Taylor-Wharton LABS Series - Manual (Page 9)

7
LABS
A. System model and serial number, and controller model and unit, if available.
B. User’s name, company, address, and phone number
C. Malfunction symptoms
If possible, the original packing material should be retained for reshipment. If not
available, consult Taylor-Wharton for shipping and packing instructions. It is the
responsibility of the customer to assure that the goods are adequately packaged for
return to the factory. All refrigerators returned to Taylor-Wharton must be clean and
sterile before return. See page 13 for cleaning instructions.
Liquid Nitrogen Supply Connection
The package included with the refrigerator includes a strainer. The liquid fill hose
from a low pressure source of liquid nitrogen must be connected to the inlet
through this fitting. This liquid nitrogen source must have a shut-off valve, and may
be any portable liquid cylinder or a bulk supply.
The liquid nitrogen supply
pressure at the inlet to the refrigerator should be in the range of 10 psig
(0.7 bar/69 kPa) to 22 psig (1.4 bar/152 kPa) for optimum performance.
Higher operating pressures will increase transfer losses and create
excessive turbulence of the liquid in the refrigerator which can generate
false signals to the liquid level controller causing the refrigerator to
under-fill. In “liquid phase” storage applications, excessive turbulence can cause
splashing which could result in personal injury and/or damage to the refrigerator.
If the liquid nitrogen supply pressure at the inlet to the refrigerator rises above
the opening pressure of the relief valve on the refrigerator, liquid nitrogen will be
discharged into the surrounding area which can cause a rapid and very dangerous
depletion of oxygen in the atmosphere. Once this pressure relief device has opened
and cooled to liquid nitrogen temperature, it will not reseat until it has warmed to
near ambient temperature. THIS COULD PERMIT THE ENTIRE CONTENTS OF THE
LIQUID NITROGEN SUPPLY SYSTEM TO BE DISCHARGED INTO THE IMMEDIATE
AREA OF THE REFRIGERATOR(S) (SEE WARNING). IT IS RECOMMENDED TO HAVE
THE FREEZER RELIEF VALVE CONNECTED TO VENT LINE THAT EXHAUSTS TO THE
OUTSIDE ATMOSPHERE.
Electrical
The liquid level controllers used with these refrigerators operate from 24/16.5 VAC.
However, the external transformer does have a 110/220 VAC primary. Disconnect
the electrical power cord from the outlet before attempting any service.
Power Supply Connection
Connect the power supply to the LABS Cryostorage System and then plug the power
supply into a surge protected 110/220 VAC outlet.
OPERATION
These instructions are for operators experienced with cryogenic equipment. Before
operating the system, become familiar with the safety precautions in this LABS
manual and in the operating manual for the controller model you are using with
your LABS unit. Make certain all applicable provisions set forth in the Installation
Section have been followed before placing a system in operation. Study this manual
thoroughly. Know the location and function of all system components.
WARNING:
In order to prevent
the relief device
on the nitrogen
refrigerator(s)
from opening
when the system
is in operation,
the liquid nitrogen
supply system must
be protected by
a pressure relief
device that will open
when the pressure
at the inlet to the
refrigerator(s) is
approximately 22
psig (1.5 bar/152
kPa). Never install
the supply system
pressure relief
device onto a liquid
service line.
WARNING:
Maintain adequate
ventilation to
prevent asphyxiation
hazard (see Safety
Precautions).
WARNING:
Electrical shock can
kill. Do not attempt
any service on these
units without first
disconnecting the
electrical power cord.
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