Gate valves are primarily designed to start or stop a flow when a straight line flow of fluid and minimum flow restriction are needed. In service, these valves are pretty much kept either fully open, or fully closed. When turned open, the disc of the gate is completely removed allowing contents to pass.
A gate system is used to open or close a pipeline entirely. This is an excellent choice if the flow rate needs to be controlled and maintained. When the actuator completely opens the valve, the channel is unobstructed, allowing even slurry fluids like crude oil to flow easier.