Purging with Gaseous Nitrogen
The UltraDoser unit must only be purged with gaseous nitrogen. Chart recommends the UltraDoser unit
be purged when not in use. However, this may not be practical for all operators. At a minimum, the
UltraDoser unit should be purged to eliminate any water that may be inside the unit after installation and
prior to startup. The UltraDoser reservoir may also require purging when there is liquid nitrogen flowing
out of the vent. The UltraDoser reservoir must also be purged when the nozzle becomes frozen shut.
This section assumes a Y-Pattern valve and Purge Kit are installed upstream of the UltraDoser unit. Chart
highly recommends each UltraDoser 2K be installed with a Y-Pattern valve and Purge Kit to isolate the
UltraDoser unit from the LN
2
source and to purge the UltraDoser unit to eliminate performance
interruptions.
A dedicated GN
2
source is required to purge the UltraDoser unit. Chart recommends a dedicated GN
2
source from the facility.
1. Manually close (clockwise) the Y-Pattern valve (blue
handle).
2. Manually open (clockwise) the ball valve (yellow handle)
on the Purge Kit.
3. On the 2K controller, go to [Maintenance] [Maintenance
Modes] screen (see page 30 for additional information).
“Disable” the dosing valve.
4. Manually close (clockwise) the valve (silver nut) on the
CryoDoser arm and power “Off” the 2K controller.
IMPORTANT: The supply pressure reading on the 2K controller may read 12 ± PSI due to the added GN
2
pressure.
IMPORTANT: When purging the UltraDoser unit, it will vent heavily and there will be a steady stream of
“fog” from the vent. This “fog” will be cold to the touch if the internal temperature of the UltraDoser unit
is still at or near LN
2
temperatures (-320 ºF; -196 ºC). Once the UltraDoser unit is at or near ambient
temperature, the “fog” will warm up.
Image 6: Y-Pattern Valve with
Purge Kit Assembly
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