ABSTRACT
The tube is also equipped by 2 differential pressure gauges. They measure the air pressure difference p1 (respectively p2) between a point at L1 = 28.5 cm (L2 = 7.4 cm) above the distributor, to a point at Lo = 2.1 cm from it. The top of the particle bed is always between 7.4 and 28.5 cm.
