T3sl4co1l,
Nope, I did mean 200psi as that is what the spec says they need for their Helium Fill. The Helium is "Ultra High Purity" (UHP) because too much "Air" or other contamination gases can cause issues with the cooler. The cold finger is running at 77K (-196C) Cryo temperature so any water content will freeze and lock the piston.
From what I have read, these micro Stirling Coolers operate with extremely tight tolerance pistons and anything but UHP and dry Helium has the potential to prevent the cooler working correctly.
200psi is not that difficult to work with but the fill port on a Stirling cryo cooler appears to be just a threaded hole with a sealing washer and threaded plug to seal it when filled. The fill nozzle would need to have a threaded exterior section, gas seal shoulder and a integrated axial tool to unscrew and screw the sealing plug. That axial tool would also have to be suitably sealed for 200psi and retained in place so that it does not become a 200psi propelled projectile when the gas is injected ! All of this is within my skill set but it is not a trivial exercise. I already have the correct twin regulators and gauges for pumpimg down and gas pressure regulations. etc. I also have the correct hoses for the task. I just need the fill port adapter and a suitable source of UHP Helium.
Note, regarding Balloon Helium..... such is pretty much an unknown gas mix when bought from most suppliers. It can be bought in cylinders that are already pressurised to over 200psi. Sadly I have been advised that such balloon gas often contains a atmospheric air mix, including oxygen, Nitrogen and other pollutants that will adversely effect the cryo cooler operation. It is also not in any way 'dried' so can contain water vapour ! There are better Helium gas types that are high purity but not UHP. They may do the job as they are supplied with a known mix specification so you know what you are getting.
Refilling a Stirling Cooler is a specialist task that was normally carried out by companies with the right equipment, full manufacturers specs, UHP Helium and LN2 cryo gas driers.
Fraser