Protection in Base Alkali Conditions

Client

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.

Products 

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.