Abstract:
The disclosure is directed to the area of electrochemical processing of liquids and production of gases, and is used for anolyte and catholyte synthesis. The electrolytic cell comprises an assembled anode and a diaphragm. Elements of the anode and the diaphragm are assembled in axial alignment with help of sleeves, and free ends of the anode and the diaphragm are fixed in a coaxial manner with solid of electrolyte input and output covers. The cathode is made solid from a single pipe with current terminals on each side. The cathode is the internal electrode of the electrolytic cell, while the anode is the external one. The anode is may be provided with a visual indicator as a positive electrode.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Estonian Patent Application No. P200800023, filed on Apr. 23, 2007, which application is incorporated herein by reference in its entirety. 
     FIELD OF INVENTION 
     The invention relates generally to chemical technology, in particular to the area of electrochemical processing of liquids and production of gases, and is used for anolyte and catholyte synthesis. 
     BACKGROUND 
     From the technical and construction, known prior art includes: electrochemical installation—Russian patent RU2104961 [1] filed on Feb. 20, 1998, electrochemical cell for processing of water solutions, installation for production of anodic oxidation products, alkaline chloride solutions or alkali-earth metals—Russian patent RU2176989 [2] filed on Nov. 1, 2000, device for electrochemical processing of water and water solutions—Russian patent RU2248940 [3] filed on Jan. 16, 2004 and bicameral coaxial electrolytic cell device—Estonian patent application P200700021 [4] filed on Apr. 30, 2007. 
     There is a great demand for electrolytic cells with oxidant performance of 100 g/h and much more. For instance, such mass technology as decontamination of ballast water in ships requires the oxidant performance to be as high as 5000 g/h, and to maintain such performance for more than two years of use. 
     Electrolytic cells [1], [3] provide performance of 10 g/h each and there are no reliable ways to connect them into blocks of overall performance of more than 400 g/h. Electrolytic cells [2] provide performance of 40 g/h and [4] of 130 g/h and in certain situations up to 54 units may be hydraulically and electrically connected. One of the disadvantages of this solution is its lower reliability due to numerous hydraulic connections, complexity of the whole construction and high maintenance costs (including those related to removal of cathodic build-up). Therefore the common disadvantage of the listed electrolytic cells is their relatively low performance. 
     There are certain boundaries to enlarging the components&#39; size in order to assemble them into a higher capacity and performance electrolytic cell, as it makes the manufacture process more expensive due to the need to use new and more expensive equipment and technologies, e.g. those for creation of protective anode layer or for manufacture of ceramic diaphragms. 
     SUMMARY 
     One of the aims of the present invention is to create a cylindrical electrolytic cell of significantly higher performance with coaxial electrodes and a diaphragm, that could be used for a long time under diverse external conditions: operation environment temperature, input and output pressure in electrolytic cell, processed liquid volume, rolling etc—without enlarging the limiting parts of the anode and the diaphragm. 
     This aim was reached through the electrolytic cell construction developed by the inventors of the construction on the basis of anode and diaphragm that are assembled in axial alignment to reach the necessary length by using the original joining sleeves. Also parts of the construction were developed to extend the functionality of electrolytic cells in the variable operation conditions: electrolytic cell terminals in the amount sufficient for stable warming up in the operation mode and under much smaller flow of electrolyte and electrolysis products; covers and joints with the channels for flow of electrolyte and electrolysis products, where the size and placement of channels provide for operation of the electrolytic cell with the declared performance with the input pressure of less than 1 bar; covers and joints with the direction of the flow of electrolyte and electrolysis products required in order to create and preserve the spiral movement of electrolyte inside the electrolytic cell (useful for both the efficiency of electrolysis and for operation of the electrolytic cell in rolling conditions); electrical and hydro isolation layers of the cover of the anode elements and the anode as such in order to protect the device from the destruction of external electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  demonstrates an exemplary electrolytic cell; 
         FIG. 2  represents a cylindrical assembly part of an anode; 
         FIG. 3  represents a sleeve; 
         FIG. 4  represents a cylindrical assembly part of a diaphragm. 
         FIG. 5  represents a cathode; 
         FIG. 6  represents a cover; and 
         FIG. 7  represents an electrolysis products output cover. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  demonstrates an exemplary embodiment of an electrolytic cell. The electrolytic cell comprises: a cylindrical anode  1  made of parts  11   a  and  11   b , a cylindrical diaphragm  2  made of parts  21 , a cathode  3 , joining sleeves  4 , an input cover  5  with channels connecting electrode chambers and supplementary containers in the cover  5  with the environment, an output cover  6  with channels connecting electrode chambers and supplementary containers in the covers with the environment, gasket rings  10  for the parts of the anode, gasket rings  20  for parts of the diaphragm, gasket rings for the cathode  30 , and flanges  32  and screws ( 33 ) required for sealing of the cathode. 
     Anode  1 , diaphragm  2 , and cathode  3  are arranged in a coaxial manner. Anode  1  is the external electrode, while cathode ( 3 ) is the internal one. 
     Assembly anode  1  is made of several cylindrical parts—one top part  11   a  (shown in  FIG. 2 ) adjoining the output cover  6  and several parts  11   b  connected with each other and part  11 a with joining sleeves  4 . The bottom part ( 11   b ) is adjoined with the input cover ( 5 ); the length of the part  11   a  is less than the length of the part  11   b  by 3-20 mm. 
     Parts  11   a  and  11   b  have the same thread  12  at the end, external bevels  13  and internal bevels  14 . Internal and abutting surfaces of the parts  11   a  and  11   b  are covered with the protective layer (not shown here). The external cylindrical surface is equipped with an electrical and hydro isolation protective cover  7 . In one embodiment, the protective cover  7  is provided with a visually recognizable color, such as red. The color red helps to avoid assembly mistakes of the manufacturing personnel as it attracts attention to the fact that parts  11   a  and  11   b  must be commuted only with the positive terminal of the power source. Each part  11   a  and  11   b  has a terminal  15  connected to the part with a weld joint  16 . Terminals  15  and the parts  11   a  and  11   b  are made from the same material. The size of terminals and the width of the weld joint provide for additional safety of the electrolytic cell as they serve to minimize the warming-up in the operation mode: Δt°&lt;35° with the current on the terminal of up to 250 A. Internal bevels  14  improve reliability as they eliminate sharp edges that are most susceptible to electrochemical corrosion. External bevels  13  provide for sealing of the ends with round gasket rings  10 . Each part  11   a  and  11   b  can serve as an independent anode for the respective electrolytic cell. n parts  11   a  and  11   b  of the anode are connected together in axial alignment along the longitudinal axis of the electrolytic cell with (n-1) threaded sleeves  4 . The number of parts (n) depends on the technical tasks. Examples of use in practice includes parts  11   a  of anodes with diameters of 60, 86 and 108 mm, lengths of 100, 120, 150, 200 and 260 mm and corresponding to parts  11   b . Anodes  1  of the maximum size are made of three parts  11   b  with the length of 265 mm and diameter of 108 mm, one part ( 11   a ) with the length 260 mm and three joining sleeves  4 ; this anode is designed for the electrolytic cell of 860 g/h performance. 
     The sleeve  4  on  FIG. 3  is made from a single block of acid and alkali-proof material that improves the reliability of the electrolytic cell. Sleeve  4  has the following elements on both of its sides: two threads  42 , two recesses  43 , two cylindrical surfaces  44 , and two recesses  45 . In the middle of the sleeve&#39;s  4  length there is a generally planar wall  46  positioned perpendicularly to the sleeve&#39;s longitudinal axis. Sleeve&#39;s  4  wall  46  has a round aperture made in it:
 
D dv ≦D o &lt;D dn , wherein
 
     D o  is the diameter of the aperture in the wall  46 , 
     D dn  is the external diameter of the diaphragm, 
     D dv  is the internal diameter of the diaphragm. 
     Cylindrical surfaces  44  of sleeve  4  are connected by channels  47  curved in the middle. Longitudinal axis of channels  47  is placed in the anode chamber spiralwise at an angle of 20°&lt;α&lt;70° to the surface of the electrolytic cell cross-section. The number of channels and the area of their cross-section correlate with the area of the electrolyte input cross-section area according to the following formula:
 
ns≧2S, wherein
 
     n is the number of channels  47 , 
     s is the area of one channel&#39;s cross-section  47 , 
     S is the smallest area of one electrolyte input channel  53  cross-section. 
     Channel  47  apertures are evenly distributed on the surface  44 . 
     For getting a better overview, on the right side upper projection of  FIG. 3  the angle α is represented only for one of n channels  47 . 
     Diameter and cylindrical thread pitch  42  of sleeve  4  is equal to diameter and external cylindrical thread pitch  12  of the anode  1  parts  11 . Recess  43  diameter is bigger than thread  42  diameter by 1-6 mm depending on the size of electrolytic cell. Size of recess  45  provides for placement of gasket rings  20 , recess  45  diameter is bigger than constructive diameter of the diaphragm by 1-6 mm. 
     Length L c  of cylindrical surface  44  provides for the proper construction of channels  47  and is selected on the basis of the following formula:
 
1.0 D va ≦L c ≦3.0 D va , wherein
 
     D va  is diameter of anode chamber input channel. 
     Assembled diaphragm  2  is made of several cylindrical parts  21  shown in  FIG. 4 . Parts  21  have the same external and internal diameters at all their length that are different from the constructive diameter by the size of manufacture tolerance ΔD. Parts  21  are assembled into the diaphragm  2  in axial alignment by using sleeves  4  and gasket rings  20 . Lengths of all parts  21  are generally the same. 
       FIG. 5  represents the cathode  3 . Cathode  3  and terminals  34  are made from a single tube stock, which makes its manufacture and electrolytic cell assembly simpler. Contact surface  35  of terminals is made flat in order to reduce electric resistance of connection to a power supply. 
       FIG. 6  represents the cover  5 . Electrolyte input cover  5  is solid, is made from a single block of acid and alkali-proof material and is characterized by the following: thread  52 , recess  53  for the gasket ring  10 , recess  55  for the gasket ring  20 , through aperture for placing the cathode  3 , four closed thread apertures for screws  33 , channel  58  for connecting anode chamber with the environment, channel  59  for connecting cathode chamber with the environment, supplementary container  54  for electrolyte input in the anode chamber, supplementary container  56  for electrolyte input in the cathode chamber. 
       FIG. 7  represents the electrolysis products output cover  6 . The output cover  6  is solid made from a single block of acid and alkali-proof material and is comprises the following: a thread  62 , a recess  63  for the gasket ring  10 , supplementary anode chamber container  64  for such amount of anolyte that would completely cover part  11   a  of the anode during the electrolysis products output through channel  68  that connects the anode chamber with the environment, recess  65  for the gasket ring  20 , through aperture for placing the cathode  3 , four closed thread apertures for screws  33 , a supplementary container  66  of the cathode chamber connected to the environment by catholyte output channel  69  and a cathode gases output channel  67  with an adjustable catholyte part. 
     Threads  42 ,  52  and  62 , recesses  43 ,  53  and  63  as well as recesses  45 ,  55  and  65  are of equal size. Diameter of supplementary chambers  54  and  64  is smaller than diameter of the internal surface of the anode by 0.6 mm so that it is possible to create an end anode seal with a rectangular gasket ring. Diameter of containers  56  and  66  is bigger than the external constructive diameter of the diaphragm by 3-10 mm, in order to simplify assembly of the electrolytic cell. Length of container  56  is 1.0-1.5 of channel&#39;s  59  diameter. Length of container  66  is 1.0-3.0 of the channel&#39;s  69  diameter. Channel  58  is round in cross-section and is directed in a tangential manner towards the circle of the chamber&#39;s  54  cross-section, the aperture in the cylindrical surface of chamber  54  is removed as far as possible from recess  53 , the angle of channel&#39;s  58  incline towards the base of cover  5  is from 0 to 45° in order to reduce hydraulic resistance of the electrolyte flow. Channel  59  has a round cross-section and is directed in parallel with channel  58  and in a tangential manner towards the circle of chamber  56 . Channel  59  and  58  apertures are located on the opposite edges of the same side of cover. Channel  59  aperture in chamber  56  is placed as close as possible to recess  55 . Channel  68  is round in cross-section and is directed in a tangential manner towards the circle of the chamber&#39;s  64  cross-section, the aperture in the cylindrical surface of chamber  64  is removed as far as possible from recess  63 , the angle of channel&#39;s  68  incline towards the base of cover  5  is from 0 to 45°. Channel  69  has a round cross-section and is directed in parallel with channel  68  and in a tangential manner towards the circle of chamber  66 . Aperture  69  in chamber  66  is placed as close as possible to recess  65 . Channel  69  and  68  apertures are located on the opposite edges of the same side of cover. Channel  67  connects container  66  with aperture on the same side of the cover where apertures of channels  69  and  68  are located. Channel  67  aperture leading to container  66  is located as far as possible from recess  65 . Gasket rings  10 ,  20  and  30  are to seal electrode chambers and the electrolytic cell as a whole and operate in contact with ionized products of electrolysis; this is why they are manufactured from the acid and alkali-proof rubber. Sizes of rings  10 ,  20  and  30  are selected according to standard rules. 
     Flanges  32  employ their flatted cone neck to pinch rings  30  and safely seal the joint between covers  5 ,  6  and anode  3 . 
     Screws  33  are standard screws, and are used for attaching flange  32  to the cover and to reinforce the cone surface. 
     Threads  12  of parts  11  of anode  1 , threads  42  of joining sleeves  4 , threads ( 52 ) and  62  of the covers  5  and  6  are axially aligned with the total deviation from the longitudinal axis of electrolytic cell of no more than 2.0 mm per 1 m of length of electrolytic cell. Recesses  43 ,  53  and  63  are axially aligned with the total deviation from the longitudinal axis of electrolytic cell of no more than 2.0 mm per 1 m of length of electrolytic cell. 
     The electrolytic cell disclosed herein operates as follows: 
     Electrolyte enters the electrolytic cell via channels  58  and  59  in input cover  5 . Channel  59  brings electrolyte into supplementary container  56 , then to the cathode chamber and then into supplementary container  66  in cover  6 . From there gases are removed via channel  67  while catholyte is removed via channel  69  and its regulated part—via channel  67 . From channel  58  electrolyte is removed into supplementary container  54  in input cover  5  and then to the anode chamber, flowing through channels  47  in sleeves  4  to supplementary container  64  in output cover  6 . Anode is fully emerged in anolyte and gases are accumulated in the upper part of supplementary container  64 . Then anolyte and gases leave electrolytic cell via channel  68  in output cover  6 . Electrolytic cell is supplied with electrical power through terminals  15  of the anode and terminals  34  of the cathode.