Optical flow cell assembly incorporating a replaceable transparent flow cell
A new liquid flow cell assembly for light scattering measurements is disclosed which utilized a floating manifold system. The assembly operates with minimal stacked tolerances by aligning the cell to the windows within a manifold and independently aligning the cell to the read head directly. This configuration enables the ability to replace the flow cell or the flow cell/manifold assembly within a light scattering instrument without the need to realign the flow through elements with the light scattering illumination source while still maintaining reproducible, quality data. Some embodiments employ wide bore cells which enable the measurement of process analytic technology (PAT) including online monitoring of reactions.
1. An optical flow cell assembly comprising:
a transparent flow cell;
a manifold configured to contain the flow cell;
a read head comprising
a beam generating light source aligned to emit a beam of light along an axis of the read head; and
wherein the read head is configured to be directly registered to the flow cell, thereby aligning the flow cell to the read head,
wherein the read head further comprises
a plurality of read head vertical alignment posts configured to contact at least one planar alignment surface of the flow cell to define a vertical read head-to-flow cell alignment plane perpendicular to the axis,
a read head top plate configured to drive the at least one planar alignment surface against the read head vertical alignment posts,
at least one read head horizontal alignment first surface boss configured to contact a first surface of an alignment step of the flow cell to define a horizontal read head-to-flow cell alignment plane perpendicular to the vertical read head-to-flow cell alignment plane,
at least one read head horizontal alignment second surface boss configured to contact a second surface of the alignment step of the flow cell, wherein the second surface is perpendicular to the first surface, and
a ball plunger configured to drive the alignment step into contact with the at least one read head horizontal alignment first surface boss and the at least one read head horizontal alignment second surface boss,
wherein the plurality of read head vertical alignment posts is distinct from the read head top plate, is distinct from the at least one read head horizontal alignment first surface boss, is distinct from the at least one read head horizontal alignment second surface boss, and is distinct from the ball plunger,
wherein the read head top plate is distinct from the at least one read head horizontal alignment first surface boss, is distinct from the at least one read head horizontal alignment second surface boss, and is distinct from the ball plunger, and
wherein the at least one read head horizontal alignment first surface boss is distinct from the ball plunger, and
wherein the at least one read head horizontal alignment second surface boss is distinct from the ball plunger.
2. The optical flow cell assembly of claim 1 wherein the manifold comprises:
a liquid sample inlet port;
a liquid sample outlet port;
an inlet path coupled to an outlet of the inlet port;
an outlet path coupled to the inlet of the outlet port; and
wherein the inlet path and the outlet path are configured to direct a flow of a liquid sample from the inlet port through the flow cell and out of the outlet port.
3. The optical flow cell assembly of claim 2 wherein the manifold further comprises vertical holes configured to allow access to the at least one planar alignment surface.
4. The optical flow cell assembly of claim 1 further comprising a compressible element configured to generate a vertical force between the flow cell and the read head to drive the at least one planar alignment surface against the plurality of read head vertical alignment posts.
5. The optical flow cell assembly of claim 4 wherein the compressible element comprises a wave washer configured to be placed between the flow cell and the read head top plate configured to be rigidly connected to the read head.
6. The optical flow cell assembly of claim 1 further comprising a spring element configured to generate a horizontal force between the manifold and the flow cell to drive the flow cell against the plurality of read head vertical alignment posts.
7. The optical flow cell assembly of claim 6 wherein the spring element comprises a leaf spring configured to be rigidly connected to the manifold and configured to be in contact with the flow cell.
8. The optical flow cell assembly of claim 7 wherein the leaf spring defines an opening along a horizontal axis of the leaf spring,
wherein the opening is configured to permit access to the flow cell.
9. A method comprising:
containing an optical flow cell within a manifold such that the optical flow cell is aligned to the manifold; and
registering directly the flow cell to a read head with read head-to-flow cell alignment elements, thereby aligning the flow cell to the read head,
wherein the read head comprises a beam generating light source aligned to emit a beam of light along an axis of the read head,
wherein the read head further comprises
a plurality of read head vertical alignment posts configured to contact at least one planar alignment surface of the flow cell to define a vertical read head-to-flow cell alignment plane perpendicular to the axis,
a read head top plate configured to drive the at least one planar alignment surface against the read head vertical alignment posts,
at least one read head horizontal alignment first surface boss configured to contact a first surface of an alignment step of the flow cell to define a horizontal read head-to-flow cell alignment plane perpendicular to the vertical read head-to-flow cell alignment plane,
at least one read head horizontal alignment second surface boss configured to contact a second surface of the alignment step of the flow cell, wherein the second surface is perpendicular to the first surface, and
a ball plunger configured to drive the alignment step into contact with the at least one read head horizontal alignment first surface boss and the at least one read head horizontal alignment second surface boss,
wherein the plurality of read head vertical alignment posts is distinct from the read head top plate, is distinct from the at least one read head horizontal alignment first surface boss, is distinct from the at least one read head horizontal alignment second surface boss, and is distinct from the ball plunger,
wherein the read head top plate is distinct from the at least one read head horizontal alignment first surface boss, is distinct from the at least one read head horizontal alignment second surface boss, and is distinct from the ball plunger, and
wherein the at least one read head horizontal alignment first surface boss is distinct from the ball plunger, and
wherein the at least one read head horizontal alignment second surface boss is distinct from the ball plunger.