Fluid mixer for mixing fluids at an accurate mixing ratio

摘要

A fluid mixer is provided which can supply a fixed amount of fluid in each of supply lines to a mixing line all the time while maintaining a highly accurate mixing ratio even if a pressure on the downstream side of a back pressure valve of the mixing line is fluctuated and moreover can change the mixing ratio of the fluids in the supply lines with high accuracy in the state where the fluids are flowed. On the upstream side from a merging point where at least two supply lines: a first supply line and a second supply line are merged to a mixing line, diaphragm parts for adjusting the flow rates of the fluids and pressure reducing valves are arranged on the further upstream side of the diaphragm parts in series with the supply lines and a back pressure valve is arranged in the mixing line. Also, the back pressure valve and a flow meter are arranged in series in the mixing line, a fixed orifice or an regulating valve is used for the diaphragm parts and the pressure reducing valves and the back pressure valve are automatic valves.