Protection in Base Alkali Conditions

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 to
against base alkali solutions.

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 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 was 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.