US2735812A - Van hoek - Google Patents

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US2735812A
US2735812A US2735812DA US2735812A US 2735812 A US2735812 A US 2735812A US 2735812D A US2735812D A US 2735812DA US 2735812 A US2735812 A US 2735812A
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membranes
liquid
membrane
electrodes
compartments
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/46—Apparatus therefor
    • B01D61/50—Stacks of the plate-and-frame type
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
    • A23C9/00—Milk preparations; Milk powder or milk powder preparations
    • A23C9/14—Milk preparations; Milk powder or milk powder preparations in which the chemical composition of the milk is modified by non-chemical treatment
    • A23C9/144—Milk preparations; Milk powder or milk powder preparations in which the chemical composition of the milk is modified by non-chemical treatment by electrical means, e.g. electrodialysis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/52—Accessories; Auxiliary operation

Definitions

  • the present invention relates to electrodialyzing apparatus, whereby use is made of two or more membranes, through which ions are transported from the dialysis compartment to the adjacent compartments. Generally, the liquids in these adjacent compartments should be refreshed regularly.
  • the simplest construction is the so-called 3-chamber apparatus, in which the anode compartment with the anode therein is separated .from the dialyzing compartment by a membrane and the dialyzing compartment is separated from the cathodecontaining compartment by a second membrane.
  • the electrical energy required for the desalting increases under otherwise similar conditions in proportion to the distance between the electrodes and with the electric resistance of the membranes. Consequently it is desirable to keep the distance between the electrodes and the membranes, and notably the mutual distance between the membranes, small. Under production conditions these distances should be fixed at determined values, otherwise locally difiering current densities may occur, which may disturb the satisfactory practice of the process. Care should be taken to prevent. the membranes from coming into contact with one another or with the electrodes.
  • Membranes having a sufliciently low electric resistance generally consist of thin, mechanically weak material, which is in itself not form-retaining, as for example regenerated cellulose.
  • the distances between electrodes and membranes and between the membranes should preferably be a few mm. at most, this makes high high demands upon the construction of the cells, since these membranes are as a rule elastic and plastically deformable and consequently must be retained in position and shape by special supporting devices.
  • the support must not increase the resistance of the electrodialyzing compartment undesirably.
  • no noticeable changes in shape should take place because of the difference in pressure in the various compartments at the working temperatures, also in case of prolonged use.
  • the supporting material should be chemically resistant to the rinsing liquids used, the composition of which varies with that of the dialysate. In the presence of chlorides or chlorine compounds in the dialysate, chlorine-resistant materials should be chosen for use in the anode compartment, for example of polyvinyl chloride or of a copolymer of vinylchloride and vinylidenechloride.
  • a drawback of many types of membrane supports is that the liquid is as a rule relatively stagnant at the edges of the support so that corroding substances formed at the electrode may increase in concentration and attack the edges of the membranes (so-called edge-effect).
  • An object of the invention is to provide a novel construction of an electrodialysis compartment, in which the distances between the electrodes and the membranes and between the membranes are small and whereby the membranes are kept in their places by supporting devices, thus avoiding attack of the membranes by electrodialysis products formed at the electrodes and whereby a good mixing of the liquid in the space between two membranes is obtained.
  • supporting devices are mounted in the electrodialysis apparatus to support the deformable membranes at a short distance from the elec trodes or from other membranes and providing spaces for rinsing between a membrane and an electrode or between two membranes, which supporting devices are arranged to maintain the correct distance between a membrane and the adjacent electrode or between two membranes, and may consist of screens or sheets of insulating material having holes or perforations therein and providing contact points for engaging and supporting the membranes which are distributed over the whole surface of the screens or sheets.
  • the screens between a membrane and an electrode should be such that they also act as diaphragms.
  • the screens may be corrugated sheets, the corrugations of which are about parallel to the direction of flow of the liquid which has been determined by inlet and outlet openings.
  • the sheets should be provided with apertures so that the movement of the ions is not hampered but the mixing of the liquid which is in contact with the electrode with the liquid in contact with the membrane is counteracted to a high degree.
  • the places at whichthe supports engage the membranes should not be long, uninterrupted lines in the current direction of the liquid, inasmuch as some attack at the edges of such a supporting line still occurs, with resulting weakening of the membrane. This objection does not arise if the places of contact between the supports and the membranes do not form long, continuous lines in the direction of fiow. For that reason perforations are also applied on the tops of the corrugations.
  • a screen of corrugated fabric may be used with even better results.
  • a fabric or gauze of thermoplastic material is used, in which the desired wave profile is produced by heating in wave-shaped moulds.
  • recesses may be applied on both sides, so that the membrane is not supported by the tops of the corrugations, but by a special pattern of points of support.
  • the active membrane area is somewhat increased by this.
  • the liquid which is in contact with the electrode should not mix too much with the liquid in contact with the membrane, the points or lines of support should not be thus sharp that they cause mechanical damage of the membrane and sufiicient support should be obtained to maintain the membranes in position, when in operation.
  • Supporting devices applied between two membranes should prevent the membranes from being pressed towards each other, or even touching each other when the pressure in the compartments is lower than that in the adjacent compartments.
  • the supporting device in these compartments need not be aligned with the supporting device in the electrode compartments.
  • the supports in the compartments between the membranes should not work as a diaphragm and should promote the mixture of the liquid in these compartments.
  • the perforated corrugated support device can be fitted in these compartments in such a way that the direction of the wave is not parallel to the direction of the liquid flow, determined by the location of the inlet and outlet openings, so that the liquid does not move in parallel directions, but is thoroughly mixed by the forced stream through the perforations.
  • the corrugated plates can advantageously be fitted in the electrode compartments in such a way that the longitudinal direction of the corrugations corresponds with the current direction, while in the intermediate dialysate compartments and rinsing compartments the corrugated plates form angles of 60 or with the current direction.
  • Figure l is a perspective view of a typical supporting device for the membrane of an electrodialyzing cell embodying the present invention.
  • Figure 2 is a perspective view of a composite supporting device or separator
  • Figure 3 is a perspective view of a further modification of the supporting device or separator
  • Figure 4 is a perspective view of the membranes, electrodes and supporting elements of a three-compartment dialyzing apparatus embodying the present invention
  • Figure 5 is a perspective view of a dialyzing cell including an additional separator between the membranes
  • Figure 6 is a schematic perspective view of a part of a dialyzing cell including a plurality of compartments.
  • Figure 7 is a view in vertical section through a typical cell embodying the present invention and including separators arranged in the manner disclosed in Figure 5.
  • the supporting elements or separators for the membranes of the electrodialyzing apparatus are formed of a non-conductive material such as a sheet of plastic or thermoplastic fabric, having a large number of holes 2 therein and a plurality of wave troughs 3 and wave tops 4 forming corrugations in the sheet.
  • the perforations may constitute as much as or more than half of the total area of the sheet. The membrane rests against the tops of the corrugations and is supported thereby.
  • Another type of support in accordance with the present invention includes two corrugated sheets 5 and 6, each similar to the support described above. 6 are disposed on opposite sides of a sheet of fabric 7 which serves to keep the corrugations from nesting together.
  • Still another form of separator may be a wave-like sheet similar to that shown in Figures 1 and 2 but provided with a plurality of protuberances or bumps 8 along the crests and troughs of the corrugations in the sheet.
  • FIGs 4, 5, 6 and 7 illustrate the manner in which the supports 1, 5, 6, etc., are utilized in an electrodialyzing cell.
  • the anode 8 has a separator or support 9 adjacent to it for supporting a dialyzing membrane 10 in spaced relation to the anode.
  • the opposite side of the middle compartment through which the solution to be treated flows is formed by the cathode membrane 11 which is supported by a support or separator 12 interposed between the membrane 11 and the cathode 13.
  • the supports or. separators 9 and 12 may be like any of those disclosed in Figures 1 to 3.
  • the dialyzing cell shown in Figure 5 is similar to that shown in Figure 4 with the exception that another separator 14 is interposed between the membranes and is arranged with its corrugations at substantially a right angle to the direction of flow of the liquid through the intermediate chamber thereby to assure mixing of the liquid.
  • Figure 6 shows a multiple compartment apparatus having ion-selective membranes therein.
  • anode 15 and cathode 16 are screens 17 and 18 having their corrugations parallel to the direction of liquid flow therein.
  • FIG 7 illustrates a typical single cell dialyzing apparatus containing electrodes and a membrane and separator structure like that shown in Figure 5.
  • the dialyzing apparatus includes a cell 25 formed of nonconductive materials such as glass or the like having outer side walls 26 and 27 with peripheral flanges 28 and 29 that are clamped together in sealing engagement with the edges of the interposed membranes and 11.
  • a rim member 30 is interposed between the edges of the membranes to hold them in position and form the central compartment.
  • the membranes are further positioned, as described above, by the interposed separator 14 and the separators 9 and 12 on opposite sides of them and in engagement with the anode 8 and the cathode 13, respectively.
  • the rim 30 is provided at its opposite ends with an inlet 31 and an outlet 32 permitting circulation of the liquid therethrough and the rinsing cells on opposite sides of the membranes are also provided with suitable inlets 33 and 34 and outlets 35 and 36. It will be understood that the cell described above may be used to house the unit shown in Figure 4, or it may be enlarged to support a multiple cell unit like that shown in Figure 6 by appropriate arrangement of the spacer rims 30 to support the various membranes or diaphragms.
  • Example I For comparison two electrodialyses were carried out. In one test, a membrane support of free-bearing gauze, consisting of a copolymer of vinylidene chloride and vinylchloride was used, whereas in the other test, a corrugated support 1 of polyvinylchloride, resting against the electrode was used. The tests were conducted in a cylindrical electrodialysis compartment with a membrane surface of 2800 cm. and a current strength of 400 amp., that is, a current density of 143 mA./cm. The distances between the electrodes and the membranes and between the membranes each amounted to 3 mm. Concentrated whey of the following composition was used as a dialysate:
  • the rinsing liquids used were: anodically 0.15 N acid (principally sulphuric acid) and cathodically 0.2 N alkali. These rinsing liquids circulated at a velocity of approx. 20 litres per minute, while the dialysate circulated with 30 litres per minute.
  • the active chlorine content of the anode rinsing liquid was kept at 50 mg. per litre at most by aerating the liquid in a chlorine desorption column with 100 litres air per minute.
  • Example II Seawater was electrodialyzed in an apparatus of the type shown in Fig. 6, with distances between the membranes and electrodes of approx. 3 mm. and between the membranes mutually of approx. 2 mm.
  • a membrane support of flat gauze formed of the above-mentioned copolymer was used, and in another test, supports 5 and 6 were used in the electrode compartments in a manner shown in Fig. 2, and in the other compartments according to Fig. 1 and sea-water was used as rinsing liquid.
  • the anode membrane broke down by attack after 7-10 working hours.
  • the second test after 40 hours no deterioration of the quality of the membrane could be detected.
  • Example Ill Brackish water with a content of 1000 mg. Clper 1. was subjected to electrodialysis in an apparatus of the kind shown in Fig. 6 for such a period of time, that the outflowing water contained 300 mg. Cl' per 1.
  • the support between these membranes consisted of corrugated perfd rated polyvinylchloride-sheets having a thickness of 0.3 mm., a weight height of 4 mm., an amplitude of 0.8 mm.; diameter of the perforations was 2.5 mm., with 1000 perforations per dm. of the flat sheet.
  • the membrane surface was 800 cm. per membrane (20 (40 cm.).
  • Example IV In an apparatus according to Fig. 6 seawater with a content of 18,000 mg. Cl/l. was subjected to electrodialysis for such a period of time that the outflowing water contained 300 mg. Cl-/l. The total number of mem branes amounted to 60.
  • the support between these membranes consisted of corrugated polyvinylchloride-sheet having a thickness of 0.08 mm., a waveof 2 mm., an amplitude of 0.175 mm.; diameter of the perforation 2.2 mm., 1200 perforations per drn. flat sheet.
  • the distance between the membranes amounted to 0.35 mm.
  • the membranes had a surface of 800 cm. per membrane (20x40 cm.).
  • electrodialyzing apparatus comprising a chamber containing electrodes and flexible permeable membranes forming compartments therebetween and means for directing liquid through said compartments including an inlet for liquid at one end of the compartment and an outlet for liquid at the other end, the combination therewith of supporting members interposed between and engaging said membranes and said electrodes to maintain them in accurately spaced relation, said supporting members comprising sheets of insulating material having a multiplicity of perforations widely distributed therein, said sheets having corrugations therein to engage said electrodes and said membranes, said corrugations being interrupted to avoid uninterrupted line contact between said supporting members and the electrodes and membranes.
  • Apparatus according to claim 1 wherein the combined areas of the perforations amounts to at least half of the area of the sheet.
  • Multi-cell apparatus according to claim 1 wherein the wave direction of the corrugations of the supporting member of at least one cell is at an angle to the wave direction of the corrugations of the supporting member in the next cell and also at an angle to the direction of flow determined by the inlet and outlet of the cell.
  • electrodialyzing apparatus comprising a charmher containing electrodes and flexible permeable membranes forming compartments therebetween and means for directing liquid through said compartments including an inlet for liquid at one end of one of said compartments and an outlet for liquid at the other end, the combination therewith of supporting members interposed between and engaging said membranes and said electrodes to maintain them in accurately spaced relation, said supporting members between said membranes and electrodes consisting of two perforated sheets having corrugations therein, said perforated sheets being separated by a flat foraminous sheet and wherein the supporting members between adjacent membranes consist of corrugated sheets, the wave directions of which are at an angle to the direction of flow of the liquid from the inlet to the outlet, the corrugations in the perforated sheets engaging said membranes being interrupted to avoid uninterrupted line contact between said supporting members and the membranes.

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  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Urology & Nephrology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
US2735812D 1952-03-13 Van hoek Expired - Lifetime US2735812A (en)

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NL318177X 1952-03-13

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US2735812D Expired - Lifetime US2735812A (en) 1952-03-13 Van hoek

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US (1) US2735812A (US06573293-20030603-C00009.png)
BE (1) BE518381A (US06573293-20030603-C00009.png)
CH (1) CH318177A (US06573293-20030603-C00009.png)
DE (1) DE1032221B (US06573293-20030603-C00009.png)
FR (1) FR1073704A (US06573293-20030603-C00009.png)
GB (1) GB736888A (US06573293-20030603-C00009.png)
NL (1) NL79468C (US06573293-20030603-C00009.png)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2881124A (en) * 1955-11-09 1959-04-07 Permutit Co Ltd Inserts for membrane spacers
US2948668A (en) * 1957-11-02 1960-08-09 Tno Electrodialysing apparatus with supported membranes
US2951027A (en) * 1956-03-06 1960-08-30 Nat Res Dev Electrodialysing apparatus with supported membranes
US2982416A (en) * 1957-04-25 1961-05-02 Marvaland Inc Dialysis apparatus
US3220941A (en) * 1960-08-03 1965-11-30 Hooker Chemical Corp Method for electrolysis
US3238703A (en) * 1963-03-07 1966-03-08 Engelhard Ind Inc Diffusion purification of gases
US3332216A (en) * 1964-03-16 1967-07-25 Union Carbide Corp Fluid permeation apparatus
US3354618A (en) * 1965-08-26 1967-11-28 Gen Electric Gas exchanger
US3490523A (en) * 1968-04-08 1970-01-20 Us Health Education & Welfare Transfer device
US3496091A (en) * 1966-04-15 1970-02-17 Ionics Electrolytic-electrodialysis apparatus
US3960698A (en) * 1974-12-23 1976-06-01 Wyandotte Corporation Electrode support for filter press cells
US4146457A (en) * 1976-11-12 1979-03-27 Imperial Chemical Industries Limited Diaphragm cells
DE3005408A1 (de) * 1979-02-15 1980-08-21 Daicel Chem Semipermeables membranelement
US4319977A (en) * 1979-04-28 1982-03-16 Imi Kynoch Limited Two-layer corrugated electrode
US4390575A (en) * 1981-12-02 1983-06-28 Baxter Travenol Laboratories, Inc. Multichanneled diffusion device
US4465573A (en) * 1981-05-12 1984-08-14 Hare Harry M O Method and apparatus for the purification of water

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL256379A (US06573293-20030603-C00009.png) * 1960-08-25
SU929581A2 (ru) * 1979-06-27 1982-05-23 Харьковский Ордена Ленина И Ордена Октябрьской Революции Моторостроительный Завод "Серп И Молот" Аппарат дл электрохимической очистки загр зненной жидкости

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1915568A (en) * 1928-08-20 1933-06-27 Northwest Paper Company Recovery and purification of materials by electrodialysis
US2049828A (en) * 1933-12-18 1936-08-04 Rubber Producers Res Ass Treatment of latex
US2225024A (en) * 1938-01-14 1940-12-17 Brosites Machine Company Inc Dialyzing apparatus
NL67903C (US06573293-20030603-C00009.png) * 1949-04-12 1951-05-15
US2664395A (en) * 1949-08-24 1953-12-29 Marchand John Felix Dialyzer
US2686154A (en) * 1950-05-24 1954-08-10 Arthur E Macneill Dialysis apparatus

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE17433C (de) * SELWIG & LANGE in Braunschweig Neuerungen an Osmose-Apparaten
US2386826A (en) * 1942-01-10 1945-10-16 Sylvania Ind Corp Process and apparatus for treating fluid compositions

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1915568A (en) * 1928-08-20 1933-06-27 Northwest Paper Company Recovery and purification of materials by electrodialysis
US2049828A (en) * 1933-12-18 1936-08-04 Rubber Producers Res Ass Treatment of latex
US2225024A (en) * 1938-01-14 1940-12-17 Brosites Machine Company Inc Dialyzing apparatus
NL67903C (US06573293-20030603-C00009.png) * 1949-04-12 1951-05-15
US2664395A (en) * 1949-08-24 1953-12-29 Marchand John Felix Dialyzer
US2686154A (en) * 1950-05-24 1954-08-10 Arthur E Macneill Dialysis apparatus

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2881124A (en) * 1955-11-09 1959-04-07 Permutit Co Ltd Inserts for membrane spacers
US2951027A (en) * 1956-03-06 1960-08-30 Nat Res Dev Electrodialysing apparatus with supported membranes
US2982416A (en) * 1957-04-25 1961-05-02 Marvaland Inc Dialysis apparatus
US2948668A (en) * 1957-11-02 1960-08-09 Tno Electrodialysing apparatus with supported membranes
US3220941A (en) * 1960-08-03 1965-11-30 Hooker Chemical Corp Method for electrolysis
US3238703A (en) * 1963-03-07 1966-03-08 Engelhard Ind Inc Diffusion purification of gases
US3332216A (en) * 1964-03-16 1967-07-25 Union Carbide Corp Fluid permeation apparatus
US3354618A (en) * 1965-08-26 1967-11-28 Gen Electric Gas exchanger
US3496091A (en) * 1966-04-15 1970-02-17 Ionics Electrolytic-electrodialysis apparatus
US3490523A (en) * 1968-04-08 1970-01-20 Us Health Education & Welfare Transfer device
US3960698A (en) * 1974-12-23 1976-06-01 Wyandotte Corporation Electrode support for filter press cells
US4146457A (en) * 1976-11-12 1979-03-27 Imperial Chemical Industries Limited Diaphragm cells
DE3005408A1 (de) * 1979-02-15 1980-08-21 Daicel Chem Semipermeables membranelement
US4500426A (en) * 1979-02-15 1985-02-19 Daicel Chemical Industries, Ltd. Semipermeable membrane elements
US4319977A (en) * 1979-04-28 1982-03-16 Imi Kynoch Limited Two-layer corrugated electrode
US4465573A (en) * 1981-05-12 1984-08-14 Hare Harry M O Method and apparatus for the purification of water
US4390575A (en) * 1981-12-02 1983-06-28 Baxter Travenol Laboratories, Inc. Multichanneled diffusion device

Also Published As

Publication number Publication date
BE518381A (US06573293-20030603-C00009.png)
DE1032221B (de) 1958-06-19
CH318177A (de) 1956-12-31
NL79468C (US06573293-20030603-C00009.png)
GB736888A (en) 1955-09-14
FR1073704A (fr) 1954-09-28

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