Approach to short measurement path-length flow cells
AssigneeWaters Investments Limited
InventorsMichael J. Leveille, Joseph M. DeLuca
Life of this patent
Estimating the term…
Abstract
A photometric measurement flow cell having measurement path-lengths that can be adjusted down to less than 0.1 mm. The measurement path-length is controlled by both a common flow cell body and the dimensional parameters of a stepped sealing optical element. The stepped optical element includes a stem portion that can be made in various lengths to create a family flow cell measurement path-lengths. The replacement of one stepped element with another having a different stem length within the flow cell creates a reliable method to adjust the measured path-length of the flow cell.
Claims15
A photometric measurement flow cell comprising:
- a cell body having a first end and a second end;
- a fluidic channel allowing the passage of fluids, contained within said cell body;
- an element holder contained within said first end of said cell body wherein said element holder has a substantially planar sealing surface for receiving an element said substantially planar sealing surface of said element to be fixed in a non-adjustable manner;
- a non-adjustable stepped element having a stem and a base, said stem having an end surface protruding into said fluidic channel creating a fixed, non-adjustable fluidic measurement pathlength and said base having a substantially planar sealing surface, said substantially planar sealing surface of said base fixedly abutting said substantially planar sealing surface of said non-adjustable stepped element to be sealably secured in a non-adjustable manner in said element holder;
- said non-adjustable stepped element contained within said element holder and sealed within said cell body by a sealing gasket positioned between said substantially planar sealing surface of said non-adjustable stepped element and said substantially planar sealing surface of said cell body whereupon pressure exerted against said substantially planar sealing surface of said non-adjustable stepped element and said substantially planar sealing surface of said cell body cause said non-adjustable stepped element to be fixed and reliably sealed in a non-adjustable manner within said cell body with said stem protruding into said fluidic channel creating said fixed, non-adjustable fluidic measurement pathlength.
A method of creating an accurate fixed measurement path-length within a flow cell, which comprises:
- providing a cell body having a fluidic channel allowing the passage of fluids within said cell body;
- configuring an element holder contained within said cell body wherein said element holder has a substantially planar sealing surface for receiving an element said substantially planar sealing surface of said element to be fixed in a non-adjustable manner;
- selecting a non-adjustable stepped element having a stem and a base, said stem having an end surface protruding into said fluidic channel creating a fixed, non-adjustable fluidic measurement pathlength, said base having a substantially planar sealing surface, said substantially planar sealing surface of said base fixedly abutting said substantial planar sealing surface of said non-adjustable stepped element to be sealably secured in a non-adjustable manner in said element holder, a length of said stem being selected to increase or decrease said fixed, non adjustable fluidic measurement pathlength;
- and
- fastening said non-adjustable stepped element within said element holder with a sealing gasket positioned between said substantially planar sealing surface of said non-adjustable stepped element and said substantially planar sealing surface of said cell body whereupon pressure exerted against said substantially planar sealing surface of said non-adjustable stepped element and said substantially planar sealing surface of said cell body cause said non-adjustable stepped element to be fixed and reliably sealed in a non-adjustable manner within said cell body with said stem protruding into said fluidic channel creating said fixed, non-adjustable fluidic measurement pathlength.
Dependencies are inferred from the claim text.