Abstract The method of controlling a process for the production of dry material on a continuous feed and discharge basis such as, for example, ore pellets, in a mill unit by the crushing, grinding or milling of the dry material is achieved by measuring the amount of material being fed and the amount of process material being discharged to obtain a first signal value and a second signal value, respectively, with each of these two signal values being thereafter fed to a first control means. The degree of fill of the milling unit is electroacoustically detected to obtain a signal value therefor which is thereafter passed to a second control means. The output signal of the second control means is passed to the first control means to adjust same to a constant value. The output signal of the first control means adjusts the first control means so that the first and second signal values of the material being fed and the material being discharged will be substantially equal during the processing of the dry material.
The method in accordance with claim 1 wherein the first signal value measuring the amount of material fed is retarded over a time period at least equal to the run-through time period of the material from the point of measurement to the discharge point of the unit.
Claim 2
Dependent Claim
141 words
The method in accordance with claim 1 wherein the dry material is fed to the crushing unit through metering feeder means to provide the first signal value and thereafter passed on to air sifter means, passing a portion of the crushed material as a recycle feed to the crushing unit and obtaining a signal value therefor, retarding the first signal value from the feeder means over the run-through period of the material to the crushing unit, summing up the first signal value of the feeder means with the signal value of said recycle feed to produce a further signal value, retarding the further signal value to an extent approximately the run-through period of the material through the crushing unit, feeding said retarded further signal value to said first control means, and controlling said metering feeder means by said first control means.
Claim 3
Dependent Claim
44 words
The method in accordance with claim 1 which includes the passing of a heated drying gas through said crushing unit in the same direction as the flow of material to be processed, the velocity of said gas being maintained at substantially a constant value.
Claim 4
Dependent Claim
71 words
The method in accordance with claim 4 wherein the pressure of the drying gas prior to passage to said crushing unit and the pressure of the drying after passing through the crushing unit and through gas draw-off means are each adjusted to obtain a constant value for each independent of one another, said adjustment being achieved by correcting the quantity of drying gas supplied and adjusting the gas draw-off means respectively.