Needle valves are used in high pressure for shut-off of small and medium flows, for instrument isolation and also as bleed-off valves. Their main features are its reliable shutoff and the possibility to regulate the flow. They have a high pressure drop.
Ball valves are used in high pressure for shut-off of large flows, for instrument isolation and also as bleed-off valves.
Their main characteristics are the speed of closing/opening with a simple 90º turn of the handle, the easy visualisation of whether the valve is open or closed by the position of the handle and the ease of automation by means of pneumatic or electric actuators. They have almost no pressure drop.
