Patent ID: 7874769

Claim:
A method for transferring particles from an upper zone, through a middle zone, to a lower zone comprising: (a) introducing a first gas stream into the lower zone; (b) transferring particles downward from the upper zone to the middle zone through an upper valveless conduit, and transferring gas from the lower zone upward through a lower valveless conduit into the middle zone; (c) increasing the middle zone pressure; (d) transferring particles downward from the middle zone to the lower zone through the lower valveless conduit, obstructing a particle flow in the lower zone with a particle impervious body comprising a planar surface, and transferring gas from the middle zone upward through the upper valveless conduit into the upper zone; (e) decreasing the middle zone pressure; and (g) controlling the transfer of particles by use of at least one of a controller, a particle level sensor, a pressure gauge, a pressure indicator, a differential pressure sensor, and a timer wherein the upper zone is at a first pressure, the lower zone is at a second pressure, and the second pressure is greater than the first pressure.