Optical flow cell for an optical measuring device
The present invention relates to an optical flow cell ( 1 ) for a measuring device, having an input light guide with a light exit surface, an output light guide with a light entrance surface, said input light guide and output light guide being integrated with a holder ( 30 ) to form optical flow cell ( 1 ), and wherein the holder ( 30 ) extends along a first axis (A) and has a through hole ( 31 ) for receiving a flow of a sample fluid, said through hole ( 31 ) being transversal to said first axis (A), and the input light guide and output light guide further are arranged in said holder ( 30 ) so that the light exit surface and the light entrance surface extend into said through hole ( 31 ) and are arranged to be in optical alignment with each other and at a first distance from each other. The invention also relates to a measuring device having at least one optical flow cell ( 1 ).
1. A measuring device, comprising:
a unitary body;
a flow channel defined by the unitary body;
a flow cell mounting site defined by the unitary body in the flow channel; and
an optical flow cell arranged to be received within the flow cell mounting site,
wherein the optical flow cell comprises:
i. an input light guide including a light exit surface,
ii. an output light guide including a light entrance surface,
iii. a holder supporting said input light guide and said output light guide,
wherein the holder extends along a first axis and has a through hole for receiving a flow of a sample fluid, said through hole being substantially transverse to said first axis,
wherein the holder defines first and second mounting holes extending to the through hole,
wherein the input light guide and output light guide further are arranged in said holder so that the light exit surface and the light entrance surface extend and protrude into said through hole and are arranged to be in optical alignment with each other and at a first distance from each other,
wherein the optical flow cell is removably and reinsertably receivable at the flow cell mounting site such that the through hole coincides with the flow channel,
wherein the flow cell mounting site is a circular holder-receiving hole along said first axis and defined by the unitary body,
wherein the circular holder-receiving hole along said first axis defines a circular opening in the unitary body, the circular opening extending transverse to the first axis for receiving the holder in the hole,
wherein the input light guide is mounted in a first light guide holder and the output light guide is mounted in a second light guide holder,
wherein the first light guide holder and second light guide holder are mounted in the holder in the respective first and second mounting holes, and
wherein the input light guide is arranged to protrude from the first light guide holder into the through hole, and wherein the output light guide is arranged to protrude from the second light guide holder into the through hole.
2. The measuring device according to claim 1 , wherein the holder comprises a material with a thermal expansion of less than 20×10 −6 m/mK.
3. The measuring device according to claim 2 , wherein the material comprises titanium or a ceramic.
4. The measuring device according to claim 1 , wherein the first distance is 0.2 mm or less, preferably 0.1 mm.
5. The measuring device according to claim 1 , wherein each light guide is held in place in its respective holder by means of an adhesive.
6. The measuring device according to claim 5 , wherein the mounting holes are threaded and the first light guide holder and second light guide holder comprise corresponding threads, whereby the distance is variable.
7. The measuring device according to claim 1 , wherein the hole defines a cylindrical volume along the first axis.
8. The measuring device according to claim 1 , wherein the holder comprises a unitary holder body.