Sleeve junction, Figure 2 – Hach-Lange PHC745 User Manual

Page 3

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6. For Red Rod probes, make sure that there is approximately 0.5 cm (0.2 in.) of KCl

crystals in the filling solution in the probe. Refer to

Table 1

. For measurements at

temperatures higher than 60 °C (140 °F), add KCl crystals through the filling hole.
Refer to

Table 1

to calculate the quantity of KCl crystals to add. The quantity of

necessary KCl crystal increases linearly from 60 to 100 °C.

7. For Red Rod probes, make sure that the KCl crystals move freely through the liquid

when the probe is inverted. If necessary, shake the probe to loosen the crystals.

8. Make sure that the sleeve junction is open before calibration or measurement (refer

to

Sleeve junction

on page 3).

9. Make sure that the filling hole is open during measurement for the correct flow of the

filling solution.

Note: For the best stabilization time, condition the probe for 2 hours in pH buffer 4.01 before use, if

the probe was not used for 3 weeks or more. In low ionic strength (LIS) samples, condition the

probe for a maximum of 5 minutes in the sample before use. In all other cases a condition before

use is not necessary.

Figure 2 Filling solution level

1 KCl crystals

1

3 Filling solution

2 Filling solution level

4 Standard solution or sample level

1

Red Rod probes only

Table 1 KCl crystal level for Red Rod pH probes

Temperature

Amount of KCl crystals

Add

Temperature

Amount of KCl crystals

Add

60 °C (158 °F)

0.5 g (0.5 cm)

0 g

90 °C (194 °F)

0.875 g

0.375 g

70 °C (158 °F)

0.625 g

0.125 g

100 °C (212 °F)

1.0 g (1.0 cm)

0.5 g

80 °C (176 °F)

0.750 g

0.25 g

Sleeve junction

The sleeve junction must be open during calibration and measurement for a correct
electrical contact between the inner electrolyte and the standard or sample. Adjust the
sleeve junction to change the flow of electrolyte. A higher flow of electrolyte can result in
better speed of response in different sample types.

1. Hold the probe over a beaker or container.
2. Lift the sleeve junction until some drops of electrolyte flow out.

3

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