The biggest difference between a knife gate valve and a flanged gate valve is that gate valve is manufactured according to ANSI , while knife gate valve meets TAPPI Standards. Gate valves are also flanged, wider in size, ANSI pressure rated, and their API leak tightness standards need to be met as well. Gate valves are bi-directional, widely used in fluid applications, and they only come with metal seats. Another difference between a knife gate valve and an ANSI gate valve is in the packing gland area. Knife gate valves have a V-shape packing group that is sealed to the shaft of the gate valve. Knife gate valves have a packing gland area that is sealed around the gate.

Knife gate valves have a thinner structure compared to ANSI gate valves. Knife type gate valves are primarily unidirectional (some are bi-directional) and feature a lug or wafer body with no flanges. Knife gate valve seats vary from resilient to metal versions.

The most significant advantages of knife gate valves are weight (16 inches, usually less than 300#) and cost.ANSI gate valves are usually more than 1200#, and more expensive.