YOKOGAWA EXA TB TB400G, Руководство пользователя

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<7. MAINTENANCE>
7-16
IM 12E04A02-02E 9th Edition : Mar. 16, 2018-00
7.15 Zero and Span Standards
7.15.1 Zero Turbidity Standard
For a low turbidity range (200 mg/L (degrees) or less), distilled water (0.03 mg/L (degrees) or
less) or tap water filtered with a zero-turbidity filter (0.02 mg/L (degree) or less) will be adopted as
the standard solution.
For a high turbidity range (more than 200 mg/L (degrees) or more), plain tap water (2 mg/L
(degrees) or less) will be adopted as the standard solution.
7.15.2 Span Standards
(1) Turbidity Calibration Plate
The calibration plate attached to this instrument is calibrated making the standard solution
described in (2) below as the reference.
(2) Turbidity Standard Solution
The turbidity indication (mg/L) of the TB400G turbidimeter adopts and indicates kaolin
concentrations defined in the JIS K0101 standard. However, kaolin differs in viscosity distribution,
particle shape, and colour depending on its place of production, quality, and production batches
leading to an error.
Therefore, Yokogawa employs a method to define formazin (FTU) as the standard solution and
to convert it to kaolin concentration.
The turbidity indication of degree is based on the polystyrene latex (PSL) concentration defined
in the Water Quality Standards. When using the PSL standard, observe the following instructions.
NOTE
• Do not shake the container when stirring the standard solution. Shaking can cause the
formation of a large amount of bubbles and thus the solution cannot be used for a while.
• Slowly rotate the container for stirring, taking care not to allow suspended matter to collect in
the bottom corners of the container.
• When diluting the solution, gently and slowly pour zero water into the container, otherwise,
air bubbles will occur, interfering with accurate calibration.