A bubble valve that comprises a liquid delivery channel and a localized heating arrangement. The liquid delivery channel includes an upstream portion and a constriction downstream of the upstream portion. The constriction has a smaller cross-sectional area than the upstream portion. The localized heating arrangement is located in the liquid delivery channel and generates heat to nucleate and enlarge a bubble in the liquid. The constriction is shaped to form a seal with the bubble. The localized heating arrangement additionally generates heat to move the bubble relative to the constriction to control the flow of the liquid. A pressure regulator that comprises a liquid delivery channel connected to a liquid outlet, a sensor located adjacent the liquid outlet, a controller that operates in response to the sensor and a localized heating arrangement. The liquid delivery channel includes an upstream portion, and a constriction located between the upstream portion and the liquid outlet. The constriction has a smaller cross-sectional area than the upstream portion. The localized heating arrangement is located in the liquid delivery channel and generates heat in response to the controller to nucleate and enlarge a bubble in the liquid. The constriction is shaped to form a seal with the bubble. The localized heating arrangement additionally generates heat to move the bubble relative to the constriction to control the flow of the liquid to the liquid outlet.