Patent ID: 8292197

Claim:
A system for continuously metering and transporting powder, said system comprising: a closed reservoir containing a mass of the powder to be transported; means for fluidizing at least a portion of the powder in said reservoir; a tube extending vertically into the fluidized powder, said tube having a lower end in the fluidized powder and an upper end located above the fluidized powder for discharging fluidized powder to the outside of said reservoir; first supply means for supplying pressurizing gas to an internal volume of said reservoir above the fluidized powder; second supply means for continuously supplying pressurizing gas; a mixing chamber having upstream and downstream ends and connected to receive pressurizing gas from said second supply means for mixing said pressurizing gas from said second supply means with the fluidized powder leaving said tube, said second supply means presenting a constriction to the flow of the pressurizing gas to said mixing chamber; and a hose for transporting the powder mixed with said pressurizing gas supplied by said second supply means, said hose being connected to the downstream end of said mixing chamber, wherein, during operation of said system, a pressure difference exists between said lower end and said upper end of said tube, which pressure difference controls the mass flow rate of fluidized powder from said tube, and said constriction produces an adjustable head loss in the flow of gas to said mixing chamber, which head loss controls the pressure difference, and wherein said second supply means are supplied with gas directly from said first supply means.