Constant volume feeder for flowable granular material

Claim 1

APPARATUS FOR TREATING FOUNDRY SAND AND LIKE FLOWABLE GRANULAR MATERIAL, SAID APPARATUS INCLUDING A BULK BIN HAVING SIDE WALLS WHICH TEND TO BECOME INCRUSTED BY THE GRANULAR MATERIAL AND FROM WHICH THE GRANULAR MATERIAL IS PERIODICALLY DUMPED IN BATCHES TO RUSH OUT OF SAID BIN, A CONTINUOUS MIXER HAVING A SUBSTANTIALLY CONTINUOUS CONSTANT VOLUME DEMAND FOR GRANULAR MATERIAL AND FEEDING MECHANISM ADAPTED TO RECEIVE THE GRANULAR MATERIAL FROM THE BULK BIN IN BATCHES AND TO FURNISH SAID MATERIAL TO SAID APPARATUS AT A CONSTANT VOLUME LEVEL, SAID FEEDING MECHANISM COMPRISING: (A) HOPPER INTO WHICH SAID BIN DISCHARGES, (B) CONVEYOR BENEATH SAID HOPPER FOR CARRYING MATERIAL AWAY FROM SAID HOPPER AT A CONSTANT VOLUME LEVEL, (C) FIRST SENSING MEANS TO DETECT WHEN THE HOPPER IS EMPTY, (D) SECOND SENSING MEANS TO DETECT WHEN THE HOPPER IS FULL, (E) GATE MEANS ON THE BIN, (F) MEANS FOR WIDELY OPENING SAID GATE MEANS TO DUMP A BATCH OF MATERIAL FROM THE BIN INTO THE HOPPER IN RESPONSE TO SAID FIRST SENSING MEANS AND TO CLOSE SAID GATE MEANS IN RESPONSE TO SAID SECOND SENSING MEANS, (G) SAID GATE MEANS COMPRISING MEANS FOR OPENING THE BIN WIDE ENOUGH TO CAUSE THE FLOWABLE GRANULAR MATERIAL THEREIN TO BE ABRUPTLY DISCHARGED AND SCOUR THE SIDE WALLS OF THE BIN AND PREVENT INCRUSTATION THEREOF.