A knife gate uses a sharpened blade sliding across a seat to cut through solids and slurries. The design has almost no cavity to pack with material, which is why it works where other valves jam.
Pulp and paper, mining, wastewater, power ash handling and bulk solids all use knife gates. They are also common on isolation duty in abrasive service where a resilient seat would be destroyed.
We buy knife gate valves in any quantity — single items, mixed pallets or whole cribs, including valves that need repair and assemblies that are missing parts. We do not require a clean inventory before reviewing a list.
| Common patterns | Wafer and lugged body, Manual handwheel, bevel gear and chainwheel, Pneumatic and hydraulic cylinders, Metal seated and resilient seated |
|---|---|
| Typical service | Pulp and paper, Mining and minerals, Wastewater |
| What we look at | Size, body material, seat type, operator type and stroke. We ask whether the blade is straight and whether the packing area is intact, because a worn packing box is the usual repair item. |
| What to keep | Keep the gate, the stem and the operator. A knife gate with a bent stem can often be repaired, but tell us. Do not cut the stem to remove an actuator. |
Patterns and variants
What turns up most often
Variants matter because they change the buyer pool. A standard pattern sells to a rebuilder or a plant with the same service; a specialised trim sells to a much smaller group but often at a higher price. If you are unsure which variant you have, the nameplate or the trim marking will usually say.
Before it leaves site
How to protect the value
Keep the gate, the stem and the operator. A knife gate with a bent stem can often be repaired, but tell us. Do not cut the stem to remove an actuator.
Where they come from
Industries and services
- Pulp and paper
- Mining and minerals
- Wastewater
Most of the surplus we see comes from plants that have replaced equipment for a reason that has nothing to do with the valve: a unit was re-rated, a line was re-piped, a control loop was upgraded or a project was re-scoped. The valve is simply the part that has to move.
Related patterns
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Read →Questions sellers ask
Do you buy knife gates with damaged blades?
Sometimes. A chipped or worn blade can be replaced; a bent one usually means a new gate. Describe the damage and we will tell you.
Are pneumatic knife gates worth more?
Generally yes, if the cylinder and controls are complete and the stroke is correct for the valve.
What about very large knife gates?
Sixteen inch and above in stainless or duplex is worth a conversation. Logistics are the main constraint.