Patent attributes
Another method of mixing at least two gases is provided. This method includes providing a mixture composition control, comprising a predetermined composition input and a composition trim input. Providing N gas flow meters, wherein N is 3 or more. Configuring the N flow meters to adjust the N gas flows to maintain the line pressure at a predetermined value, while maintaining the predetermined composition. Adding the N measured gas flow, thereby determining the total gas flow at the first predetermined intervals of time. Adjusting the composition trim input to vary the composition of the mixed gas, without modifying the predetermined composition input. And sounding an alarm, and/or terminating both the N gas flows, if either of the following exceed a predetermined range value: the instantaneous calculated theoretical percentage for any of the N gas flows, or the cumulative calculated theoretical percentage for any of the N gas flows.
