Chemistry: electrical and wave energy – Apparatus – Electrophoretic or electro-osmotic apparatus
Reexamination Certificate
1999-09-03
2002-08-20
Bell, Bruce F. (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrophoretic or electro-osmotic apparatus
Reexamination Certificate
active
06436264
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrodeionization water producing apparatus used in the semiconductor manufacture industry, pharmaceutical industry, food industry, power stations, laboratories and the like which require deionized water.
2. Description of the Related Art
Basically in a conventional electrodialysis device, the liquid to be treated is desalinated and concentrated by supplying direct currents to a unit in which a plurality of cation and anion exchange membranes are alternately arranged via spacers and desalination and concentrating chambers are formed by the spacers, so that the anion and cation exchange membranes do not contact one another. Moreover, in an electrodeionization water producing apparatus heretofore practically used, a gap formed by the cation and anion exchange membranes is basically filled, for example, with a lamination of anion and cation exchange resin layers or a mixed ion exchange resin layer as an ion exchanger to form a desalination chamber. Feed water is passed through the ion exchange resin layer(s), while direct currents are applied via both ion exchange membranes, so that deionized water is produced while ions in the feed water are electrically discharged to concentrated brine flowing outside both the ion exchange membranes, and the anion and cation exchange membranes do not directly contact each other.
FIG. 5
is a schematic sectional view of a typical conventional electrodeionization water producing apparatus. As shown in
FIG. 5
, cation exchange membranes
101
and anion exchange membrane
102
are alternately arranged apart from one another, and every other space formed by the cation exchange membrane
101
and anion exchange membrane
102
is filled with a mixed ion exchange resin
103
of cation and anion exchange resins to form a desalination chamber
104
. Moreover, portions formed by the anion and cation exchange membranes
102
,
101
positioned adjacent to the desalination chambers
104
and not filled with the mixed ion exchange resin
103
are formed as concentrating chambers
105
for passing concentrated brine.
Moreover, as shown in
FIG. 6
, the cation exchange membrane
101
, anion exchange membrane
102
, and mixed ion exchange resin
103
(omitted from
FIG. 6
) filling the inside form a deionizing module
106
.
Specifically, the cation exchange membrane
101
is sealed/attached on one side of a hollowed frame
107
, the hollowed portion of the frame
107
is filled with the mixed ion exchange resin
103
, and subsequently, the anion exchange membrane
102
is sealed/attached in the other side of the frame
107
. Additionally, since the anion exchange membrane
102
is relatively soft, in general, a plurality of ribs
108
are vertically provided in the hollow space of the frame
107
in order to prevent the ion exchange membrane from being curved and prevent the layer filled with mixed ion exchange resin
103
from becoming non-uniform, when the inside of the frame
107
is filled with the mixed ion exchange resin
103
and opposite surfaces thereof are sealed with the ion exchange membranes.
Moreover, although not shown in the drawings, a feed water flow inlet is formed in an upper portion of the frame
107
, while a deionized water flow outlet is formed in a lower portion thereof.
FIG. 5
shows that a plurality of deionizing modules
106
are arranged in parallel via spacers (not shown) disposed therebetween, a cathode
109
is disposed on one end of the arranged deionizing modules
106
, and an anode
110
is disposed on the other end. Additionally, a space between the deionizing modules
106
disposed in parallel via the spacer is a concentrating chamber
105
. Moreover, cation exchange membranes, anion exchange membranes, simple diaphragms having no ion exchange property or other compartment membranes
111
are disposed on opposite external sides of both end concentrating chambers
105
as required, and portions compartmentalized by the compartment membranes
111
and contacting both electrodes
109
,
110
are formed as a cathode chamber
112
and anode chamber
113
.
When deionized water is produced by the electrodeionization water producing apparatus, operation is performed as follows:
Specifically, a direct current voltage is applied between cathode
109
and anode
110
, feed water flows in via a feed water flow inlet A, concentrated brine flows in via a concentrated brine flow inlet B, and electrode liquid flows in via electrode liquid flow inlets C and D. The feed water that flows in via the feed water flow inlet A flows downward in each desalination chamber
104
as shown by solid lines and arrows, and is passed through the filling layer of the mixed ion exchange resin
103
, in which impurity ions are removed, and the deionized water is obtained via a deionized water flow outlet a. Moreover, the concentrated brine that flows in via the concentrated brine flow inlet B flows downward in each concentrating chamber
105
as shown by dotted lines and arrows, receives the impurity ions moving via both ion exchange membranes, and is discharged as the concentrated brine with the impurity ions concentrated therein via a concentrated brine flow outlet b. Furthermore, the electrode liquid that flows in via the electrode liquid flow inlets C and D is discharged via electrode liquid flow outlets c and d.
Since the impurity ions in the feed water are electrically removed, and concentrated in the concentrated brine by the operation described above, the deionized water can continuously be obtained without regenerating the filled ion exchange resins with chemicals.
When the conventional electrodeionization water producing apparatus is used, a reverse osmosis membrane device or a water softening device is usually installed as a pretreatment stage, so that the deionized water for use in various industries is supplied extremely effectively.
However, the conventional electrodeionization water producing apparatus has a complicated structure, and requires considerable time and labor to manufacture. Especially, the deionizing module forming the desalination chamber uses the frame with a plurality of ribs arranged in the hollow space to assure the filling of ion exchangers and uniform filling, which causes a problem that the configuration of the apparatus is restricted.
Therefore, an object of the present invention is to provide an electrodeionization water producing apparatus which maintains a deionizing efficiency as in a conventional case, has a simple structure, is easy to be manufactured and which has a high degree of freedom of apparatus configuration.
SUMMARY OF THE INVENTION
In such circumstances, the present inventor went back to a deionizing principle in an electrodeionization water producing apparatus, conducted a various studies and, as a result, has acquired the following information:
(1) A desalination chamber is filled with ion exchangers, i.e., ion exchange resins for the purpose of adsorbing ions in feed water. On the other hand, an ion exchange membrane is used for the purpose of transferring the ions adsorbed by the ion exchange resin to a concentrating chamber, and not transferring opposite ions of the concentrating chamber to the desalination chamber. Although the ion exchanger and the ion exchange membrane are different in purpose from each other, materials are substantially the same.
(2) When operation is performed without filling the ion exchange resins, the deionizing efficiency is remarkably deteriorated.
(3) Water electrolysis easily occurs in a portion where the ion exchange membrane and ion exchange resin come into contact with each other, and H
+
or OH
−
ions generated by the water electrolysis can be expected to chemically regenerate the ion exchange resin.
From the above (1) to (3), it has been found that when the desalination chamber is constituted by holding a channel for passing the feed water and allowing the cation exchange membrane to contact the anion exchange membrane, the same deionizing efficiency as in the conven
Bell Bruce F.
Fish & Richardson P.C.
Organo Corporation
Parsons Thomas H
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