NO863294L - PROCEDURE FOR THE MANUFACTURE OF ELECTROCHEMICAL CELL AND AN ELECTROCHEMICAL CELL. - Google Patents

Description

The present invention relates to an electrolysis unit completely manufactured from several parts put together in a unique way. Several such units placed in operable combination are particularly applicable in the production of chlorine and caustic.

"Electrolysis cell" as the term is used herein means an assembly containing at least an anode in an anode compartment and a cathode in a cathode compartment, wherein the anode compartment and the cathode compartment are separated by an ion-exchange active, substantially hydraulically impermeable membrane.

"Electrolysis unit" means an assembly containing at least two electrode components separated by a planar support portion. The electrode components in an electrolysis unit can be oppositely charged as is the case in a bipolar unit, or equally charged as is the case in a monopolar unit. Thus, monopolar devices could be either anode or cathode devices.

"Electrode component" means an electrode or an element associated with an electrode such as a current distribution grid or current collector. The component can be in the form of a wire cloth, woven wire, punched plate, metal sponge, expanded metal, perforated or non-perforated metal plate, flat or corrugated lattice work, separated metal strips or rods or other forms known in the field.

Chlorine and caustic are basic chemicals in large volumes that are most often produced electrolytically from an aqueous solution of an alkali metal chloride in electrolysis cells. In recent times, a number of technological advances have been made to minimize the gap between the anode and the cathode in an electrolytic cell in order to minimize the electrical resistance of the electrolytic cell and thus make the electrolytic cell run more efficiently. Advances are such things as dimensionally stable anodes, ion exchange membranes, depolarized electrodes, zero-gap cell configurations, and solid polymer electrolyte membranes.

There are two main types of electrolysis cells that are normally used for the production of chlorine and caustic, i.e. monopolar and bipolar cells.

A bipolar cell consists of several electrochemical units in series, in which each unit except the two end or terminal units acts as an anode on one side and a cathode on the opposite side. Electrolysis units are sealably separated by an ion exchange active membrane which thereby forms an electrolysis cell or series of electrolysis cells. Electrical energy is introduced into a terminal cell at one end of a series of bipolar cells, passes through the series of cells and is removed from the terminal cell at the other end of the series of cells. An alkali metal halide solution is introduced into the anode compartment or compartments where a halogen gas is formed at the anode. Alkali metal ions are selectively transported through the ion-exchange active membrane(s) to the cathode compartment or compartments where the alkali metal hydroxide is formed.

Monopolar electrolytic cells comprise at least two terminal cells and several anode units and cathode units placed every other in between. The monopolar units are separated by an ion-exchange membrane, which thus forms several monopolar cells. Each unit is equipped with an inlet through which electrolyte can be fed to the unit, and with at least one outlet through which liquids and gases can be removed from the unit. Each unit is electrically connected to an energy source. Energy is supplied to a monopolar unit and removed from an adjacent unit.

To take advantage of the new technological advances, a number of electrolysis unit designs have been proposed. However, many of these are rather complicated and require the use of expensive materials. A straightforward electrolysis unit using readily available, inexpensive materials would be highly desirable. It is an object of this invention to provide such an electrolysis unit which can be used either as a monopolar or a bipolar unit.

The invention is a method for producing an electrolysis unit with

a substantially planar electrical current transmission element comprising a generally planar carrier portion, an edge flange portion, and;

a plurality of lugs projecting from each side of the carrier portion;

the flange portion is constructed of at least one section and has an interior surface that sealably accommodates all of the outer edges of the carrier portion;

which procedure consists of the steps:

concatenation in any order of:

(a) multiple lugs to at least one side of the carrier portion; (b) at least one section of the flange portion to the outer edges of the carrier portion; and (c) multiple liner sections to at least one portion of the lugs on at least one side of the carrier portion.

The invention also includes a method for manufacturing an electrolysis unit by assembling an electric current transmission element with at least three parts, i.e. a frame-like flange part, lugs and a planar support part. Opposite sides of the thus formed transmission element can be flattened before, during and after the finished assembly of the parts. A side liner is then placed on at least one part of at least one side of the composite transmission element.

The invention can be better understood by reference to the drawings which illustrate the invention and where like reference numbers refer to like parts in different drawn figures and where: Figure 1 is a partially broken away perspective view of an embodiment of the electrolysis unit in the present invention taken apart; Figure 2 is a side cross-section of an embodiment of the electrolysis unit shown in Figure 1 taken apart; Figure 3 is a cross-section of several electrolysis units placed in operable combination forming a series of electrolysis cells; Figure 4 is a cross-section of an electrolysis unit with a side liner made of several components.

With particular reference to Figures 1 to 3, the present invention uses an electrical current transmission element 14, hereinafter referred to as ECTE, as a component in an unlined electrolysis unit 10 or lined electrolysis unit 11. Preferably, the ECTE comprises a generally planar carrier part 17 which has sufficient structural integrity to become a carrier for several lugs 18 and 18A, a frame-like flange portion 16 and bushings 26 or 26A if bushings are used. The ECTE is significantly more massive and stiffer than liner 26 or 26A and all electrode components 36, 36A,

46 or 46A which are normally used in electrolysis cells.

The ECTE can be made of a variety of materials that satisfy the requirements outlined above. However, the material is preferably selected from ferrous metals such as iron, cast iron, malleable iron (hereinafter called wrought iron), steel and stainless steel and nickel, aluminum, copper, magnesium, lead, alloys of each and alloys thereof.

Preferably, the ECTE is constructed from ferrous metals whose primary constituent is iron. Even better, the ECTE is constructed from low carbon steel or wrought iron because it is cheap and readily available. Wrought iron has more dimensional stability when it cools after casting. Low carbon steel is more weldable.

In such cases where the electrolysis unit 10 or 11 is used as a bipolar electrolysis unit, the lugs 18 and 18A should be sufficiently conductive to transmit electrical energy through its mass or parts of its mass in a vertical direction and the planar carrier part 17. The electrical conduction takes place through the lugs 18 and 18A instead through the mass of the planar carrier part 17, except in the case where the lugs 18 and 18A are displaced, - then the planar carrier part 17 must be sufficiently conductive to conduct electrical energy through its mass or parts of its mass.

In those cases where the electrolysis unit 10 or 11 is used as a monopolar electrolysis unit, the ECTE is preferably sufficiently conductive to conduct electrical energy through its entire mass. This makes it possible to connect an electrical connection from an energy source to the flange part 16 or to a point on the plane carrier part 17 itself and to distribute the electrical energy to different points of an electrode component in electrical contact with the plane carrier part.

Regardless of whether the ECTE is used as a monopolar or as a bipolar device, it is possible to construct the ECTE from materials that are readily available and generally inexpensive without having to worry too much about the specific resistance of the material. This is possible due to the large mass and cross-sectional area of the ECTE which is sufficiently large in cross-sectional area to minimize its electrical resistance. The fact that the ECTE has a large cross-sectional area allows the use of materials with a higher specific resistance than could be used in previously known configurations. Thus, ferrous metals such as iron, steel, wrought iron and cast iron are perfectly suitable for use in the present invention. Specifically, metals with resistivities as high as or higher than copper can be used economically to form the ECTE. Even more economically, metals with greater specific resistance than approx. 10 micro-ohm-cm is used. Most economically, metals with specific resistances as high as or higher than approx. 50 micro-ohm-cm is used.

When the electrolysis unit 10 or 11 in the present invention is used as a monopolar unit, the planar carrier part 17 of the ECTE 14 may have one or more lined passages connecting opposite sides thereof. The passages enable electrolyte or gases to pass from one side of the planar carrier part 17 to the other side. Such passages should not occupy more than approx. 60 percent by volume of the total volume of the planar support part 17. The openings make it possible to use less metal when forming the planar support part and thus make the cell more economical. In addition, the openings can be spaced to direct electrical current to specific parts of the cell.

Several lugs 18 and 18A are attached to opposite sides of the planar carrier part 17. These lugs protrude a predetermined distance from the planar carrier part 17 in an area which will eventually become an electrolyte space. The knobs can be electrically connected either directly to an electrode 36, 36A, 46 or 47A, or indirectly to the electrode through a side liner. Preferably, the ends of the lugs 18 and 18A lie in the same geometric plane respectively and are essentially compact. However, they may contain internal voids as a result of casting.

The lugs 18 and 18A can be placed in a back-to-back relationship to each other through the planar carrier part 17. Optionally, they can be offset relative to each other through the carrier part 17. They can be placed in a number of other cross-sectional configurations from each other.

The lugs 18 and 18A can be made from the same metals as the metal used for the carrier part 17. Optionally, the lugs can be made from a different metal from that used to construct the carrier part 17. Preferably, the lugs are made from ferrous metals, such as iron, cast iron , wrought iron, steel, stainless steel or from nickel, aluminium, copper, magnesium, lead, alloys of each and alloys thereof. Preferably, the lugs are constructed of wrought iron or low carbon steel due to its stability, low cost and easy availability.

The lugs 18 and 18A are preferably separated in such a way that they can rigidly support all electrode components 36, 36A, 46 or 46A, which are desired to be used in the electrolysis cell. The distance between the lugs on each side of the carrier part 17 will generally depend on the specific electrical resistance of the particular electrode element used. For thinner electrode elements or with higher specific resistance, the distances between the lugs will be smaller and thus give a closer number of points for electrical contact. For thicker electrode components or with less specific resistance, the spacing of the lugs may be larger. Normally the space between the studs is within 5 to 30 cm, although larger or smaller spaces can be used depending on the overall construction considerations.

The knobs can be easily welded or tied to the carrier part 17, or they can be screwed into the carrier part 17 as shown by the reference number 93. In both cases it is desirable to make the attachment so that the electrical contact between the carrier part 17 and the knobs is maximized. In the case of an unlined electrolytic unit 10 or in the case where only a liner is used, it is preferred that the lugs are welded, even though they are screwed into or bonded to the carrier part 17. In the case of a lined electrolytic unit 11, it is preferred that the lugs are not welded, but could contain a butt weld.

The lugs may have a flat surface 28 and 28A which is machined before, during or after assembly of the unit. These surfaces are prepared to be attached to a liner or to an electrode component by means of intermediate coupons (30, 30A, 31 or 31A).

Around the outer edges of the carrier part 17 there is a frame-like flange part 16. It is a window frame-like structure with a thickness greater than or at least equal to the thickness of a lug-containing barrier part 17. Preferably, the flange part 16 extends further from the plane of the carrier part 17 than the ends of the lugs 18 and 18A does. This provides a space for electrode components 36, 36A, 46 or 46A which will be present when the electrolysis unit 10 or 11 in the present invention is stacked together in operable combination. Preferably, the thickness of the flange part is at least approx. 2 to 6 times greater than the thickness of the carrier part. Even better, the edge flange part is approx. 60 to 70 mm thick when the flat carrier part 17 is approx. 20 to 25 mm thick.

The flange part 16 can be made of a number of materials that satisfy the requirements outlined above. The materials may be metals and may be the same or different from the metals used to form the carrier portion 17. If the metals are different, the different metals are preferably weldably compatible. Otherwise, a metal spacer that is weldably compatible with both metals can be placed between the two metals. Preferably, the metals are selected from ferrous metals such as iron, gray iron, and malleable iron, wrought iron, steel, stainless steel or from nickel, aluminium, copper, molybdenum, magnesium, lead, alloys of each of these metals and alloys thereof. Preferably, the edge flange portion 16 is made of wrought iron because of its stability, low cost, and ease of availability.

If the planar support part is made of a ferrous metal, the flange part can be made of copper or any of the other metals suitable for use in the support part.

Optionally, the flange part can be made of a synthetic resin material. Without being limited to the specific synthetic resin materials hereinafter mentioned, examples of such suitable materials are polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinyl chloride, acrylonitrile, polystyrene, polysulfone, styrene acrylonitrile, butadiene and styrene copolymers, epoxy, vinyl esters, polyesters and fluoroplastics and copolymers thereof. It is preferred that a resin material such as polypropylene be used for the flange portion, as it provides a form with proper structural integrity at higher temperatures, is readily available,

and is relatively cheap compared to other suitable resin materials.

The flange portion 16 may be a simple unitary picture frame-type structure, or it may be several pieces spliced together from more than one structural piece and form a complete frame-type structure around the outer edges of the planar support portion 17. The flange portion provides sealing surfaces 16A and 16C located at approximately plane as the flat ends 28, 28A of the lugs 18 and 18A after they are attached to the carrier part 17. If the flange part consists of separate pieces, they can be attached to the carrier part 17 before or after the lugs are attached to the carrier part. The carrier part 17 and the lugs can be flattened (machined) before or after the flange part is attached to the carrier part if necessary.

If the electrolysis unit is to be used as a bipolar unit, the flange part 16 need not be made of an electrically conductive material because it need not conduct electricity. If, however, the electrolysis unit is to be used as a monopolar unit, the edge flange part is preferably electrically conductive. The flange part provides a suitable device for conducting electrical energy into and out of the electrolysis unit 10 and 11 which is present in an operational series of units. Less preferably, the flange member is made of an electrically non-conductive material and provided with passages therethrough which provide a path for conductors to pass through the flange member to conduct electrical energy into and out of the electrolysis unit.

If the flange part 16 is not formed as a one-piece body with the carrier part 17, it is preferably firmly connected to the carrier part. A fixed connection ensures dimensional stability of the electrolysis unit and maintains the desired opening between the electrode components of adjacent units. Preferably, the flange parts are attached to the carrier part by welding.

When the electrolysis unit is to be used as a bipolar unit and the unit is not lined, it is particularly important to weld the flange portion sealably to the carrier portion to prevent fluid flow from one side of the carrier portion to the other side.

When several electrolysis units 10, 11 are put together in operative combination, an ion exchange active membrane 27 and 27A is placed between adjacent electrolysis units 10, 11. A membrane is used between either bipolar or monopolar electrolysis units. In each case, the membrane separates an electrode compartment from an adjacent electrode compartment.

The membrane 27 and 27A suitable for use herein

invention, may contain a number of ion-exchange active points. For example, they may contain sulfone or carboxylic acid ion-exchange active sites. Optionally, the membrane can be a bi-layer membrane and have a type of ion exchange points in the second layer. The membrane may be reinforced to prevent deformation during electrolysis or it may be unreinforced to maximize electrical conduction through the membrane. Ion-exchange active membranes which are

suitable for use in electrolytic cells in the present invention, are well known in the field.

Other elements that can be used in connection with the present invention are compositions for zero-gap configurations or solid polymer electrolyte membranes. The devices of the present invention can also be adapted for a gas chamber for use in conjunction with a gas consuming electrode, sometimes called a depolarized electrode. The gas chamber is required in addition to the liquid electrolyte chambers. A number of cell elements that can be used in the present invention are e.g. described in US patents 4,457,823, 4,457,815, 4,444,623, 4,340,452, 4,444,641, 4,444,639, 4,457,822 and 4,448,662.

Liners 26 or 26A are preferably formed with a minimum of stresses in them to minimize warping. Avoidance of these stresses in the liner can be achieved by hot forming the liner in a press at a higher temperature from 482°C to 704°C. Both the liner metal and the metal press are heated to this high temperature before pressing the liner into the desired shape. The liner is held in the heated press and cooled during a programmed cycle to prevent the formation of stresses in it as it cools to room temperature.

Liners 26 or 26A suitable for use in chloralkali cathode rooms are preferably selected from ferrous metals, nickel, stainless steel, chrome, monel and alloys thereof. Suitable liners for use in chloralkali anode rooms are preferably selected from titanium, vanadium, tantalum, columbium, hafnium, zirconium and alloys thereof.

In order to ensure the maximum physical and electrical contact between the liner and the lugs, it is preferred that the liner is welded to the flat ends 28, 28A of the lugs 18 and 18A. Optionally, the liner may be welded, not only at the flat ends of the lugs, but at various other places where the two come into contact with each other. Capacitor discharge welding is a preferred welding technique that can be used to weld the liner to the lugs. For fluid sealing purposes between the diaphragm 27 or 27A and the sealing rafts 16A or 16C located on the flange portion 16, it is preferred that the liners 26 or 26A are shaped like a pan with an offset lip 42 or 42A running around its edge. The lip 42 and 42A are flush with the sealing surfaces 16A or 16C. An edge part of the membrane 27 or 27A runs flush against the lining lip 42, and an edge sealing strip 44 runs flush against the other side of the edge part of the membrane 27 or 27A. In a series of electrolytic cells, the sealing strip 44 is flush with the lip 42A of the liner 26A and flush with the sealing face 16C when there is no liner.

If the liners 26 and 26A are made of titanium and the ECTE 14 is made of a ferrous metal, they can be connected by resistance welding or capacitor discharge welding. Resistance or capacitor depletion welding is performed indirectly by welding the liners to the flat ends 28 and 28A of the lugs 18 and 18A through metal spacers, preferably the vanadium wafer 30 or 30A. Vanadium is a metal that is weldably compatible with titanium and ferrous metals. Weldable compatible means that a weldable metal will form a tough solid solution with another weldable metal after welding the two metals together. Titanium and ferrous metals are not normally compatible with vanadium. Accordingly, vanadium wafers 30 and 30A are used as an intermediate piece between the ferrous metal lugs and the titanium liners 26 and 26A to achieve their welding together forming an electrical connection between the liners and the ECTE 14 and to form a mechanical support device for the ECTE of the carrier liners 26 and 26A.

Preferably, a second metal spacer or wafer 31 and 31A is used and placed between the wafer 30 and 30A and the liner 26 and 26A. The second wafer is preferred, because when only one wafer is used, it has been found that the corrosive materials that come into contact with the liner during cell operation and produce chlorine and caustic appear to penetrate the titanium-vanadium weld and corrode the weld. The corrosive materials also penetrate the body of the ECTE and corrode it. Instead of using a thicker liner, it is much more economical to insert another wafer 31 and 31A of sufficient thickness to minimize the possibility of corrosive materials penetrating the ECTE.

In order to introduce reactants into the electrolysis cells which are formed when several electrolysis units 10 and 11 are stacked in operable combination, several nozzles (not shown) are preferably present in each electrolysis unit. Although a variety of constructions and shapes can be used, a preferred construction is as follows. Several metal nozzles are formed, e.g. by ambient casting. The die casting is machined to the desired size. A series of slots are made in each flange portion 16 at multiple desired locations to receive the nozzles. The slots have a size that corresponds to the thickness of the nozzle to be inserted into the slot to ensure a seal when the elements of the electrolysis cell are finally assembled. If a liner 26 or 26A is used, it is cut to fit around the nozzle. The nozzle is preferably attached to the liner 26 or 26A, e.g. when welding. The liner-nozzle combination is then placed in the electrolysis unit 10 or 11, and the covers 32, 32A of the liners are then welded to the lugs 18 and 18A.

When several electrolysis units 10 or 11 are assembled against each other, sealing strips 44 are preferably placed between the units. The sealing strips serve three main functions: sealing, electrical insulation and fixing the electrode gap. There are a number of suitable sealing strip 44 materials that can be used, such as, for example, rubber sealing strips. Although only one sealing strip 44 is shown, the invention also encompasses the use of sealing strips on both sides of the membrane 27 or 27A.

To the ECTE 14 or liner 26 or 26A, if liners are used, is an electrode component 36, 36A, 46 or 46A which may be attached or pressed to the liner or ECTE. Preferably, the electrode component has the same extent as the carrier part 17 and does not enter the flange part 16 area. Otherwise, it would be difficult to seal adjacent electrode assemblies when placed in operative combination.

Electrode components are preferably perforated structures which are essentially flat and may be made from a sheet of expanded metal, perforated sheet, punched sheet or woven metal wire. Optionally, the electrode components can be current collectors that have contact with an electrode or they can be electrodes. Electrodes may optionally have a catalytically active coating on the surface. The electrode components may be welded to the lugs or to the liner if a liner is used. Preferably, the electrode components are welded because the electrical contact is better.

Other electrode components that can be used in connection

with the present invention are current collectors, spacers,

and other elements known to a person skilled in the art. Special elements or compositions for zero-aperture configurations or solid polymer electrolyte membranes can be used. The electrolyte units of the present invention can also be adapted for a gas chamber for use in conjunction with a gas consuming electrode, sometimes called a depolarized electrode. Gas chambers are required in addition to the liquid electrolyte chambers. A number of electrode elements that can be used in the present invention are well known to those skilled in the art and are, for example, described in US patents no. 4,457,823, 4,457,815, 4,444,623, 4,340,452, 4,444,641, 4,444,639, 4,457. 822 and 4,448,662.

The electrodes 36, 36A, 46 or 46A preferably have their edges rolled inwards towards the ECTE and away from the ion exchange active membrane 27 and 27A. This is done to prevent the sometimes jagged edges of these electrode components from coming into contact with the ion exchange active membrane and tearing it open.

The electrolysis unit 10 and 11 can be produced in a number of ways using a number of elements. Each of the basic elements used in the manufacture of the electrolysis unit in the present invention, i.e. the planar carrier part 17, the frame-like flange part 16 and the lugs 18 and 18A can be assembled from several pieces. For example, the carrier part 17 can be constructed from several pieces that are assembled. Likewise, the flange part 16 can be constructed from several pieces which are connected together. Similarly, the lugs 18 and 18A may be one-piece units which pass through the carrier part 17, or they may be sub-units which do not pass through the carrier part 17, but are only attached to one surface or the opposite surface thereof.

The basic elements can be assembled by first attaching the lugs to the carrier part 17 and then attaching the flange part 16 to the edge of the carrier part 17. In a different order, the flange part 16 is first attached to the carrier part 17 and then the lugs are attached.

To ensure that the electrolysis unit 10 or 11 is as flat as possible, the surfaces of the assembled or partially assembled electrolysis units can possibly be flattened or leveled. The electrolysis unit can be flattened by one or more of the different composition steps for the electrolysis unit. For example, it can be flattened: after all the lugs have been attached to one side of the carrier part 17;

after only part of the lugs have been attached to the carrier part 17;

after all or part of the lugs have been attached to the carrier part 17, but before the flange part 16 has been attached; or after all the lugs and the flange part 16 have been attached.

The electrolysis unit of the present invention can be flattened for the use of a number of techniques well known to a person skilled in the art, such as belt sanding and mechanical painting. Preferably, the unit is flattened sufficiently, so that when two units are adapted to each other in operable combination, the number of leaks is minimized. For use in chloralkali electrochemical cells, it is preferred that the electrolysis unit 10 or 11 has a flatness deviation of less than approx. 0.4 mm throughout its mass.

Attaching the lugs 18 and 18A to the carrier portion 17 of the ECTE 14 can be accomplished using a variety of techniques. For example, the carrier part 17 can be cast as a compact unit and later have holes drilled and tapped through the thickness, or partially through the thickness of the carrier part. The knobs can be threaded and then screwed into the holes in the carrier part 17 from both sides. Optionally, the lugs can be threaded over half their length and then screwed halfway through the carrier part 17. Preferably, the ends of the lugs are mechanically flattened before they are attached to the carrier part 17.

Another way to attach the knobs is by welding. Preferably, the lugs and the carrier part 17 are made of metals which are weldably compatible. If the two metals are not weldably compatible, a metal spacer that is weldably compatible with both metals can be inserted between the two metals. Preferably, the lugs are welded slowly, so that the warping of the carrier part 17, which is caused by the heat during welding, is minimized.

If desired, a liner 26 or 26A can be placed over the area of the electrolysis unit that will come into contact with a corrosive environment. Optionally, the flange part 16 of the ECTE can also be lined, although the flange part does not need to be exposed to a corrosive environment. Optionally, a lining can be placed on one side of the ECTE or on both sides of the ECTE. The liner may be constructed of a single unitary piece, or it may be constructed of several pieces bonded together (as shown in Figure 4). However, it should be of sufficient thickness to be essentially completely hydraulically impermeable.

The liner 26 or 26A may have the same extent as the carrier part 17 of the ECTE, or it may have the same extent as the entire length and width of the ECTE including the edge flange part 16.

When several electrolysis units are assembled against each other, sealing strips 44 are preferably placed between the adjacent units. Sealing strips serve three main functions; 1) sealing, 2) electrical isolation and 3) fixing and maintaining the electrode opening. There are a number of suitable sealing strip 44 materials that can be successfully used, such as e.g. ethylene-propylene-diene terpolymer, chlorinated polyethylene, polytetrafluoroethylene, perfluoroalkoxy resin.

Preferably, the electrodes 36, 36A, 46 or 46A have the same extent as the carrier portion 17 and do not extend over the edge flange portion 16. Otherwise, it would be difficult to seal adjacent electrolysis units when placed in operable combination.

A particularly suitable way of manufacturing the ECTE according to the present invention is to use a flat piece of material to place the ECTE on which previously had holes drilled and tapped in its carrier part to accommodate the lugs. Several knobs are cut to the same length and each knob is given a threaded middle part. The non-threaded end portions have different diameters. One end part has a smaller diameter than the other part and has a diameter smaller than the diameter of the hole drilled in the carrier part. The smaller end part of a cam is passed through the hole and until the threaded part of the cam comes into contact with the threaded part of the hole. The lugs are screwed into the threaded holes in the carrier part until they touch the flat piece of material. In this way, it is easy to ensure that all the knobs protrude the same length from the barrier part.

Example 1

A 122 cm x 244 cm bipolar flat plate filter press type ion exchange membrane cell was constructed as follows.

A 122 cm x 244 cm steel plate, 1.27 cm thick, was drilled and tapped to have 116.25 mm holes in it in a square pattern. The steel plate was used as the supporting part of the ECTE and had a 19 mm thick, 70 mm wide low carbon steel picture frame type flange part welded around its edge.

Several 25 mm threaded steel rods were screwed into each of the 116 holes. On the side that would become the anode side, a vanadium wafer was placed over the end of each rod and a titanium cover was then placed over the rod and vanadium wafer. The cover was welded to each of the 116 rods through the vanadium wafer. On the side that was to become the cathode side, a nickel cover was placed over and welded to each of the 116 rods. As nickel can be relatively easily welded to steel, no intermediate wafer was required on the cathode side. The vanadium wafer was approx. 0.13 mm thick. The cover was approx. 0.9 mm thick.

For corrosion protection, the anode compartment was lined with 0.9 mm thick titanium lining which was made from a flat titanium plate welded to a U-shaped titanium side cover on all four edge sides. The titanium bushing had 116 holes concentric to the holes on the carrier part to fit over the connecting rods. The titanium liner was welded to the titanium cover of the connection.

The cathode compartment was lined with a 1.5 mm thick nickel liner made from a flat nickel plate welded to a U-shaped nickel side cover on the edge sides. The nickel liner also had 116 holes concentric to the holes on the carrier part to fit over the connecting rods. The nickel lining was welded around each nickel cover.

The anode was a 1.6 mm thick, 40 percent open expanded titanium cloth with a 0.65 mm (SWD) x 1.3 mm (LWD) diamond pattern. The anode was resistance welded to the titanium covers on top of the connections on the anode side.

The cathode was made of a nickel grid with the same specifications as the titanium grid. The cathode was resistance welded to the nickel covers on top of the connections on the cathode side.

A 13 mm diameter titanium tube was welded to the titanium liner through a hole in the bottom to the left of the anode compartment for the salt-water inlet. Another 19 mm diameter tube was welded to the titanium liner through a hole at the top to the right of the anode compartment for salt water and chlorine gas outlet. In a similar manner, nickel tubes were welded to the cathode compartment for catholyte inlet and outlet.

The cell was constructed in such a way that the anode grid ran approx. 0.4 mm down below the titanium side sealing flange, and the cathode grid went approx. 0.9 mm down below the nickel side sealing flange. With an expanded polytetrafluoroethylene sealing strip of approx. 1.3 mm compressed thickness between the membrane and the cathode sealing flange and no sealing strip between the membrane and the anode sealing flange, the nominal gap between the electrodes was approx. 2.5 mm.

The distance between the planes of the ends of the lugs was 65.4 mm for this bipolar cell, which can be called the carrier part thickness. The total unit cell thickness from the outside of the nickel electrode component to the outside of the titanium anode component was 71.1 mm. Thus, the cell element thickness was 92% of the total unit thickness.

Claims (12)

1. Procedure for manufacturing an electrolysis unit with a substantially planar electrical current transmission element comprising a generally planar carrier portion, an edge flange portion, and; a plurality of lugs projecting from each side of the carrier portion; the flange is constructed of at least one section and has an inner surface that sealably accommodates all outer edges of the carrier member; characterized in that the method consists of the steps: attach in any order: (a) multiple lugs to at least one side of the carrier portion; (b) at least one section of the flange portion to the outer edge of the carrier portion; and (c) multiple lining sections for at least one part of the lugs on at least one side of the carrier part. 2. Method according to claim 1, characterized in that it includes the step of attaching at least one section of the flange part to the carrier part by welding. 3. Method according to claim 1 or 2, characterized in that it includes the step of attaching all the lugs before flattening the unit. 4. Method according to claim 1, 2 or 3, characterized in that it includes the step of flattening the at least partially assembled unit. 5. Method according to each of the preceding claims, characterized in that it includes the step of constructing the carrier part, at least a section of the flange part and the lugs from metals' selected from ferrous metals, nickel, aluminum, copper, magnesium, lead, alloys of each and alloys thereof. 6. Method according to each of claims 1 to 4, characterized in that it includes the step of constructing the carrier part and the lugs from a castable metal selected from ferrous metals, nickel, aluminium, copper, magnesium, lead, alloys of each and alloys thereof, and where in at least a section of the flange portion is made of a synthetic resin material and attached to an edge of the carrier portion. 7. Method according to each of the preceding claims, characterized in that it includes the step of constructing the flange part with a thickness of at least twice greater than the thickness of the carrier part. 8. Method according to each of the preceding claims, characterized in that it includes the steps of covering both the knob-containing sides of the carrier part with a lining. 9. Method according to each of the preceding claims, characterized in that it includes the steps of selecting the liner from a ferrous metal, nickel, chromium, titanium, vanadium, tantalum, columbium, hafnium, zirconium and alloys thereof. 10. Method according to each of the preceding claims, characterized in that it includes the steps of attaching at least one electrode component to the liner(s) and attaching an electrical connection device to a part of the carrier part that has the same extent as the electrode component. 11. Method according to each of claims 1 to 9, characterized in that it includes the step of attaching an electrical connection device to the flange part. 12. Object, characterized in that it is produced by the method according to each of the preceding claims. 1. Procedure for manufacturing an electrolysis unit with a substantially planar electrical current transmission element comprising a generally planar carrier portion, an edge flange portion, and; a plurality of lugs projecting from each side of the carrier portion; the flange is constructed of at least one section and has an inner surface that sealably accommodates all outer edges of the carrier member; characterized in that the method consists of the steps: attach in any order: (a) multiple lugs to at least one side of the carrier portion; (b) at least one section of the flange portion to the outer edge of the carrier portion; and (c) multiple lining sections for at least one part of the lugs on at least one side of the carrier part. 2. Method according to claim 1, characterized in that it includes the step of attaching at least one section of the flange part to the carrier part by welding, and flattening the at least partially assembled unit. 3. Method according to claim 1 or 2, characterized in that it includes the step of attaching all the lugs to the carrier part. 4. Method according to each of the preceding claims, characterized in that it includes the step of constructing the carrier part, at least a section of the flange part and the lugs from metals selected from ferrous metals, nickel, aluminum, copper, magnesium, lead, alloys of each and alloys hence. 5. Method according to each of claims 1 to 3, characterized in that it includes the step of constructing the carrier part and the lugs from a castable metal selected from ferrous metals, nickel, aluminium, copper, magnesium, lead, alloys of each and alloys thereof, and where in at least a section of the flange portion is made of a synthetic resin material and attached to an edge of the carrier portion. 6. Method according to each of the preceding claims, characterized in that it includes the step of constructing the flange part with a thickness of at least twice greater than the thickness of the carrier part. 7. Method according to each of the preceding claims, characterized in that it includes the steps of covering both the knob-containing sides of the carrier part with a liner. 8. Method according to each of the preceding claims, characterized in that it includes the steps selecting the liner from a ferrous metal, nickel, chromium, titanium, vanadium, tantalum, columbium, hafnium, zirconium and alloys thereof. 9. Method according to each of the preceding claims, characterized in that it includes the steps of attaching at least one electrode component to the liner(s) and attaching an electrical connection device to a part of the carrier part which has the same extent as the electrode component. 10. Method according to each of claims 1 to 8, characterized in that it includes the step of attaching an electrical connection device to the flange part.