Patent ID: 6638434
Filing Date: 2003-10-28
Classification: C02F

Abstract:
A method for automatically controlling the level of dissolved oxygen in water based on a pressure tank system equipped with a sterilizer comprising the steps of:supplying crude water to a water retention chamber of a closed type tank by means of an automatic water supply device to obtain a prescribed amount of retained water; mixing air or oxygen and nitrogen gas with the retained water in the closed type tank at a predetermined mixing ratio, and simultaneously feeding the gas mixed water into a circulation channel for circulating the retained water in the closed type tank through a pressure tank by means of a pressure pump; circulating the retained water in the closed type tank in a circulation channel by means of a circulating pump, and activating the water by means of a ceramic pipe and an infrared ray irradiation device both of which are arranged in the circulation channel, thereby injecting the activated water into the retained water in the closed type tank by means of a gas injection nozzle; adjusting the mixing ratio at which air or oxygen and nitrogen gas is mixed with the retained water in the closed type tank by means of a device for adjusting the levels of oxidation-reduction potential and dissolved oxygen according to the level detected by a sensor for detecting the levels of oxidation-reduction potential and dissolved oxygen, and changing the revolution number of the said pressure pump by means of a pump motor controller to change the pressure in the said pressure tank, and changing the revolution number of the said circulating pump to change the injecting pressure of the said gas injection nozzle; filtering sludge by allowing the retained water in the closed tank to pass through a filtering device by means of a filtration pump, and further allowing the water to pass through a ceramic-filled device thereby adjusting oxidation-reduction potential of the water to a desired level and still further allowing the water to pass through an ultraviolet ray irradiation device to sterilization followed by bringing back the water to the closed type tank; and taking out the retained water in the closed type tank.