Fluid Flow Applications of Solid Freeform Fabrication: Valves in Single Build

Abstract

There is a constant need for custom designed and manufactured valves that are capable of precision flow control. The applications vary, such as medically related fluid situations; a check valve for a feeding tube for example. The fluids under consideration are diverse: air, water and blood, to name a few. Solid freeform fabrication (SFF) has immense potential for creating intricate valve structures without the limitations and numerous machining processes involved in conventional methods of valve assembly. This research demonstrated the usefulness of SFF in novel fluid mechanics applications. The primary goal was the design and fabrication of a functional valve in one build using a stereolithography apparatus. A valve with linear motion was designed that was rapid prototyping compatible and was fabricated using stereolithography under the NSF sponsored REU program in the summer of 2002. The valve was fully functional as a sealed system. Its performance was evaluated and compared to that of a traditional gate valve. Precision flow control and improved sealing were two goals that this research program achieved in summer of 2003. Through proper design, an angle valve has been built that retains the flow and sealing characteristics of a traditional valve, but has the advantages associated with SFF. The highlight of this work was the fact that moving parts, integral O-rings, and threaded connections were all shown to be possible and the entire valve prototyped in a single build using SFF. In addition, a downsized valve, 0.4 inch inside diameter, has been built that will broaden the applications of this technology. The accomplishments of this research will allow functional prototypes of valves to be built and tested using solid freeform fabrication and influence the use of specialty valves in medical and engineering applications.