Model SMM 770 Scanning Magnetic Microscope System
TRISTAN TECHNOLOGIES --Page
17
2.1 LIQUID NITROGEN MAINTENANCE
The system nitrogen level can be measured with a small fiberglass stick (supplied)
2.2 NORMAL INSTALLATION AND OPERATION
2.2.1 PROBE INSTALLATION (WARM DEWAR)
•
Inspect dewar and verify internal cavity is free from ice, moisture, or other
contaminants. CONTAMINANTS COULD RESULT IN INCORRECT
MEASUREMENTS OR PROBE DAMAGE!
2.2.2 NITROGEN TRANSFER
•
Verify Nitrogen level in Microscope dewar.
•
Open transfer port at top of dewar.
•
Begin Nitrogen transfer observing all standard cryogenic handling and safety
procedures.
•
Observe transfer levels. *
Note: Dewar capacity is 2.29 liters
.
•
Plug transfer port after allowing sufficient vent time.
•
Verify all connectors at top of probe are free from moisture.
2.3 SAFETY PRECAUTIONS FOR HANDLING CRYOGENIC LIQUIDS
The potential hazards of handling liquid nitrogen stem mainly from the following
properties:
WARNING
1. T
HE LIQUID IS EXTREMELY COLD
2. T
HE ULTRA
-
LOW TEMPERATURE OF LIQUID
N
ITROGEN CAN CONDENSE AND SOLIDIFY AIR
.
3. V
ERY SMALL AMOUNTS OF LIQUID
N
ITROGEN ARE CONVERTED INTO LARGE VOLUMES OF
GAS
.
4. N
ITROGEN IS NOT LIFE SUPPORTING
.
2.3.1 EXTREME COLD-- COVER EYES AND EXPOSED SKIN
Accidental contact of liquid nitrogen or the cold gas that results from its rapid evaporation
may cause a freezing injury similar to a burn. Protect your eyes and cover the skin where
the possibility of contact exists. Eye protection should always be worn when transferring
liquid nitrogen.
2.3.2 KEEP AIR AND OTHER GASES AWAY FROM LIQUID NITROGEN
The low temperature of liquid nitrogen, vacuum pumped liquid nitrogen, or cold gaseous
nitrogen can solidify another gas. Solidified gasses and liquid, particularly solidified air,
can plug pressure-relief passages and foul relief valves. Plugged passages are hazardous
because of the continual need to vent the nitrogen gas that evolves as the liquid
continuously evaporates. Therefore, always store and handle liquid nitrogen under positive
