Patent ID: 8757515

Claim:
A system, comprising: a spray gun, comprising: a first liquid passage configured to flow a first liquid in a generally downstream direction toward a spray tip; a second liquid passage configured to flow a second liquid in a generally upstream direction such that the second liquid impinges upon the first liquid at an outlet to the second liquid passage as the first liquid is flowing in the generally downstream direction and the second liquid is flowing in the generally upstream direction, wherein the upstream direction is substantially opposite from the downstream direction; and a check valve disposed at the outlet to the second liquid passage, wherein the check valve comprises a valve body and a shaft disposed within a cavity of the valve body, a head of the shaft is configured to contact the valve body to substantially block flow of the second liquid through the outlet while the valve is in a closed position, the head of the shaft and the valve body are shaped to form a substantially annular orifice that facilitates flow of the second liquid through the outlet while the valve is in an open position, and the substantially annular orifice is configured to provide a generally even distribution of the second liquid into the first liquid passage.