Open-source multi-purpose sensor for measurements in continuous capillary flow

Abstract

Limited applicability and scarce availability of analytical equipment for micro- and millifluidic applications, which are of high interest in research and development, complicate process development, control, and monitoring. The low-cost sensor presented in this work is a modular, fast, non-invasive, multi-purpose, and easy to apply solution for detecting phase changes and concentrations of optically absorbing substances in single and multi-phase capillary flow. It aims at generating deeper insight into existing processes in fields of (bio-)chemical and reaction engineering. The scope of this work includes the application of the sensor to residence time measurements in a heat exchanger, a tubular reactor for concentration measurements, a tubular crystallizer for suspension detection, and a pipetting robot for flow automation purposes. In all presented applications either the level of automation has been increased or more information on the investigated system has been gained. Further applications are explained to be realized in the near future. Article highlights • An affordable multipurpose sensor for phase differentiation, concentration measurements, and process automation has been developed and characterized • The sensor is easily modified and can be applied to various tubular reaction/process units for analytical and automation purposes • Simple integration into existing process control systems is possible Graphical abstract

Development of a Low-Cost Multi-Wavelength Inline Detector for Slug Detection in Continuous Flow

“…In conclusion, in this publication we report a significant enhancement on the previously published low-cost inline detector from Höving et al [6] by changing the detector to one that can measure multiple wavelengths simultaneously and changing the irradiation source to a white LED. As a result, we were able to obtain real-time inline spectral data from a flow reactor operating in a slug flow regime, indicating when slugs pass the detector even when undetectable to the human eye.…”

“…The later publication from Höving et al [6] was the basis of a much simpler design. In the Höving et al publication, the flow reactor tube was sandwiched between a coloured LED (Light Emitting Diode) and LDR (Light Dependent Resistor) and held together in a specially designed 3D printed housing.…”

“…Using the "Version B" flow cell design from the Höving et al publication [6] as a starting point, an initial prototype detector housing was designed in Tinkercad. [8] Although only 2.6 x 1.8 cm in size, the Adafruit AS7341 sensor board is significantly larger than an LDR as used in the previous publication.…”

From Coiled Flow Inverter to Stirred Tank Reactor – Bioprocess Development and Ontology Design

“…With this information, the reaction rate can be calculated as formed product per time. The sensor converts incident light into an electrical signal [23,24] as shown in Fig. 6.…”

P03 - Electrical Conductivity Sensor with Open-Source Hardware for the Microfluidic Determination of Reaction Parameters

“…Due to the miniaturization of equipment in microprocess engineering and flow chemistry, the miniaturization of sensors and analytical devices for automated inline process control is also necessary [1]. For example, electrolytic conductivity is suitable as a measured variable for the quantitative determination of ion concentration and reaction progress in microfluidics [2].…”