Filter pulse-down cartridge cleaning mechanism

In a particulate material recovery system wherein a flow of gas entraining particulate material is passed through a filter having an upstream side and a downstream side with the particulate material remaining on the upstream side while the gas flows to the downstream side, and wherein the downstream side exhausts through an opening into a plenum chamber wherein the gas pressure is less than the gas pressure on the upstream side and wherein a second valve is provided for intermittently providing a cleaning gas flow in the reverse direction through the filter to remove particulate material from the upstream side, means for providing cleaning gas under pressure to the second valve, opening of the second valve permitting cleaning gas to flow therefrom, the improvement comprising a first valve for controlling gas flow through the opening, the first valve operating in synchronism with the second valve substantially to stop flow through the filter from the upstream side to the downstream side when the second valve provides such cleaning gas flow, the first valve including a cylindrical throat having a first end and a second end, the first end coupled to the second valve to receive the intermittent cleaning gas flow therefrom, means defining in the throat a seat, a valve member having a head reciprocably slidably engaging the throat and captured between the first end and the seat, the valve member further comprising a valve closure portion and a stem for coupling the valve closure portion to the valve head, the stem providing a cleaning gas passageway between the head and closure portion when the second valve is providing cleaning gas flow.