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Helium compressor charging |
This section explains how to recharge the compressor if the dynamic pressure has dropped below 325 Psi
When charging it is very important to take the following precautions:
It is very important that you use pure Helium. Since we still haven't got the 7/9 pure Helium, we use 6/9 (99.9999% pure).
Further you should be careful not to contaminate the Helium bottle! Make sure that the trapped volume of air in the regulator doesn't get mixed with the helium in the bottle. If this happens the bottle will loose its impurity and will become useless
When you are going to charge, make sure to always open the regulator before you open the bottle. That way any trapped air between the regulator membrane and the bottle valve gets blown out by the Helium.
Needed:
- Helium bottle
- Pressure regulator
- small adjustable spanner
For compressor connections click here.
Steps to charge:
Charging has to be done with the compressor running and with a cold head connected. Only that way you can read the real dynamic pressure on the pressure gage.
- Turn knob on the regulator a couple of turns clockwise (the regulator is now open)
- Open bottle, so there's just a bit of Helium flow. Leave this, so the regulator and the hose get purged
- Take the brass cap of the charge port of the compressor.
- Open the charge valve so there's just a bit of Helium escaping. This is best checked by putting your thumb on the nipple of the charge port and turn the knob until you feel the pressure.
- Connect the hose to the nipple and tighten with a spanner.
- Fully open bottle and pressure regulator.
- Slowly open the charge valve until the pressure starts to rise. Charge to 325 Psi (dynamic pressure)
- Close the charge valve.
- Close the bottle.
- Release pressure regulator by turning knob anti-clockwise, Helium will escape.
- Take off the hose and put the brass cap back on the charge port.
Remember to fill in the datasheet which is on the compressor.
Last updated 10/04/02, Michiel van der Hoeven
