Metrohm 774 Oven Sample Processor - Manual (Page 18)

2 Installation
774 Oven Sample Processor, Instructions for use 12
2.4.2 Equipping the guide head
• Screw the needle adapter (6.1808.150) onto the
bottom of the guide head.
• Attach the outlet hollow needle (6.2816.060) to the
Luer connection of the needle adapter.
• Carefully introduce the hollow injection needle
(6.2816.050) into the guide head from above (see
arrow). Pull the needle downwards to the full ex-
tent.
• Now lead the gas inlet (6.1805.470) through the
lift head from above and screw it onto the guide
head (see arrow). Connect the other end of the
tubing to the gas outlet opening on the top of the
tower. Take care that the connections are tight.
If necessary, the injection needle may be lifted by attaching
the PTFE spacer ring (that is supplied with) to the needle.
If you wish to avoid the penetration of the sample by the
needle, you may lift the injection needle by the use of two
different M6/M8 adapters (order no. 6.1808.040 and
6.1808.090). The injection needle must only puncture the
vial's seal by a few milimeters.
2.4.3 Adjusting the sample rack
• Check the positioning of the sample rack. After switching on the 774
Oven Sample Processor place the rack on the instrument and let it move
to the first sample position by pressing the <Í> key. The circular
opening of sample position 1 of the rack must coincide with the opening
of the oven block beneath it.
• If this is not the case then loosen the three Allen screws (see diagram) on
the sample rack. Carefully adjust the upper part of the rack and then re-
tighten the Allen screws.
• Now place a sample vial with a septum cap closure in sample position 2
and press the <Í> key again. By carefully pressing the <Ð> key to
lower the lift it is now possible to check whether the penetration needle
correctly penetrates the center of the sample vial septum and that the vial
is pressed down into the oven opening without tilting.
Warning!
Do not lower the needle too far. It must not contact the base of the vial and
become bent.
• Press the <RACK> key in order to return the sample rack and lift to the
starting position.
• Readjust the sample rack, if necessary.
Guide head
Needle adapter
Hollow outlet
needle
Hollow injection
needle