a sheet material to be saturated with a fast - reacting saturant , approximately one minute at room temperature , passes under a trough positioned across the travelling web and having a longitudinal slot through its bottom . a threaded rod having a diameter larger than the slot width is laid over the slot in the trough . the fast - reacting saturant is supplied to a traversing dispensing device located above the trough . this traversing device dispenses the saturant into the trough . the threaded rod co - acts with the slot in the bottom of the trough to meter the amount of fast - reacting saturant flowing through the trough and onto the sheet material moving under and contacting the bottom of the trough .