PerkinElmer Frontier IR, User Manual

Page: 76 / 104

76 . Frontier IR Dual-Range Systems User's Guide
1. Remove the MCT coolant cover (Figure 40).
Figure 40 Location of MCT coolant cover
2. Remove the plug from the dewar.
3. Ensure that the funnel guide, which helps prevent overspill entering the instrument
body rather than the dewar, is in place.
4. Make sure the supplied plastic funnel is dry.
CAUTION
Stand where you can see the inside of the funnel as you pour the
nitrogen in. Pour slowly, so that neither the funnel nor the dewar
overflows. Take care not to overfill the funnel and splash liquid nitrogen
onto the instrument covers.
5. Insert the plastic funnel into the funnel guide and slowly fill the detector dewar with
liquid nitrogen.
NOTE: Make sure that the detector dewar is filled to the top with liquid nitrogen before
selecting the detector. Prevent radiation from reaching the detector by obstructing
the beam path in the sample area during filling.
6. Stand back and wait two minutes.
This nitrogen also vaporizes as the dewar continues to cool. The two-minute wait allows
the bubbling to settle down and the pressure of the vaporizing nitrogen to dissipate.
7. Continue to pour liquid nitrogen into the funnel, adding a little more each time the
funnel empties.
The funnel takes longer to empty as the dewar fills. This happens after two or three
more funnels of liquid nitrogen. Because the dewar has now cooled, the liquid nitrogen
does not vaporize, but instead fills the dewar.
8. Remove the funnel and wait two minutes.
The liquid nitrogen settles down and bubbling slows.
MCT coolant cover