The dirty air enters the side of the hopper so that, due to the low velocity, much of the entrained dust (particularly the large size of the dust particles) will drop directly into the hopper. Continuing upward, the air encounters the tube sheet where it passes through the collars and in to the filter bags. The dust in the air does not penetrate the bags and remains as a deposit on their inside surfaces. The air itself, however, does pass through the bag material, then continues upward and out through the top of the compartment from there it is directed through an exhaust manifold.

 

At specific intervals, a cleaning cycle is initiated in which the air flow through the module is stopped and air moving in the opposite direction is introduced. This reversed flow and the partial collapse of the bag which it produces causes the accumulated dust to break loose and fall out of the bags. The dislodged dust drops in to the hopper and is removed by dust handling equipment. After the dust had a few moments to settle, the valves are reset to their position for filtering.

 

The air to be filtered is moved through the dust collector by the ID Fan installed downstream of the exhaust manifold. Because air is being pulled through the system, each module discharges into an exhaust manifold which connects to the fan creating the suction. The main air valve and the reverse air valve are both located on the exhaust side of the module. The reverse air is forced into the compartment from the clean air side. The reverse air fan draws air from the system exhaust and blows it into the reverse air manifold which connects to each module at the reverse air valve.

 

The system requires the reverse air be hot to avoid the problems which would arise if moisture condensation occurs in the system – particularly on the bags.