Figure 8-1.C-O-TWO recharge or transfer unit (supply
cylinder without a syphon tube).
A typical C-O-TWO recharge unit is shown
in figure 8-1 and consists of a supply cylinder
containing 50 pounds of CO2, a tilting rack for
inverting the supply cylinder, a motor-driven
pump, a rack for inverting the cylinder being
recharged, a scale for determining the weight of
the cylinder being recharged, and the necessary
high-pressure hoses, control valves, adapters, etc.,
to properly hookup the equipment. The two units
are covered in detail in the PR 1 & C.
Before learning the operation of any specific
type of recharge equipment, you should be
familiar with the following general information,
which applies to all units.
Carbon dioxide recharge equipment pumps
CO2 in its liquid state only, and the amount of
liquid CO2 a cylinder contains varies with the
temperature and pressure. For example, a
standard 50-pound supply cylinder contains
approximately 38 pounds of liquid CO2 and 12
pounds of gaseous CO2 at a temperature of 70°F.
It follows, then, that the cooler the supply cylinder
and cylinder being recharged, the more efficient
the operation of the transfer equipment. For this
same reason, the time required to recharge an
empty cylinder increases with the temperature of
Figure 8-2.CO2 supply cylinder.
When recharging a cylinder, it remains cooler
and may be filled faster if inverted, rather than
left in an upright position. Large cylinders, which
are impractical to invert, may be placed in a
horizontal position for charging.
Standard commercial supply cylinders in
50-pound sizes are obtained with or without a
syphon tube. When transferring from a cylinder
without a syphon tube, the cylinder must be
inverted. Supply cylinders with syphon tubes
should be maintained in an upright position, not
more than 60 degrees from vertical.
CO2 SUPPLY CYLINDERS
Figure 8-2 illustrates the standard supply cylin-
der used universally in recharging various types of
CO2 cylinders. A cutaway view of the cylinder
valve is also shown. Table 8-1 lists some of the
most pertinent data concerning supply cylinders.
INSPECTING CO2 CYLINDERS
Cylinders, including some of those of new
manufacture, continue to bear ICC markings and,
8 - 2