Case Study

Pump Protected from Sodium Hypochlorite

Protection in Base Alkali Conditions



Chemical Processing, UK.


Scope of Work 

A newly manufactured pump casing, impeller and cover would be subject to service conditions of sodium hypochlorite at a maximum concentration of 15%. To prolong the service life of the pump, all wetted internal surfaces required protective lining against base alkali solutions.



Corroglass AR4

Plasmet ZF

Corrothane AP1


Coating System

  • The pump casing was rebated to accommodate the coating process, all areas not requiring coating were masked and all parts abrasive blasted.
  • A blow down, sweep and vacuum followed to remove all dust.
  • Corroglass AR4, a specialist coating designed to give best resistance in base environments, was applied in multiple coats to achieve a DFT of 1000-1200µm.
  • The impeller was check balanced, pre and post coating, on Corroserve’s Schenk dynamic balancing machine. This was to ensure it remained in the required tolerance for final installation.
  • Thickness and spark testing was also completed to ensure no holidays were present and to guarantee the quality of the coating work completed.
  • Finally, the externals of the pump casing were coated with Plasmet ZF a surface tolerant coating and a top coat of Corrothane AP1.
  • With complete corrosion protection, the pump could be expected to benefit from an extended service life carrying an aggressive alkali solution.



Pump and parts on arrival to workshop

Post abrasive blasting

Corrothane AR4 applied on all internal surfaces - close up of coated vanes of the impeller

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