Abstract: A paper corrugator machine has a closed loop for delivering warm adhesive from a source to a pan from which the adhesive is applied onto the crests of the corrugated paper flutes. To insure a delivery of the correct amount of adhesive to the flute crests, a predetermined amount of adhesive is first accumulated in a graduated column. Then, the adhesive delivery feed is switched from the closed loop to the graduated column. A detector senses upper and lower limits of the amount of the adhesive in the column. The rate of the delivery of adhesive is determined by how long it takes for the predetermined amount of adhesive to be delivered from the column to the corrugating machine. Responsive to this determination, the corrugating machine may be adjusted to apply more or less adhesive to the flute crests.