what is a gate valve

A gate valve, also known as a sluice valve, is a linear-motion isolation valve that opens by lifting a barrier (gate) out of the path of the fluid. It is used to allow unobstructed fluid flow or to stop the fluid flow. Gate valves require very little space along the pipe axis and hardly restrict the flow of fluid when fully open. They are mostly used with larger pipe diameters (from 2" to the largest pipelines) since they have no obstruction in the flow path, resulting in very low flow resistance. Gate valves are used to shut off the flow of liquids rather than for flow regulation, which is frequently done with a globe valve. Gate valves are the most common valve for water supply systems and are used to isolate specific areas of the water supply network during maintenance, repair works, new installations, as well as to reroute water flow throughout the pipeline. They are usually controlled by a manual handwheel that requires more than a 360-degree turn to fully open or close. Gate valves can be actuated by a threaded stem that connects the actuator (e.g. handwheel or motor) to the gate and are characterized as having either a rising or a non-rising stem. Gate valves are slower than quarter-turn valves and should only be used in the fully open or closed position, not to regulate the flow.