PH-adjusted water production device
A pH-adjusted water production device has a configuration in which a platinum group metal support resin column, a membrane-type degassing device, and a gas dissolving membrane device are provided on an ultra-pure water supply line, and a pH-adjuster injection device is provided between the platinum group metal support resin column and the membrane-type degassing device. An inert gas source is connected to the gas phase side of the membrane-type degassing device while an inert gas source is connected also on the gas phase side of the gas dissolving membrane device, and a discharge line communicates with the gas dissolving membrane device.
1 . A method of providing pH-adjusted water production comprising sequentially providing: a platinum group metal support resin column and a membrane-type degassing device on an ultra-pure water supply line, wherein the membrane-type degassing device includes a membrane,
providing a pH-adjuster injection device, configured to inject a pH adjuster, is between the platinum group metal support resin column and the membrane-type degassing device, wherein the pH adjuster is ammonia, hydrochloric acid, citric acid or hydrofluoric acid,
providing an inert gas dissolving device, configured to dissolve an inert gas, at a stage subsequent to the membrane-type degassing device,
providing a gas concentration measurement part is provided at a stage subsequent to the membrane-type degassing device and the inert gas dissolving device,
and providing a mechanism to maintain a concentration of the inert gas, comprising a gas flow regulating valve and a control part, wherein the control part is connected to each of the gas concentration measurement part and the gas flow regulating valve, and the mechanism to maintain the concentration of the inert gas always in the vicinity of or more than a saturation solubility of the inert gas and at 15 ppm or more at the stage subsequent to the inert gas dissolving device, so as to maintain a saturated state of the inert gas in the subsequent stage.
2 . The method of providing pH-adjusted water production device according to claim 1 , wherein the membrane-type degassing device is configured to inject the inert gas by applying suction.
3 . The method of providing pH-adjusted water production device according to claim 1 , further comprising providing a pH measurement part at the stage subsequent to the membrane-type degassing device and the inert gas dissolving device.
4 . The method of providing pH-adjusted water production device according to claim 1 , wherein the control part comprises a processor.