Fill and Install the Dewar

 

The equipment images in this topic may differ slightly from your equipment; however, the instructions are the same unless otherwise noted.

  1. Fill the Dewar with the analysis bath liquid (such as liquid nitrogen) to no higher than 2 1/4 in. (5.7 cm) from the top. Filling the Dewar higher than this will cause an error in the free space measurement.
  Incorrect fluid levels can lead to measurement errors. Check the level of the bath liquid before each analysis.
  1. Insert the dipstick and check the level of the analysis bath liquid. Condensation should not exceed the level indicator mark.
  1. Wetness or frozen condensation indicates bath liquid level
  2. Level indicator mark

  1. For best results, if the Dewar has not been used for a while, allow approximately 30 minutes for the temperature of the Dewar to stabilize with the bath liquid, then recheck the level of the bath liquid. Add additional liquid if necessary.
  2. Slide the Dewar cover to approximately 3/4 in. (19 mm) from the sample port nuts to ensure a proper seal on the top of the Dewar.
  3. Place the Dewar on the elevator.
  4. Close the safety shield on the front of the analyzer.
  Ensure the analyzer safety shield is in place before beginning an analysis. If the analyzer is operated at an excessive pressure, the sample or balance tube could become dislodged from its port, possibly causing personal injury or damage to the equipment.