8
Introduction to the Integra 750Plus
·
Operating the system in a manner not specified within this manual or under conditions
outside of the specifications, see Integra 750Plus specifications , may result in the
protection offered by the equipment being impaired.
·
Never leave a freezer unattended when running a program.
·
Avoid nitrogen build up: anywhere liquid nitrogen is used must be well ventilated to
reduce the risk of nitrogen build up. Small volumes of liquid nitrogen convert to very
large volumes of gas. This can result in drowsiness, or in extreme cases,
asphyxiation.
·
When liquid nitrogen is used in confined spaces, oxygen-deficiency alarms must be
installed. Guidance on ventilation requirements are given in BCGA Code of Practice
CP30, The safe use of liquid nitrogen dewars up to 50 litres.
·
When there is a risk of reduced or insufficient ventilation when a room is unoccupied,
then alarms to indicate oxygen deficiency must be installed and positioned outside of
the room so that operators are aware of the hazard before entering. The operational
status of such an alarm should also be visible from outside the room.
·
If liquid nitrogen is used in an area that requires forced ventilation, an alarm to indicate
its failure should be fitted.
·
When dispensing or potentially being exposed to liquid nitrogen, protect the face with
a shield and wear gloves, boots and a protective apron. Prevent spillage into shoes
and onto unprotected parts of the body.
·
Handle vessels containing liquid nitrogen carefully. Liquid nitrogen boils at -196ºC and
both liquid and gas can cause rapid and severe frostbite. Delicate tissue, e.g. the
eyes, can be damaged by an exposure to the cold gas, which may be too brief to
affect the skin of the hands or face.
·
Stand clear of boiling and splashing liquid nitrogen and its gas when filling a dewar at
normal room temperature or when inserting objects (such as a pump) into the liquid.
·
Use tongs or wear cryogloves when handling cold or hot objects. Cryogloves are
available as an accessory from Planer. When running a program, the chamber and
contents may get cold enough to cause frostbite or hot enough to cause burns.
·
If a dewar with a pump is being used, it must be depressurised before the pump can
be removed. This is achieved by opening the pressure-relief valve mounted on the side
of the pump, which seals an orifice in the pressure system by toggle action. Avoid
contact with cold nitrogen gas when depressurising the dewar.
·
The dewars used with this equipment must never be used to store any liquid other
than liquid nitrogen.
·
Only use vessels designed for working with liquid nitrogen.
·
Secure the liquid nitrogen container to prevent toppling.
·
Ensure that the delivery pipe connections are secure and leak-free before supplying
liquid nitrogen to the freezer.
·
Liquid nitrogen pressure must not exceed 1.5 bar (22 psi).
·
To maintain protection against electric shock, the mains lead must be properly fitted
to a 3-way mains connector plugged into an earthed mains outlet.
·
Because of the potentially wet laboratory environment, the operator should be provided
with additional protection against electric shock by supplying mains power to the
freezer through a residual current circuit breaker (RCCB) operating at a differential of
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