US Patent 8240522 Dual function dispensing head for carbonated beverage machine

A dispensing head incorporates multiple constant flow valves for controlling the flow of multiple liquids, e.g., syrup and carbonated water fed to a dispensing nozzle. The valves are normally closed and are opened by inlet pressures above selected threshold levels. Once open, the valves maintain the liquid flows at substantially constant flow rates and pressures, irrespective of variations of liquid input pressures and viscosities. A closure mechanism serves to close the valves at inlet pressures both above and below the threshold levels. The closure mechanism may be deactivated to simultaneously allow the valves to assume their modulating functions at inlet pressures above the threshold levels.