Laminar-Flow Refractometer With In-Tube Measurement Window
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Solution Overview
Problem
Conventional refractometers face challenges in process monitoring due to complex flow arrangements, which disturb boundary layers and induce chemical reactions, leading to colloidal formation and slow temperature measurement responses, especially with nucleation-sensitive materials, and require expensive and fragile sapphire disks for sealing.
Innovation Solution
A refractometer design with a measurement window inside the process liquid flow tube, maintaining laminar flow to minimize stress on the fluid, using plastic materials for the flow channel and optics, and attaching the prism solidly to the chassis to reduce thermal expansion issues, with a thinner thermal sensor wall for improved temperature measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the measurement window is placed outside the process tube with complex flow arrangements, then the sealing structure can be simpler, but the flow disturbances occur causing boundary layer disruption, vorticity, and potential colloidal formation
Solution Approach 1:
The measurement window is nested inside the process tube, with the optical path embedded within the flow channel structure. This integration eliminates the need for external sealing arrangements while ensuring laminar flow conditions are maintained throughout the measurement zone.
Solution Approach 2:
A thin-walled flow channel structure acts as an intermediary between the process fluid and the measurement window, allowing optical measurements while maintaining laminar flow. The thin wall provides thermal contact for rapid temperature response without significantly disrupting the flow profile.
2Reliability
If a floating structure with Teflon sealing between prism and sapphire disk is used, then the sealing can be made tight, but large forces are required making the structure complicated and the sapphire disk fragile and expensive
Solution Approach 1:
The expensive and fragile sapphire disk is removed from the design. Instead, a simple Teflon sealing is used directly between the prism and the flow channel wall, eliminating the need for complex floating structures and large clamping forces while maintaining adequate sealing reliability.
Solution Approach 2:
The design accepts that the Teflon sealing may wear over time and can be replaced, rather than investing in expensive sapphire disks and complex mechanical structures. This approach reduces initial cost and structural complexity while maintaining functional reliability.
3Strength
If the thermometer is in contact with the sapphire disk through a thick wall, then the structure can be more robust, but the thermal contact is insufficient causing slow responding time to temperature changes
Solution Approach 1:
The flow channel wall thickness is varied locally: thin-walled at the measurement window area to ensure rapid thermal contact between the process fluid and thermometer, and thicker in other areas to provide structural robustness. This localized optimization resolves the contradiction between strength and thermal response speed.
4Ease of operation
If the flow arrangement is complex with re-directions in the tube, then the measurement window can be outside the process tube, but the boundary layers are disturbed and chemical reactions may be induced leading to colloidal material formation
Solution Approach 1:
Instead of placing the measurement window outside the process tube with complex flow re-directions, the measurement window is inverted to be positioned inside the process tube. This allows the flow to pass directly over the measurement surface in a simple, laminar configuration, eliminating boundary layer disturbances and preventing colloidal formation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances measurement accuracy and reduces material costs by using plastics and minimizing flow disturbances, allowing for faster temperature equilibration and reducing the risk of breakage, while maintaining precise optical measurements.
Implementation Method 1
A refractometer structure to be used in a refractometer comprises an optical module (4) arranged floatingly inside a housing structure, which module comprises an optical window (2) to be positioned in a process fluid (3), and means for forming an illuminating beam and for directing it into the process fluid (3) through the optical window (2) and for directing back the part of the illuminating beam that is reflected from the process fluid
Implementation Method 2
means for forming an illuminating beam and for directing it into the process fluid (3) through the optical window (2) and for directing back the part of the illuminating beam that is reflected from the process fluid
Implementation Method 3
The embodied structure has laminar flow profile, so avoiding causing stress to the process liquid to change its phases of the constituents and/or composition, by the changes in the flow profile. According to an embodiment of the invention the flow channel has measures to provide a flow essentially at the laminar flow regime.
Implementation Method 4
the wall between the process liquid and thermometer being thick, which consequently can cause slow responding time to the temperature changes, as the thermometer (8) is in contact with the sapphire disk
Data Source
AI summary
The present disclosure concerns a refractometer including a measurement window inside a flow channel of the flow vessel of the refractometer, the flow channel being designed to allow process fluid flow at least at the measurement window in laminar flow regime of the dedicated process liquid.