AP970A

AP970A - Electrochemical cell.

Info

Publication number: AP970A
Application number: APAP/P/1997/001162A
Authority: AP
Inventors: Mikhailovich Bakhir Vitold; Georgievich Zadorozhny Jury
Original assignee: Mikhailovich Bakhir Vitold; Electro Chemical Tech Limited; Georgievich Zadorozhny Jury
Priority date: 1996-04-18
Filing date: 1996-04-18
Publication date: 2001-05-30
Also published as: CZ290114B6; EP0842122B1; EP0842122A1; CZ408897A3; WO1997038942A1; AP9701162A0; ES2149474T3; OA10551A; US5635040A; GR3034432T3

Abstract

An electrochemical cell for the treatment of water and/or water solutions comprises an internal electrode having a middle section and a pin-end at each end thereof, the diameter of each pin-end being not more than 0.75 of the diameter of the middle section; an external electrode mounted around the 1 internal electrode; and a coaxial ceramic diaphragm mounted in a separate inter-electrode space in an electrode chamber of the cell. The external electrode is mounted in lower and upper dielectric bushings. Both the internal electrode and the external electrode are connected with positive and negative poles of a power supply. The cell further includes an upper dielectric collector head and a lower dielectric'collector head which each have an axial channel; each collector head-being installed in the bushirig slots and adapted for turning therein. The diaphragm being fastened by elastic gaskets mounted in the slots of the bushings. The diameter of the middle section of the internal electrode being defined by the formula: 2M < D < 4M where: D = diameter of the middle section of the internal electrode in mm, and M = distance between electrodes in mm. Tne length of the middle section of the internal electrode is either shone: than the lenath of the external electrode on the value 2M or longer than the length of external electrode on the value of not less than 2M.

Description

ELHCTXOCHHMrC.iL CHLL

Tills invention relates to chemical technology, and more particuiariv to electrochemical cells for the treatment of water and/or water solutions and can be used for electrochemical regulation of acid-alkaline properties, OxidationReduction Potential ^rOR?) and catalytic activity of water and/or water solutions, as in electrochemical manufacturing of different products by the electrolysis of water solutions.

background of me invention

In the field of applied electrochemistry, different design electrolyzers are used either for water and/or water solutions treatment, or for different product manufacturing for instance. there are electroiyner* widi flat electrodes pressed azainst the dianhrazm (see the Authors cerdScate USSR To. 3829

AP/P/ 9 7/01162 uu or electrolyzers with coaxial cylindrical electrodes and a ceramic diaphragm between them (see the published patent appiieancn of Japan To I-104387, 1989).

However, module electrolyzers are the most advanced because they mo vide the required production capacity’ by joining together the necessary number of modules. Tms reduces the design and production expenses of electrolyzers depending upon the required capacity and also helps to unify' pans and reduce the time for assembly and disassembly of such electrolyzers.

Tie closest by the technical design and achieved result is a device for water treatment, executed by the module principle using electrochemical ceils which contain coaxial cylindrical and rod electrodes and a coaxial ultrankraxion ceramic diaphragm made from materials using as their base zirconium, aluminum and yttrium oxides (see US Patent To. 5,427,667). The water treatment technical approach is chosen as a prototype.

Tie rod electrode is made with variable sections in the prototype and the diameter of its pin-ends is 0.75 of the diameter of its middle section. This allows

AP 00970 for the improvement of hydraulic mode. In addition, dimensions of the electrodes and the diaphragm are specified in the formula, limiting their mutual change.

In the prototype, he rod and he cylindrical electrodes, as we'd as he diaphrnem, arc fixed in special dielectric bushings with channels for the ucuied water supply to be fed into and to he discharged from he rod electrode chamber, 'there are channels on the lateral surface of the cylindrical electrode, on its upper and lower pans, to supply and discharge treated water from the chamber of the cylindrical electrode, water is treated while passing through he cell chambers from he bottom to he top.

Required production capacity devices are assembled with he number of cells by using special collectors, which are made either as a monolithic detail or special separate blocks for one cell and provided with joining and sealing tools. The order m which the electrodes connect to the poies of the power supply depends on he type of desired application.

The prototype treats water or water solution efficient at low energy’ consumption. The prototype is sufficiently simple in use, assembly and disassembly.

However, the prototype has disadvantages. Special collectors enlarge he size of he device, increase its hydraulic resistance and require he 'use of more powerful pumps. It also requires numerous joint pans and seals for hem. Tire prototype does not work effectively under he different poianry of electrodes due to its constructive features. So when he rod electrode works as an anode, he coating wears outs rapidly in places of transition from the middle pan to he pm ends (not including the holes whose share of he surfaces a small). Ail of the remaining place of transition is in the field of the cylindrical electrode and is subjected to an intensive influence of high intensity electric f eld (concentration of field m he places of changing form). It is not possible to control gas-filling of the treated solution in he prototype. The prototype device is also complicated in fabrication, because strict coaxiality for all details and he diaphragm arc required. The fixation system for the rod electrode has difficulties in manufacture, due to he annular deepening on he internal sumacs of he bushings channels and placing seals in hem.

Tie object of he present invention is to simplify he ceil design and make u possible to place he required amount of cells in a smaller space; simplification of he fixation system for the elements of he cell; improving he reliability and increasing he lifespan of he cell due to he elimination the influence of a curved electrical field in he space between electrodes, as well as expansion of the functional abilities lor the cell by making it possible to regulate the influence of gas-rilling of the electrolyte on the electrochemical process.

This objective can be achieved when he electrochemical cell for water and/or water solutions treatment is made from vertical cvimdrical coaxial parts

J * such as an internal electrode of variable sections (the diameter of its end parts being not more then 0.75 of he diameter of its middle part), an external electrode and a coaxial ceramic diaphragm (made front znaterials having as heir base

AP/P/ 9 7/01 162

AP 00970 zirconium oxides with additives of aluminum and yttrium oxides) which separates the inter-electrode space in the electrode chambers. The electrodes are made from material that is nonsoiuble during electrolysis. The external electrode is installed' in lower and upper dielectric bushings. Moreover there are slots on the butt-ends of upper and lower bushings, and the ceil contains uoper and lower dielectric collector heads, which have an axial channel. Moreover the heads are installed in the slots of bushings with the capability of turning. The diaphragm is fastened by elastic gaskets, which are placed in bushing slots. The diameter of the middle section of internal electrode is denned by the following formula:

2M<D<4M where: D “ the diameter of the middle section of the internal electrode in mm, and

M = the distance between electrodes in mm.

Depending on the execution and polarity of the clccuudes. the length of the middle section of the internal electrode can be either sooner than '.he length of the external electrode on the value of 2M. or longer man the length of the external eisetrnde on the value vf not less than 2M. The oreferred distance electrodes is 2.3 me internal electrode is fastened inside heads by elastic gaskets placed in the axial head channels. The purpose of the channels in the lower and upper heads and in the lower and upper bushings is to supply and discharge treated water and/or solution into the internal and external chambers of the electrodes. The channels reach to lateral surfaces and arc provided with outlets. The length of the external electrode can be varied from 50 mm to 240 mm depending on need

Materials for the electrodes can be chosen mom existing sources and the

AP/P/ 97/01162

Should chansons the noiaritv of electrodes not be mourned, titanium electrodes coated by titanium oxide and ruthenium oxide, or titanium electrodes coated by precious metals or manganese oxide or tin oxide or cobaitous oxide, can be used as an anode. Polished titanium or polished tantalum or polished zirconium coated by pvrographite or glass carbon or other coatings can be used as a cathode. If changing he poiaritv of electrodes is required, titanium electrodes coated by platinum or piannum-indium can be used. It is possible to use different combinations of the materials listed above or othti materials known in applied electrochemistry.

Tne diaphragm of the electrochemical ceil is made from ceramics made from zirconium, aluminum and yttrium oxides, and can contain additives such as niobium oxide, tantalum oxide, titanium oxide, gadolinium oxide, hafnium oxide and others. Depending on the application, the diaphragm can be made as an ultrafiltration, a micronltration or a nanoiiitration. Tne forms of the diaphragm can be vaned. The diaphragm can be a truncated cone with the conicity value 1; (100 - 1000) and a like thickness of walls equal to 0.4 mm - 0.8 mm on the whole length of the diaphragm. The diaphragm can. be installed in the cell either its big base facing downward or its big base facing upward.

AP 00970

The external (or internal) surface of the diaphragm can also be made as a cylinder, with the remaining surface (internal or external) made as a cone with the conicity value 1; (100 - 1000). in this case, the wall thickness of one buttend is 0.4 mm - 0.5 mm and the wall thickness of the other butt-end is 0.7 mm 5 O.S mm. The diaphragm is installed in the cell with its the butt-end with thickest wall either facing downward or facing upward.

The external and internal surfaces of the diaphragm can also be made as truncated cones with the conicity value 1: (100-1000). Moreover the cone tops are positioned at opposite end of the diaphragm and die thickness of the wails of ic one butt-end is 0.4 mm - 0.5 mm and the thickness of the other butt-end is 0.7 mm - O.S mm. The diaphragm is installed in the cell so that the butt-end with the thickest wall, either is turned downward or is turned upward.

The internal and external surface of diaphragm can also be made as a cylinder with the waJl thickness 0.4 mm - 0.7 mm. Deviation from the geometric is correct surface of the diaphragm should be not more than 0.05 mm in any part of its surface. Tne internal electrode is made either solid or hollow inside. The internal electrode can include several details, which are made from one or more materials, and are united by different methods (depending on materials), such as laser beam welding, vacuum welding, mechanically joining and the like. A thread is provided on the pin-ends of the internal electrode for adjustment of the head by manipulating washers and· nuts.

Different combinations of internal electrode dimensions can be used, depending on the order in which the electrodes are connected with poles of the power supply. For instance, if the external electrode is connected with the negative pole ofthe power supply and the internal electrode is connected with the positive pole of the power supply, the length of the middle section of the internal electrode exceeds the length of the external electrode by a value of not less than 2M and the internal electrode is installed in the cell symmetrically to the external electrode. If the external electrode is connected with the positive pole of the power supply and the internal electrode is connected with the negative pole of the power supply, then the internal electrode middle section length is equal or less than the external electrode length on the vaiue of 2M, and the internal electrode is installed in the cell symmetrically to the external electrode.

To provide strict coaxiality of electrodes in the cell, different variants are to be used for fastening of the internal electrode in the axial head channels depending on the dimensions ofthe electrodes.

When the length ofthe internal electrode exceeds the length of the external electrode by sufficient length, the axial head channel is contained within the valuable section and the middle section of internal electrode with the bis diameter forms a slot joint with the axial channels of the heads in which the clastic gaskets are placed. If the middle section of the internal electrode forms a slot joint with the axial channels of the upper and lower heads, then elastic gaskets are placed in the grooves of the middle section of the internal electrode. If the internal electrode is fastened by pin-ends, the axial head channel diameter is equal to die diameter of the pin-ends of the internal electrode; elastic gaskets are placed in

AP/P/ 9 7/01162

AP .0 0 9 7 0 grooves on the pin-ends of the internal electrode; or axial head channels having a diameter equal to the diameter of the internal electrode pin-ends and having an extension in the butt-ends; elastic gaskets are placed in this extension. In addition, the cell has clamping dielectric bushings which are also placed in this extension.

These improvements result in a better functioning and superior cell. Using coaxial electrodes and a diaphragm, and installing them in dielectric bushings and heads, allows for an optimal hydraulic regime and the simplification of the cell assembling. There is no need to drill a holes in the external cylindrical c electrode, thus making it simple to manufacture. Because it is possible to turn the heads and regulate the outlet position, several cells can be assembled together compactly in one device.

Brief Description ot the Drawings shows a cross section of the electrochemical cell of the present shows one version of a structure for the fastening of the internal the collecting heads of the electrochemical cell of the present shows a second version of a structure for the fastening of the ,: Figure invention.

Figure electrode in invention.

Figure internal electrode in the collecting heads.

Figure 4 shows a third version of a structure for the fastening of the internal electrode in the collecting heads.

Figure 5 shows a fourth version of a structure for the fastening of the »_* ·<—<

?5 internal electrode m the collecting heads.

Figure ό shows a first alternative diaphragm design used in the electrochemical cell of the present invention.

Figure 7 shows a second alternative diaphragm design used in the electrochemical cell nf the present invention.

Figure 8 shpw§ a third alternative diaphragm design used in the electrochemical cell of the present invention.

Figure 9 shows a fourth alternative diaphragm design used in the electrochemical cell of the present invention.

Figure 10 shows a fifth alternative diaphragm design used in the is electrochemical cell of the present invention.

Figure 11 shows a sixth alternative diaphragm design used in the electrochemical cell of the present invention.

Figure 12 shows a seventh alternative diaphragm design used in the electrochemical ceil of the present invention.

4c Figure 13 shows an eighth alternative diaphragm design used in die electrochemical cell of the present invention.

Detailed Description of the Preferred Embodiments With reference to Figure 1, the electrochemical cell of the present ¢5 invention comprises a coaxial external cylindrical electrode I, an internal

AP/P/ 9 7/01162 ciectrodc 2 and a ceramic diaphragm 3 placed benveen them. The external electrode 1 is fixed tightly and hermetically in lower dielectric bushing 4 and upper dielectric bushing 5, each of which have channels for treated water and/or water solutions suppiv into and discharge from the chamber of the external electrode. The channels reach to the lateral surface of the bushings and are provided '.villi pipe connections. The lower dielectric collecting head 6 and the upper dielectric collecting head 7 have channels for treated water and/or water solutions to be supplied into and to discharge from the chamber of die internal electrode 2. Tne dielectric collecting heads 6,7 are joined to the dielectric bushings 4,5 by slot joints. Tne head channels also teach to the lateral surface and are provided with pipe connections. There are also axial channels in the dielectric collecting heads 6,7. The pin-ends of the internal electrode 2 enter into axial channels. Tne diaphragm 3 is sealed in the dielectric collecting heads 6,7 hy gaskets 8 and 9, respectively, which are placed in the slot joints between the bushings and heads. Tne internal electrode 2 is sealed by elastic gaskets 10 and 11. 'There is a thread on the pin-ends of the internal electrode to which washers 12 and 13 and nuts 14 and 15 are fastened. Assembling and sealing of the cell is achieved by bolting with nuts 14, 15 and washers 12, 13 of the bushings and heads together to the bun-end of the external electrode 1 after the determination of the position of the head.

The position and type of elastic gaskets 10 and 11 depends on the construction of the internal electrode. When the middle section of the internal electrode 2 and the axiai channel of the head 7 form a slot joint (Fig.2), the seal 11 is located in the slot joint, i.e. where the internal electrode 2 mid the axiai channel each change its diameter, In this case, the seal is loaded uniformly, which reduces the nsk of its deformation. Tne seal 10 is similarly installed in the head 6.

Wmen the middle section of the internal electrode 2 snd the axiai channel of head 7 form a slot joint in a place of connecting diameters, the top part of the electrode 2 has grooves for the sea! 11 (Fig-3). Tne internal electrode 2 is a combination of a hollow cylinder 17 and a solid pin-end 18 as is shown in Figure

If the diameter of the axial channel of head 7 is equal to the diameter of the pin-ends of the internal electrode 2, then grooves for the seal 11 can be made 25 on the end parts (Fig.4); or the axiai head channel is wider at the bun-end for placing the seal 11 and adding washers 16 (Fig. 5).

The internal electrode is made with variable sections. Tne diameter of the pin-ends of the electrode is not more than 0.75 of the middle section diameter of the electrode. Tnis ratio provides optimal hydrodynamic characteristics and 40 makes it possible to reliably fasten an electrode in the heads by different ways of elastic gaskets to set up. Tne internal electrode can be made as either a solid cylinder or a hollow cylinder with solid pin-ends to provide a required form of k the electrode. Ways for joining parts can be different depending on the applicable material. Either mechanical joining or other types of joining, such as vacuum welding or laser beam welding, can be used to obtain durability and reliable

AP 00970 conductivity. Using a hollow electrode nor only reduces weight of device and saves materials, but also allows to direct work on current electrochemical process due to changing conditions for the forming of surface charge of electrode. Besides, an internal electrode works as a joint detail, since there is a thread on its pin-ends for washers and nuts setting, which joins the ceil and provides hermetic scaling, as well as fixing the heads in the given working position.

The diaphragm is made from ceramic materials based on 2irconium oxide with additives of aluminum oxide and yttrium oxide and the diaphragm possesses high resistance to acids, alkaline and aggressive gases, has a long lifetime and is easy regenerated. Different additives allow for the adjustment of the characteristics of diaphragm surface and have a direct influence on the electrochemical process, which is particularly important when the electrochemical cell is used for obtaining some special product. The dianhrasm can be made mom different materials either as ultrafiltration, microfiltration or nanonitration, depending on problem to be solved.

The form of the diaphragm, as well as the manner of the diaphragm installation affects on working conditions of the cell comparative to the treated water flow. Tne diaphragm may take many different forms.

As shown in Figures 6 and 7, the diaphragm 3 can be a truncated cone with the conicity value 1: (100 -1000) and alike thicknesses of wails from 0.4 mm to 0.8 mm on the whoie length; it can be installed in the ceil either big base downward (Fig, 6) or big base upward (Fig. 7).

As shown in Figures 8 and 9, the external surface of diaphragm 3 can be executed as a evlinder and the internal surface of the dianhraam can be executed -· · ·->

as a cone with the conicity value 1: (100 - 1000) with either big base down (Fig.

•v* jj

8) or big base up (Tig. 9). Alternatively as shown m. Figures 10 and 11, the internal surface of diaphragm 3 nan he executed as a cylinder and the external surface of the diaphragm can be executed as a cone with the conicity value 1: (100 - 1000) with either big base down (Tig. lOj or big base up (Fig. 11). In cither case, a wall thickness of one butt-end is 0.4 mm - 0.5 mm, a wall thickness

9 1 I 0 / L 6 /d/dV of another butt-end is 0.7 mm - 0.8 mm: and the diaphragm is installed in the cell thereby, with, the bun-end with the thicker wail turned downward or turned upward.

As shown in Figures 12 and 13, both the external and internal surfaces of diaphragm 3 can also be made as a truncated cone with the conicity value 1: (100-1000). In this alternative, the tops of the cones arc directed to opposite sides and the thicknesses of walls are such that one butt-end is 0.4 mm - 0.5 mm, another one is 0.7mm- 0.8 mm. Tne diapnrasm is installed in the cell with the butt-end with the thicker wall either turned downward (Fig 12) or turned upward ‘V (Fig. 13), Using a diaphragm with a lower conicity value does not produce different results in comparison with a cylindrical diaphragm. When using a diaphragm with higher conicity value, as well as one with increased wail thickness, ii is necessary’ to alter the dimensions of the cell and increase the inter-electrode distance which causes increasing power consumption for the « electrochemical process. A. wall thickness lower than above mentioned increases

AP 00970 δ

the brittleness of the diaphragm and decreases its lifespan, making it more difficult to assemble and disassemble a cell. It is possible to regulate the electrochemical process by using a diaphragm with a variable profile. For instance, the diaphragm is installed in the cell in the wav that the cross section of s the chambers is increased from the bottom to the top of cell for the processes with high evolution of gas. Alternatively, die diaphragm is installed in the cell in the way that the cross section of the chambers is decreased from the bottom to die top in order to increase gas-filling in the top of cell and reduce the intensity of die electrochemical treatment of solution in the last cut of cell. Using ;o diaphragms which provide a variable profile for only one chamber (ops surface is a cone and another surface. is a cylinder) allows a difference in the volume of evolution of gas in both chambers during the process. Besides that, such diaphragms (as well as the diaphragms with both the external and internal surfaces being cones and the tops of the cones are directed in the opposite way) can be used for different quality and content solutions treatment in electrode chambers of cell.

The internal and external surfaces of the diaphragm can be made as both cylinders with the wall thickness 0.4mm - 0.7 mm. This type of diaphragm is vew effective for very diluted solutions treatment. Deviation from the geometric correct surface of the diaphragm should be not more than 0.05 mm in any place on its surface. Otherwise, conditions for creating dual electric layer on the surface of diaphragm are altered and influence of dual electric layer on the resistance of the diaphragm is altered also, causing low quality of solutions treatment due to unequal work along the surface.

;s The diaphragm is fasten by elastic gaskets, which are placed in bushing grooves,'making it easy to assemble a cell and provide coaxiality.

It is essential that a restriction for the diameter of the middle section of internal electrode by effected by the correlation;

2M<D<4M y where; D = diameter of the middle section of internal electrode in mm, and

M ~ inter-electrode distance in mm.

Inter-electrode distance should be 2.8mm - 3.3 mm. ’when reducing this distance, the capillary effect reduces the effectiveness of the electrochemical nrocess. ’when increasing this distance, power consumption is also increased and is impossible to achieve a mass and energy exchanging self-organizing process.

It is also important that the length of the middle section of the internal electrode be either shorter than the lengths of the external electrode on the value of 2 M, or longer than the lengths of the external electrode on the value of not less than 2 M. Tne length of the external electrode may vary from 50 mm to 240 mm, thus providing the optimal gas-filling of treated liquid in any working condition of the cell.

Mutual correlation of internal and external electrode dimensions is determined by the polanty of the electrodes. If the external electrode is connected with the negative pole of the power supply, and the internal electrode is connected with the positive pole of the power supply, then the length of the i 9 ι V 0 ! L 6 /U/dV

AP 00970 middle section of the internal electrode exceeds the length of the external electrode at the value of not less than 2M. If the external electrode is connected with the positive pole of the power supply and the internal electrode is connected with the negative pole of the power supply, then the internal electrode middle section length is equal or less than the external electrode length at the value of 2M. 'Ine internal electrode is installed in the cell symmetrically to the external electrode in any case. Such a design prevents the coating of the electrodes from wearing out in places of high intensity electric field (concentration of the field m places of changing form or on the pin-ends). Precise internal electrode fastening .c is imponant for the efficient working of the cell. Fastening of the internal electrode in the heads by elastic gaskets placed in the axial head channels, provides a strict coaxiality with relatively simple assembling. The design of the cell can be different to meet requirements for electrode coaxiality. For instance_τwhen the length of the middle section of the internal electrode exceeds he length it of the external electrode, he internal electrode must be made long enough to form slot joints with he axial head channels. Elastic gaskets are placed in the slot joints. Tne axiai channels of the head have a variable section. This provides coaxiality and avoids deformation of he elastic gaskets. Alternatively, he middle section of the internal electrode forms slot joints with he axial channels of the m upper and lower heads, hen elastic gaskets are placed h grooves on middle section of internal electrccs. This design makes assembling easy. If fastening of he internal electrode m me heads is provided by the packing of its pin-ends (when the middle section is smaller than the length of he external elecmode, or he middle section is longer, but does not reach the location of the heads), then he diameter of the axial head channel is equal to the diameter of he internal electrode pin-ends, and elastic gaskets are placed in grooves, which are made on he surfaces of the internal electrode pin-ends situated in he axial head channels. Alternatively, he diameter of the axial head channels is equal to the diameter of the pin-ends of the internal electrode and the axial channels are wider at the end of the head to allow for elastic gaskets and additional clamp dielectric bushings.

Water is treated while passing through the cell chambers from the bottom io the top. Treated water and/or solution flow' through the electrode chambers of he cell separately.

is

AP/P/ 9 7/01162

The invention can be illustrated by he following examples which are not intended to exhaust all of he invention possibilities.

If not mentioned separately, an ultrafiltration ceramic diaphragm (composition: zirconium oxide - 60% mass, aluminum oxide - 27 % mass, yttrium oxide - 3 % mass) is used in all examples.

Example I. Cell for water disinfection. The external electrode is connected to the negative pole of he power supply and is made from polished titanium. The internal electrode is made from titanium coated with manganese oxide and connected to he positive pole of the power supply. The length of the external electrode is 80 mm. The distance between electrodes is 2.9 mm. Tne diameter of he middle seenort of the internal electrode is 9.0 mm; he ltugh of he middle section is 86 mm. Tne diaphragm is a cylinder with wall hickness 0.5

AP 90970

- :o mm along its entire lengih. The mineralization of the treated water was 0.5 g/1. Tne amount of microorganisms m the treated water was 10- colonies in 1 ml. Tne mineralization of water remains the same after treatment, but microorganisms are eliminated.

; Conclusion; It is reasonable to 'use a cell with dimensions close to minimum values (as specified in the formula) for water sterilization by portable devices in the field.

Example 2. Cell for production of disinfectant. Tne external electrode is connected to the negative pole of the power supply and made from glass carbon, io Tne internal electrode is made from titanium, coated with ruthenium oxide and connected to the positive pole of the power supply. Tne length of the external eicctrode is 240 mm, Tne length of the middle section of the internal electrode is 250 mm. The diameter of the middle section is 10 mm. The distance between electrodes is 3 mm. Tne diaphragm is a cylinder with the wall thickness of 0.6 ;s mm.

Tne treated solution was sodium chloride with a concentration of 2 g/1, Tne fow rate of the treated solution was 30 1/hour through the anode chamber and was 5 1/hour through the cathode chamber. As a result, two solutions with the following parameters were obtained;

:c - anode chamber output (anolyte): pH = 6.0, OR? = —800 mV

- cathode chamber output (cathoiyte): pH ~ 8.6, OR? = -600 mV Tne power consumption is 0.95 kWt.hour/cub.m.

Example 3. A process for obtaining disinfectants by means of the ceil was conducted under the same conditions as in example 2, but the diaphragm was a is truncated cone with the conicity value 1:500 and a wail thickness of 0,7mm, constant along the entire length of the diaphragm. Tne diaphragm was installed with the big base facing upward. After processing, anolyte was obtained with oH = 5.5 and OR? - -900 mV and cathoiyte was obtained with pH = 8.0 and

ORP = -550 mV.

When the diaphragm was installed with the big base facing downward, anolvte was obtained with oH = 6.3 and ORP = -650 mV and caiholvte was » g obtained with pH - 9,1 and ORP =-750 mV.

Example 4. A process for obtaining disinfectants and washing solution by means of the cell was conducted under foe same conditions as in example 2, but is the external surface of the diaphragm was a cylinder and the internal surface of the diaphragm was a cone with a wall thickness of the upper butt-end 0.5 mm and the lower butt-end 0.8 mm. The width of the cathode chamber was a constant through the cell, but the anode chamber is wider at the top end. The results of treatment arc as follows: pH of anolyte was 5.6, ORP of anolyte was

-900 mV, pH of catolvte was 8.7 and ORP of cathoiyte was -780 mV.

Example 5. The ceil for obtaining chlorine (a mixture of oxidants which are chlorine and oxygen mainly) by means of the electrolysis of sodium chloride water solution. The external electrode is made from titanium, coated with ruthenium oxide and connected to the positive pole of the power supply. The internal electrode (cathode) is made from titanium and coaxed with pyrographite.

AP/P/ 9 7/01162

AP 00970

The length of the external electrode is 240 mm. The length of the middle section of the internal electrode is 23.0 mm. The diameter of the middle section is 11 mm. The distance between electrodes is 3.1 mm. The diaphragm is a cylinder with the wail thickness 0.6 mm. Sodium chloride water solution, with a concentration 300 g/1 was introduced and treated in the anode chamber of the cell. Tap water with a mineralization 0.5 g/1 was introduced and treated in the cathode chamber. Water and solution were treated while flowing through the cel! chambers from the bottom to the top. As a result, 10 liters of gas were obtained. The gas contains Chlorine 70%, chlorine dioxide 201k Oxygen 7% and the rest o (admixtures) 3%. Tne conversion degree of chloride is about 30% after passing through the cell.

Tne cathode chamber output is sodium hydroxide with pH ·-= 13. This solution can be used in galvanic production or other technologies. Inis examples proves that the ceil can be effectively used for chlorine manufacturing.

.1 The invention simplifies the design of the cell, makes possible the placing together of a required amount of cells in a smaller space, simplifies me fixation system for the elements of the cell, provides high reliability and increases the lifespan of the cell due to elimination of the influence of curved electrical field in the space between electrodes and expands the functional abilities of the ceil :: making it possible to regulate the gas-filling of the electrolyte during me electrochemical process. Tne cell can be effectively used for water purification and disinfection, for obtaining solutions with predetermined characteristics and for obtaining products by means of the electrolysis of water solutions.

Claims

12 Having now particufariy described and •«.•erutined my/our said invemic·!·. . · ·>' hat manner the same is to ίκ· pc.·:, >r j ί/we dee’are that what l/\vc vkrim is —

Claim 1. An electrochemical cell for the treatment of water and/or water solutions comprising:

a) a vertical, cylindrical, variable section niicuml electrode navmg a middle section and a pin-end at each end thereof, the diameter of each pin-end being not more than 0.75 of the diameter of the middle section;

b) a vertical, cylindrical external electrode mounted around the internal electrode;

c) a coaxial ceramic diaphragm made from a base composition of a mixture of zirconium, aluminum and yttrium oxides and mounted in a separate inter-electrode space in an electrode chamber of the ceil;

d) the electrodes are made from materials that arc nonsotuble during electrolysis;

ci the external electrode is mounted in a lower dielectric bushing and an upper dielectric bushings, each having a slots on a butt-end thereof;

f) both the internal electrode and the external electrode are connected with a positive pole and a negative pole of a power supply;

g) the cell further including an upper dielectric collector head anti a lower dielectric collector head which each have an axial channel; each collector head being installed in the bushing slots and adapted for turning therein;

• h) the diaphragm being fastened by elastic gaskets mounted in die slots of the bushings;

i) the diameter o he middle spption of the. internal electrode being detuned bv the formula:

2M <D<4M where:

D = diameter of the middle section of the internal electrode in mm, and

M. = distance between electrodes in mm

j) the length of the middle section of the internal electrode being either shorter than the length of the exiemai electrode on the vaiue 2M or longer than the length of external electrode on the vaiue of not less than 2M;

k) the internal electrode being fastened inside the collector heads by elastic gaskets mounted in the axial head channels; and

l) the lower head and the upper head and the lower bushing and the upper bushing having channels for the treated water and/or treated solution supply to be sent into and discharged from the chambers of the internal external electrodes.

AP/P/ 97/01162

Claim

2. Tne cell as claimed in claim 1 wherein the length of the external electrode is from 50 mm to 240 mm and the distance between electrodes is from 2.8 mm to 3.3 mm.

Claim

3. The cell as claimed in anyone of claims 1-2, wherein the bushings and head channels reach to the lateral surface and are provided with pipe

45 connections.

ftp 0 0 9 7 0

Claim

4, The cell as claimed in anyone of claims 1-3, wherein me diaphragm is made from ceramics having a base composition from the group consisting essentially of zirconium, aluminum and yttrium oxides, with additives of

5 niobium, tantalum, titanium, gadolinium and hafnium oxides.

Claim 5. Tne cell as claimed in anyone of claims 1-4 wherein the diaphragm includes either ultrafiltration, microfiltration or nano filtration properties.

o

Claim

6. The cell as claimed in anyone of claims 1-5 wherein the diaphragm is made as a truncated cone with a conicity value of 1: (100-1000) and a like thickness of walls from 0.4 mm tn 0.8 mm along its length and is installed in the cell either big base downwards or big base upwards.

Claim

7. Tne cell as claimed in anyone of claims 1-5 wherein the external surface of the diaphragm is made as a cylinder and the internal surface as a cone with a conicity value of 1: (100 - 1000); the wall thickness at a first butt-end is 0.4 mm-0.5 mm and the wall thickness at a second butt-end is 0.7 mm-0.8 mm; the diaphragm is installed in the cell with the butt-end having the thicker wall cither turned downwards or turned upwards.

Claim

8. Tne cell as claimed in 'anyone of claims 1-5 wherein the external and internal surfaces of the diaphragm are each made as a truncated cone with a conicity value of 1: (100 - 1000); the tops of the cones are positioned at the opposite ends; the wall thickness of a first butt-end is 0.4 mm-0.5 mm and the wall thickness of a second butt-end is 0.7 mm-0,8 mm, the diaphragm is installed in the cell with a butt-er.d with the thicker wall either is turned downward or is turned upward.

AP/P/ 9 7/01162

Claim

9. The cell as claimed in anyone of claims 1-5 wherein the internal and external surfaces of diaphragm are cylinders with a wall thickness of 0.4 mm 0.7mm.

Claim

10. The cell as claimed in anyone of claims 1-9 wherein the deviation is from the geometric correct surface is not more than 0.05 mm in any place along the length of the diaphragm.

Claim

11. The cell as claimed in anyone of claims 1-10 wherein the internal electrode is either solid or hollow inside.

Claim

12. Tne cell as claimed in anyone of claims 1-11 wherein there is a thread on the pin-ends of the internal electrode and pressing washers and nuts are used for fastening.

βρ '0 0 9 7 9

Claim Η The cell as claimed in anyone of claims 1-12 whcicin me external electrode is connected with a negative pole of a power supply, the internal electrode is connected with a positive pole of the power supply; the internal electrode is designed so that the length of its middle section with the bie s diameter exceeds the length of the external electrode on a value of not less than double the distance between the electrodes; and the internal· electrode is installed in die cell symmetrical to the external electrode.

Claim 14. The cell as claimed in anyone of claims 1-13 wherein the external :c electrode is connected with a positive pole of a power supply, die internal electrode is connected with a negative pole of the power supply; the internal electrode is designed so that the length of its middle section with the big diameter is less than the length of the external electrode on a value equal to double .the distance between electrodes; and the internal electrode 13 installed In die cell is symmetrical to the external electrode.

Claim 15. The cell as claimed in anyone of claims 1-13 wherein the axial head channel has a variable section; the middle section of die internal electrode forms slot joints with the axial head channels; and elastic gaskets are placed in die slot ioints.

Claim 16. 'he cell as claimed in anvone of claims wherein the axial head channel has a variable section; the middie pan of internal electrode forms slot joints with the axial head channels; die middle section of the internal electrode forms slot joints with the axial head channels; the surface of internal electrode has grooves in the lower and higher parts of its middle section with the big diameter; and elastic gaskets are placed in the grooves.

AP/P/ 97 / 0 1162

Claim 17. Tue cell as claimed in anyone of claims i-14 wherein the diameter of the axial head channel is equal to the diameter of the internal electrode pin-ends; the internal electrode pin-ends have grooves on their surfaces; and elastic gaskets •are placed in the grooves.

Claim 18. The cell 22 claimed Lu anyone of claims i-i4 or 17 wherein die 35 diameter of the axial head channels is equal to the diameter of internal electrode pui-ends and the axial head channels are wider in the butt-end of the head; elastic