Case Study

Client

Power utility specialising in importation, generation, transmission and distribution of electricity.

Application date

October 2017.

Scope of work

Refurbishment of rotary strainer wheel, experiencing corrosion as a result of service in an environment with high salt water.

Products

Primer: Polyglass PPA. A peroxide catalysed glass flake polyester primer.

Coating: Corroglass 600 series. A high build glass flake vinyl ester lining and repair material.

Coating system

• Removed existing drive pins (96 off) and manufactured replacements using BS70-431-S29 high strength St. Steel.
• Cleaned filter elements with UHP water jetting. Lightly blasted with a fine glass abrasive. Fitted 20mm thick plywood boards to both sides of the filter elements to prevent any damage.
• Removed existing mechanical seal sleeve (2 off).
• Machined both sealing faces removing as little material as possible.
• Machined mechanical seal sleeves outside diameter ensuring concentricity (TIR 0.05mm) to bearing diameters.
• Manufactured and fitted replacement mechanical seal sleeves using BS9070-316-S11 St. Steel.
• Masked areas not requiring treatment, removed filter element clamps.
• Grot blasted to ISO5201-1: internals and wetted areas to Sa2 1/2. Jet washed with Chlor*rid to bring salt content to the surface. Repeated process until salt level reading was under 2.5mg mms cm2.
• Primed using Polyglass PPA.
• Cleaned and replaced filter element clamps.
• Applied multiple coats of Corroglass 600 series to achieve a minimum of 1.5mm dry film thickness.
• Built up sealing faces to a minimum of 2.5mm dry film thickness. Following coating, post machined both sealing faces.
• Machined mechanical seal sleeve seats ensuring concentricity (TIR 0.05mm) to bearing diameters.

Coating credentials

Corroglass 600: a two pack cold cured vinyl ester glass flake. Excellent in immersed environments. Excellent resistance to solvents, acids and de-mineralised water. Excellent flexibility, undercutting resistance and sliding abrasion resistance.