Replacement Plates

At minimum the damaged plate and any neighbor that shows the same damage. Look at where the failed plates sit in the pack. A cluster near the inlet points to a flow or solids problem that will claim the next plates too, while scattered pitting suggests the alloy is wrong and a full material change deserves a price.

The serial number gives the pack's pattern sequence, and on the plate itself the clearest clue is the chevron angle of the corrugations. If a plate carries a stamped marking near the hanger, include a close photograph of it. Do not judge by the look of the herringbone alone, since two patterns can look nearly identical side by side.

Number the plates with a marker as they come off the carrying bar, and note which way each one faces. Alternate plates are rotated, so a plate hung the wrong way around breaks the channel arrangement. Put each new plate in the exact position and orientation of the one it replaces, then check the pack edge for a regular honeycomb pattern before tightening.

Generally not. Plates are thin pressed sheet, and a weld distorts both the corrugation and the gasket groove, so the repaired plate either leaks or crowds the channel next to it. Take the cracked plate out, replace it, and examine the plates around it for the stress or cycling that caused the crack.

Erosion concentrated at the inlet port and distribution area means velocity or particles, and new plates in the same position will wear the same way. Before ordering, look for a missing or damaged strainer upstream and check wether flow has risen since the unit was rated. Sometimes the answer is more plates to bring velocity down rather than identical replacements.

It still applies when the plate count has not changed and the full gasket set is renewed. If you have added or removed plates, the dimension changes with the count and has to be recalculated. Measure at every tie bolt position as you close, because a new plate beside a worn one can hide a pack that is drifting out of square.