Patent ID: 8544499

Claim:
A variable valve for varying the flow of airborne particulate coal through a single channel flow conduit comprising: a conduit having a diameter; a first planar plate having an upstream edge and a downstream edge, said plate being fixedly mounted within and extending across the diameter of said conduit in a plane which is parallel to the flow direction of said stream; a second planar plate having an upstream edge and a downstream edge and angularly moveably mounted within and extending across said conduit with the downstream edge closely contiguous to the downstream edge of the first plate such that the first and second plates form an acute included angle therebetween wherein the included angle opens toward the flow of particulate coal; and a mechanical structure for selectively varying the angular relationship between the first and second plate such that about half of the cross-sectional area of the conduit remains open irrespective of the position of the second plate.