Abstract: Disclosed are apparatus and method for bead coating a web with liquid composition with a pressure differential applied across the bead of composition between the lip of the slide hopper and the web. An enclosure is disposed under and open to the bead. Vacuum is applied to the enclosure by a turbine driven by an AC induction motor. Servo means are provided for regulating the speed of the motor and thereby the pressure differential across the bead. The AC motor and the servo means allow the desired pressure to be maintained without surges and allows the differential pressure to be rapidly changed, as for the passage of a splice in the web through the bead.