Apparatus and method for controlling and monitoring mixing of two or more gases

摘要

An apparatus for controlling and monitoring the mixing of at least two streams of gases comprises a gas flow controller for each stream of gas and a programmable microprocessor for operating the controllers. Control dials for percent gas mixture and total flow rate of gases provide inputs to the microprocessor. The microprocessor in turn adjusts percentage concentration of a gas in the mixed stream of gases by adjusting the flow rate setpoint to the gas flow controllers. The gas flow controller measures the gas flow rate and outputs a signal to the microprocessor which is representative of the actual measure of flow rate. The microprocessor has a display for the calculated percentage mixture of the gases in the mixed gas stream based on the value measured by the flow controller. The operator may then vary the percentage mixture dials until a desired mixture and the total flow rate, as displayed, are achieved.