A small fabric filter system with four bags is used to clean a gas stream containing a dust load of 10gr/ft3 with a cake bulk density of 30.0lb/ft3. If the system must be cleaned when there is 1.125 inches of cake on the bags in order to retain its near 100% efficiency, what is the filtering time allowed between each cleaning? Given: Bag diameter =12 in Bag height =10ft Flow rate =4000ft3/min