Pneumatic pressure conveyor for fine material

A pneumatic pressure conveyor for fine material comprising two superimposed pressure vessels, the upper of which has a closable material inlet connected to a source of fine material and has a lower end in the form of a cone with a bottom outlet, the lower vessel having a material inlet connected through a valve to the bottom outlet of said cone, and having a pneumatic feed outlet conduit connected to its lower portion, and a valved conduit connected to both vessels for equalizing the pressure therein to pressurize the upper vessel after the inlet of the upper vessel has been closed and before said valve is opened, wherein the improvement comprises means for breaking up a heavily compacted mass of fine material which has been compressed into said cone during pressurization of the upper vessel, to cause the contents of the upper vessel to be dumped into the lower vessel upon opening of said valve, said means comprising:

• a. a plurality of nozzles uniformly distributed over the length and periphery of said cone, which have an internal diameter between 0.2 and 0.6 mm.,
• b. said nozzles being connected to a source of gas under an absolute pressure at least 4 percent but not more than 89.3 percent greater than the absolute pressure in said vessels, to produce jets which penetrate deeply into the heavily compacted mass of fine material so as to break up bridges in the material,
• c. the interior of said cone being unobstructed, and
• d. control means for causing the gas to be supplied in pulsations at least 0.2 second in duration, with an interval of 0.25 to 30 seconds between pulses.