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## Esam

*   .
  				         				           				     .     				          				 /         				 ()   /      				          				.*

 				  :

             1820     				       				*  .*   				       				            				             				  .      .          				            				 .
				             				1945           				            				             				    . 				*  				           				      ,     				       .*
				           				            				          1952   				 1000             				       .*
 
  				           				 ,      ,   				           				  ,          				       .
  				            				,           				          				          .*
 
				   				 : 				  				     (   				 				metal oxides  				  )         				   .     				       				.
    -  				  				Electro-Chemical Process  				Electrical Currents  				Anodic Reaction  				:
  M  				→ M+     				+ e-      				  :  Fe   				→     Fe++      				+      2e-    				free  				electrons 				 				    				       ()    				         				   : 2H+   				hydrogen 				ions 				in 				solution+  				2e-   				 				→    				H2  (gas)  neutral solutions 				  				       .  				:   				O2      				+     				2H2O   + 				     				4e-   				 				→   4OH   				(alkali)   				        (     				    ) :   				 				      				         				             				.
				     :
				             				            				           				           				   .
				            				          				 .
Galvanic Anode DC  				.
				          				           				           				     . *  

  				        ɡ   				          				          				          				.
  				          				           				 /     ,   				            				              				       (2.5) .
 *   				Sacrificial  				Anodes*  				     / *   				CP  				Transformer  				Rectifier* 
  
           * CP  				by  				Sacrificial  				Anode*

  				             				  (  )  ,    				     /      				. 
  
  				           				 ,        				 .
 *   				Magnesium  				Anode*  				       				          				     /  /  /*   				Aluminum / Zinc / Galvalum / Indium Alloys*  				.

        * Impressed  				Current  				Cathodic  				Protection*

 *   				CP  				by  				Sacrificial  				Anode*  .
  .
  				           				           ,   				      *   				Silicon-Cast Iron* *   				Mixed  				Metal  				Oxide* *   				Graphite* *   				Platinum  				or  				Titanium  				coated  				alloys* *   				Silicon-Cast Iron*  				           				            				       ,    				        .   				    *   				Flexible*  				"*Anodeflex*" 				*  				tubular  				anodes*  				 .

  				            				 				  /  (10-50)*   				Transformer  				Rectifier  				Units*.
				  50  100         .
  				         (25 -50  				) .
  				     /*   				Transformer  				Rectifier  				Units*  				            				           				        80- 150 ,   				     10  100 ,    				       .
 *   				Right-of-Way*  				(*ROW*) 				 *   				Deep  				Well  				Ground  				Beds*  				   60         20  				-25 *   				Conductive  				Coke  				Breeze*  .

 *   				Coke  				Breeze*  				            				,          				    .
  				    /*   				Transformer  				Rectifier  				Unit*  .


      /  * Transformer  				Rectifier  				Unit*

  				   /        				 *   				Out  				Put*  .
  				   /         				     :
				.  *   				Air - Cooled T/R* 
				.  *   				Oil - Cooled T/R* 
				.  *   				Explosion  				Proof  				T/R* 
 *   				Special  				DC - Power Sources* 
				.  *   				Solar  				Power  				Unit* 
				.  *   				Thermo  				Electric  				Generators* 
				.  *   				Wind  				Generators* 

 *   				DC / DC*  .
  .



        * CP  				Test  				Posts  				and  				CP  				Isolation*

 *   				Structures* *   				Posts* *   				Structure-To-Soil Potential Measurements*  				,   .
 *   				Block Valve or Metering Stations*  . 
 *   				Surge  				Arrestors* *   				Insulating  				Joints* 				        				       ,  				        ,    				     *   				Polarization  				Cells* *   				The CP - DC Current*  .
 *   				Polarization  				Cells*  .

     *   				Other  				Design  				Considerations*

  				            				   15 -30        				   *   				by  				Impressed  				Current  				Cathodic  				Protection*  				 10  15         				*   				CP  				Sacrificial  				Anode*  				.
 *   				Premature  				Anode-End  				Corrosion*  .
 *   				Coke  				Breeze  				Current  				Rating*  .

   * Measurements  				and  				Acceptance  				Criteria*

 *   				CP  				Electrochemical  				Potential  				is  				Measured* *   				Reference  				Electrodes*::* *  
*  				1. Copper-copper(II) sulfate electrodes are used for structures  				in contact with soil or fresh water.

				2. Silver chloride electrodes are suitable for seawater  				applications (compatible electrolyte).  *
:*
				1. *  / .  				 .*
				2.*  				Cathodic Protection - R.L.Kean, K.G.  				Davies* 

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