Taylor-Wharton LS Series - Manual

LS
SERIES
Laboratory Systems
TW-348
Operating Instructions
SAFETY
Before using any cryogenic refrigerator, read
the Handle with Care booklet provided with the
unit. It details safety precautions that must be
understood before using the equipment. If a
replacement booklet is needed, order publica-
tion TW-10 Handle with Care from your sup-
plier.
Following are a few of the safety precautions
described in the Handle with Care booklet.
Please be sure to read the entire booklet.
Store and use these containers only in well
ventilated areas. In a confined area, nitrogen
gas from these units may cause suffocation by
displacing air needed for breathing. Install a
suitable oxygen monitor.
Do not touch liquid or cold metal surfaces
with your bare skin. The liquid nitrogen
refrigerant is extremely cold: -196°C (-320°F).
Exposure to skin or eyes to liquid, cold gas or
frosted parts could result in a severe frostbite-
like injury. Because of the extremely low
temperature, a face shield and gloves must be
worn when transferring liquid nitrogen and
material into or out of these containers.
Use only the necktube covers supplied with
this unit or a listed replacement part. A tight
fitting plug or stopper will cause a pressure
increase in the container that may damage the
container and/or cause personal injury.
OPERATION
Filling: Adding liquid nitrogen to a warm
container may cause splashing and will gener-
ate a significant volume of nitrogen gas as cold
liquid contacts warm refrigerator surfaces. Add
liquid slowly to minimize these effects. Be sure
there is adequate ventilation. Keep your head
clear of the heavy volume of vapor that may be
produced. It is extremely cold and could cause
personal injury.
WARNING:
DO NOT OVERFILL. Over-filling may result in personal
injury due to liquid spillage.
DETERMINING LIQUID LEVEL
Liquid level must be checked at regular inter-
vals – refrigeration depends on the pressure of
liquid nitrogen. The liquid level in the container
can be determined with a dipstick. Insert the
dipstick straight into the container so that it rests
on the rack positioning fixture on the bottom of
the unit. After 5 to 10 seconds, withdraw the
dipstick and wave it back and forth in the air. A
frosted section will form representing the depth
of the liquid in the container.
WARNING
Never use hollow rods or tubes as dipsticks. When a
warm tube is inserted into liquid nitrogen, liquid will
spout from the top of the tube and may cause personal
injury.
The liquid level chart shows volume of liquid
nitrogen vs. depth for LS Series refrigerators.
These values are approximate and are based
on a standard condition with no stored material
in the container. With store material, the liquid
volume will be slightly less than the value of
the chart.
INSERTING OR REMOVING RACKS
To prevent unnecessary loss of liquid nitrogen
and accumulation of ice, the necktube core
(the stopper) should remain in the container
when the stored material is not being ac-
cessed. When accessing stored material, the
necktube should be removed as briefly as
possible.
When removing material from the racks,
withdraw the rack just far enough to remove
contents. Completely withdrawing the rack will
unnecessarily
expose the stored
material to warm
room temperature
conditions.
WARNING
Some boxes have
liquid drain openings,
some do not. If racks
are completely
removed from the
container, liquid
nitrogen may remain
in the either rack and
boxes, or simply drain
from the bottom. When
removing racks, stop
briefly at the necktube
to allow liquid to drain
completely, then
handle the rack carefully to prevent personal injury.
Avoid direct rack contact with bare skin. The use of
proper personal protective gear is strongly urged –
cryogenic gloves, face shield and gown – to protect
against splashing.
When room temperature is added, slowly lower
the rack into the refrigerator to reduce the
boiling of refrigerant and the surge of cold
nitrogen gas. When inserting the rack, tilt the
bottom of the rack in the direction of the index
ring notch. The numbers and colors on the
rack handles are a convenient aid to inventory
control.
SECURING CONTENTS
The contents of all models may be secured
with a seal or lock through tabs on the edge of
the lid opposite the hinge.
ROUTINE CARE AND MAINTENANCE
If ice accumulates inside the necktube, a
general cleaning of the refrigerator should be
scheduled as soon as the stored material can
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