Dual layer fusion bond epoxy coating for continuous sucker rod

Abstract

Embodiments of the present disclosure generally relate to apparatus and methods for manufacturing continuous sucker rods with protective coatings. One embodiment provides a coating system including a first drive station disposed on a first end of a coating line, a second drive station disposed on a second end of the coating line to move a continuous sucker rod along the coating line from the first drive station to the second drive station, a heater disposed along the coating line, and a first coating station disposed along the coating line.

1 . A coating system, comprising:
 a first drive station disposed on a first end of a coating line;   a second drive station disposed on a second end of the coating line to move a continuous sucker rod along the coating line from the first drive station to the second drive station;   a heater disposed along the coating line; and   a first coating station disposed along the coating line.   
     
     
         2 . The coating system of  claim 1 , wherein the first coating station is disposed downstream to the heater at a first predetermined distance so that the continuous sucker rod moving at a substantially constant speed arrives at the first coating station at a desired temperature. 
     
     
         3 . The coating system of  claim 2 , further comprising:
 a second coating station disposed along the coating line downstream to the first coating station at a second predetermined distance.   
     
     
         4 . The coating system of  claim 3 , wherein each of the first and second coating stations comprises one or more spray guns configured to dispend a powder coating towards the continuous sucker rod passing through the corresponding coating station. 
     
     
         5 . The coating system of  claim 1 , further comprising:
 a surface preparation station along the coating line.   
     
     
         6 . The coating system of  claim 5 , wherein the surface preparation station comprises:
 a wheelabrator;   an air blaster; and   a solvent washer.   
     
     
         7 . The coating system of  claim 1 , further comprising an inspection station disposed along the coating line adjacent the second drive station. 
     
     
         8 . The coating system of  claim 1 , further comprising a repair station disposed along the coating line, wherein the first drive station moves the continuous sucker rod from the second drive station to the first drive station to align a stretch of the continuous sucker rod with the repair station. 
     
     
         9 . The coating system of  claim 1 , further comprising a central control unit. 
     
     
         10 . A method for coating a continuous sucker rod, comprising:
 moving the continuous sucker rod at a substantially constant speed a long a coating line; and   while moving the continuous sucker rod,
 heating the moving continuous sucker rod at a first location of the coating line; and 
 applying a first coating on an outer surface of the moving continuous sucker rod at a second location of the coating line. 
   
     
     
         11 . The method of  claim 10 , further comprising: while moving the continuous sucker rod,
 applying a second coating on the moving continuous sucker rod at a third location on the coating line, wherein the third location is downstream to the second location, and a distance between the second and third locations is selected to allow the first coating to solidify for the second coating.   
     
     
         12 . The method of  claim 11 , further comprising, while moving the continuous sucker rod, preparing the outer surface of the continuous sucker rod at a fourth location along the coating line upstream to the first location. 
     
     
         13 . The method of  claim 12 , wherein preparing the outer surface comprises:
 grit blasting the outer surface;   air blasting the outer surface; and   washing the outer surface with a solvent.   
     
     
         14 . The method of  claim 12 , further comprising, while moving the continuous sucker rod, inspecting the continuous sucker rod at a fifth location along the coating line downstream to the third location. 
     
     
         15 . The method of  claim 14 , further comprising:
 moving the continuous sucker rod at a reverse direction along the coating line to align a stretch of the continuous sucker rod with a repair station disposed along the coating line; and   repairing the stretch of the continuous sucker rod at the repair station.   
     
     
         16 . The method of  claim 10 , wherein a distance between the first and second locations is selected to allow a surface temperature of the continuous sucker rod to reach a target value at the second location. 
     
     
         17 . The method of  claim 11 , wherein the first coating comprises a first fusion bond epoxy, and the second coating comprises a second fusion bond epoxy. 
     
     
         18 . A continuous sucker rod, comprising:
 a body;   a first coating applied on an outer surface of the body, wherein the first coating comprises a thermosetting polymer and has a first thickness; and   a second coating applied on the second coating, wherein the second coating comprise a thermosetting polymer and has a second thickness, and the second thickness is bigger than the first thickness.   
     
     
         19 . The continuous sucker rod of  claim 18 , wherein the first coating is formed from a first fusion bond epoxy and the second coating is formed from a second fusion bond epoxy. 
     
     
         20 . The continuous sucker rod of  claim 18 , wherein the second thickness is between about 3 times to about 30 times the first thickness.