If the gauge is malfunctioning, it should be removed from the container
and repaired. The following procedure should be followed (see Figure H):
1. Open the vent valve and release any pressure that is in the container.
2. Remove the nylon sight gauge protector (Item 3).
3. Unscrew and remove the sight gauge (Item 5).
4. Replace any damaged parts, stretched springs or bent floats.
5. Adjust the sight gauge assembly as follows:
a. Hold the sight gauge assembly allowing the float to hang freely.
b. The top of the indicator's white tip should be in the empty zone.
c. Loosen the spring retainer (Item 8) and adjust the spring up and
down the float rod until the indicator hangs freely in the right
location. Tighten the spring retainer.
d. Replace the O-Ring/Gasket (Item 7).
e. Insert the float and sight gauge assembly into the container. Make
sure that it engages in the float guide located approximately 21
inches into the container.
f. Tighten the sight gauge to 1/4 turn past hand- tight (150in/lb) and
replace the protector.
Warning
Remove all pressure from the Cryo-Cyl before repairing the
liquid level gauge. Gloves should be worn when handling the float rod to
prevent burns. DO NOT clean the plastic sight gauge with solvent
cleaners.
180 liter LN2 Supply Tank 6-5
Thermo Scientific
Section 6
Service and Maintenance
Level Gauge
(continued)
