A Novel Piezoelectrically Driven Miniature Proportional Pneumatic Control Valve Utilizing a Microfabricated Orifice Array

In this paper, we report a new valve architecture enabling the use of a piezostack actuator in miniature valves without the need for a motion amplifier. Normally, the small stroke length of the piezostack would reduce the flow capacity of the valve to a small fraction of the flow capacity of the valve orifice. The novel feature of the valve consists of replacing a single orifice with an array of micro-orifices having the same cumulative area, but each orifice having a diameter of four times the stroke length of the piezostack. The micro-orifice array enables achieving the full flow capacity of the equivalent single orifice while exploiting the low-power and high-speed capabilities of the piezostack. Using a piezostack, the open-loop linearity of proportional flow control is improved in comparison to an electromagnetically actuated valve. A prototype valve is characterized to assess the performance attributes possible with the valve architecture. The characterization of the first prototype revealed that it achieved similar flow rates to those of other miniature valves, all the while demonstrating a response time of 295 μs, and a steady-state power consumption of 41 μW.