KR790001015B1 - Apparatus for securing a fabricated diaphragm to electrodes in an electrolytic cell - Google Patents

Abstract

Diaphragm cell for electrolysis of a water soluable chrolic solution electrode cell was composed of 4 contacting diaphragms which at uniform interval in parallel with each bored electrode retained on the contacting and open side. One bar serves as a device for securing the diaphragm placed along the lst side of the electrde cell, and the other for securing along the 3rd side, and having many clamps, placed adjacently to one of the two bars and touching one bar so each contacting side of the diaphagm is sealed between the clamp. and bar.

Description

Diaphragm fixation

1 is a partial side perspective view of an electrode compartment with a septum;

2 is a plan perspective view of assembly A according to FIG.

3 is a plan view of another embodiment of FIG. 2 for attaching a septum to an electrode.

4 is a partial side perspective view of an electrode compartment using additional embodiments for diaphragm attachment.

The present invention relates to a diaphragm electrolyzer for electrolysis of aqueous saline solution, and more particularly, to an apparatus and method for fixing a prepared diaphragm to an electrode.

For years, commercial diaphragms have been used for the production of chlorine and caustic soda using immersed fibrous diaphragms, usually asbestos.

This is quite satisfactory for chlorine production, while caustic soda has a relatively low concentration and contains significant amounts of unnecessary sodium chloride.

Recently, diaphragm materials have been produced that can significantly reduce the content of sodium chloride and produce concentrated sodium hydroxide. These materials with ion exchange properties are produced from one polymer or combination of polymers. These materials can be fabricated in the form of a continuous sheet to spread over a group of electrodes. They may also be made in the form of envelopes or gloves to attach to the individual electrodes. It is very important to effectively seal the manufactured diaphragm so that there is no unnecessary leakage from or into the electrode compartment.

Leaks due to poor sealing along the assembly result in a decrease in current efficiency. For example, methods are known in which a clamp attaches a diaphragm made using an expandable retainer. One of them is a clamp having an offset claw shape that opens the two ends of the diaphragm covering the electrode. To tighten them together and then press the sides between the clamp and the support plate. This method does not effectively seal the area across the tops of the electrodes, so the diaphragm must be tightened separately to each electrode without cooperation between adjacent clamps.

Flexible crests that use U-shaped compressive crests with crescent shaped expansive crests have also been used. The crescent shaped retainer is arranged to cover the diaphragm on the side between the adjacent cathodes so that one end extends over a portion of one cathode and the other end covers the portion of the adjacent cathode. The U-shaped retainer is placed on top of the cathode so that it tightens below one end of each of the two adjacent crescent shaped retainers.

However, it has been found that the use of flexible materials results in insufficient sealing between the various components and diaphragms because these materials relax under pressure. In addition, where the components are combined, a composite plane of mating surfaces is formed that does not adequately prevent leakage.

Therefore, there is a need for an improved apparatus that effectively adheres the manufactured diaphragm to one or a plurality of electrodes and allows cooperation between the components thereof.

It is a first object of the present invention to provide a novel apparatus and method thereof useful for diaphragm electrolysers for the production of chlorine and alkali metal hydroxides.

It is a second object of the present invention to provide a novel apparatus and method for securing a manufactured diaphragm to an electrode.

It is a third object of the present invention to provide a novel apparatus and method for securing a manufactured diaphragm to be assembled outside the diaphragm electrolyzer.

The above and other objects of the present invention are attained by an apparatus and method for fixing a manufactured diaphragm to each of a plurality of perforated electrodes arranged in parallel at intervals. The electrodes form an electrode section in which the first and third sides face and the second and fourth sides face each other. The diaphragm closes each electrode and has adjacent two side open ends. The device has two bars, one bar along the first side of the electrode compartment and one along the third side. Multiple clamp elements are disposed within the gap between the electrodes and each clamp element is adjacent to one of the bars. The attachment device attaches each clamp element to one of the bars, and the joining edges of each of the two adjacent diaphragms are sealed between the clamp element and the clamp bar.

Figures 1-2 illustrate the new diaphragm attachment device of the present invention wherein the same parts have been given the same numbers in all figures.

1 and 2 show a part of the electrode compartment 10 in which a plurality of electrodes 12 are attached to the electrode plate 14. The capsule-shaped diaphragm 16 is open along three sides and open along one side. The diaphragm 16 closes the electrode 12 with the open side 18 adjacent to the electrode plate 14. The bar 20 is bolted to the upper side of the electrode compartment 10. The U-clamp 24 inserted in the gap between the adjacent electrodes 12 is bolted to the bar 20 to seal the open side 18 of each of the adjacent diaphragms 16. The rod 26 is bolted to the outer side surface 13 of the electrode compartment 10 to seal the open side 18 of the diaphragm 16 along the outer side 13.

The J-clamp 28 is bolted to the bar 20 to seal the open side 18 of the diaphragm 16 along the top side of the electrode compartment 10. Adjacent U-clamps 24 are also bolted to each other, and J-clamp 28 is bolted to the adjacent U-clamp 24.

3 shows a portion of the electrode compartment 10 in which the base 30 extends beyond the outer side 13 of the electrode compartment 10. The support 32 attaches the base 30 to the electrode plate 14 at intervals. A gasket 34 is disposed between the base 30 and the bar 20. The clamp 36 has a top 37, a center 38, and a bottom 39. The intermediate portion 38 is bolted to the outer side 13 of the electrode compartment 10. The upper part 37 is held at the central part 38, and the upper part 37 and the lower part 39 are held to the base part 30 by bolts 40, and a gasket 34 surrounds the base part 30. The diaphragm 16 is sealed between the upper portion 37 of the clamp 36 between the central portion 38.

In FIG. 4, the diaphragm 16 is open along the side. U-clamp 24 and J-clamp 28 have arms extending along the length of electrode 12. The sides 17 are sealed between the extended arms of adjacent U-clamps 24 which are bolted to each other at intervals along the extended arms. The sides of the diaphragm surrounding the outer cathode are sealed by bolting the arms extending between the J-clamp 28 and the adjacent U-clamp 24. The open sides 18 of the diaphragm 16 adjacent to the electrode plate 14 are sealed between the U-clamp 24 and the bar 20 or between the J-clamp 28 and the bar 20.

Bars disposed along the upper and lower sides of the electrode compartment may be attached to the side of the electrode compartment or the electrode plate.

Appropriate attachment devices such as bolts are used to allow the bars to be removed when desired. In a preferred embodiment, the bars are attached to the sides of the electrode compartment such that the diaphragm assembly closes the electrodes into the electrode compartment outside the electrolytic cell.

Any structure of material that is inert to the electrolyte or gas in the electrolyzer may be used in the bar. Suitable materials include metals such as titanium or plastics such as polytetrafluoro ethylene or polyvinyl chloride. If electrically conductive materials are used, non-conductive gaskets should be inserted and insulated from the cathode.

The bar must be flexible and provide a solid solid surface to which the diaphragm will adhere. The bar has one or two openings for attaching the clamp element. In a preferred embodiment, the bar preferably has a wave like shape along the side to which the clamp element is to be attached.

The clamp element is removably and adjustablely attached to the bar or electrode plate by any suitable means such as bolts. These devices are disposed within the gap between adjacent electrodes to seal one side of each of the two adjacent diaphragms against the bar. Appropriately shaped elements such as wedges, ellipses, parabolas and the like can be used, but a U-shaped element is preferred in which curved portions are attached to the bars and arms are disposed perpendicular to the electrode plate as illustrated in FIG.

A preferred embodiment has means for attaching adjacent clamp elements to each other to additionally seal the diaphragm sides. It is also possible to use suitable adjustable attachment means, such as bullets.

Where the diaphragm has two open sides, the arms of the clamp element may extend along the full length of the electrode as shown in FIG. One open side is sealed between one arm of each of the two adjacent clamp elements, for example by bolting them at a selected interval.

A rod may be used to seal the outer side of the septum surrounding two electrodes arranged at the end of the electrode compartment. The rods are properly attached to the electrode side by bolts or the like to seal the diaphragm with the electrode. Clamp elements are attached to the upper and lower ends of the rod to further seal the diaphragm edge. This element has a C or J shape, for example, and is attached to adjacent clamp elements as illustrated in FIG.

The novel clamp device of the present invention can also be used for diaphragm electrolysers, wherein the electrodes are finger-shaped or tubular structures that bridge the electrolysers. The preferred type of electrolytic cell is that both the negative electrode and the positive electrode are attached to an electrode plate arranged vertically.

Normally the diaphragm closes the cathode while the new device of the present invention can also be used to seal the diaphragm to the anode.

Any suitable diaphragm, i.e. osmotic membrane, may be sealed to the electrode by using the device of the present invention by making the plate or tubular suitably prior to attaching the diaphragm to the electrode. Thus, both hydraulically permeable or impermeable materials can be used. The hydraulically permeable diaphragm consists of an inert material that is permeable to fluids and impermeable to halogens or alkali metal ions. The diaphragm may be a fabric woven of a polymer such as ethylene in polyethylene, polypropylene or polytetrafluoro. The diaphragm may also be a hybrid of an ion exchange membrane or an ion exchange resin reinforced with a suitable metal or fibrous network. A hydraulically permeable diaphragm material is a perfluorocarbon polymer composite membrane composed of a copolymer of tetrafluoro ethylene and sulfonated perfluorovinyl ether supported on a polyfluoro-olefin fabric.

The electrode compartment is composed of 3-100 electrodes and preferably 5-50 electrodes. These electrodes are separated and parallel to each other. The assembled electrode compartment is attached to the electrode plate using conventional methods such as attaching the electrode to the electrode plate with bolts. This electrode plate is arranged vertically or horizontally and has conductors attached to supply the current to the electrode.

The electrically active area of the electrode is the pore surface. When the electrode acts as a cathode, the surface of the electrode is made of a metal mesh and has resistance to caustic alkali such as iron, steel, nickel or tantalum.

If the diaphragm surrounding the electrode is an anode, the perforated anode surface may be flat or uneven and may take various forms, such as a foamed mesh such as horizontal, vertical or inclined slits. Other suitable forms include sheets or strips, bars or conductors with flat or uneven strips, for example woven wire cloth, arranged vertically and having holes, slits or scaly openings. Plates and the like.

Preferred anode surface is a pore network, which is an electrical conductor. Valve metals such as titanium or tantalum or metals such as aluminum, copper, steel or iron deposited with valve metals such as tantalum or titanium are preferred. At least a portion of the valve metal surface is coated with platinum-based metals, platinum-based metal oxides, platinum-based metal alloys or mixtures thereof.

If desired, a liquid sealant such as a silicone sealant may be used in addition to the clamp device to seal the open side of the diaphragm.

The apparatus of the present invention provides a means for completely sealing the open end of the manufactured diaphragm which closes the electrode along the outer side of the electrode compartment. This new device completely prevents the anolyte from leaking into the cathode compartment or the hydrogen from leaking into the chlorine. The sealing of the open end between these parts by the diaphragm fixed by the novel device of the present invention can be accomplished entirely by using a sealant or heat sealing.

Placing the diaphragm on the electrode finger portion and later sealing the open side is accomplished by attaching the bars to the top and bottom of the electrode compartment or by attaching the bars in the proper position to the electrode plate. The diaphragm covered along at least two sides slides the electrode finger portion and fits around it, while the open ends of the diaphragm are sized so as to contact the electrode base structure attached adjacent to the electrode plate. If desired, when the diaphragm material is hydraulically permeable, the diaphragm may be wetted with water, for example, before tilting the electrode finger portion. Clamp elements are then placed and attached to the bar and interconnected with adjacent clamp elements to seal the diaphragm sides. The rods are then attached along the outer sides of the outermost electrode in the electrode compartment.

Claims (1)

Two electrode holes each arranged in parallel with an interval between them, forming an electrode compartment having four junction sides with the first side and the third side facing each other and the second side and the fourth side facing each other. A device for securing a diaphragm having a junction edge and an open end to cover each of the electrodes, the device having two bars, one of which is along the first side of the electrode compartment Disposed along the third side and having a plurality of clamp elements such that each clamp element is disposed adjacent to one of the bars within a gap between two of the electrodes, the clamp element being attached to one of the bars. A diaphragm fixation device having an attachment means for attaching such that one joining edge of each of two adjacent diaphragms is sealed between the clamp element and the bar.

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