Abstract: The invention relates to a valve with time-controlled opening, provided for use in containers, receptacles or sealed elements. The valve can be a system integrated in the container, receptacle or sealed element itself, or an external system which is added to the element at the moment at which it is to be used. A valve of this type emits a signal at the time of opening, once determined temperature or vapour generation conditions have been achieved. In this way, the valve is activated by the increase in temperature of the sealed space, enabling it to be timed such that said activation occurs at the time and under conditions that have been previously determined, and enabling the user to have greater control.