2' is less than about 100 microns. In most cases applicablc plastics are polyester and polyolefins, such as polyethylene and polypropylene, whereby the thickness of a 30 plastics layer is preferably about 12-25 microns.
A
,.
It must ba noted that the heat transfer efficiency of a laminate d~pends inversely directly on the thickness of the plastic layer 2, 2', whereas the good heat conductivity of the metal 1, 1' allows the free use of metal foils of diFferent thicknesses without the heat transfer efficiency cor,siderably decreasing. Thus the 5 thickness of the plastic layer 2, 2' must be adjusted so that ~t provides sufficient strength to ~he laminate 3, 3', but is not excessiveiy thick thus decreasing theconduct3vity of the laminate 3, 3'. The ~otal thickness of the laminate 3, 3' istypically less than about 200 microns.
Heat exchange units 8 may be formed by means known per se from lamellas 4, 10 4 in accordance with the drawings to provide units of differen~ sizes for different purposes. Lamellas 4, 4' may be attached one a~ter another in a supporting frameto form a lamella cassette, as is known per se. A desired nurrlber of cassettes m~y be set within the same casing to form an evaporator.
Thus it is possible to manufacture a rather rigid, but yet flexible heat exchange 15 lamella 4, which is corrosion resistant yet of sufficiently strong construction so as to ba used as an evaporator, e.g. for evaporating waste iiquids in a cellulose pulp mill. It operates, for example with respect to Fig. 3, as a falling film evaporator 8 in such a way that the condensing stearn is supplied into the intarior of the lamella 4 at inlet 10, and the liquid being evaporated (e.g. waste water) is caused to flow 20 over the outer surface of the lamella 4, as indicated at 9 in Fig. 3. Vapour obtained in the evaporation is withdrawn from the space betw0en the lamellas 4 at 11. Thetreated liquid (concentrate) is withdrawn at 12 and the condensate formed in theinterior of the lamella is withdrawn at 13. The condensate 13 (clean water) is recycled back to the process.
25 By causing a pressure difference between the heat surfaces the condensing temperature is brought higher than ~he evaporation temperature. Thus it is possible to transfer the condensing temperature through the laminates 3 for evaporation (temperature differenoe T is a function of the pressure difference and the boiling point elevation of the liquid being evaporated).
The above description illustrates the use of a laminate 3 formed by combining atleast two different materials for the manufacture of evaporators, but the use of the laminates is not limited for this. Instead it may be used as a heat transfer surface also in many other applications, such as in effecting heat transfer betw0en two 5 liquids.
While the invention has been dsscribed in connection with what is presently considered to b2 the most practical and preferred ernbodiment, it is to be understood that the invention is not to be lirnited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent 10 arrangements inciuded within the spirit and scope of the appended claims.
.. ~,.
Claims (34)
1. A heat exchanger having a plate-like heat exchange element comprising a laminate of at least two layers of different materials, a metal foil layer, and a plastics layer.
2. A heat exchanger as recited in claim 1 wherein said laminate consists essentially of three layers, two plastics layers with a metal foil layer sandwiched therebetween.
3. A heat exchanger as recited in claim 1 wherein said metal-plastic laminate has a thickness of less than about 200 microns.
4. A heat exchanger as recited in claim 3 wherein said metal foil has a thickness of less than about 100 microns.
5. A heat exchanger as recited in claim 4 wherein said plastic layer has a thickness of less than about 100 microns.
6. A heat exchanger as recited in claim 3 wherein said metal foil is an aluminum foil.
7. A heat exchanger as recited in claim 6 wherein said aluminum foil has a thickness of about 5-40 microns.
8. A heat exchanger as recited in claim 6 wherein said aluminum foil has a thickness of about 9-18 microns
9. A heat exchanger as recited in claim 3 wherein said metal foil is selected from the group consisting essentially of aluminum, brass, and copper.
10. A heat exchanger as recited in claim 9 wherein said plastic layer is selected from the group consisting essentially of polyester and polyolefins.
11. A heat exchanger as recited in claim 1 wherein said plastic layer is selected from the group consisting essentially of polyester and polyolefins.
12. A heat exchanger as recited in claim 11 wherein said plastics layer has a thickness of about 12-25 microns.
13. A heat exchanger as recited in claim 2 wherein each of said plastic layers has a thickness of less than about 100 microns.
14. A heat exchanger as recited in claim 13 wherein each of said plastic layers has a thickness of about 12-25 microns.
15. A heat exchanger as recited in claim 14 wherein said plastics layer has a thickness of about 12-25 microns.
16. A heat exchanger as recited in claim 15 wherein said metal foil has a thickness of about 5-40 microns.
17. A heat exchanger as recited in claim 1 wherein said metal foil has a thickness of about 5-40 microns.
18. A heat exchanger as recited in claim 1 wherein said metal foil layer and plastics layer are laminated together with adhesive.
19. An evaporator comprising first and second spaced plate-like heat exchange elements, each element comprising a laminate of a metal foil layer and a plastics layer, with a space for the transport of heat exchange fluid therebetween.
20. An evaporator as recited in claim 19 wherein the metal foil layer of each plate-like element is on the interior of said evaporator, bordering said interior passage.
21. An evaporator as recited in claim 19 further comprising a third layer of plastics material, said metal foil layer sandwiched between said plastics layers.
22. An evaporator as recited in claim 19 wherein said laminate has a thickness of less than about 200 microns.
23. An evaporator as recited in claim 22 wherein said metal foil layer is selected from the group consisting essentially of aluminum, brass, and copper.
24. An evaporator as recited in claim 23 wherein saw plastics layer is selected from the group consisting essentially of polyester and polyolefins.
25. An evaporator as recited in claim 24 wherein said metal foil has a thickness of about 5-40 microns, and said plastics layer has a thickness of about 12-25 microns.
26. An evaporator as recited in claim 20 further comprising an interior corrosion resistant coating on said metal foil.
27. A method of evaporating an effluent from a cellulose pulp mill utilizing an evaporator surface comprising a metal-plastic laminate having a thickness of less than about 200 microns, comprising the steps of: a) passing pulp mill liquid effluent in a falling film over the metal plastic laminate surface.
28. A method as recited in claim 27 wherein said step a) is further practiced by passing the pulp mill effluent in contact with the plastic layer of the metal-plastic laminate.
29. A method as recited in claim 28 comprising the further step of passing steam into contact with the metal layer of the metal-plastic laminate.
30. A method as recited in claim 27 wherein said laminate consists essentially of three layers, two plastics layers with a metal foil layer sandwiched therebetween.
31. A method as recited in claim 30 wherein said step a) is further practiced by passing the pulp mill effluent in contact with the plastic layer of the metal-plastic laminate.
32. A method as recited in claim 31 comprising the further step of passing steam into contact with the metal layer of the metal-plastic laminate.
33. A method of evaporating a liquid effluent utilizing an evaporator surface comprising a metal-plastic laminate having a thickness of less than about 200 microns, comprising the step of passing the liquid effluent in a falling film over the metal plastic laminate.
34. A method as recited in claim 33 wherein said step is further practiced by passing the liquid effluent in contact with the plastic layer of the metal-plastic laminate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI915424A FI93145C (en) | 1991-11-18 | 1991-11-18 | Heat |
| FI915424 | 1991-11-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2083118A1 true CA2083118A1 (en) | 1993-05-19 |
Family
ID=8533512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2083118 Abandoned CA2083118A1 (en) | 1991-11-18 | 1992-11-17 | Heat exchanger |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0612397A1 (en) |
| JP (1) | JPH07501393A (en) |
| AU (1) | AU2901992A (en) |
| CA (1) | CA2083118A1 (en) |
| FI (2) | FI93145C (en) |
| NO (1) | NO941840D0 (en) |
| WO (1) | WO1993010416A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2129686C1 (en) * | 1993-09-03 | 1999-04-27 | Кабусики Кайся Секуто Кагаку | Heat-insulating panel and method of heat insulation |
| FI98859C (en) * | 1995-10-03 | 1997-08-25 | Hadwaco Ltd Oy | Heat exchanger and method of construction thereof |
| US6464666B1 (en) | 1999-10-08 | 2002-10-15 | Augustine Medical, Inc. | Intravenous fluid warming cassette with stiffening member and integral handle |
| US6742576B2 (en) * | 2001-09-27 | 2004-06-01 | E. I. Du Pont De Nemours And Company | Heat exchanger barrier ribbon with polymeric tubes |
| US7394976B2 (en) | 2003-03-25 | 2008-07-01 | Arizant Healthcare Inc. | Fluid warming cassette and system capable of operation under negative pressure |
| US7316666B1 (en) | 2004-04-12 | 2008-01-08 | Arizant Healthcare Inc. | Fluid warming cassette with rails and a stiffening member |
| GB2491623A (en) * | 2011-06-09 | 2012-12-12 | Alberto Martinez Albalat | Multilayer fluid heat exchanger comprising plastic and metal layers |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2204788A1 (en) * | 1972-10-30 | 1974-05-24 | Tranter Mfg Inc | Plate heat exchanger unit - made from two flat plates spot welded together in rhombus pattern |
| JPS50448A (en) * | 1973-05-09 | 1975-01-07 | ||
| US4969507A (en) * | 1977-06-30 | 1990-11-13 | Rosenblad Axel E | Integral blow down concentrator with air-cooled surface condenser |
| DE2757370A1 (en) * | 1977-12-22 | 1979-07-05 | Bayer Ag | GAS-TIGHT PLASTIC-ALUMINUM COMPOSITE FILMS |
| DE3102523C2 (en) * | 1981-01-27 | 1985-10-10 | Ludwig 8448 Leiblfing Penzkofer | Counterflow heat exchanger |
-
1991
- 1991-11-18 FI FI915424A patent/FI93145C/en not_active IP Right Cessation
-
1992
- 1992-11-16 WO PCT/FI1992/000309 patent/WO1993010416A1/en not_active Application Discontinuation
- 1992-11-16 EP EP92922936A patent/EP0612397A1/en not_active Withdrawn
- 1992-11-16 JP JP5509013A patent/JPH07501393A/en active Pending
- 1992-11-16 AU AU29019/92A patent/AU2901992A/en not_active Abandoned
- 1992-11-17 CA CA 2083118 patent/CA2083118A1/en not_active Abandoned
-
1994
- 1994-05-16 FI FI942259A patent/FI942259A/en not_active Application Discontinuation
- 1994-05-16 NO NO941840A patent/NO941840D0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FI93145B (en) | 1994-11-15 |
| FI915424A0 (en) | 1991-11-18 |
| WO1993010416A1 (en) | 1993-05-27 |
| AU2901992A (en) | 1993-06-15 |
| NO941840L (en) | 1994-05-16 |
| EP0612397A1 (en) | 1994-08-31 |
| NO941840D0 (en) | 1994-05-16 |
| FI942259A0 (en) | 1994-05-16 |
| JPH07501393A (en) | 1995-02-09 |
| FI942259A (en) | 1994-05-16 |
| FI915424A (en) | 1993-05-19 |
| FI93145C (en) | 1995-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |