Specifications

7
THEORY OF OPERATION
18
Filling Procedures
The following recommendations should be used to op-
timize liquid cylinder filling:
* Keep the transfer lines as short as possible. Long
uninsulated transfer lines will result in higher fill
losses and longer fill times.
* Anytime liquid can be entrapped in a line between
two valves, the line must be equipped with a
safety relief device.
* Conduct the filling operation in as short a time as
possible.
* Do not over fill; fill only to the weight allowable by
specification.
* Use a minimum number of bends, valves and re-
ducers.
* Use as large a transfer line as possible – at least
1/2" ID.
Chart recommends the "Lo-Loss" system for liquid
cylinder filling. For information ask for Form 2072 on
the "Lo-Loss" from Chart.
The liquid cylinder should be visually inspected before
every fill for possible damage, cleanliness and suit-
ability for its intended gas service. If damage is
d
etected (e.g. serious dents, loose fittings, etc.) re-
move it from service and repair the unit as soon as
possible.
All Chart liquid cylinders are tested for performance
with low-purity liquid nitrogen. For this reason liquid
cylinders intended for use in another service should
be thoroughly purged with the applicable gas prior
to filling.
When filling a liquid cylinder with a cryogenic liquid,
the transfer may be made with a centrifugal pump or
through a pressure transfer operation.
Pressure Transfer
Liquid will always flow from a vessel of higher pressure
to one with low pressure. This method is commonly
used to fill liquid cylinders by connecting a transfer line
between the delivery source and the Fill/Liquid valve of
the liquid cylinder. The transfer takes place as the vent
valve of the liquid cylinder is opened. This allows gas to
escape and lowers the pressure in the liquid cylinder.
This method should always be used for liquid only ves-
sels such as the Cryo-Cyl LP. Figure N shows the
pressure transfer method of filling.
VAPORIZER
PRESSURE
BUILDING
COIL
LIQUID
IN
GAS
OUT
GAS
Liquid
VAPORIZER
SPRAY
HEADER
PRESSURE
BUILDING
COIL
LIQUID
IN
Figure N
Figure O
Pressure Transfer
Pump Transfer