The purified water storage tank is also referred to as the pure water storage tank for short. Purified water is water for pharmaceutical use, obtained by distillation, ion exchange, reverse osmosis, or other appropriate methods, without any additives. Ordinary water contains various ions, such as sodium ions and chloride ions. In some chemical or physical fields, extremely pure water that cannot contain any ions is required, and ordinary water cannot meet the needs of pharmaceutical, food, chemical, and other industries. Thus, ions in water are removed through certain equipment to produce purified water.
In the United States Pharmacopeia, a comparison is made between the quality standards of purified water and water for injection. Their physicochemical indicators are the same, but water for injection has higher requirements for pyrogens and microorganisms than purified water. The difference between purified water and water for injection also lies in the water – making process. There can be various options for the preparation process of purified water, but the pharmacopoeias of various countries have restrictive conditions for the preparation process of water for injection. For example, the United States Pharmacopeia clearly stipulates that the preparation process of water for injection can only be distillation and reverse osmosis, while the Chinese Pharmacopoeia stipulates that the production process of water for injection must be distillation.
The storage cycle of purified water should not be longer than 24 hours. Therefore, the purified water storage tank is preferably made of stainless steel materials or other materials that are verified to be non – toxic, corrosion – resistant, and do not leach out polluting ions. A hydrophobic sterilizing filter that does not shed fibers is installed at its ventilation port. The inner wall of the purified water storage tank should be smooth, and there should be no dead corners or sand holes at the nozzles and welds. The purified water storage tank uses sensors that display parameters such as liquid level, temperature, and pressure without causing stagnant water pollution. The storage tank should be regularly cleaned, disinfected, and sterilized, and the cleaning and sterilization effects should be verified.
