| 摘要 |
PURPOSE:To ensure characteristics, e.g. a displacement amount, at given levels even when a working atmospheric air temperature is high, by forming a lamination type displacement element of an electro-mechanical converting material to indicate that a piezoelectric strain constant is a maximum value in a temperature region higher than an ordinary temperature. CONSTITUTION:In a flow rate control valve, a lamination type displacement element 21 is formed of an electro-mechanical converting material to indicate that a piezoelectric strain constant d33 is a maximum value in a temperature region higher than an ordinary temperature, and a diaphragm 17 is driven such that it can make contact with and separate away from a valve seat 15. A heating means is provided where occasion demands so that the lamination type displacement element 21 is actuated at temperature in the vicinity of a temperature region where the piezoelectric strain constant d33 indicates a maximum value. Since, even when organic metallic gas having a boiling point of 50 - 150 deg.C is an object, the piezoelectric strain constant d33 of a material of which the lamination type displacement element is formed holds an sufficiently high value, the stroke of a diaphragm is high and an enough flow rate can be provided. |
