Large-aperture variable-volume view cell for the determination of phase-equilibria in high pressure systems and supercritical fluids

A high-pressure, variable-volume view cell incorporating a custom engineered, optically transparent sapphire piston is described. The view cell has an unbroken field of vision that enables the entire sample volume to be observed at all times. When lit from the rear of the cell, a near perfect view of any physical transition or change in state is available to the experimenter. The system has been shown to be particularly suitable for the determination of phase equilibria and cloud point measurements in supercritical fluid systems and has been rated for experiments up to 400 bar, 200 °C.