Blast gates are used to open and close dust collector branch ducts to divert airflow only to those machines in operation. This conserves air volume and keeps suction strongest where dust is being produced, thus maximizing dust extraction. The outer case is made from cast aluminum with a sliding steel gate and locking knob. Typical blast gates allow debris to accumulate in the groove preventing the gate from closing fully, causing leaking and reducing suction. The slot on these units extends entirely through the back of the base to allow debris to be pushed out of the groove thus preventing buildup.