inlet pipe 27 and splashes against the side of the tank 50 opposite the inlet and drains down to the body of the slurry in the tank 28 the height of slurry in tank 50 is controlled by the height sensor 34 at the bottom of the tank the sensor 34 is at an angle of about 60 u00b0 c from the center line of the inlet pipe 27 the sensor controls the flow in outlet pipe 32 by operating the valve 25 between the deaeration tank and the washer the body of slurry in tank 28 is swirled by filtrate from washer 33 the velocity of filtrate entering the deaeration tank 28 is 6 1 meters per second 20 feet per second at a 2 pulp consistency the velocity may range from 4 57 to 12 19 meters per second 15 to 40 feet per second this filtrate enters the tank through the filtrate swirler inlet 56 the filtrate swirler inlet 56 has a vertical center line that is between the bottom of the tank 50 and the surface of the slurry it usually would be located from the bottom of the tank a distance equal to one half of the distance between the bottom of the tank and the nominal height of the pulp slurry in a tank in which the nominal height of the slurry is 0 8 34 d 34 the vertical center line of the filtrate inlet 56 would be 0 4 34 d 34 it is preferred that the filtrate swirl inlet be located from the bottom of the tank a distance equal to 10 25 of the height of the tank the horizontal center line of the filtrate swirler inlet 56 is between a tangent to the tank.