Gate valves incorporate a sliding gate to block fluid flow (slide gate valves). The design of the valve operating and sealing systems typically requires that they should be operated either fully open or fully closed.Get more news about electric gate valve,you can vist our website!
They open by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature is the sealing surfaces between the gate and seats are planar. The gate faces can form a wedge shape or they can be parallel. Typically, they should never be used for regulating flow, unless they are specifically designed for that purpose.
Upon opening, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening. This means that flow rate does not change evenly with stem travel. Also, a partially open gate disk tends to vibrate from the fluid flow. Most of the flow change occurs near shutoff with a relatively high fluid velocity causing disk and seat wear and eventual leakage if used to regulate flow. Typically, they are designed to be fully opened or closed. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss.
They are characterized as having either a rising or a non-rising stem. Rising stems provide a visual indication of valve position. Non-rising stems are used where vertical space is limited or underground.