Bio-processing applications frequently require centrifugation to separate liquids containing biological materials, mixtures, or solutions such as, by way of example and not limitation, those produced by fermentation, in cell-growth chambers, reagent mixtures or other biological processing mechanisms. Centrifuge rotors with the capacity to hold large sample containers or bottles have been developed that can withstand rotational forces of above 15,000 times gravity, relative centrifugal force (RCF). Examples of large capacity rotors are FIBERLite™ rotors F6-6x 1000y and F6 4x100y (FIBERLite™ Piramoon Technologies Inc., Santa Clara, Calif.). Several bottles are commercially available for use with large capacity rotors but many, such as the Hitachi centrifuge bottle, have a maximum capacity of only about 920 ml, despite being referred to as a one-liter bottle.
One problem with developing true one-liter or larger bottles for these types of rotors has been that the fixed well diameters of the rotors limits the diameters of the bottles, and the fixed depths of the wells limits the heights of the bottles that can be received in the wells. Bottle diameters are typically designed to fit closely within the well of a rotor, although usually not tight. The heights of centrifuge bottles are generally such that the closure ends of the bottles touch, or nearly touch, at the focal point of the rotor.
To increase the heights of the bottles, one might reduce the amount of space allowance required for the closures to fit within the rotor. This reduction might be accomplished by reducing the overall thickness of the walls of the closure. However, thin closures are more susceptible to fail under the extreme g-forces encountered during centrifugation. Other conventional bottles have been modified to have larger capacity by, for example, sacrificing features that aid removal of the bottle from the rotor. To remove these types of bottles from the rotor, a separate tool may be required. Thus, loss of the tool may impede utilization of these modified bottles. A need therefore exists for large volume centrifuge bottles with closures that maximize the capacity thereof while providing reliable closure of the bottles.