Why GPHE (Gasketed Plate Heat Exchanger) Fails To Seal After Opening & Reassembly

1. Gasket related issues (Top #1 cause)

1. Gasket permanent creep / fatigue after first compression

   Rubber gaskets cannot fully rebound once compressed during operation. After disassembly, original gaskets lose elasticity; micro-set prevents full sealing contact again.

Marine note: EPDM/FKM gaskets working with seawater & thermal cycling accelerate creep.

2. Gasket dislocation, popping out of plate groove

   Clip-on gaskets easily shift during dismantling. Minor offset creates leakage channels. Glued gaskets may lose adhesion after repeated opening.

3. Hidden gasket damage

   Micro-cracks, surface abrasion, swelling or hardening from seawater, marine oil & temperature swings often cannot be seen visually.

4. Dirty sealing surfaces

   Marine sediment, salt crystal, scale, grease trapped between plate and gasket break continuous sealing.

2. Incorrect clamping & assembly operation

1. Failed to follow factory specified A-dimension (clamping length)

   Most common mistake: technicians do NOT record the original compression dimension before opening.

• Too loose: insufficient gasket compression

• Too tight: over-compression crushes gasket, may permanently deform titanium plate corrugations

2. Uneven bolt tightening

   Must tighten diagonally & gradually. One-sided tightening makes the plate pack skew, plates lose parallelism; partial sealing pressure disappears.

3. Wrong plate stacking order / reversed plates

   Plate flow direction misalignment distorts gasket geometry.

3. Titanium plate damage & surface defects (critical for marine Ti GPHE)

1. Plate corrugation plastic deformation

   Over-tightening in previous service or disassembly handling permanently warps Ti plates. The gasket groove no longer sits flat.

2. Scratches, pitting or salt deposits on sealing land

   Sealing band contamination / mechanical scratches create permanent leak paths.

Reminder: TA1 titanium is corrosion-resistant but prone to mechanical scratch during cleaning. Do NOT use hard brushes.

4. Operating & marine system factors after re-commissioning

1. Water hammer / pressure surges (very common onboard ships)

   When restarting cooling water (seawater circuit), sudden flow shock pushes gaskets out of grooves immediately after assembly.

2. Fast thermal shock

   Rapid temperature rise onboard causes uneven thermal expansion; gasket compression stress drops temporarily and triggers leakage.