1) This valve is called a gate valve because it contains a closure element called a gate that stops flow. The gate acts like a shutter that separates the inside of a house from the outside or a door that separates two rooms.
2) A disc housed in the gate valve's body slides up and down at right angles to the direction of flow in the pipe, closing or opening the valve. Flow is blocked by using the wedge-lock effect of the valve's disc.
3) Gate valves are suitable for on and off flow control. Turning the handle counterclockwise raises the disc, allowing flow through a straight passageway. Turning the handle clockwise lowers the disc, impeding flow.