Abstract: A flow rate control valve has a first housing portion with separated admission and discharge chambers and a first seat, a second housing portion with a main chamber and auxiliary chambers, a valve member movable between a closed position of the valve and abutting against the first seat to interrupt a passage of fluid from the admission chamber to the discharge chamber, and a second position corresponding to an open position of a valve to allow a passage of fluid from the admission chamber to the discharge chamber, a second seat between the auxiliary chamber and the discharge chamber, and a driving element spring-biased against the second seat and activated to withdraw from it and allow passage of fluid between the auxiliary member and the discharge chamber when pressures within the valve are unbalanced and a pressure in the admission chamber forces the valve chamber away from the first seat to open the valve and to allow passage of fluid from the admission chamber to the discharge chamber.