What is a knife gate valve?
Knife gate valves are mainly designed for open/closed applications and to isolate specific sections in pipelines. Knife gate valves are particularly suitable for sludge, viscous, corrosive, and abrasive media. The valves have a minimal pressure drop in fully open position, are easy to operate, have a relatively low weight and are cost-effective.
Where are knife gate valves used?
Knife gate valves are designed to operate in the most severe and aggressive conditions, and the plate acts like a knife cutting through thick media.
They are especially useful in wastewater applications where corrosion can be a major problem. In addition to the knife plate design, which is optimized for sludge media, the knife plate is made of acid-proof stainless steel which reduces the risk of damage due to corrosion, so that the maintenance frequency can be reduced, and replacement of the knife plate can be avoided.
Knife gate valves should only be used for applications that require a fully open or fully closed position. In addition, knife gate vales are designed to open and close slowly to counteract the effects of water hammer. For accurate flow control it is necessary to use a V-port knife gate valve.
What are the similarities and differences between knife gate valves and gate valves?
Both gate valves and knife gate valves are mainly designed for an open/close function, where the valve is completely open or completely closed. A gate valve is not suitable to use for flow control, while this is possible with a knife gate valve with a V-port. Both valve types are designed to open and close slowly to reduce the risk of water hammer.
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Knife gate valves |
Gate valves |
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Sludge |
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Waste water |
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Heavy oils |
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Non-flammable viscous fluids |
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Dry substances |
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Clean water |
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The knife gate valve has a short face-to-face length compared to a gate valve, which is dimensionally wider. Consequently, a knife gate valve is lighter in weight compared to a gate valve.
Knife gate valves are typically found in wastewater treatment plants, biogas installations, chemical plants, mining, cement plants as well as in many other industrial applications while gate valves are typically found in drinking water mains, water distribution networks and drinking water pump stations.
