Pneumatic conveying apparatus

Claim 1

PNEUMATIC CONVEYING APPARATUS COMPRISING A HOPPER INCLUDING SPACED FORWARD AND REARWARD WALL PORTIONS, A DISCHARGE CHAMBER HAVING A DISCHARGE OUTLET, A BARREL CONNECTING SAID HOPPER AND SAID DISCHARGE CHAMBER, SAID BARREL BEING IN COMMUNICATION WITH SAID HOPPER THROUGH SAID FORWARD WALL PORTION AND IN COMMUNICATION WITH SAID DISCHARGE CHAMBER AT A POINT ADJACENT AND SPACED FROM THE DISCHARGE OUTLET, SHAFT BEARING MEANS LOCATED REARWARDLY FROM SAID REARWARD WALL PORTION, A ROTATABLE SHAFT SUPPORTED BY SAID SHAFT BEARING MEANS AND EXTENDING THEREFROM THROUGH SAID HOPPER WALL PORTIONS INTO SAID BARREL, SAID SHAFT TERMINATING ADJACENT SAID DISCHARGE CHAMBER, MEANS FOR ROTATING SAID SHAFT, HELICAL MEANS ON SAID SHAFT FOR ADVANCING AND COMPACTING MATERIAL FROM SAID HOPPER THROUGH SAID BARREL TO SAID DISCHARGE CHAMBER, A COLLAR ON SAID REARWARD WALL PORTION SURROUNDING SAID SHAFT, A SHAFT SEAL SPACED FROM SAID COLLAR AND IN SEALING ENGAGEMENT WITH SAID SHAFT, FLEXIBLE COUPLING MEANS CONNECTING SAID SHAFT SEAL AND SAID COLLAR TO FORM A PRESSURE TIGHT COUPLING THEREBETWEEN, SAID FLEXIBLE COUPLING MEANS BEING ADAPTED TO PERMIT LIMITED MOVEMENT OF SAID SHAFT SEAL, SAID FLEXIBLE COUPLING MEANS BEING SPACED FROM SAID SHAFT TO PROVIDE AN ENLARGED ANNULAR SPACE BETWEEN SAID SHAFT, SHAFT SEAL, COLLAR AND COUPLING MEANS, AN OPENING IN SAID COLLAR IN COMMUNICATION WITH SAID ENLARGED SPACE, A SOURCE OF GAS UNDER PRESSURE, MEANS FOR DIRECTING AT LEAST ONE STREAM OF GAS FROM SAID SOURCE AGAINST THE COMPACTED MATERIAL PASSING FROM SAID BARREL INTO THE DISCHARGE CHAMBER, TO AGITATE AND ENTRAIN THE MATERIAL THROUGH THE DISCHARGE OUTLET, AND MEANS FOR ADMITTING GAS UNDER PRESSURE THROUGH SAID COLLAR OPENING TO SAID ENLARGED SPACE TO PREVENT THE LEAKAGE OF MATERIAL FROM SAID HOPPER INTO CONTACT WITH SAID SEALING ELEMENT.