| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a chemical feeder which allows a wide range of the amount of a chemical injected, causes no significant variation of possible chemicals and enables efficient operation of chemical feed pumps. <P>SOLUTION: The chemical feeder includes two chemical feed pumps 16a and 16b having equal volumes for injection of chemicals to be injected into target water. When the deviation of pH detected by a pH detector 23 of a deviation determination section 25 from a target value is decided to be equal to or smaller than a predetermined value, a section 26 selecting the number of chemical feed pumps selects one of the chemical feed pumps 16. When the deviation is decided to be larger than the predetermined value, the section 26 selects the two chemical feed pumps. A one-pump operation controller 27 operates one chemical feed pump selected, and a two-pump operation controller 28 operates two chemical feed pumps at the same number of strokes, to control injection of the chemicals so as for the pH of the target water to become equal to the target value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
