I–L–4

This apparatus serves the same purpose as the FNb 42 model, namely, to screen large areas.

The drums of smoke acid is marked: "Nebelsäure".

The apparatus consists of a drums of smoke acid, a 240 Volt A.C. motor, an eccentric pump, the spray tube and nozzle, and the instrument box. The motor and pump fit into the hole in the side of the smoke acid barrel just as the FNb 42 apparatus. The nozzle opening on the spray tube is adjustable to an operating rate of 0.5 liters per minute un-der a pressure of 50 pounds per square inch. At this setting, 125 liters of smoke acid will produce a screening smoke for four hours. With the opening plat adjusted to one liter per minute, the apparatus will produce smoke for two hours. From 10 to 18 of these smoke spray units can be controlled electrically from one panelboard and this is the usual prac-tice.