Hach DR/850, Руководство по процедурам, Страница: 29 / 460

29
CHEMICAL ANALYSIS INFORMATION
, continued
6. Use the thumb and forefinger to twist the turret cap to the next higher
volume position to ensure quantitative transfer of the sample. The “F”
position provides full blowout.
7. With the tip in contact with the side of the receiving vessel, slowly
and smoothly press down on the turret cap until it reaches the stop
and the solution is completely discharged.
Mixing Water Samples
The following two methods may be helpful in tests that require mixing
sample with chemicals (usually indicated by "invert to mix" instructions).
1. When mixing sample in a round sample cell or mixing cylinder, invert
the cell or cylinder; see
Figure 4 . Hold the cell in a vertical position
with the cap on top. Invert the cell so the cap is on the bottom. Return
the cell to the original position. Do the same with the mixing cylinder.
2. Swirling is recommended when mixing samples in a graduated
cylinder or a titration flask. Grip the cylinder (or flask) firmly with
the tips of three fingers; see
Figure 5 . Hold the cylinder at a 45-
degree angle and twist the wrist. This should move the cylinder in an
approximately 12-inch circle, creating enough rotation to complete
the mixing in a few turns.
These mixing procedures are the most gentle. Both methods are simple
but take a bit of practice to obtain the best results.
STEP 6
STEP 7