Ulvac CRYO-U Series Instruction Manual page 70

Maintenance
◇The gas charge inlet of the compressor unit is 1/4B male flare.
◇Use helium gas with purity of 99.999% or more.
Charge helium gas as follows:
１．When mounting the regulator on a new helium bottle, perform the following procedures
in order to remove air and fill helium gas in the gas line between the regulator and the
bottle valve first.
ａ ． Open the regulator a small amount by slightly turning the regulator handle
clockwise.
ｂ． Slowly open the bottle valve, and purge the regulator and gas line for several seconds.
ｃ．Turn the regulator handle counter-clockwise to close the regulator.
Do not open the bottle valve immediately after attaching a regulator, as it diffuses the air
between the regulator and bottle valve into the helium bottle, and contaminates helium gas.
Never bring your face in front of the pressure gauge when opening the bottle valve or turning
the regulator handle.
２．Remove the front panel of the compressor unit.
３．Connect the helium charging hose as follows:
ａ．Connect the charging hose to the regulator.
ｂ．Loosely connect the charging hose to the charge inlet on the compressor unit so that
helium gas can be slightly blown out here.
ｃ．Open the regulator until the outlet pressure reaches 0.1 to 0.2 MPaG. Allow helium
gas to flow out from the charging hose for about half a minute. Meanwhile, open the
charge valve slightly in order to drive out the air that exists between the charge
valve and the charge inlet.
ｄ．Tighten the flair nut at the end of charging hose and close the charge valve. Helium
gas charge in the line between the regulator and the charge valve on the compressor
has been completed.
４．Adjust the outlet pressure of the regulator at 1.8 MPaG. Pressure relief valve has to be
mounted as well as the regulator. The set pressure of the pressure relief valve is
2.4MPaG.
8-6
CAUTION
WARNING
ULVAC CRYOGENICS INCORPORATED