5
CS200
Control Systems
Safety
Precautions
Liquid Nitrogen
Nitrogen is an inert, colorless, odorless, and tasteless gas making up four-fifths of the
air you breathe – and can be very dangerous. Air is roughly one-fifth oxygen. Liquid
nitrogen is at a temperature of -196°C (-320°F) under normal atmospheric pressure.
Cryogenic freezers are used in LN
2
service only.
Extreme Cold - Cautionary Statement
Accidental contact of liquid nitrogen or cold issuing gas with the skin or eyes may
cause a freezing injury similar to frostbite. Handle the liquid so it won’t splash or
spill. Protect your eyes and cover the skin where the possibility of contact with the
liquid, cold pipes and equipment, or cold gas exists. Safety goggles or a face shield
should be worn when operating this equipment. Insulated gloves that can be easily
removed and long sleeves are recommended for arm protection. Trousers without
cuffs should be worn outside boots or over the shoes to shed spilled liquid.
Keep Equipment Area Well Ventilated
Although nitrogen is non-toxic and non-flammable, it can cause asphyxiation in
a confined area without adequate ventilation. Any atmosphere not containing
enough oxygen for breathing can cause dizziness, unconsciousness, or even death.
Nitrogen, a colorless, odorless, and tasteless gas that cannot be detected by the
human senses, will be inhaled normally as if it were air. One (1) liter of liquid
nitrogen is equivalent to 24.6 scf of nitrogen gas. Without adequate ventilation, the
expanding nitrogen will displace the normal air resulting in death.
Liquid Nitrogen System
The liquid nitrogen supply pressure at the inlet to the freezer should be in the
range of 10 psig (0.7 bar/69 kPa) to 20 psig (1.4 bar/138 kPa) for optimum
performance. Higher operating pressures will increase transfer losses and create
excessive turbulence of the liquid in the freezer, which can generate false signals
to the liquid level controller causing the freezer to under-fill. In “liquid phase”
storage applications, excessive turbulence can cause splashing which could result
in personal injury and/or damage to the freezer. When installing piping or fill hose
assemblies, make certain a suitable safety relief valve is installed in each section
of plumbing between any two isolation points. Trapped liquefied gas will expand
greatly as it warms and may burst hoses or piping causing damage or personal
injury. A relief valve is installed in the freezer plumbing to protect the line between
the customer-supplied shut-off valve and the freezer solenoid valve. Relief valves can
be piped to the outside of the building.
Electrical
• This product is not intended for a life support function.
• This product is intended to be used in hospitals and clinics.
• This product has no Radio Transmitter (Intentional Radiator) functions.
• This product is not intended for electromagnetic shielded rooms only.
WARNING:
The following safety
precautions are for
your protection. Before
installing, operating,
or maintaining this unit
read and follow all
safety precautions in this
section and in reference
publications. Failure
to observe all safety
precautions can result
in property damage,
personal injury, or
possibly death.
WARNING:
Maintain adequate
ventilation to prevent
asphyxiation hazard
(see Safety Precautions).
WARNING:
Inlet pressure should not
exceed 22 psig
(1.5 bar/152 kPa).
Higher pressures could
result in damage to
equipment.
WARNING:
Electrical shock can
kill. Do not attempt
any service on these
units without first
disconnecting the
electrical power cord.
Caution:
When installing field
fabricated piping, make
certain a suitable safety
relief valve is installed
in each section of piping
between any two
isolation points.
Summary of Contents for CS200
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