Patent attributes
A method of mixing at least two gases is provided. This method includes providing a mixture composition control, including a predetermined composition input and a composition trim input. Providing N gas flow meters, including a N gas flows, and N desired gas flow rates determined by the mixture composition control, wherein N is 3 or more. Mixing the N gas flows, thereby producing a mixed gas flow at the predetermined composition and at a line pressure. 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. And adjusting the composition trim input to vary the composition of the mixed gas, without modifying the predetermined composition input.
