US Patent 7533684 Dispensing valve with back flow protection

A dispensing valve assembly with a housing having a plurality of inlet passageways connectable at a respective upstream end to a respective supply source. Each inlet passageway is in communication with a pressure responsive valve element. The valve element is biased to abut a discharge valve seat in a closed position about an upstream end of an outlet passage. The valve element is moveable to an open position when pressure in its respective inlet passageway exceeds a predetermined value. Each outlet passage is in fluid communication with a common dispensing outlet.