Patent ID: 8631767

Claim:
An apparatus comprising: a first canister containing a first blower that selectively imparts a first airflow through an outlet of the first canister; a second canister containing a second blower that selectively imparts a second airflow through an outlet of the second canister; a first flexible connector connected to the first canister's outlet; a different second flexible connector connected to the second canister's outlet; a rigid piping manifold having a first manifold inlet connected to the first flexible connector and a second manifold inlet connected to the second flexible connector, so that the first flow passes entirely through the first flexible connector before entering the rigid piping manifold and the second flow passes entirely through the second flexible connector before entering the rigid piping manifold, the rigid piping manifold fluidly combining the first and second manifold inlets into only one manifold outlet; and a backflow preventer device between the second blower and the manifold outlet, selectively preventing the first airflow from entering the second canister.