Design Strategy of a Piezoelectric Valve for a Color Sorter

摘要

A color sorter is a kind of machine for separating foreign bodies in grain and consists of a feeder, a shoot, a sensor with a lamp and an ejector with a solenoid actuator driven pneumatic valve. A solenoid actuator has some merits, such as a long actuation displacement, a strong attraction force and a long durability, but also has some weak points, such as an attraction force that depends on the operating temperature and a very high power consumption. The drop off in attraction force in a color sorter is a very core parameter for the user or consumer because the color sorter is used in tropical and temperate regions. High power consumption also leads to more and more energy consumption to use the color sorter. This paper presents a new mechanism for the color sorter and discusses the flow characteristics of a piezoelectric driven pneumatic valve, which has a multilayered piezoelectric actuator and two ports for air flow. In order to design the piezoelectric driven pneumatic valve, we analyzed the flow dynamics theoretically, and we researched the processes for fabrication of the multilayered piezoelectric actuator. Finally, we manufactured a pneumatic valve with a multilayered piezoelectric actuator, and based on experiment, we discuss the characteristics of the displacement and the blocking force of the piezoelectric actuator and the flow capability of the manufactured pneumatic valve.