Switching valve and an electro-pneumatic pressure converter utilizing the same

摘要

A switching valve has at least one plate-shaped piezo-electric element having a free end which is supported in a sealed chamber, at least two fluid directing nozzles arranged to be opened or closed due to the position of the free end of the piezo-electric element and a fluid output passage communicating outwardly from said sealed chamber. An electric-pressure converter uses the switching valve, a pilot relay for converting a fluid pressure signal delivered from the output passage into a standard air pressure signal, a pressure sensor for converting the pressure signal from said pilot relay into an electrical signal, pulse-width modulating means for providing a pulse-width modulated signal, which corresponds to the deviation between the electrical signal from the pressure sensor and an external reference electric signal, for energizing the plate-shaped piezo-electric element in the switching valve.