the chip chute circulation liquor from the chip chute 104 through the feeder 114 through the sand separator 109 and through the in line strainer 105 back into the chip chute 104 in the in line strainer 105 excessive liquor is removed from the chip chute circulation and fed into the level tank 110 the chamber of the feeder 114 is pressurized by a fluid entering at l 1 and the chamber pressure can be controlled by fluid flow l 2 out of the casing the pressure controlling fluid flow l 2 can be pumped by the chip chute pump 108 through the sand separator 109 and through the in line strainer 105 to the chip chute 104 when the flow channel filled with low pressure slurry comes into an open position aligning with the connections for high pressure circulation the high pressure liquid coming from the digester through the top circulation pump 113 flows into the feeder 114 through the connection for high pressure inlet and displaces the slurry from the flow channel through the connection for high pressure discharge into the top separator 112 simultaneously filling the flow channel with high pressure liquid the feeder 114 shown in fig4.