US Patent 7033108 Turf playing surface aeration and drainage system

A perforated pipe network beneath a playing surface. A blower connected to the pipe network drawing an air flow through the pipe network to create a vacuum. A drain pipe connecting to the pipe network. An air/water separator connected upstream of the blower for separating water from the air flow prior to entering the blower and channeling the water into the drain pipe for discharge. A flow control unit having a unit inlet connected to the drain pipe downstream of the air/water separator and a unit outlet discharging water to a drain outlet. The flow control unit blocking air flow through the unit inlet into the drain pipe when the blower is in the vacuum mode, and opening the unit inlet when a waterhead buildup at the unit inlet exceeds the vacuum level established by the blower to discharge water through the drain outlet.