We were having problems lowering the Heliox insert into the storage dewar, the vacuum can would touch the top of the liquid Helium before the seal could be made, resulting in a rapid and somewhat violent boil-off of Liquid Helium. Frozen fingers ensued, as did cursing at the wastage of gas. Unfortunately I don’t have any pictures of said shenanigans, mainly because I was trying to desparately help get the seal made at the time.
But I do have a picture of our cunning solution:
A nifty set of bellows made from the flexible hose stuff that you attach to tumble dryers and some nice adapters to mount it onto the fridge fittings, courtesy of our technicians. I take no responsibility for the crazy MacGyver-ness this time, it was all my colleagues’ doing 🙂
(You can actually buy vacuum bellows from places like Kurt J. Lesker, but they cost hundreds of pounds, and this would probably have been specified as a custom job anyway, which can sometimes increase the price by an order of magnitude).
Anyway, the hose confines the boiling gas as you lower the insert. Which seems to work rather well. It also adds a nice steampunk touch to an otherwise commercial fridge assembly.