Phase detection in multi-phase fluids

Patent metadata

Field	Value
Publication number	US-9441996-B2
Application number	US-201414511636-A
Country	US
Kind code	B2
Filing date	Oct 10, 2014
Priority date	Oct 11, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

The present disclosure relates to phase detection in multi-phase fluids where two fluid phases can be present in the fluid. Phase detection apparatus and methods are disclosed for determining the phase(s) (e.g., supercritical, liquid, and/or gas) of a fluid in a multi-phase fluid system, such as carbon dioxide based separation and chromatography system.

First claim

What is claimed is:

1. An apparatus for detecting the phase of a fluid in a multi-phase fluid system comprising:
a conduit defining a fluid flow path;
a circuit comprising an optical radiation source and a photo detector;
a housing fixing the relative position of the conduit and the circuit, the housing comprising a first aperture adjacent to the optical radiation source and a second aperture adjacent to the photo detector, wherein the first aperture is sized and shaped to filter optical radiation from the optical radiation source to the fluid flow path, wherein the second aperture is sized and shaped to filter the optical radiation from the fluid flow path to the photo detector, and wherein the circuit measures the refractive index of a fluid in the fluid flow path, thereby determining the phase of the fluid; and
a controller in communication with the fluid phase detector, the controller being capable of modulating at least one variable affecting the physical state of the fluid flow based upon the fluid phase detected by the fluid phase detector.

2. The apparatus of claim 1 , wherein the controller modulates at least one variable affecting the physical state of the fluid flow, to bias the fluid flow to the liquid state, when the fluid phase detector detects a gas or mixed gas-liquid phase in the fluid flow.

3. The apparatus of claim 1 , wherein the housing flexibly fixing the relative position of the conduit and the circuit, thereby preventing damage to the circuit while maintaining the relative position of the conduit and the circuit.

4. The apparatus of claim 1 , wherein the circuit delivers a signal change when the phase of the fluid changes between a gas, a liquid, or a mixed gas-liquid phase.

5. The apparatus of claim 1 , wherein the housing prevents rotation of the conduit, thereby preventing damage to the conduit.

6. The apparatus of claim 1 , wherein the conduit is substantially transparent to the optical radiation.

7. The apparatus of claim 1 , wherein the fluid comprises CO 2 .

8. The apparatus of claim 1 , wherein the optical radiation source comprises an IR diode and the photo detector comprises a photodiode.

9. The apparatus of claim 1 , wherein the first aperture is configured to prevent optical radiation that is not incident on the center of the fluid flow path from reaching the conduit.

10. The apparatus of claim 1 , wherein the second aperture is configured to prevent optical radiation that does not pass through the center of the fluid flow path from reaching the photo detector.

11. A separation system comprising:
a fluid flow source, a separation device in fluid communication with the fluid flow source, and a phase detection apparatus for detecting the phase of the fluid in at least one region of the separation system, wherein the phase detection apparatus comprises:
a conduit defining a fluid flow path,
a circuit comprising an optical radiation source and a photo detector, and
a housing fixing the relative position of the conduit and the circuit, the housing comprising a first aperture adjacent to the optical radiation source and a second aperture adjacent to the photo detector, wherein the first aperture is sized and shaped to filter optical radiation from the optical radiation source to the fluid flow path, wherein the second aperture is sized and shaped to filter the optical radiation from the fluid flow path to the photo detector, and wherein the circuit measures the refractive index of a fluid in the fluid flow path, thereby determining the phase of the fluid.

12. The system of claim 11 , wherein the phase detection apparatus is disposed upstream of the separation device.

13. The system of claim 11 , wherein the phase detection apparatus is disposed downstream of the separation device.

14. The system of claim 11 , wherein the separation device comprises supercritical fluid chromatography or supercritical phase extraction.

15. The system of claim 11 , wherein the phase detector apparatus is integrated between the fluid flow source and the separation device by fittings on each end of the conduit to minimize disruption of the fluid flow.

16. A method for detecting the phase of a fluid in a separation system, comprising:
flowing a fluid through a conduit defining a fluid flow path, wherein the conduit is fixed in a position relative to a circuit comprising an optical radiation source and a photo detector by a housing defining a first aperture and a second aperture;
directing optical radiation from the optical radiation source through the first aperture onto the fluid flow path;
directing the optical radiation from the fluid flow path through the second aperture onto the photo detector;
measuring the refractive index of a fluid in the fluid flow path, thereby determining the phase of the fluid; and
modulating at least one variable affecting the physical state of the fluid flow, to bias the fluid flow to the liquid state, when the fluid phase detector detects a gas or mixed gas-liquid phase in the fluid flow.

17. The method of claim 16 , wherein the fluid comprises CO 2 .

18. The method of claim 16 , further comprising performing a supercritical phase chromatography or separation on a sample.

Assignees

• Waters Technologies Corp

Inventors

• Hill Ryan
• Shreve Joshua A
• Dumas Robert
• Cormier Sylvain
• Denecke Edwin
• Plant Kenneth R
• Joudrey Kurt D

Classifications

• G01N30/74

  Optical detectors {(measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J)} · CPC title

• G01F1/74 Primary

  Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid · CPC title

• G01N21/41 Primary

  Refractivity; Phase-affecting properties, e.g. optical path length (G01N21/21 takes precedence) · CPC title

• G01N21/4133 Primary

  Refractometers, e.g. differential · CPC title

• G01N2021/4153

  Measuring the deflection of light in refractometers · CPC title