Liquefying air at home with my new cryopump

i have a new toy it's a cryo pump used for high vacuum applications this pump is capable of temperatures down to 10 kelvin which means 10 kelvin warmer than absolute zero the first box contains the code head itself and the lines to connect it to the compressor [Music] the second much larger and heavier box contains the compressor it's an 80 kilograms behemoth here you can see the connections for the high pressure and low pressure lines leading to the cold head as well as the connections for the cooling water on the other side there is a switch and the gauges for the pressure on the low and high pressure side in the future i want to use this pump as it was intended and use it to build a high vacuum chamber for different experiments like sputtering until i get everything i need to build the vacuum chamber i will use the cryo pump to liquefy different gases which means i have to remove everything from the pump that i don't need here you can see the internals of the pump all of these surfaces are coated with activated carbon to aid the adsorption of molecules when i make the video about the vacuum system i will build i will explain in detail how these pumps work to optimize the heat transfer all of the metal to metal contact points were lined with indium foil it's comparable to a thermal compound you would use when installing a heatsink to a cpu the huge benefit when using indium is that it won't outgas under very low pressures indium is a very soft metal as you can see and i kept all of these scrap pieces if you have any idea what to do with it write me a comment when i put the pump back together i will replace all of the indium with fresh indium foil as you can see i am wearing gloves when handling the insides of the pump to prevent contamination by oils from my skin so it was time to connect the helium lines and test the pump the red hose is for the high pressure helium and the greenhouse is for the low pressure helium i'm waiting for you to crucify me in the comments for not using a proper wrench when tightening the connections the other end of the hose gets connected to the cold head on the right side you can see the temperature gauge that goes down to 14 kelvin on the left side you can see kf flanges to connect the roughing pump and vacuum gauges there is also a three pin electrical connector to drive the valve motor it was finally time to turn on the pump for the first time [Music] well that did not go as planned when looking at the gauges i noticed that the pressure was much lower than it should be and after opening the compressor i noticed that the cut-off circuit is only connected to the gauges so it had to be the helium pressure the compressor probably lost some helium in the many years it's set unused which means i have to refill it the compressor has a charge port according to the label below it wants 99.995 percent pure helium so it's quite convenient that there's helium for balloons available that is 99.996 pure so i got myself some proper party factory helium certified for the use in cryo pumps because i did not have the correct connectors i watched together a more than questionable construction to refill the compressor and after turning it back on it finally worked let's liquify some air i insulated the first stage of the cold head to minimize the condensation of water and i fixed a k-type thermocouple to the second stage to monitor the temperature as an improvised dual flask i wept a thermos with foam so it would seal against the foam inside the pump when inserting the cold head into the flask i already ordered a proper dual flask to increase the yield i think a lot of my liquid air is lost due to evaporation in my receiving flask here you can see the whole setup while running because the thermos was too tall i had to improvise and put the pump on some wooden blocks the compressor needs to be water cooled so i just ran some tubes into my bathroom and 3d printed a connector to connect it to my tap it uses approximately 1.5 liters per minute i am thinking about building a self-contained cooling unit to save water but all the heat from the radiators would heat up my small room immensely nice when it is winter but hell in the summer this is the readout from the thermocouple it shows approximately negative 186 degrees c which is 87 kelvin it's not very precise since it uses the ambient temperature as a reference just touching the leads and warming them up changes the temperature readout because i'm creating a temperature differential at the junction of two dissimilar metals which creates a potential difference due to the sebek effect i just thought that's an interesting fact the temperature did not fall any further probably due to the condensation heat of oxygen and argon preventing the pump from reaching lower temperatures so five hours have passed let's get the thermos and see if we have liquefied any air and as you can see there's around 50 milliliters of liquid air in the flask that's not a lot considering the pump ran for several hours according to another person that has a similar pump it should be possible to produce around 400 grams per hour due to the temperature of the cold head and the bluish color of the liquid gas i think it's mostly oxygen so i thought i would try to reignite some paper so i want to use this opportunity to thank the person that gave me this pump for very little money normally equipment like this is really expensive and i would not be able to afford it awesome people like this make it possible for me to do this interesting stuff i will try to increase the yield and liquefy one gas at a time for a future video if you have any ideas for interesting experiments i could do with the cryo pump before i integrate it in my vacuum system write me a comment what i was always interested in is how cesium would react in contact with liquid oxygen so i think that's a great idea for a future video thank you a lot for watching

Channel: Advanced Tinkering

Views: 23,266

Keywords: liquid nitrogen, liquid air, liquid oxygen, liquid nitrogen generator, air liquefier, flüssiger stickstoff, flüssiger sauerstoff

Id: UPl4ZZvZyiw

Length: 8min 48sec (528 seconds)

Published: Tue May 17 2022