There are two compressed air chambers to collect and deliver cleaning air into the bags: One on the right and one on the left side of the top of the kiln. Each one feeds half of the bags (14 rows) (in total 28 rows). The sequence of bag cleaning assures pulsing bags of one row of right and other of left side of the filter. This happens in opposite direction (left 1�14) & (right 28�15).