Knife gate valves are designed mainly for on-off and isolation services in systems with high content of suspended solids. Knife gate valves are especially beneficial for handling slurry in addition to viscous, corrosive and abrasive media. The valves have a minimised pressure drop in fully open position, they are easy to actuate, they have a relatively low weight and are cost-effective.
Where Are Knife Gate Valves Used?
Knife gate valves are built to perform in some of the toughest conditions, featuring a sharpened blade designed to cut through thick or heavy liquids.
They are particularly effective in wastewater treatment and other applications where corrosion poses a major concern. To withstand such environments, these valves often feature blades made from acid-proof stainless steel, which enhances resistance to corrosion and reduces the need for frequent maintenance or replacement.
Knife gate valves are best suited for applications that require either a fully open or fully closed position. They are not intended for throttling flow—unless specifically designed for that purpose—as forcing fluid through a partially open gate can lead to vibrations that wear down the disc and seat over time. Additionally, these valves are engineered to open and close slowly, helping to minimize the risk of water hammer.
What Is the Difference Between Knife Gate Valves and Gate Valves?
Wedge-type gate valves and knife gate valves are both primarily designed for on-off applications, meaning they should be either fully open or fully closed during operation. Neither valve type is suitable for regulating flow, as partially closing them can lead to vibration and cavitation, which may eventually damage the valve seat and body. To mitigate the risk of water hammer, both are designed to open and close gradually.
Despite their differences in design, both valve types are suitable for handling:
– Slurries
– Heavy oils
– Non-flammable viscous fluids
– Wastewater
– Clean water
Key Differences Between Gate Valves and Knife Gate Valves
One notable difference is that knife gate valves feature a sharpened disc designed to cut through slurry or viscous media more effectively. In addition, knife gate valves have a shorter face-to-face dimension compared to the typically wider gate valves, making them significantly lighter in weight. These characteristics are among the most important advantages of knife gate valves.
Knife gate valves are commonly used in demanding industrial environments such as wastewater treatment facilities, chemical plants, mining operations, and cement plants. In contrast, gate valves are more frequently found in clean water systems, including drinking water mains, distribution networks, and pump stations.
Key Differences Between slide Valves and Knife Gate Valves
These two types of gates are often confused with one another, but a knife gate and a slide gate are NOT the same. A knife gate valve is a component that uses a blade to cut through very thick liquids or hard clumps of clogged material. A slide gate valve is a component that utilizes a stainless steel, rectangular slide plate to shut off or open the flow of dry material. The slide plate actuates between two, compression-loaded, hard polymer plates. Knife Gates and Slide Gates are used in a wide variety of industries, including Food, Plastics & Petrochemical, Animal Feed, Energy, Mining & Minerals, and Chemical Industries.