“Safety Valve”: A Metal-Based, Self-Securing Switchable Microvalve for Medical Applications

Abstract:
Drug dosing systems require fail-safety in order to prevent patients’ harm. We present a passive microvalve without external control or energy consumption designed to regulate the flow path of a microfluidic drug dosing system. The metal-based self-securing switchable microvalve for medical applications is experimentally characterized for water flow rates and fluidic resistance. Additionally, we characterize a microfluidic delivery system comprising a piezoelectric mi-cropump in combination with the microvalve for delivered water flow rate and find a maximum of (13.8 ± 0.7) ml/min, as well as fail-safe state leakage rates with an average of (31.8 ± 5) mul/min. Among the manufactured and tested mi-crovalves, several valves exhibit pressure-induced flow obstruction. Dedicated FEM simulations of the flow inside the microvalve show flow field-induced phenomena as reasons for this malfunctioning, which lays the basis for a deeper understanding of the functionality of the component.