VOLUMETRIC GAS MIXING DEVICE

摘要

A gas mixing apparatus including a plurality of selected volume gas chambers (20, 22; 66, 67, 68), a pressure regulated gas supply line (15, 16) to each chamber, a valve (40, 41; 69, 70, 71) in the supply line, an outlet line (42, 43; 88, 89, 90) of each chamber to a mixed gas reservoir (46, 73), and an outlet valve (47, 48; 69, 70, 71) in each outlet line. Each outlet line may also include a variable orifice throttle valve (85, 86, 87), enabling proportional mixing during the whole cycle of emptying the chamber. The selected volume gas chambers (66, 67, 68) may have variable volumes and may be cylinders (25, 31) with pistons (24, 30; 66a, 67a, 68a) moveable to change the selected volumes of the chambers. The inlet and outlet valves to the chambers may be a single three-way valve (69, 70, 71) having three gas lines extending therefrom, with one being the pressure regulated gas supply line, a second being a combination of inlet line and outlet line, and a third being a line to the mixed gas reservoir. A baffle (81) in the mixed gas reservoir (46, 73) is useful in mixing the gases upon entry.