Fluid shut-off device

A fluid shut-off device comprising:

• a valve body;
• said valve body at least partially delimiting an inlet duct and an outlet duct, said inlet duct having a predetermined transverse inlet duct dimension;
• said valve body comprising an intermediate portion, said intermediate portion at least partially delimiting an intermediate chamber, said intermediate chamber providing a fluid connection between the inlet duct and the outlet duct;
• wherein
• said inlet duct comprises an inlet duct connection edge formed by an intersection between the intermediate portion and the inlet duct;
• said intermediate chamber comprises a sealing surface;
• said intermediate chamber accommodates a diaphragm;
• said diaphragm has a body in a single piece;
• said diaphragm comprises a diaphragm sealing portion, and said diaphragm sealing portion, in a closing position of the inlet duct, cooperates, by a diaphragm support surface, with the sealing surface to occlude the inlet duct;
• said diaphragm comprises a diaphragm bending portion, and said diaphragm bending portion permanently connects the diaphragm sealing portion to the valve body so as to operate exclusively under bending;
• said diaphragm sealing portion delimits a diaphragm seat;
• said fluid shut-off device further comprises a control element;
• said control element comprises a control stem having a predetermined transverse control stem dimension;
• said control stem is integrally received in the diaphragm seat;
• said control stem transmits a movement to the diaphragm sealing portion at least between the closing position of the inlet duct and an opening position of the inlet duct, moving along a predetermined diaphragm movement direction;
• wherein
• said sealing surface is a flat sealing surface placed orthogonally to the predetermined diaphragm movement direction;
• said diaphragm support surface is a flat support surface placed orthogonally to the predetermined diaphragm movement direction;
• said predetermined transverse control stem dimension is between a value greater than the predetermined transverse inlet duct dimension and a dimension that leaves a distance, measured on a plane orthogonal to the predetermined diaphragm movement direction, between the control stem and the inlet duct connection edge, lower than 25% of the predetermined transverse inlet duct dimension;
• and
• wherein
• said control stem comprises a self-tapping stem thread that screws on by entering into the body of the diaphragm creating a diaphragm thread in the diaphragm seat, thus creating a close coupling between a profile of the self-tapping stem thread and the body of the diaphragm,
• said self-tapping stem thread is a thread of a cortical type that deforms the body of the diaphragm by screwing into a wall of the diaphragm seat, so as to penetrate into the body of the diaphragm with a resistant section of the body of the diaphragm that is subjected to thrust during closing and to pulling during opening of the diaphragm, and
• at least one of said inlet duct and said outlet duct has a gravitational lower surface at a same height as said sealing surface.