Continuous digester wood chip level control

Abstract

Abstract APPARATUS AND METHOD FOR CONTINUOUS POULPING IN AN UPRIGHT ELONGATED REACTION VESSEL BY FEEDING SUBSTANTIALLY CONTINUOUSLY WOOD CHIPS AND A LIQUID INTO THE REACTION VESSEL AT ITS LOWER END TO MAINTAIN THEREIN A COLUMNAR MASS OF COMPACTED WOOD CHIPS WITH ITS LOWER END NORMALLY SPACED UPWARDLY FROM THE LOWER END OF THE VESSEL AND ADVANCING THE WOOD CHIPS UPWARDLY THROUGHOUT THE LENGTH OF SAID COLUMN BY ADVANCING LIQUID UPWARDLY THROUGH A LIQUID PROPELLING ZONE IN THE LOWER PORTION OF THE COLUMN. THE VESSEL HAS THREE VERTICALLY SPACED PRESSURE SENSING MEANS WITH THE LOWER TWO OF THE PRESSURE SENSING MEANS SPACED RESPECTIVELY ABOVE AND BELOW THE NORMAL POSITION OF THE LOWER END OF THE CHIP MASS AND THE UPPERMOST ONE OF THE PRESSURE SENSING MEANS SPACED ABOVE SAID LOWER TWO TO SENSE SAID POSITION FOR CONTROL THEREOF. COMPARATOR MEANS ARE CONNECTED TO EACH OF THE LOWER AND UPPER TWO OF THE PRESSURE SENSING MEANS FOR COMPARING THE SENSED SIGNALS THEREFROM PROVIDING OUTPUT SIGNALS RESPOSIVE TO SAID POSITION AND MEANS ARE PROVIDED FOR COMPARING THE OUTPUT SIGNAL FROM THE LOWER TWO OF THE PRESSURE SENSING MEANS WITH THE OUTPUT SIGNAL FROM THE UPPER TWO OF THE PRESSURE SENSING MEANS TO PRODUCE A CORRECTED OUTPUT SIGNAL RESPONSIVE TO THE POSITION OF THE LOWER END OF SAID CHIP MASS BY MEANS OF WHICH THE PROPELLING LIQUID FLOW RATE IS CONTROLLED TO CONTROL SAID POSITION.

Inventors

• 👤 Lawrence Allan Carlsmith

Bibliographic Details