Venturi 2 : A pipe through which fluid flows that has a short, narrow, straight throat between two tapered sections; it is used to measure flow velocities or to meter fuel or other liquids, such as foam compounds, into a water stream
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}