THE DOPE DISCHARGE CHANGE METHOD, PLANT, AND THE PUMP CHANGE METHOD OF DIAPHRAGM PLANT MADE FROM SOLUTION

摘要

PROBLEM TO BE SOLVED: To continuously supply dope of a constant flow rate while suppressing a variation in discharge pressure when a plurality of pumps are changed over. SOLUTION: An inlet pipeline 26 is divided into two pipelines 26a and 26b. The pipelines 26a and 26b are connected to an outlet pipeline 27. First and second liquid feed pumps CP1 and CP2 are installed in the pipelines 26a and 26b. A first pressure sensor PS1 is installed in the outlet pipeline 27. A return pipeline 28 branches from the outlet pipeline 27 on the upstream side of the first pressure sensor PS1 and is connected to the inlet pipeline 26. A first valve CV1 is installed in the return pipeline 28. The first valve CV1 is PID controlled on the basis of a pressure value detected by the first pressure sensor PS1. While the discharge of the first liquid feed pump CP1 being used is reduced to make the dope 31 from the pipelines 26a and 26b approximately constant, the discharge of the second liquid feed pump CP2 to be changed over is increased to change over from the first liquid feed pump CP1 to the second liquid feed pump CP2. COPYRIGHT: (C)2008,JPO&INPIT