Hampson-Linde air liquefier - Beginnings

Initial concept of building a Hampson-Linde cycle air liquefier. Patented independently by William Hampson and Carl von LInde in 1895, this is a conceptually very simple, albeit inefficient, way to liquefy air. Explanation of system operation, and testing temperature drop using a coil of copper pipe and expansion valve.

Category:

Science & Technology

Tags:

• hampson-linde
• liquid nitrogen
• liquid air
• liquefier
• cryocooler
• cryogenics
• joule-thompson
• refrigeration
• DIY

[bkraz333]

Neat! The temperature drop that you get at the expansion valve is linearly related to the pressure differential for a given gas temperature. Search for the Joule-Thomson effect for more info. There is a commercial liquid nitrogen generator called the "Elan 2" that probably operates as a Joule-Thomson refrigerator. It's compressor is likely 3000 psi (scuba tank, paintball filling). I built a liquid nitrogen generator (search for DIY liquid nitrogen) using a Stirling cryocooler.

[tesla500]

@bkraz333 Thanks! Does higher pressure equal higher efficiency? If I double the pressure and half the flow, deltaT on both the expansion valve and (possibly?) the recuperator double, which should mean the same efficiency, if I'm thinking right. If so, why is high pressure preferred?

Would you have any idea where to find info on recuperator calculations, ie how long does it need to be to get a certain deltaT?

I couldn't find your DIY Liquid Nitrogen video, is it still up?

[colt4547]

It's amazing how simple the concept is but it certainly seems like it would be very difficult to execute. I'm very interested to see more of this project. Thanks.

[tesla500]

@colt4547 Yes, it's very simple in concept, but I'm sure there are major hurdles to overcome. Getting the air clean and dry enough, and making an expansion valve work at cryogenic temperatures come to mind, but I'm sure there are more.

[Aussie50]

Thats a really neat concept!, I must try it one day!. I'm way behind on my experiments quota :D

[tesla500]

@Aussie50 Thanks! I've wanted to do this for a long time, finally getting around to it.

[Assi2004]

@tesla500 higher pressure = less volume for the same work = less perfect heatexchanger does the job (or a smaller one)

lets just say at 200bar the exchanger has to exchange 1l/min

--> at 10bar, it would have to handle 20l/min with the very same efficiency to be as good. it would be much bigger then, so its also more expansive and u got more insulation loses

im also trying to do this in the near future - i got a 9bar (abs) supply, but with more power then urs (>1m³/min at 9bar)

[NOBOX7]

is your condesore getting hot?

[NOBOX7]

i did not listen to every thing u said in the vid so if u mention your valve posibly being maybe to big then forgive my mention. , the spud of a propane torch might work better, great video by the way , i love this devcie, do you intend to finnish this device?

[NOBOX7]

hey friend as far as i know your machine may work better then it performed in this video, you see you must have your expansion valve adjusted exactly right for the flow rate of your compressore this process is so finiky you may even need a smaller valve also future designs use capilary tubes, the accuracy or percision

is very hard to acheive and its best to calibrate it with a gas that liquifies easier then air like r12 or butane if it will liqify butane it will liqify air at that setting



[bkraz333]

@tesla500 Search google for DIY liquid nitrogen to find my blog entry and video. I am not sure about finding exact refrigerator calculations, but using a higher system pressure will definitely help. You are right that in theory using a lower pressure and higher flowrate should produce the same amount of cooling. In practice, the lower temperature drop means that the air must circulate the system many more times, creating more chance for losses. Try silica gel towers (as I did) to dry the air.

[lazaglider]

I will watch this project with interest.