Performance of piezoelectric actuators in gas microvalves: An engineering case study

Abstract

Microvalves used to control gas flow in water heaters are traditionally based on low cost ubiquitous solenoid technology. The demand for a better flux control and for reducing the dependence on the solenoid Cu and rare earth magnetic materials, underlines the need for alternative solutions. In this work we report an engineering case study with experimental validation where a substituting solution to a commercial heater solenoid microvalve is provided by a low-cost high stroke piezoelectric bender for gas flow control. We established the relations between applied voltages, bender displacements, gas pressure drops through the microvalve and associated flow rates and demonstrate that the operation conditions of the piezoelectric microvalve resemble those of the solenoid one. By manipulating the electrical potential difference applied to the bender it is possible to control the pressure drop associated with the microvalve. The piezoelectric microvalve behaves in a continuous mode, not as a on-off device, what is a significant advantage over the solenoid one. We have proven that it is possible to directly incorporate a piezoelectric bender in a commercial solenoid- driven microvalve without significant changes in the valve design. The resultant piezoelectric driven valve is faster, partial, high voltage but low current, and silent.