Flow through cell for optical spectroscopy

• US 20070052956A1
• Filed: 11/11/2003
• Published: 03/08/2007
• Est. Priority Date: 11/12/2002
• Status: Active Grant

• Current Assignee: Agilent Technologies Australia (M) Pty., Ltd. (Agilent Technologies, Inc.)
• Original Assignee: Varian Australia Pty., Ltd. (Agilent Technologies, Inc.)
• Inventors: Blair, Robert
• Granted Patent: US 7,379,178 B2
• Time in Patent Office: Days
• US Class Current: 356/246
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 30/74 Optical detectors measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J

Abstract

A flow through cell (100) for use in a spectrophotometer for analysis of dissolved chemical substances in a flowing liquid stream is made up of at least an intermediate body member (114) located between two other body members (112, 116). The body members are of regular shape, for example rectangular parallelepiped and are clamped together, for example by machine screws (134, 136). Thus the cell is relatively easily manufacturable. The clamped together body members define a flow through passage which includes a hole (118) through the intermediate body member (114) and a liquid inlet region at one end of the hole and a liquid outlet region at the other end of the hole, which regions may be provided by galleries (150, 152) in scaling gaskets (130, 132) between the body members. The two other body members each include an optically transparent window (142, 146) at an end of the hole (118) thereby providing an optical pathway (A, A′) through part of the flow through passage. The liquid inlet and outlet regions at the ends of hole (118) are such that the liquid flow on entering and leaving the optical pathway (A, A′) occurs adjacent the optical windows transversely of the flow along the optical pathway. Thus the liquid flow sweeps across the optical windows (142, 146) and flushes the hole (118) of the optical pathway by successive increments of the liquid with minimal mixing.

Claims

1. A flow through cell for use in a spectrophotometer for analysis of dissolved chemical substances in a flowing liquid stream, comprising

a plurality of body members including an intermediate body member located between two other body members, the plurality of body members being clamped together and providing a small volume flow through passage,

wherein a part of the flow through passage comprises a hole through the intermediate body member together with a liquid inlet region at one end of the hole and a liquid outlet region at the other end of the hole,

wherein the two other body members are each associated with an optically transparent window aligned with a respective end of the hole through the intermediate body member thereby providing an optical pathway through said part of the flow through passage,

wherein the liquid inlet and liquid outlet regions are provided by respectively, a portion of the flow through passage through which liquid flows into or out of a said region substantially immediately adjacent the optically transparent window transversely of the direction of the hole.

2. A flow through cell as claimed in claim 1 including a resilient sealing gasket located between facing surfaces of the intermediate body member and, respectively, each of the two other body members, wherein each gasket includes a gallery which provides said portion of the flow through passage.

3. A flow through cell as claimed in claim 2 wherein the gallery in the gasket on an inlet side of the flow through passage is in the form generally of a spiral.

4. A flow through cell as claimed in claim 1 wherein each of said other two body members includes a gallery which provides said portion of the flow through passage.

5. A flow through cell as claimed in claim 4 wherein at least the intermediate body member, or at least each of the other two body members is resilient to provide for sealing contact between adjacent body members.

6. A flow through cell as claimed in any one of claims 1 to 5 wherein the optically transparent window associated with each of the other two body members is a window assembly sealingly mounted within a hole in a body member.

7. A flow through cell as claimed in any one of claims 1 to 5 wherein the optically transparent window associated with each of the other two body members is provided by respectively a transparent plate sandwiched between the intermediate body member and one of the other body members.

8. A flow through cell as claimed in any one of claims 1 to 7 wherein the body members are of rectangular parallelepiped shape.

9. A flow through cell as claimed in any one of claims 1 to 8 wherein the body members are clamped together by screw fasteners.

10. A flow through cell as claimed in claim 9 wherein the screw fasteners pass through holes in one of the other body members and the intermediate body member and engage in threaded holes in the other body member.

11. A flow through cell as claimed in any one of claims 1 to 10 wherein the flow through passage includes another part located between further optically transparent windows associated with the two other body members thereby defining a second optical pathway.

12. A flow through cell as claimed in claim 11 wherein the second optical pathway is shorter than the first defined optical pathway.

13. A flow through cell as claimed in any one of claims 1 to 10 wherein the body members also provide an optical pathway separated from the flow through passage for a reference beam to be passed through the cell.