Anaerobic digester

Claim 1

AN ANAEROBIC DIGESTER WHEREIN SUSPENDED PUTRESCIBLE SOLIDS CAN BE BIOLOGICALLY DIGESTED, COMPRISING A CLOSED TANK HAVING SIDE WALLS WITH A BOTTOM AND A TOP PROVIDED WITH GAS WITH GAS WITHDRAWAL MEANS FOR MAINTAINING THEREIN A BODY OF SUCH LIQUID, MEANS FOR FEEDING SUCH LIQUID TO THE TANK, OVERFLOW MEANS FOR DISCHARGING FROM THE TANK AT A LEVEL DETERMINED THEREBY TREATED LIQUID FROM WHICH SUCH SOLIDS HAVE SETTLED, DISCHARGE MEANS FOR WITHDRAWING FROM THE TANK SETTLED SOLIDS AS SLUDGE, A DRAFT TUBE TERMINATING BENEATH THE LIQUID LEVEL THROUGH WHICH THE SUSPENSION IS IMPELLED FROM THE BOTTOM TO THE TOP OF THE LIQUID BODY TO DESCEND WITHIN THE SPACE SURROUNDING THE DRAFT TUBE WHILE DIGESTION-INDUCED GAS BUBBLES IN THE IMPELLED SUSPENSION ARE RELEASED THEREFROM AT THE LIQUID LEVEL WITHIN AN AREA ENCIRCLED BY AN ENDLESS CURTAIN BAFFLE HEREINAFTER DEFINED, SUCH AN ENDLESS BAFFLE THAT IS SMALLER IN DIAMETER THAN THE TANK TO PROVIDE COMMUNICATING PASSAGE BETWEEN THE TANK AND THE LOWER EDGE OF THE BAFFLE AND THAT SLOPES DOWNWARDLY AS WELL AS OUTWARDLY TO DEFINE AN UPPER LIMIT OF A BODY OF TURBULENT DIGESTING LIQUID AS WELL AS A LOWER LIMIT OF AN ANNULAR BODY OF RELATIVELY QUIESCENT LIQUID, SAID CURTAIN BAFFLE HAVING A PLURALITY OF SUBMERGED PORTS THERETHROUGH LOCATED ABOVE THE LOWER EDGE OF THE BAFFLE AT A HORIZONTAL DISTANCE INWARDLY FROM THE OVERFLOW MEANS THROUGH WHICH PORTS PASS STREAMS OF SUSPENDED SOLIDS TO RISE RELATIVELY NON-TURBULENTLY FROM THE TURBULENT BODY INTO THE QUIESCENT BODY WHILE A QUANTITY OF SOLIDS SETTLING FROM THE QUIESCENT BODY ONTO THE BAFFLE DESCEND ALONG ITS SLOPE TO PASS THROUGH THE COMMUNICATING PASSAGE BETWEEN THEPERIPHERY OF THE BAFFLE AND THE TANK INTO THE TURBULENT BODY WHILE TREATED LIQUID OF THE QUIESCENT ANNULAR BODY PASSES FROM THE TANK BY WAY OF THE OVERFLOW MEANS.