Alfa Laval Olmi shell-and-tube high pressure

Visually inspect tube bundle for scaling, sediment, or biofilm deposits. Measure pressure drop across shell and tube sides; marked increase indicates fouling. Advanced inspection: eddy current testing (ECT) or ultrasonic thickness measurement (UT) to assess internal fouling. If fouling present, remove bundle and flush seawater passages with fresh water.

Visually inspect tubes for pitting, erosion marks, or de-zincification (pinkish copper discoloration). Use fluorescent dye (UV light) for microscopic perforation detection. For ferrous tubes: NFT, RFT, MFL, or IRIS testing. For Cu/Ni: Eddy current testing (ECT). Apply ultrasonic thickness mapping (UT) to identify wall thinning and erosion patterns. Check that seawater pressure remains lower than jacket water pressure to prevent seawater intrusion if perforations occur.

Drain both shell and tube sides completely. Visual inspection of tubesheets and nozzles for visible cracks. Apply soap bubble test: pressurize shell side to working pressure, mask one tubesheet completely, apply soapy liquid on opposite side—leaking tubes create bubbles. Alternative: fluorescent dye solution (dissolve sodium crystals in water surrounding tubes, view under UV light for fluorescent halos indicating small leaks). Perform pressure test to confirm repair after remedial work.

Remove and inspect zinc anodes fitted on cover/shell-side. Measure remaining thickness; replace if degraded below ~6 mm. Never use chemical descaler (phosphoric or proprietary acid) while anodes are installed—acids destroy zinc instantly. For seawater-cooled units: ensure sacrificial anode or impressed current cathodic protection (ICCP) system is operational. Check electrical continuity and voltage of ICCP system if installed. Document anode replacement date and condition in log.

Monitor outlet water color for rust or discoloration (iron oxide formation). If present, drain exchanger and inspect interior shell walls and tube exteriors for reddish-brown deposits. Perform chemical cleaning: isolate unit with shutoff valves, circulate phosphoric acid-based descaler (safe for Cu/Ni) via small pump for 30–90 minutes (avoid proprietary acid during anode presence). Flush thoroughly with fresh water after chemical cleaning. Remove anodes before and refit after chemical treatment. Check cover gaskets for damage and renew if necessary.

For air-cooled units (ACE models): inspect fins visually for salt spray deposits, algae, or debris accumulation (reduces air flow). Check header box plugs for seepage under pressure (Alfa Laval SealTight system reduces this risk). Apply low air-side pressure + soapy water on seawater side to detect leak locations (bubbles form at leaks). Mechanical cleaning: gentle water spray or compressed air. If high plugging risk suspected, inspect plug gaskets and threading. For marine environments, monitor corrosion of aluminum fins and apply protective coatings if necessary.