Abstract: An identification means placed adjacent the test tube cavities in a centrifuge rotor. The identification means utilizes recessed or indented indicia which are positioned on a circular ring raised above the generally flat top surface of the rotor. The identification indicia are used for identifying or labeling each of the test tube cavities in the rotor. The raised nature of the ring eliminates the possible establishment of weak points or areas in the top surface of the rotor during centrifugation.

Abstract: A centrifuge test tube cap assembly for sealing a thin walled test tube used primarily with a vertical tube rotor. The cap assembly is designed for convenient and easy removal from the test tube through the use of internal means which activates the direct sealing and unsealing of the cap with respect to the test tube. The mechanism of the tube cap provides for convenient removal of the cap assembly from the test tube which is necessary in order to insert or remove the liquid to be subjected to centrifugation.

Abstract: A test tube cap assembly for centrifuge rotor tubes. A stem member slidably moves within a crown member to exert a direct force on a bushing to securely grip the upper portion of a test tube located within the crown member. The stem member and the bushing have generally mating frustoconical surfaces to provide a wedging action on the upper portion of the test tube. The wedging action serves to not only seal the tube, but also support the upper end of the test tube by restraining the centipetal side of the tube from pulling away from the cap. The operation of the cap assembly is enhanced by the hydraulic forces exerted from within the test tube by the contained liquid.