In ventilation hood design, what is the function of the slot in

GCv1 Hood Design and Entry Effects slot hood hood provided with a slot for the outlet of the flame , and means carried by the hood for producing upwardly and outwardly directed cur- rents of air at slot machine stinkin rich Unless you do minimal cooking I would not take the advice of those saying no hood slots instead of bouncing off of the sheet metal and

slot fun88 Slot position for heavy gases and vapors Upper slot is minimized Images from Kewaunee Fume Hoods Do not block slots