Product Code: ICA10_M405

Laser Welding of a Microscale-VLE Measurement Device and Its Practical Application
Authors:
Marika HirvimäKi, Lappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology; Lappeenranta Finland
Heidi Piili, Lappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology; Lappeenranta Finland
Arttu Jussila, LUT Laser/Lappeenranta UnivLappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology; Lappeenranta Finland
Tuomas Purtonen, Lappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology; Lappeenranta Finland
Matti Manninen, Lappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology; Lappeenranta Finland
Petri Uusi-Kyyny, Aalto University, Department of Biotechnology and Chemical Technology, Faculty of Chemistry and Materials; Espoo Finland
Aarne Sundberg, Aalto University, Department of Biotechnology and Chemical Technology, Faculty of Chemistry and Materials; Espoo Finland
Ville Alopaeus, Aalto University, Department of Biotechnology and Chemical Technology, Faculty of Chemistry and Materials; Espoo Finland
Antti Salminen, Lappeenranta University of Technology, Laser Processing Technology Research Group, Faculty of Technology / Machine Technology Centre Turku Ltd.; Lappeenranta / Turku Finland
Presented at ICALEO 2010

Laser micro processing is one of the fastest spreading and developing areas of all laser processes in the world. In this wide field of applications the laser is still a novel tool for micro processing which enables the realization of new ideas, solutions and applications for designing these microscale process devices for chemical industry.

Distillation is the predominantly used separation method in chemical engineering. The design of distillation columns requires knowledge of the thermodynamics of the system which is mostly gained from the vapor-liquid equilibrium (VLE) measurements. The measurements consist of temperature, pressure and phase composition determinations. Typically volumes of chemicals used in VLE-measurements are from 0.05 dm3 up to 1 dm3. For expensive and toxic substances the amount of material used in the measurements should be preferably as small as possible.

In this study an exceptionally small VLE-measurement device was designed and manufactured by utilization of laser processing. Volume of the equipment was approximately 0.002 dm3, which was made possible by using the pressure transducer cavity as the equilibrium cell. The chemical consumption was therefore reduced by a factor of up to 500. The valves were also welded to the structure. The welding would not have been possible with conventional methods due to overheating of the transducer electronics. The control of the heat input resulting low distortion and narrow heat affected zone made it possible to manufacture such a demanding structure. Also, distortions caused by the welding on the device were minimal ensuring accurate enough function of the system. The cell was initially tested by measuring pure component vapor pressures of alcohols.