PREPROCESSING DEVICE FOR ONLINE MEASUREMENT IN WATER SYSTEM, ONLINE MEASUREMENT DEVICE PROVIDED WITH SAME, AND PROCESSING METHOD FOR ONLINE MEASUREMENT

摘要

The purpose of the present invention is to prevent fouling by substances reaching sizes of several millimeters and fibrous substances, and reduce maintenance frequency in online measurements. A preprocessing device for an online measurement is provided with a hollow fiber membrane, which is a plurality of long external pressure hollow fiber membranes that filter sample water introduced from a water system wherein water quality is measured online by cross-flow filtration, the hollow fiber membrane having a fixed first end part, which is the lower end part in the usage state.