Abstract
Cleaning-in-place (CIP) of food processing equipment usually requires a huge amount of water. For reduction of water required in its final rinsing step, performance of air-water two-phase flow as a rinsing medium was studied. Horizontal and vertical straight pipes of 23 mm inner diameter were artificially soiled with millet jelly and rinsed with air-water two-phase flow at flow rates of 400, 600, and 800 L/min for air and 2, 3, and 4 L/min for water. At the lowest flow rate of air, the two-phase flow was not completely annular and rinsing efficiency was quite low. At higher air flow rates, however, the two-phase flow was shown to save about 90% of rinsing water with no or slight extension of rinsing time, compared with water flow rinsing at 40 L/min. For non-straight piping parts (tees, elbows, and a diaphragm valve), the air-water two-phase flow was shown to save about 80% of rinsing water but to take twice as much rinsing time as 40 L/min water flow.
