A pressure regulator is a valve that automatically shuts off the flow of a gas or liquid at a certain pressure. These regulators are used in order to allow high-pressure fluid tanks or supply lines to be reduced to a safe pressure. Its primary function is to match the gas flow through the regulator to the demand for the gas that is placed within the system itself. If the load flow decreases then the regulator flow also decreases. If the load flow increases then the regulator flow must increase to keep the controlled pressure from decreasing.