Membrane electrode assembly incorporating unified encapsulation and electrocoat paint systems incorporating the same

Abstract

A membrane electrode assembly incorporating an encapsulation assembly process that separates the counter-electrode, and the electrocoat medium from contacting the electrode, which is located behind the membrane ion exchange layer. The encapsulation process provides of method of singularly encasing independent components that comprise the membrane electrode assembly, without the assistance of first structures used in enclosure, framing, enclosure sealing or bonding the components in place, individually, and or in groups thereof from the electrocoat medium, while providing an internal chamber within the membrane electrode assembly, for independent fluid circulation. In further embodiments of the invention, electrode membrane cells having an internal fluid routing system, protective guard around the periphery of the encapsulation layer, a membrane support system adjacent to the membrane, a nonconductive barrier, the membrane, the electrode, and membrane inner spacer bonded by the encapsulation material, cells utilizing the encapsulation method of construction and assembly processes providing the final electrode membrane cell assembly.

Description

BACKGROUND OF INVENTION

The present invention relates to membrane electrode cells used in electro-deposition processes. More particularly, in the embodiments, the present invention describes advantages in simultaneously encapsulating membrane electrode assemblies wherein layered structural components of the electrode membrane cell assembly, including the membrane are intergraded into a single encapsulated bond, creating an assembly of the individual structures/components of the membrane electrode cell without the need of a first structures-frames to provide the enclosure.

The industry employees two commonly known electro-coating processes Anionic and cationic, both of these processes are still in commercial use.

Membrane electrode cells are currently commonly used in electro-deposition systems. The purpose of these cells is to Isolate the electrode from the paint bath, provide a chamber to contain the internal circulating fluid, Exchange electrical energy to the paint bath, while removing ions during the process.

The membrane electrode cell can have many shapes, most commonly in order tubular, C semi-circular and flat. Electro deposition processes utilizing such membrane electrode cells are disclosed in U.S. Pat. Nos. 4,851,102, 4,711,709 and 4,834,861

The membrane commonly used for this process is ion exchange or neutral. The membrane is arranged in support structures to separate the electro-coating bath from the electrode. A fluid flows between the inside of the face of the anode and the membrane. This fluid typically is comprised of RO or DI water with either a small amount of acid or amines depending on process. The solution is used to flush ions and contaminants from the inner chamber.

To separate the electrode from the paint bath it is common practice to provide a seal or bonding of the membrane to another structure member of the cell. These seals in the past have been accomplished by mechanical means such as bolted flanges, which provide sealing by compressing a seal between the flange, membrane, and outer membrane housing along the outside rim of the housing. This method proves difficult to maintain and repair.

Yet another method commonly used incorporates the membrane bonded to an independent first structural component using compression-independent sealing, or bonded arrangement, Disclosed in U.S. Pat Application 20040231992 The first structural component typically contains an electrode that is spaced behind the membrane to create a chamber within a first structural component. The electrode can be mechanically fixed to an enclosure or is sealed in a channeled first structure using many common commercially practiced methods of bonding to the first structural member completing the chamber for the above fluid. A non-conductive coating is applied to the backside of the electrode to insulate the electrode. This above process uses multiple bonding processes and mechanical framing to provide the sealed chamber within the cell. Further more the fluid delivery systems typically in either example are simply attached internally to the first structural member by epoxy at certain points along the first structure. The membrane and electrode assembly is dependant on other periphery or first structural members to provide the chamber, sealing support and integrity to the cell. These methods, though better than the first method still incorporates multiple applications of bonding material to a frame or structural support mechanism which increase chances of sealing failure. The necessity of periphery structural members adds increased thickness to the cell, and more resources in which to produce a chambered membrane electrode cell.

Upon reflection of these and other background in the field, there remains a need for assemblies further simplified in design, which enables a faster assembly and eliminates excessive bonding requirements to enclosures and first structures, which in turn provides a membrane electrode cell with increased usable electrode area and a smaller footprint in the electro-deposition tank.

SUMMARY OF INVENTION

In light of this, one aspect of the present invention provides a membrane electrode system for electro-deposition of the conductive fluid coating medium to the counter anode. A system for electro-deposition of paint onto a counter electrode, in which the system incorporates an electro-deposition main tank containing electrically conductive liquid medium consisting of pigment, resins, water, acids, or other. Further included at least one membrane electrode assembly in contact with the above medium. Said membrane and electrode assembly including operational structures for the membrane electrode cell encapsulated simultaneously to provide, a single medium encasing, a sealed chamber between the counter-electrode, internal fluid delivery and return system, and electrical input within said electro-deposition medium, wherein passage of electrical current between said counter-electrode and said membrane electrode cell through said liquid medium causing electro-deposition of said pigments and resins on to the said counter-electrode. In preferred embodiments, the electrode within the membrane cell is flat or semi-circular shape, the membrane and other operational structures are encased using encapsulation assembly, relieving necessity of primary frames, first structures, or bonding components including membrane to said structures.

A system for electro-deposition of paint onto a counter electrode, in which the system incorporates an electro-deposition tank containing electrically conductive liquid medium and a membrane electrode assembly. Further included at least one membrane electrode in contact with the above medium. Said membrane electrode assembly including an electrode, membrane and operational components for separating said electrode from above liquid medium. Said membrane and electrode including operational structures for the membrane electrode assembly are encapsulated simultaneously to provide a continuous single medium bond, to provide sealed chamber there between the counter-electrode. In preferred embodiments the encapsulated cell being of box or semi-circular shape is fitted with an edge guard to protect the encapsulation layer.

In the preferred embodiments, the electrode within the membrane electrode assembly is a flat or semi-circular shape electrode, and the encapsulation process can be generated by non-electro conductive: liquefied polymers, liquefied plastics, Liquid epoxies, Viscous binding agents, Multi component epoxies, single component adhesives and similar.

Further embodiments, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The assembly comprises of an encapsulation process, which includes various components such as, but not limited to, the electrode, fluid supply channel, non-conductive sheet, membrane, and membrane support layers. In certain embodiments the electrode is flat or semi-circular and the encapsulated membrane electrode assembly is then encased in a periphery guard for further protection of the assembly.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The encapsulation process of the components provides the required space for the chamber that contains the space to circulate and pass internal fluids.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. Wherein a chamber is created internal to the encapsulation medium between the electrode and membrane, creating a path for the incoming fluid that is used in the circulation of said fluid.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The internal chamber used for supplying the path for the flushing fluid is incorporated throughout the encapsulation layer. Providing at least one opening to supply the fluid through encapsulation layer to the chamber. Another embodiment provides at least one opening for an outlet of the fluid through the encapsulation layer.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The encapsulation layer provides sealing of the electrode electrical connection from the chamber wherein the fluid is circulated.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The encapsulation process provides one or more layers of membrane retaining material. The first of which is an epoxy saturated woven blend adjacent to the membrane followed by the second layer of structural mesh. The layers provide containment of internal chamber pressure, reducing chamber swelling under pressure.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. The encapsulation process incorporates a transparent sheet of electrically insulating material, behind the electrode, electrically sealing the back of the assembly. In another embodiment the transparent sheet is utilized to inspect the electrode for wear.

In another embodiment, the present invention provides a membrane electrode assembly for use in electro-deposition system as previously described. During the encapsulation of all the membrane electrode components a periphery guard is attached to protect the edges of the assembly.

Additional features, embodiments and advantages of the invention will be apparent to those of ordinary knowledge in the art derived from the descriptions herein.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 Provides a perspective view of a preferred membrane electrode cell assembly, of the invention. Viewings of Side, Front and Back

FIG. 2 Provides a partial cut away view (A-A) of the cell assembly of FIG. 1

FIG. 3 Provides a cross sectional view of the cell assembly of FIG. 1, Taken along line (B-B) and (C-C) and viewed in the corresponding direction.

DESCRIPTION OF PREFERRED EMBODIMENTS

To promote an understanding of the principles of the invention, reference will be made to certain preferred embodiments, in specific terminology to describe the same. It will be understood that no limitation of the scope of the invention is thereby intended, such alterations, further modifications and application principles of the invention as described herein being disclosed as would normally occur to one skilled in the art to which the invention applies.

As described above, the present invention provides membrane electrode assemblies incorporating an encapsulation process for electrodepositing paint on a counter-electrode.

Generally speaking, the encapsulated membrane electrode assemblies of the invention, and used in Electro-coating systems will include membrane and electrode assembly including operational structures for the membrane electrode cell encapsulated simultaneously to provide, a single medium encasing, a sealed chamber between the counter-electrode, internal fluid delivery and return system, and electrical input within said electro-deposition medium, wherein passage of electrical current between said counter-electrode and said membrane electrode cell through said liquid medium causing electro-deposition of said pigments and resins on to the said counter-electrode.

With reference now to FIG. 1, Disclosed is a membrane electrode assembly of the present invention. Membrane electrode assembly includes exterior components, such as Non conductive barrier—2, Outer membrane support—7, Encapsulation guard—9, Anolyte inlet—10, Anolyte outlet—11, Power lead—12.

With Reference to FIG. 1 and FIG. 2 together additional components of the assembly will be described. FIG. 2, A-A shows a partial cut-away of the assembly in order to reveal the layers of construction. Outer membrane support—7 provides the outermost layer, followed by the inner membrane support—6, followed by the membrane—5, and is separated from the electrode by the inner chamber formed during the encapsulation process. An inner membrane guard 8 formed of a suitable nonconductive material is placed in-between the membrane and electrode in the provided channel. The anolyte channel—4 provides the distance required to create the chamber between the electrode and the membrane. The electrode (anode)—3 and non conductive barrier—2 finish the operation layers of the invention. The encapsulation layer—1 is protected from impact by the encapsulation guard—9, which is of electrically non-conductive material.

With reference to FIG. 3 and FIG. 2 Showing the encapsulation process and the layers as described in FIG. 2. Referring now to FIG. 3, B-B Encapsulation material—1, anolyte channel 4, non-conductive barrier layer—2, electrode (anode)—3, inner membrane guard—8, membrane—5, inner membrane support—6, outer membrane support—7. The assembly further shows the Encapsulation guard—9 removed from the assembled invention. Referring now to FIG. 3, C-C, This view provides a look at the encapsulation of the components non conductive barrier—2, Electrode (anode)—3, Spacer and/or anolyte channel—4, membrane—5, inner membrane support—6, outer membrane support—7, inner membrane guard—8, and encapsulation guard—9, while maintaining an opening for the internal fluid circulation provided by the anolyte channel—4. The same format is used with the anolyte outlet—11

while the invention has been illustrated and described in detail in the drawings and description, the same is to be considered as not restrictive and illustrative in character. Furthermore, only the preferred embodiments have been shown and described and that all changes and modifications that come from the essence of the invention are desired to be protected.

Claims

1. A system for electro-deposition of paint onto a counter electrode, in which the system incorporates an electro-deposition main tank containing electrically conductive liquid medium consisting of pigment, resins, water, acids, or other; at least one membrane electrode assembly in contact with the above medium, said membrane and electrode assembly including, but not limited to operational components for the membrane electrode cell encapsulated simultaneously to provide a single medium encasing, to provide a sealed chamber between the counter-electrode, internal fluid delivery and return system, and electrical input within said electro-deposition medium, wherein passage of electrical current between said counter-electrode and said membrane electrode cell through said liquid medium causing electro-deposition of said pigments and resins on to the said counter-electrode, while attracting processed released ions to the chamber, relieving necessity of primary frames, first structures, or bonding components including membrane to said structures, while in turn reducing overall dimensions of the membrane electrode assemblies.

2. A system according to claim 1, wherein said electrode is a flat or c shaped electrode.

3. A system according to claim 1, wherein said membrane electrode structure, including components, electrical contact, and structures are encapsulated by resins simultaneously.

4. A system according to claim 1, wherein the said membrane electrode structure including operational components, and structures are encapsulated by extrusion simultaneously.

5. A system according to claim 1, wherein the said membrane electrode structure including components and structures are molded together in unison.

6. A system according to claim 1, wherein the said membrane structure including components and structures is laminated in multi-layer bonding.

7. A system according to claim 1, wherein after encapsulation process, the medium incorporated provides, the integrity of the encapsulated components, the enclosure, the sealing, and strength to a fully encapsulated membrane electrode cell.

8. A system according to claim 1, wherein after said encapsulation process the medium seals included structural components simultaneously.

9. A system according to claim 1, wherein after said encapsulation process the medium provides, said internal space between the membrane and electrode for fluid passage.

10. A system according to claim 1, wherein within the encapsulation medium a provision for at least one opening to direct fluid into the chamber.

11. A system according the claim 10, wherein the fluid leaves the channel in at least one port.

12. A system according to clam 1, wherein the encapsulation process provides at least one opening for said fluid to exhaust the chamber.

13. A system according to claim 1, wherein the encapsulation process provides at least one membrane support structure.

14. A system according to claim 13, wherein membrane support structures are electrically non conductive.

15. Systems according to claim 13, wherein the membrane support structures are porous.

16. A system according to claim 1, wherein encapsulation process provides electrical insulation of the chamber using a barrier sheet of non-conductive material.

17. A system according to claim 1, wherein an edge-guard can be applied around the perimeter of the encapsulation to protect it from impact.

18. A system according to claim 1, wherein the said membrane is an ion-selective membrane.

19. A system according to claim 1, wherein the membrane is non-ion selective.

20. A system according to claim 1, wherein the said electrode is formed from conductive material.

21. A system according to claim 1, wherein the assembly process can provide an ultra slim profile of an electrode membrane cell.