2 tubing connections – Metrohm 757 VA Computrace User Manual
Page 50
3 Installation
757 VA Computrace – Hardware
46
max. 0.5 mm
3.9.2 Tubing
connections
For operation of the 757 VA Computrace Stand with 813 Compact Autosampler and
772 Pump Units, the accessories and tubing connections must be installed accord-
ing to Fig. 16. Proceed as follows:
1 Install accessories at 757 VA Computrace Stand
• Instead of the 6.1415.210 measuring vessel, install the 6.1456.210 meas-
uring vessel at the 757 VA Computrace Stand.
• Cut PFTE tube 43 (6.1819.010) inserted in opening 67 of the measuring
head 20 to a length of
max. 30 mm (see Fig. 6 and 17).
• Cut PFTE tube 45 (6.1819.010) inserted in opening 66 of the measuring
head 20 to a length of
max. 20 mm.
• Cut PFTE tube 120 (6.1819.010) to a length of max. 20 mm and insert
from above in opening 53 of the measuring head 20.
• Cut the bottom end of PFTE tube 121 (6.1819.010) diagonally and insert
from above in opening 52 of the measuring head 20. To ensure that the
solution is siphoned off as completely as possible, the end of the tube
must be located in the deepest part of the 6.1456.210 measuring vessel
(left rear when viewed from front).
• Screw FEP tubing 118 (6.1805.180) into threaded openings 52 and 66.
• Screw FEP tubing 119 (6.1805.100) into threaded opening 53 of the
measuring head 20. Screw a 6.1808.000 tubing coupling to the other end
of FEP tubing 119 and insert the coupling in a slot of the tubing holder at
the rear of the 757 VA Computrace Stand.
2 Connect 813 Compact Autosampler
• Install accessories at 813 Compact Auto-
sampler (see Instructions for Use 813).
• Adjust 6.1835.030 Pipetting needle at the
757 Compact Autosampler to ensure that
the lower end of the needle is positioned
max. 0.5 mm above the bottom of the
sample vessel (see Fig. 18). This is essen-
tial to guarantee a complete transfer of the
sample from the sample vessel into the
measuring vessel of the 757 VA Com-
putrace Stand.
• Insert 6.1822.410 transfer tubing connected
to 6.1826.020 pump tubing from above into
opening 57 of the measuring head 20 at
the 757 VA Computrace Stand (see Fig. 6)
and fix it by screwing the nipple.
Fig. 18: Adjusting the
pipetting needle