Review of PZT Piezoelectric Valve

: In the world of electrically controlled pneumatic valves, solenoid valves are the absolute standard. Nevertheless, piezo valves offer many advantages over the prominent solenoid valves and open entirely new areas of application. Low energy consumption and no heat generation: Thanks to their capacitive principle, piezo valves require virtually no energy to maintain an active state. The valves do not generate heat Piezo technology is ideal for use in the “very-low-power” range of battery-powered devices . Piezoelectric valves made with piezo technology offer many advantages. They are small, lightweight, extremely precise, durable, fast, and save energy. presented a work on “Design and Simulation of MEMS Based Piezoresitive Pressure Sensor for Microfluidic Applications” This paper presents the design and simulation of MEMS based piezoresistive pressure sensor for microfluidic applications. Geometrical parameters are very much considerable when designing microstructure of the pressure sensor. Hence, an analysis is carried out by changing the dimensional parameters of three different diaphragm geometries namely square shaped diaphragm, circular shaped diaphragm and cross sectional beam shaped diaphragm respectively. This is performed in three dimensional mesh plots using Matlab. The Finite Element Method (FEM) analyses are performed in COMSOL and by comparing the results, the square type diaphragm is chosen as best diaphragm geometry for the microfluidic applications. In addition, modal analysis is carried out by using Ansys to identify the natural frequency of the best diaphragm geometry. Also Piezoresistive sensing elements are designed and simulated by performing coupled field analysis using COMSOL Multiphysics. Simulation results reveal that piezo resistive square type pressure sensors have high sensitivity in a wide range of pressures. [2] presented paper on “A Piezoelectric Actuator-Based Direct-Drive Valve for Fast Motion Control at High Operating Temperatures” In this paper experimentally investigates the control performances of a piezostack actuator direct-drive valve (PADDV) operating at high temperatures. In this study, the PADDV system is designed based on special specifications featuring a high operating temperature (150 °C) and wide control bandwidth (200 Hz). After manufacturing the PADDV with design limitations such as size and maximum input voltage to the piezostack actuator, the displacement of a spool located inside the valve system, which is directly related to the flow rate, is controlled at several different temperatures and motion frequencies. In order to undertake this, the PADDV ystem is installed inside a heat chamber equipped with air vessels and pneumatic–hydraulic cylinders. The piezoelectric actuator is partially insulated using an aerogel to prevent permanent damage due to high temperatures above 120 °C, which is higher than the Curie temperature. To control the valve system, a PID (proportional–integral–derivative) controller is realized in which control gains are properly tuned using fuzzy logic according to the change of temperature and frequency. It is shown from the experimental results that the proposed PADDV with thermal insulation can provide the target dynamic motion of 200 Hz at 150 °C by implementing the fuzzy-based PID controller. presented paper on “Development of a piezoelectric high speed on/off valve and its application to pneumatic closed-loop position control system” this authors that The use of smart materials-based high speed on/off valve has exhibited the potential to replace traditional servo and proportional valves in fluid power systems. In this paper, a novel pneumatic high speed on/off valve driven by a piezoelectric stack actuator is developed