A self-regulated valve assembly contains a valve body which, in the lower part, has an input section for a connection to a tank intended to contain a fluid under pressure and, in the upper part, an output for connection to a pipe system. A piston is movable in the valve body along a first axis between an open position, enabling the fluid to communicate between the input section and the output, and a closed position. A spring type module is coupled to the piston and to the valve body and interacts dynamically with the piston at least after an actuation of the valve and during the entire cycle of self-regulation of the valve, imposing a positioning of the piston between its open and closed position. The spring type module is positioned beneath the lower sealing section of the piston and the dimensions of the valve assembly can be considerably reduced.