Abstract:
A multi purpose segmented Titanium Mixed Metal Oxide coated impressed current cathodic protection anode assembly (Ti MMO anode assembly). The Ti MMO anode assembly includes combinations selected from four anode components and four connection components. The various components may be assembled for different applications in liquid or soil environments for the prevention or reduction of corrosion and loss of structural integrity. For example, the Ti MMO anode assembly may be applied to protect pipelines, buried structures, piers and internal surface protection of tanks and vessels in different arrangements such as deep wells, shallow ground beds, or distributed individual anodes.

Description:
[0001]    The present application claims the priority of U.S. Provisional Patent Application Ser. No. 61/370,742 filed Aug. 04, 2010, which application is incorporated in its entirety herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an impressed current anode assembly and more particularly to a segmented titanium Mixed Metal Oxide (MMO) coated anode assembly. 
         [0003]    Known MMO cathodic protection anodes are selected and shipped as a unit including attached anode wires to a final location for installation. Such known MMO cathodic protection anodes are selected from an inventory which may be either a small inventory requiring compromises in selection, or a large inventory which is very expensive to maintain. Known vertical deep well ground bed installations require parallel PVC vent pipes for venting gasses created by the cathodic protection and further, multiple anodes require wire splices to connect the anode wires together, or require extending each anode wire to ground level to individually connect to a junction box. Using multiple independent anodes compromises ground bed resistance and stability and reduces the effectiveness of anodes because multiple anode lead wires and vent pipes isolate the anodes from the ground bed decreasing the effective surface area of the anodes. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention addresses the above and other needs by providing a multi purpose segmented titanium Mixed Metal Oxide coated impressed current cathodic protection anode assembly (Ti MMO anode assembly). The Ti MMO anode assembly includes combinations selected from four anode components and four connection components. The various components may be assembled for different applications in liquid or soil environments for the prevention or reduction of corrosion and loss of structural integrity. For example, the Ti MMO anode assembly may be applied to protect pipelines, buried structures, piers and internal surface protection of tanks and vessels in different arrangements such as deep wells, shallow ground beds, or distributed individual anodes. 
         [0005]    In accordance with one aspect of the invention, there is provided a vented titanium MMO anode assembly. Vented titanium MMO anode segments includes a hollow pass through hollow center and ports through walls of the vented titanium MMO anode segments allowing gases released during operation to enter the vented titanium MMO anode segments and pass through and out of the vented Titanium MMO anode segment assembly. 
         [0006]    In accordance with another aspect of the invention, there are provided threaded MMO coated titanium couplers and MMO coated anode segments. Combining the threaded mixed metal oxide coated titanium couplers with the MMO coated anode segments, allows creation of a scalable segmented anode. A power supply to the MMO coated anode segments is then connected to a wire connection anode section which comprises a foot long tube with no perforations and a press fit method of cable connection which is made in a neck portion preferably at the center of the tube. 
         [0007]    In accordance with yet another aspect of the invention, there are provided threaded MMO coated titanium couplers and MMO coated anode segments providing an electrical path through the anode segments to the surface. The multiple anode wires of known anode assemblies are eliminated thereby significantly improving the ground bed stability and simplifying installation. The anode segments have a minimum wall thickness of about 0.08 inches to provide necessary electrical conductivity. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0008]    The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
           [0009]      FIG. 1A  is a side view of a vented Mixed Metal Oxide (MMO) coated impressed current cathodic protection titanium anode segment (vented MMO anode segment) according to the present invention. 
           [0010]      FIG. 1B  is a top view of the vented Titanium MMO anode segment according to the present invention. 
           [0011]      FIG. 2  is a cross-sectional side view of the vented Titanium MMO anode segment according to the present invention taken along line  2 - 2  of  FIG. 1A . 
           [0012]      FIG. 3A  is a side view of a non-vented MMO coated impressed current cathodic protection titanium anode segment (non-vented MMO anode segment) for use in liquid mediums, according to the present invention. 
           [0013]      FIG. 3B  is a top view of the non-vented Titanium MMO anode segment according to the present invention. 
           [0014]      FIG. 4  is a cross-sectional side view of the non-vented Titanium MMO anode segment according to the present invention taken along line  4 - 4  of  FIG. 3A . 
           [0015]      FIG. 5A  is a side view of a vented wire connection anode section according to the present invention for connection with the vented MMO coated impressed current cathodic protection titanium anode segment. 
           [0016]      FIG. 5B  is a top view of the vented wire connection anode section according to the present invention for connection with the vented MMO coated impressed current cathodic protection titanium anode segment. 
           [0017]      FIG. 6  is a cross-sectional side view of the vented wire connection anode section according to the present invention for connection with the vented MMO coated impressed current cathodic protection titanium anode segment taken along line  6 - 6  of  FIG. 5A . 
           [0018]      FIG. 7A  is a side view of a non-vented wire connection anode section according to the present invention for connection with the non-vented MMO coated impressed current cathodic protection titanium anode segment. 
           [0019]      FIG. 7B  is a top view of the non-vented wire connection anode section according to the present invention for connection with the non-vented MMO coated impressed current cathodic protection titanium anode segment. 
           [0020]      FIG. 8  is a cross-sectional side view of the non-vented wire connection anode section according to the present invention for connection with the non-vented MMO coated impressed current cathodic protection titanium anode segment taken along line  8 - 8  of  FIG. 7A . 
           [0021]      FIG. 9  is a PVC joint according to the present invention, allowing connection of PVC or PE pipe to the wire connection anode sections. 
           [0022]      FIG. 9A  is a cross-sectional view of the PVC joint according to the present invention, taken along line  9 A- 9 A of  FIG. 9 . 
           [0023]      FIG. 10  is a titanium joint for connecting consecutive anode segments. 
           [0024]      FIG. 10A  is a cross-sectional view of the titanium joint according to the present invention, taken along line  10 A- 10 A of  FIG. 10 . 
           [0025]      FIG. 11  is a titanium cap according to the present invention, for closing an exposed end of a non-vented anode segment used in a liquid medium. 
           [0026]      FIG. 11A  is a cross-sectional view of the titanium cap according to the present invention, taken along line  11 A- 11 A of  FIG. 11 . 
           [0027]      FIG. 12  is a titanium isolation joint according to the present invention, for installing in the wall of a tank or hull and connecting the non-vented wire connection anode section. 
           [0028]      FIG. 12A  is a cross-sectional view of the titanium isolation joint according to the present invention, taken along line  12 A- 12 A of  FIG. 12 . 
           [0029]      FIG. 13  is a length of PVC or PE pipe for attachment to the PVC joint. 
           [0030]      FIG. 14  shows a tank protected by non-vented MMO anode assemblies. 
           [0031]      FIG. 15  shows a buried pipeline protected by vented MMO anode assembly. 
           [0032]      FIG. 16  shows a pier protected by a non-vented MMO anode assembly. 
           [0033]    Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
         [0035]    A side view of a vented Titanium Mixed Metal Oxide coated impressed current cathodic protection anode segment (Ti MMO anode segment)  10  according to the present invention is shown in  FIG. 1A , a top view of the vented Ti MMO anode segment  10  is shown in  FIG. 1B , and a cross-sectional side view of the vented Ti MMO anode segment  10  taken along line  2 - 2  of  FIG. 1A  is shown in  FIG. 2 . The vented Ti MMO anode segment  10  is a primary element of a multi purpose segmented titanium Mixed Metal Oxide coated impressed current cathodic protection anode assembly (Ti MMO anode assembly)  72   a,    72   b,    80 , and  91  (see  FIGS. 14-16 ) according to the present invention. The vented Ti MMO anode segment  10  is hollow and includes ports  12  allowing gasses generated during operation of the vented MMO anode segment  10  to vent through the vented Ti MMO anode segment  10 . The vented Ti MMO anode segment  10  has an external MMO coating  18  and an internal MMO coating  16 . The MMO coating is preferably 10 g/m 2  of MMO made up of Iridium, tantalum and titanium oxides for soil mediums, and 20 g/m 2  for liquid mediums. Preferably, the coating is omitted on female threads  14 . The vented Ti MMO anode segment  10  is preferably constructed of titanium having a thickness to provide sufficient electrical conductivity. 
         [0036]    The vented Ti MMO anode segment  10  has a length L 1 , an outside diameter D 1 , and a wall  11  thickness T. The length L 1  is preferably approximately 24 inches, the diameter D 1  is preferably approximately 1.25 inches, and the wall  11  thickness W is preferably at least 0.08 inches, and more preferable approximately 0.08 inches The ports  12  are preferably in opposing pairs with each pair rotated 90 degrees from adjacent pairs. The consecutive pairs of ports are spaced a distance L 2  apart and have a diameter D 2 . The length L 2  is preferably approximately one inch and the diameter D 2  is preferably approximately 0.25 inches. Each end of the vented Ti MMO anode segment  10  includes internal female threads  14  having a length L 2 . The length L 2  is preferably approximately 0.5 inches. The female threads  14  are preferably 1.25 inches by acme 2G threads, or M29 threads. 
         [0037]    A side view of a non-vented MMO coated impressed current cathodic protection titanium anode segment (non-vented MMO anode segment)  20  according to the present invention is shown in  FIG. 3A , a top view of the non-vented Titanium MMO anode segment  20  is shown in  FIG. 3B , and a cross-sectional side view of the non-vented Titanium MMO anode segment  20  taken along line  4 - 4  of  FIG. 3A  is shown in  FIG. 4 . The non-vented Titanium MMO anode segment  20  includes the external MMO coating  18  and does not include the ports  12 . 
         [0038]    The non-vented Titanium MMO anode segment  20  has a length L 3 , an outside diameter D 3 , and a wall  11  thickness T. The length L 3  is preferably approximately six inches, the diameter D 3  is preferably approximately 1.25 inches, and a wall  11  thickness W is preferably approximately 0.08 inches. The non-vented Titanium MMO anode segment  20  is otherwise similar to the vented Ti MMO anode segment  10 . 
         [0039]    A side view of a vented wire connection anode section  30  according to the present invention for connection with the vented Ti MMO anode segment  10  is shown in  FIG. 5A , a top view of the vented wire connection anode section  30  is shown in  FIG. 5B , and a cross-sectional side view of the vented wire connection anode section  30  taken along line  6 - 6  of  FIG. 5A  is shown in  FIG. 6 . The vented wire connection anode section  30  includes a smaller diameter neck  30   a  center portion for connection of an insulated lead  26 . The insulation on the lead  26  may be selected to the environment the lead  26  resides in. The neck  30   a  is filled with an isolation material  24  which is preferably a two part epoxy or the similar material. The lead  26  reaches into the neck  30   a  and is electrically connected to the vented wire connection anode section  30  through a press fit wire connector  23  into the neck  30   a  of the wire connection anode section  30 . 
         [0040]    A major failure mode of known cathodic protection systems is due to the breakdown of the electrical connection between the cable joints and anodes. These failures will take place, when the anodes connections are joined by ring terminals or other methods of connection. To prevent such failures, electrical connections between the lead  26  and wire connector  23  are preferably made using crimping of the wire connector  23  over a stripped end of the lead  26 . The wire connector  23  is preferably crimped over an end portion of the lead  26  with insulation stripped to retain and make electrical contact with the lead  23 . The wire connector  23  is preferably copper. 
         [0041]    A vent tube  22  connects upper and lower portion of the vented wire connection anode section  30  to allow gasses collected by the vented Ti MMO anode segment  10  to pass through the vented wire connection anode section  30  to be released. The vent tube  22  is preferably approximately 0.5 inches in diameter. The vented wire connection anode section  30  preferably includes the same female threads  14  as the vented Ti MMO anode segment  10 . The vented wire connection anode section  30  has an outside diameter D 5  and a length L 4 . The diameter D 5  is preferably the same as the diameter D 1 , and the length L 4  is preferably approximately twelve inches. 
         [0042]    A side view of a non-vented wire connection anode section  40  according to the present invention for connection to the non-vented Titanium MMO anode segment  20  is shown in  FIG. 7A , a top view of the non-vented wire connection anode section  40  is shown in  FIG. 7B , and a cross-sectional side view of the non-vented wire connection anode section  40  taken along line  8 - 8  of  FIG. 7A  is shown in  FIG. 8 . The non-vented wire connection anode section  40  does not include the vent tube  22  but is otherwise similar to the vented wire connection anode section  30 . 
         [0043]    A side view of a PVC/Teflon® joint  50  according to the present invention, allowing connection of PVC pipe  66  (see  FIG. 13 ) to the wire connection anode sections  30  and  40  is shown in  FIG. 9  and a cross-sectional view of the PVC/Teflon® joint  50 , taken along line  9 A- 9 A of  FIG. 9  is shown in  FIG. 9A . The PVC/Teflon® joint  50  includes male threads  52  cooperating with the female threads  14  at a lower end, and an opposite end including male threads  53 , which threads  53  are preferably two inch NPT threads. The opposite end further includes a recess  54  for receiving the PVC pipe  66 . The PVC/PE pipe  66  may be retained in the PVC/Teflon® joint  50  by gluing or by a standard threaded interface commonly available. The lower end has a length L 5  of approximately one inch and the opposite end has a length L 6  of approximately one inch. The PVC/PE joint  50  is preferably made from PVC or Teflon®. 
         [0044]    A side view of a titanium joint  56  for connecting consecutive anode segments is shown in  FIG. 10  and a cross-sectional view of the titanium joint  56 , taken along line  10 A- 10 A of  FIG. 10  is shown in  FIG. 10A . The titanium joint  56  exterior defines male threads  52  for electrically and mechanically connecting consecutive anode segments  10  and  20 , and the wire connection anode sections  30  and  40  and has a hollow interior to allow gasses collected by the vented Ti MMO anode segment  10  to pass through the titanium joint  56  to be released. The titanium joint  56  preferably includes the internal MMO coating  16  of approximately 20 g/m 2  allowing use in soil and liquid mediums. 
         [0045]    A titanium cap  58  for closing an exposed end of a non-vented anode segment  20  is shown in  FIG. 11  and a cross-sectional view of the titanium cap  58 , taken along line  11 A- 11 A of  FIG. 11  is shown in  FIG. 11A . The titanium cap  58  exterior defines male threads  52  for mechanically connecting to the non-vented anode segment  20 , and preferably includes the internal MMO coating  16  and the external MMO coating  18  of approximately 20 g/m 2 , except the threads  52  which are not coated. 
         [0046]    A titanium isolation joint  60  according to the present invention, for electrically isolating the Ti MMO anode assembly from a tank, hull, vessel, or any structure requiring protection, is shown in  FIG. 12  and a cross-sectional view of the titanium isolation joint  60  taken along line  12 A- 12 A of  FIG. 12  is shown in  FIG. 12A . The titanium isolation joint  60  includes one threaded end to connect to the vented and non-vented wire connection anode sections  30  and  40 . The titanium isolator joint  60  includes a steel outer sleeve  63  with male threads  62  for engaging wall of a tank or hull, or a designed flange, a titanium inner sleeve  61 , and insulation  62  between the titanium inner sleeve  61  and the steel outer sleeve  63 . The insulation  62  is preferably GRE or Nomex® material to electrically isolate the inner sleeve  61 . The lower end of the inner sleeve defines the threads  52  for connecting mechanically and electrically with the vented and non-vented wire connection anode segments  30  and  40 , and the inner sleeve  61  preferably includes the internal MMO coating  16 . 
         [0047]    A length of PVC/PE pipe  66  for attachment to the PVC/Teflon® joint  50  is shown in  FIG. 13 . The PVC/PE pipe  66  forms a non-active portion of the Ti MMO anode assembly reaching though a solid or liquid medium. The lead  26  passes through the PVC/PE pipe  66 . 
         [0048]    A tank  70  protected by non-vented Ti MMO anode assemblies  72   a  and  72   b  is shown in  FIG. 14 . The non-vented MMO anode assemblies  72   a  and  72   b  comprise at least one non-vented Titanium MMO anode segment  20  if required, the wire connection anode section  40 , the titanium joint  60 , and the PVC/PE pipe  66 . Tanks  70  often contain a layer of water  71  at the bottom of the tank and a layer of oil or other liquid  73  above the water  71 . The length of PVC/PE pipe  66  generally resides in the oil layer. The lengths of the non-vented MMO anode assemblies  72   a  and  72   b  are determined by the number of non-vented MMO anode segments  20  included in each assembly. The lengths of the non-vented MMO anode assemblies  72   a  and  72   b  may be selected based on space available and protection requirements. The length of PVC/PE pipe  66  may be selected to position at least a portion of the non-vented MMO anode assembly  72   b  at a desired depth in the tank  70 , preferably in the lower portion of the tank  70  containing the water  71 . 
         [0049]    A buried pipeline  82  protected by a vented MMO anode assembly  80  is shown in  FIG. 15 . The vented MMO anode assembly  80  is buried proximal to the buried pipeline  82  and a number of vented MMO anode assembly  80  may be buried along a single pipeline  82 . A length of PVC, PE, or the like pipe  66  may be used in a non-active zone of the ground bed and the lead  26  passes through the pipe  66  and connects the vented MMO anode assembly  80  to a rectifier assembly  86 , and a second lead  88  connects the rectifier  86  to the buried pipe. The gasses created by operation of the Ti MMO anode assembly pass through the pipe  66  to an atmospheric region  83 . 
         [0050]    A pier  90  protected by a non-vented MMO anode assembly  91  is shown in  FIG. 16 . The pier  90  includes vertical members  96 , a top horizontal member  98 , and a horizontal support member  99  near the water line  94 . A non-vented MMO anode assembly  91  is preferably connected to the horizontal support member  99  by the titanium isolator joint  60 . The lead  26  connects the non-vented MMO anode assembly  91  to the rectifier  86 , and a second lead  88  connects the rectifier  86  to the pier  90 . 
         [0051]    For better isolation and pressure resistance, the internal section of the wire connection anode sections  30  and  40  may be sealed by epoxy resins. The epoxy resins plug the center of the wire connection anode sections  30  and  40 . The internal surfaces of the wire connection anode sections  30  and  40  may be coated with MMO coatings except where titanium threads of the wire connection anode sections  30  and  40  contact the titanium threads of the joint  56  and isolation joint  60  (see  FIG. 10 ). Ends of the non-vented Titanium MMO anode segment  20  immersed in an electrolyte may be capped using the titanium cap  58  (see  FIG. 11 ). 
         [0052]    The Ti MMO anode assembly described above simplifies the design process for engineers by simplifying the resistance calculations, and anode length requirements. The installation of anodes is simplified by removing the need for parallel PVC vent pipes, reduced amount of wires needed for connection to each individual anode from the ground bed to the power supply, removes the need for anode wire holders removing the situation of multiple wires needing control during anode ground bed installation via descent into the well. The Ti MMO anode assembly thus may be easily used in different environments and arrangements such as offshore, tanks, vessels and different soil arrangements such as horizontal, shallow and deep well ground beds by use of four different couplers and joints. 
         [0053]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.