Knife-Gate Valve Seat Reclamation
Worn slurry knife-gate valve seat and gate guides rebuilt and lined so the blade shuts off square again, no replacement valve.
A job completed with Belzona. This describes what the Belzona system does and how it goes on, not a record of a specific project by this distributor.
The challenge
A knife-gate valve on a stock line wore out where the abrasive slurry runs hardest. The seat and the gate guides lost metal, so the blade no longer dropped square against a clean seat and the valve passed when it should have shut off tight. A valve that will not isolate cannot be trusted to take a section of the line out of service for work downstream, and the leak-by carries product where it does not belong. The usual fix is a new valve, which is costly and can sit on a lead time while the line waits.
The Belzona approach
The valve is pulled and opened up to show where the slurry took the metal. Blasting the seat pocket and the guide faces back to clean, profiled metal gives the repair its bond, and the worn seat and guides are rebuilt with a composite that stands up to the same abrasion that wore the originals. The seat is reformed so it carries the blade evenly across its face, and the wetted pocket is lined against the slurry. With the valve closed back up, the gate shuts off square, the guides hold the blade true, and the body goes back on the line instead of being scrapped for a replacement.
- Open and assessThe valve is pulled, the body is opened, and the wear from the slurry is mapped across the seat and the gate guides.
- Blast to clean metalThe seat pocket and the guide faces are grit-blasted back to a clean, profiled surface so the composite bonds to bare metal.
- Rebuild seat and guidesAn abrasion-resistant composite rebuilds the worn seat and guide faces, applied cold with no welding on the body.
- Reform and lineThe seat is reformed so the blade seats evenly across its face, and the wetted pocket is lined against the slurry.
- Reassemble and return to serviceThe valve is closed back up, the blade is confirmed to shut off square, and the body goes back on the line.
The result
- Worn seat and gate guides rebuilt in place without a replacement valve
- Seat reformed to carry the blade evenly so the gate shuts off square
- Wetted pocket lined against the abrasive slurry that wore the original metal
- Valve returned to the line by factory-trained and factory-certified Belzona applicators
In the field
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Belzona Houston is the authorized Belzona distributor for South Texas and the Gulf, based in Alvin, Texas, we’ll survey your equipment and recommend the right cold-applied Belzona system, with 24-hour support.