Abstract: A control valve includes a valve body having an inlet port and an outlet port which receives an orifice plate mounted to the valve body. Set within the valve body is a plunger which cooperates with the orifice plate to selectively communicate the inlet port with the outlet port. The plunger is acted upon by a stem for displacement in an axial direction between a closing position and an opening position and provided with a servo system for maintaining the desired position of the plunger. The servo system includes a slide gate which is connected to the stem and opens and closes the fluid passageways between the inlet port, outlet port and a pressurizing chamber above the plunger.