Pressure regulator's primary function is to match the flow of gas through the regulator to the demand for gas placed upon the system. If the load flow decreases, then the regulator flow must decrease also. If the load flow increases, then the regulator flow must increase in order to keep the controlled pressure from decreasing due to a shortage of gas in the pressure system. A regulator includes a loading element, a measuring element, and a restricting element. Modern gas regulators can vary its operation by the use of stiffer springs, pre-amplification, velocity boosting, and lever ratio.