Two-stage valve

Abstract

The present invention describes a two-stage valve comprising a first stage constituted by a main valve body provided with at least one fluid inlet duct and with at least one fluid outlet duct, between which is interposed at least one shutter element configured to put selectively in fluid communication such ducts. The valve comprises a second stage constituted by a pilot valve body provided with at least one fluid inlet duct and with at least one fluid outlet duct, between which is interposed at least one shutter element configured to put selectively in communication such ducts. The opening of the shutter element of the pilot valve generates a fluid flow passing through the fluid inlet duct of the pilot valve and the fluid outlet duct of the pilot valve, the pressure of such a fluid flow generating the opening of the shutter element of the main valve. The shutter element of the pilot valve is actuated by an actuator device comprising at least one wire made of a shape-memory alloy, capable of applying a force onto the shutter element of the pilot valve as a consequence of a temperature variation determined by the Joule effect by the flow of an electric current through such a wire.