| 摘要 |
<p>PURPOSE: To reduce the consumption of a treating liquid to make it possible to perform replacement of the treating liquid by a method wherein while a first treating liquid is discharged from the bottom of a treating tank, a second treating liquid is fed from the upper part of the treating tank and the balance between the discharge rate of the first treating liquid and the feed rate of the second treating liquid is kept. CONSTITUTION: An on-off valve 16 and an on-off valve 17 are respectively changed over into an on-state and an off-state and while pure water (a first treating liquid) in a treating tank 1 is discharged from the bottom of the tank 1 into a discharge drain 18, a three-way valve 6 is changed over from the side of a discharge drain 7 to the side of an integrally constituted mixing valve 9. Moreover, on-off valves 10a to 10d, which are respectively communicated and connected with one of chemical feeding parts 11a to 11d for feeding a chemical to be used, and an on-off valve 12, which is communicated and connected with a pure water feeding part 13, are changed over into an on-state and the chemical (a second treating liquid) is diluted into a prescribed concentration and is fed from the upper part of the tank 1. Here, a liquid level height control part 25, controls the flow rate of a flow rate control valve 21 and the balance between the discharge rate of the pure water and the feed rate of the chemical is kept.</p> |
