OVERVIEW: The internals of the valve were heavily graphitised and requiring refurbishment with the guide channel for the valve entirely corroded away. A replacement would have taken up to 12 weeks. Chemcote’s refurbishment saved replacement costs and significant delays.
ENVIRONMENT
Sea water
SUBSTRATE
Cast iron Valve body
CHALLENGE
The internals of the valve were heavily graphitised requiring refurbishment as a replacement would have taken up to 12 weeks because this is an imperial non-standard item. Guide channel for the valve was entirely corroded away. Coating and refurbishment had to be completed within 120 hours to prevent disruption to existing shutdown schedule.
SOLUTION
Chemcote recommended RB 300 at 1200μm nominal thickness, a glass-flake filled vinyl ester which provides a tough impermeable barrier that will last in excess of 10 years. Externals finished with top-coat RL 500PF, a moisture and surface tolerant coating.
SCOPE
Protect critical sealing faces
Abrasive blast to remove graphitised metal
Grind rebates on flange faces to allow coating to wrap around preventing crevice corrosion due to misaligned gaskets
Remove graphitised material with air chisel
Hot pressure wash – re-grit blast to AS 1627.4 cleanliness standard with a minimum 75μm profile
Application of 3 coats of RB 300
Install nylon bars to replace corroded guide
Test valve operation
External application of RL 500PF in 2 coats
PRODUCTS
Chem-tect™ RB 300 Series – Internals
Epo-chem™ RL 500PF – Externals
OUTCOME
The valve was refurbished, saving the client replacement costs and waiting time. The client was extremely satisfied with this job and have since awarded other items to be refurbished by Chemcofe using similar methods.
RELATED CASE STUDIES
Air Receiver Restoration for Long-Term Durability
Pitting corrosion near shaft landing After first abrasive blasting After 2nd Abrasive blast holes were found requiring composite reinforcement Filling void in difficult to reach
High Performing Replacement for 316L SS
On inspection flange corrosion Deep pitting on forged section Application of 1st coat Ready to be put into service for 25+ years of life OVERVIEW:
Power Station Debris Filter Lining Repair
Damage to existing rubber lining Internal void to be filled in around the circumference of the screen Close up of repair area for the full