Surgical system pump with flow sensor and method therefor

The automatically controlled pump supplies pressurized irrigation fluid to a surgical site. The pump system includes a motor in a housing and a pump in a housing defining input and output ports. The pump has a rotatable impeller. The motor is powered by one or more batteries. An ON/OFF motor switch is controlled by fluid flow above a nominal flow by a sensor typically mounted downstream of the pump. The system operates in conjunction with a downstream manual control valve. Flow above a system minimal flow is detected by a negative buoyancy poppet having a "leaky" valve seat. When the poppet moves into a flow chamber, the switched motor is ON. Various position sensors may be used, i.e., an optical sensor. The method automatically controls a pump by monitoring fluid flow above a system minimal flow and turning ON/OFF the motor based upon flow above the minimum.