A gas-generating apparatus includes a reaction chamber having a first reactant, a reservoir having an optional second reactant, and a self-regulated flow control device. The self-regulated flow control device stops the flow of reactant from the reservoir to the reaction chamber when the pressure of the reaction chamber reaches a predetermined level. Methods of operating the gas-generated apparatus and the self-regulated flow control device, including the cycling of a shut-off valve of the gas-generated apparatus and the cycling of the self-regulated flow control device are also described.