Abstract: Disclosed is an improved centrifuge apparatus for separating substances of varying density and a method of controlling the speed of a rotor of the centrifuge apparatus. A vent-view port is mounted for in-out adjustment within an access aperture formed in a lid of the centrifuge apparatus so as to provide for selective opening of vent holes formed in the vent-view port. In addition to venting, the vent-view port has a sensor mount with a transparent window for receiving a tachometer probe for rotor speed monitoring. Additionally, a desired centrifugal force and a desired accumulative centrifugal force can be entered by a human operator. A control unit adjusts the rotor speed and operational cycle time to meet the inputted desired force values while displaying the actual accumulative centrifugal force at the end of the operation cycle.

Abstract: The containment of biohazardous substances, which may exist in the streams of sample material that are being separated in air into droplets in a testing chamber of equipment, such as cell sorters and cytofluorometers, is attained by subjecting the testing chamber to negative air pressure, so that inward air flow at the open face of the chamber is sufficient to inhibit biohazardous substances from exiting out from the face of the chamber. A region of air stagnation is created around the sample streams so that the streams are not deflected from their paths, such paths being pertinent to their testing of the biological sample material. The air stagnation region is formed by interposing an air diverter between the sample streams and the air flow exhaust port at the rear of the testing chamber.