Thermo Scientific NICOLET FT-IR User Manual page 22

Warning
18 Thermo Fisher Scientific
1. Open the dewar cover and remove the plastic stopper from
the dewar.
Make sure you pour the liquid nitrogen slowly when you fill the
vacuum bottle or the detector dewar. Pouring too quickly can cause
liquid nitrogen to spray out. Wear protective clothing and eyewear,
and follow standard laboratory safety practices to prevent injury.
2. Fill the metal vacuum bottle with liquid nitrogen.
3. Insert the funnel into the detector dewar.
Plastic
stopper
Dewar cover