Patent ID: 11926536
Assignee: NOMURA MICRO SCIENCE CO., LTD.
Field: Environmental technology (Chemistry)
Classification: CPC C  F | IPC C  F

Claim 0:
1. A method for starting up a hot ultrapure water production system that produces hot ultrapure water by heating ultrapure water to a supply water temperature for supply to a point of use, the method comprising:
alternately passing heated water and cooled water through a hot ultrapure water pipe made of a polyvinylidene fluoride (PVDF), through which ultrapure water pipe the hot ultrapure water flows, the heated water being obtained by heating the ultrapure water to a temperature higher than room temperature and the cooled water being obtained by cooling the ultrapure water to a temperature lower than the temperature of the heated water in a range of from room temperature to the supply water temperature, the passing of the heated water through the ultrapure water pipe being for from 3 to 24 consecutive hours per water passing and the passing of the cooled water through the ultrapure water pipe being for from 3 to 24 consecutive hours or less per water passing, thereby leaching fluorine contained in the hot ultrapure water pipe, as a part of a starting up of the ultrapure water production system.