flow rate of blood through filter elements 80 81 and 82 first chamber 44 will fill in a very small fraction of the time that it takes to wet filter elements 80 81 and 82 the pressure head at the bottom of first chamber 44 will be larger than the pressure head at the top of first chamber 44 because of the height difference between the top and bottom of first chamber 44 therefore liquid will start to come through filter element 82 into second chamber 447 from the bottom up as second chamber 447 fills from the bottom up with blood the remaining air in second chamber 447 will be forced from second chamber 447 through vertical channel 487 through front outlet port 6 through link port 11 through outlet port 10 through outlet tubing 53 into receiving blood bag 55 because the total volume of second chamber 447 is small to minimize holdup second chamber 447 may fill with blood from the bottom up before the upper part of filter element 82 has wet with blood once second chamber 447 is filled with blood the blood from the top of second chamber 447 will flow through vertical channel 487 through front outlet port 6 through link port 11 through outlet port 10 through outlet tubing 53 into receiving blood bag 55 once blood starts to flow through outlet tubing 53 the pressure head.