Hanna Instruments HI931, Руководство пользователя, Страница: 149 / 218

11-5
MAINTENANCE PERIPHERALS
• Reinsert the piston into the syringe.
• Reinsert the syringe by screwing it in the valve with your fingers.
• Reinsert the protective cap to the bottom of the burette assembly. Carefully position the cap into the burette.
• Slide the burette into the burette stand. Notice the position of the piston shaft to the pump couple.
• Priming the burette three times with new titrant is recommended.
11.1.6. BURETTE PREPARATION (TITRANT FILLING)
Before starting a titration, the burette must be properly filled with titrant in order to obtain an accurate and repeatable result. To fill
the burette, follow the next steps and recommendations:
• If necessary, clean the burette and make sure it is empty.
• From the main screen press .
• Highlight Prime Burette option and press .
• Enter the number of times the burette needs to be rinsed (minimum three rinses are recommend allowing air bubbles to be
evacuated).
• Press .
To avoid the presence of the air bubbles inside the burette, make sure to have a continuous liquid flow inside the burette. A little air
just above the liquid level at the first filling is normal. The next filling will evacuate all of the air; no air will be left in the valve.
Sometimes during this process, slight finger tapping on the tubes is helpful to remove any residual air bubbles from the tubes.
If air bubbles are still present:
• Remove the aspiration tube from the titrant bottle.
• Repeat burette preparation procedure.
• If this is not successful, clean the burette again.