Sub-block Sealing for Electrochemical Seperation Devices

• US 20200129926A1
• Filed: 07/11/2018
• Published: 04/30/2020
• Est. Priority Date: 07/11/2017
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Inventors: Muse, Michael J., Griffis, Joshua, Liang, LI-Shiang, Shaw, Michael, Dukes, Simon P.
• Granted Patent: US 11,673,096 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2313/041 Gaskets or O-rings
• CPC Class Codes: B01D 2313/042 Adhesives or glues
• CPC Class Codes: B01D 61/463 comprising the membrane sequence AC or CA, where C is a cation exchange membrane
• CPC Class Codes: B01D 61/50 Stacks of the plate-and-frame type
• CPC Class Codes: B01D 63/0822 Plate-and-frame devices
• CPC Class Codes: B01D 63/085 specially adapted for two fluids in mass exchange flow
• CPC Class Codes: B01D 65/003 Membrane bonding or sealing
• CPC Class Codes: C02F 1/4693 electrodialysis
• CPC Class Codes: C02F 1/4695 electrodeionisation
• CPC Class Codes: C02F 2201/004 Seals, connections

Abstract

An electrochemical separation device includes a first electrode, a second electrode, and a cell stack including a plurality of sub-blocks each having alternating depleting compartments and concentrating compartments and each including frame and channel portions disposed between the first electrode and the second electrode. An internal seal formed of a first material is disposed between and in contact with the channel portions between adjacent sub-blocks in the cell stack and configured to prevent leakage between depleting compartments and concentrating compartments in the adjacent sub-blocks. An external seal formed of a second material having at least one material parameter different from the first material is disposed between and in contact with the frames of the adjacent sub-blocks in the cell stack and configured to prevent leakage from an internal volume of the electrochemical separation device to outside of the electrochemical separation device.

Claims

1. An electrochemical separation device comprising:

a first electrode;

a second electrode;

a cell stack including a plurality of sub-blocks each having alternating depleting compartments and concentrating compartments disposed between the first electrode and the second electrode, each of the sub-blocks including a frame and channel portions;

an internal seal formed of a first material disposed between and in contact with the channel portions between adjacent sub-blocks in the cell stack and configured to prevent leakage between depleting compartments and concentrating compartments in the adjacent sub-blocks; and

an external seal formed of a second material having at least one material parameter different from the first material disposed between and in contact with the frames of the adjacent sub-blocks in the cell stack and configured to prevent leakage from an internal volume of the electrochemical separation device to outside of the electrochemical separation device.

2. The device of claim 1, wherein the external seal is configured to withstand a higher pressure across the external seal without leaking than the internal seal.

3. The device of claim 1, wherein the internal seal is configured to prevent leakage between the depleting compartments and concentrating compartments under conditions in which the channel portions exhibit sinks of less than about 1 mm in depth.

4. The device of claim 3, wherein the external seal is configured to prevent leakage from the internal volume of the electrochemical separation device under conditions in which the frames exhibit pits of less than about 250 μ

m in depth.

5. The device of claim 4, wherein the internal seal includes closed-cell silicone foam.

6. The device of claim 5, wherein the internal seal includes a plurality of separate sections of the closed-cell silicone foam.

7. The device of claim 6, further comprising internal volume displacement sections disposed between adjacent sections of the internal seal.

8. The device of claim 7, wherein the internal volume displacement sections are formed of a same material or a softer material than the sections of the internal seal.

9. The device of claim 5, wherein the external seal is formed of a sheet of silicone rubber.

10. The device of claim 9, wherein apertures are defined in the external seal over closed portions of the frames.

11. The device of claim 1, further comprising:

an end-block housing an electrode;

a sub-block adjacent the end-block including a spacer bonded to a face thereof over the frame and channel portions;

an O-ring groove defined between the spacer and the end-block; and

an O-ring disposed within the O-ring groove.

12. The device of claim 1, further comprising an end-block housing an electrode, having a plurality of O-ring grooves defined between the end-block and a sub-block adjacent the end-block, and an O-ring disposed in each O-ring groove.

13. A method of applying a seal to an end-block of an electrochemical separation device, the method comprising:

disposing sections of an internal seal in a jig having cutouts configured to retain the sections of the internal seal, the sections of the internal seal formed of a first material;

placing a sub-block of the electrochemical separation device including a channel portion and a frame on the jig;

adhering the sections of the internal seal to the channel portion on a side of the sub-block;

removing the sub-block from the jig; and

applying an external seal to the frame on the side of the sub-block, the external seal formed of a second material including at least one material parameter different from the first material.

14. The method of claim 13, further comprising forming the sections of the internal seal from the first material.

15. The method of claim 14, further comprising forming the external seal from the second material, the second material being harder than the first material.

16. The method of claim 15, further comprising forming apertures in the external seal in locations in the external seal that are to be disposed over bare areas of the frame.

17. The method of claim 15, wherein forming the sections of the internal seal from the first material comprises forming the sections of the internal seal from silicone foam.

18. The method of claim 17, wherein forming the external seal from the second material comprises forming the external seal from a sheet of silicone rubber.

19. The method of claim 13, further comprising disposing sections of volume displacement material within the jig between adjacent sections of the internal seal.

20. The method of claim 19, further comprising adhering the sections of volume displacement material to the channel portion on the side of the sub-block.