Abstract: An improved collecting chamber for use with centrifuges for separating particles of different density suspended in a fluid, especially for separating the various fractions in human blood.The chamber is provided with a partition or dam and a plurality of outlet tubes. These tubes are positioned so that they can draw off the various separated components of the blood. The divider prevents the mixing of the fractions after they enter the chamber. By properly regulating the output flow of the lines containing the packed red cells, and the plasma and red cells, the content of the buffy collect line is defined and can be maintained constant over relatively long periods of time without operator intervention.

Abstract: Positioning apparatus is disclosed which positions an object with respect to two predetermined lateral positions. In addition, the object is indexable by the apparatus in a step-by-step manner in an incidental direction with respect to each of the two lateral positions. It includes an endless sprocket chain entrained about two sprocket wheels. The chain carries a first member which is pivotably connected to the chain. A second member is affixed to the first member and is adapted to support the object. The second member is slidably mounted to a movable third member which in turn is guided by guiding means such as rails that guides the third member means in a predetermined aligned relationship with the reaches of the chain. In addition, chain guide means guide the chain along the first and second reaches. Driver means are coupled to one of the sprocket wheels to drive the endless chain.