Patent ID: 8333570

Claim:
A pump for dry particulate material, comprising: a manifold body having a bore; a cylindrical gas permeable filter located in said bore, an annular space being provided between said filter and said bore, said filter having an interior volume, said interior volume comprising a pump chamber, said annular space being connectable to a source of negative pressure and a source of positive pressure, said source of positive pressure being connectable to a first compressed air inlet; a first pinch valve and a second pinch valve wherein each said pinch valve comprises a member that defines part of a flow path for material through the pump, and wherein said pinch valve members open and close in response to pneumatic pressure applied thereto; wherein during pump operation material flows into said pump chamber when said chamber is connected to said source of negative pressure and material flows out of said pump chamber when said pump chamber is connected to said source of positive pressure; said first and second pneumatic pinch valves being operable to control flow of material into and out of said chamber; wherein said pump chamber is open at opposite ends thereof, said pump chamber having a first opening at one end of said pump chamber and a second opening at an opposite end of said pump chamber, wherein material enters and exits said pump chamber through said first opening, and a purge gas inlet comprising a second compressed air inlet into said pump chamber is provided at said second opening, said second compressed gas inlet being connectable to a source of purge gas.