The spray pattern of flat fan nozzles features a sharply delimited line due to internal flow characteristics. The coverage width can be varied by modifying the geometric configuration of the nozzle orifices, where the liquid is shaped into flat, fan-like spray patterns. The flat liquid body takes on a laminar form and disintegrates into droplets as its distance from the nozzle orifice increases. Parabolic, trapezoidal or rectangular impact areas are achieved by adequately determining the functional and geometric dimensions.

Tongue-type nozzles represent a special kind of flat fan nozzle. The flat fan pattern is generated by a solid stream, impinging upon an external deflector plate (“the tongue”). Tongue-type nozzles are particularly clog-proof and produce a sharply delimited flat fan pattern.