| 摘要 |
An apparatus for determining the phase of a fluid (e.g. carbon dioxide) by measuring its refractive index comprises a conduit 12 which defines a flow path, a circuit with an optical radiation source 16 (e.g. an infrared diode) and a photo detector 18 (e.g. a photodiode), and a housing 20 with a pair of apertures 22, 24 adjacent to the optical emitter and detector and configured to fix the relative position of the conduit and the circuit and to guide the light to pass through the flow path of the liquid. The apparatus can include a controller that affects the physical state of the fluid and bias it to the liquid state when a gas or mixed gas-liquid state is detected. The apparatus may be part of a supercritical fluid chromatography separation system, integrated with fittings 36 on each end of the conduit so that is does not disrupt the fluid flow. A method for detecting the phase of a fluid in a separation system using the apparatus is also disclosed. |
