The Science Behind Diffusion Vacuum Pumps: How They Work
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- čas přidán 25. 06. 2024
- I decided to make a video about my diffusion vacuum pump and explain the working principle behind those pumps and talk about the advantages and disadvantages. Diffusion pumps are used in high vacuum systems as an easy and cheap alternative to turbomolecular pumps.
It is not my normal style of content, but if you like it, let me know and I will make some more videos about different vacuum pumps, vacuum gauges and other equipment that is not vacuum related. I am still trying to get a feeling for what my audience wants to see and what they already know. So a short feedback would help a lot!
Applied Sciences video about his glass diffusion pump: • Giant glass diffusion ...
Cranktown Citys video about his homemade pump: • Homemade Oil Diffusion...
If you want to support me on patreon, I would greatly appreciate it: / advancedtinkering - Věda a technologie
I worked with mercury diffusion pumps in grad school (for organometallic synthesis). The main advantage is that they are immune to air/oxygen intrusion, so there is no need to bypass the pump when evacuating large flasks/chambers. This simplifies valving and saves time. Of course, the trade-off is that you always have 10kg of mercury refluxing in a large and complex glass apparatus right next to where you are manipulating flasks, stir plates, heat guns, cold traps, lecture bottles, etc.
Thank you for the information!
Now I'm curious, how did you set up the cold traps for this vacuum system? I would imagine you need at least 2 (or 2x2) one between the difussion pump and the oil pump, as to not contaminate the oil with a bunch of mercury. And one between your vacuum system and the difussion pump to not get solvents etc into the mercury.
@@merlin1371 The diffusion pump itself was water cooled, with an extra water cooled condenser on the low vacuum side (between the rotary vane pump and the diffusion pump). A liquid nitrogen trap was used between the diffusion pump and the main vacuum manifold and kept full of LN2, except for maintenance shut downs (about once a year, when maybe a mL or so of mercury would be recovered, mostly from a McCleod gauge on the main manifold). Four work stations depended from the main manifold, each with a LN2 trap for collecting solvents. Two of the work stations were identical high vacuum manifolds (with a sub manifold for three sodium/benzophenone solvent vacuum stills, connection to a mercury manometer/bubbler, scrubbed argon, and the reaction apparatus - typically a "flip-frit", but also sublimators, reflux set-ups, etc.). One work station was a 4 port Schlenk line. And the last work station was an automated Toepler pump system (for measuring gas consumed or evolved and analyzing evolved gases). Here is a link to a page with some pictures of the vac-line with Toepler pump: wolczanski.chem.cornell.edu/lab-tour/ . Not sure if they are still using a mercury diffusion pump on this line (which I used from 1981 to 1986).
Screw wrecked a plane stranded in the woods movies, lost at sea movies, deserted island movies, submarine movies, stuck underwater movies, stuck in space movies, lost is space movies, stranded in space movies, trapped in a broken submarine/boat/spaceship/cistern/receptacle/bunker/relationship movies AND this mercury rerefibulater thing.
.....but also I want one 😮
Guess we can't go and leave the mayflower, poisoned oracle, odysseus or lead water
So far yet so close
I actually watched your video to pick it to pieces but it is VERY GOOD! Nothing to pick on!
Thank you! I really enjoy watching your videos!
Additional pro/con: A diffusion pump, because it doesn't have moving parts, isn't going to create any vibrations like a turbo will (or, if it does create them, they will be significantly smaller). That said, if your turbo is making lots of vibrations, you have different problems!. Con: You can only run them in one orientation (vertically). Turbos can be run upside down/sideways/etc and are nice for chambers where you want the pump coming into a different orientation. Then again, you can usually find right angle flanges...
excellent insight
Yup that was an issue with upgrading a SEM. The vibrations needed to be dealt with. 🤔
Definitely welcome these style videos. While you can always Google around there aren't a lot of channels for these niche of topics/hardware
We used to call it a "Jet Tower" pump just to be pedantic since there is diffusion against the gradient. Glad someone is keeping this information alive.
Please do more of these style of videos. Would love to support that
Great video! Work with these all the time in the aerospace industry w/ vacuum furnaces. Usually use 704 silicone oil very efficient. Always found these pumps fascinating
Thank you! Yes, they are similarly fascinating like vortex tubes.
This kind of explainer is excellent - I learned something, and would be very glad for more content of this sort. Well done!
Thank you for the feedback! :)
Try tutorial
Excellent. Best explanation I've found. Thank you!
Congrats to 10k subscribers. You totally deserve it.
Cool, used to rebuild Varian mass specs in the 80’s working at a large aerospace corporation. I always enjoyed working on those instruments, thanks for the video.
Hey thank you for the video. I was researching vacuum pumps yesterday and found Cody’s Lab’s video on the Sprengle pump using mercury. It s VERY cool.
I've got a lot of appliances from an early vacuum tube shop from the 1920s. The shop later specialized in TX tubes refurbishment until the 60s. With it came 2 early glass diffusion pumps (unfortunately cracked) still with some mercury droplets in them. Also with some asbestos isolation. Apparently they were used with a Bunsen flame back then. They look beautiful really.
Awesome videos thanks. I am not familiar with these types of pumps and found the video very helpful.
Cool stuff. I've never needed to take one apart, thankfully, but use one pretty regularly.
Since I do many applications utilizing vacuum (mostly vacuum distillations of high-boiling materials), I'm very happy to learn more about it. Pumps, gauges, tubing, flanges, sealing etc. For example, lately I have been interested in how much influence the type of oil has on the resulting vacuum of a rotary (belt driven) oil pump. It has to be of certain parameters, fresh (not contaminated with volatiles) and in proper amount. Otherwise the vacuum drops significantly. Other influence (hosing, sealing, aparatus size, number of connections, even freezing - no significant importance is observed). I'm thinking about incorporating the diffusion pump to our systems, too.
Excellent presentation!
I like this video and I don't know anything about chemistry and its hardware so I do enjoy learning these things. ☺️
I worked 40 years in microelectronics manufacturing, I was in charge of various processes steps all using vacuum systems. Diffusion pumps were popular until about 20 years ago. Since then the, drawbacks of, size, orientation and most of all oil backstreaming, has rendered these pumps obsolete in manufacturing processes, all have been replaced by turbo molecular and Cryogenic pumps. RIP diffusion pumps.
Thank you 😊 tmrw i have exam and you almost cleared all my doubts
I remember upgrading a Joel SEM that had a mercury diffusion pump. We swapped it out for a turbomolecular pump. It got to vacuum way quicker. Did a lot of other upgrades on that scope as well. 😁
Thanks for making this.
I first knew about high vac diffusion pump through my interest with aluminizing telescope mirrors. I saw a diagram of pump and how it works in Amateur Telescope Making 3, and was amazed by it.
very informative, thank you!
Thanks man. I have been aware of this technology for a while. It is nice to see a small bench top version in pieces.
ps your pov video is quite useful.
pps Ben is a cool guy
Thank you very much! I'm a particle physicist; vacuum was the complicated mysterious thing that would fail and cause us to not be able to take beam until it was fixed. I'm pretty sure that even in big beam pipe volume accelerator systems, they use diffusion pumps as the primary pump (backed by big mechanical roughing pumps).
I'm so glad for your thorough explanation. I've seen diagrams of diffusion pumps, but just of the tree shapes and the oil sprays. I've never seen a diagram with the heater and the cooling jacket. That makes so much more sense.
Thanks!
Meanwhile, for me, vacuum is simple even if temperamental, and beam generation and beam optics are the mysterious thing.
interesting technology! I have never even heard of this type of pump before today
Thanks for posting 😀
I'm glad you learned something new today! They are fascinating devices.
Thanks this was cool!
I have one of these, I use it for a thermal evaporation setup to coat microphone diaphragms with a 150 angstrom layer of gold. I always thought that it worked by magic. Good explanation.
You need a public "amazon wishlist" :)
Sadly most of the stuff I need is not on Amazon. But I will think about it! :)
YOKOGAWA fluid gyro compasses for ships still have their older CMZ-700 units in service, there is about 10 cc. of Mercury inside the unit along with medium weight mineral oil and water treated with a preservative. Their newer CMZ-900 are mercury free and only have the mineral oil and treated water. I used to service those units and about 1 out of 10 jobs was an old CMZ700 so I had an annual overhaul kit of mercury, oil, treated water, and o-rings, and cleaning solvent. BTW love your channel, your explanations are excellent!
I spent half an hour yesterday looking for this video. Unfortunately it didn’t exist yet. So yes I like this style, please make more. I would also appreciate if you explained some of the basic principles. I am sure I actually understand what diffusion is. So while I understand better what is happening mechanically, I am not 100% sure why it works. Thank you.
Thank you for the feedback! I will make more of those videos. Sometimes I am a little hesitant to take a detailed video about the basic principles because I am not a physicist and I might get some things wrong.
But I will try to :)
I was hoping for an animation. But this was a good explanation.
Yeah, I liked the video. Don't know much about this sort of thing but it's interesting.
a video about different vacuum gages will be great
Ours at work have an oil separator on the exhaust side of the pump and a cooling jacket around it as well. We have them from shoebox size to the size of a small car.
There really is nothing new under the sun, is there? It's astonishing to find out the lengths that human ingenuity has gone to and the breadth of invention areas explored.
I occasionally use a diffusion pump. I get the oil from Dekont-Vukuumservice-GmbH (Germany). I use Dekonol DIFFM100 (€37.96/kg), a mineral oil specifically for diffusion pumps. They also have the Dekonol D705 variety (€218.54/kg), an oxygen-insensitive silicone oil for higher demands. But so far I've gotten along well with the mineral oil.
Greetings from Germany.
I believe that Cody from Cody's Lab channel made mercury pump. The idea is that chunks / drops of mercury is flowing through narrow tube trapping air in between the drops and thus sucking / pumping. Very slow but very energy efficient. And usable even with hundred years old technology.
I have two large ones, a small one amd one very large one. Very cool.
Nice explanation, I was wondering where did you get such a small diffusion pump....!!
I replied to your email. I got the pumped used so I unfortunately can not tell where it originally came from.
Best explanation _ theoretically as well practically 🙏🏻👍... Helpful in min. _ Tomorrow is my Msc physics final year examination n it will work out ..hope so😊....
Thank you! Good luck tomorrow!
@@AdvancedTinkering ty 🌸✌️🤞
Good video. Do you use it in a 2-stage set-up? i.e. mechanical bulk vacuum pump 1st stage followed by the 2nd stage diffusion finishing pump. Also, suggestion for future video: the Hilsch Vortex Tube.
Very cool! Simplicity can be very impressive! Forgive my mechanical comparison but for novelty and interest rather than practical use this is comparable with engines! It’s with some similarities like a carburettor vs mechanical injection! Definitely would like to see it suck! And that vacuum figure is not a number I can comprehend! a heap of vac to me is 30inhg or perhaps a stock engine at idle or an a/c compressor!
Yeah, I was going to say that this video is an interesting companion to Cranktown City's home-built pump... but you said it yourself.
After all of your comparisons to your turbo-molecular pump, I'd quite like to see details of that too.
.hey Brainiac, that explanation was as clear as mud. Also, you forgot to mention why anyone would give a crap about that crummy gadget.
We have rough vacuum in the chamber. How is heat transferred from oil vapour to the cooling elements?
If you degass the basic silicone oil (long enough), I guess it would also work.
Because it must be removing lower boiling point stuff to make the special mineral oil from basic industrial grade silicone oil.
Does it have any advantages over an ion pump aside from not needing a high voltage supply?
Hello, do you build the pump by yourself? Are building instructions available? Thanks Hans
Originally I thought that this might be used at the output of a Bussard Collector for picking up extra hydrogen fuel instead of just bouncing it away which takes away from the inertia.
Accumulate and use.
Something else to fling it through a small hole into a big tank for a pump which can add pressure later.
Excellent video. Earned a new sub here. Btw Ben of *Applied Science channel has an entirely see thru glass one of these for demonstrations that’s absolutely fascinating to see if anyone is interested*
interesting ive only seen these as glass fixtures..
I knew it was too good to be that good... I had to scoff at that price of oil.
Because it's so expensive and the pump is almost bulletproof, it would be well worth trying all kinds of things as the liquid.. There must be something a lot cheaper than that.
Mercury is still in use to pump tritium, the radioactive isotope of hydrogen. The radioactivity breaks down most normal oils, so you need to use mercury instead.
Very interesting!
I can’t remember where I saw it, but in the 19th century they used a vacuum pump design that looked like a bicycle wheel with tiny buckets set around the rim. When the wheel spins each bucket picks up one drop of mercury from a sump, carries it up and over and throws it into a funnel that shoots a drop of mercury across the vacuum chamber and into another funnel that leads back to the sump. When the drop flies across chamber it pushes out any gas molecules that went into the exit tube and that is how it creates the vacuum.
What you are referring to is called a "Sprengel pump". Also a very interesting and cool concept.
Cody'sLab made a video about a DIY version of this type of pump.
You can use "cheap" regular vacuum pump oil
The moka espresso pot of knowledge.
0:57 Foreline pump? Fourline pump? Fohrlein pump? What is it? (I've never heard of it, let alone got one!)
Anyone happen to have experiences with cheap eBay rotary vane vacuum pumps? Do they break up quickly? Can they really go to 5 Pascals?
All is good but I'm unable to understand one thing that what thing forces the air molecules in vacuum chamber to come in the inlet of the pump. I mean what creates suction at the inlet of diffusion pump.
As in rotary-vane pump we have blades fixed on rotor which create suction at the inlet.
There is nothing forcing the air molecules into the pump. That's the weird thing at very low pressures. In the molecular flow region you basically have to wait for the air molecule to fly into your pump where it is then excluded from the vacuum by the pump. That's also the reason why vacuum hoses or pipes for high vacuum applications have a large diameter. The chance is much higher, that an air molecule will fly though a larger opening than a smaller one.
👍👍
Use cesium as a working fluid :D
I have a same vacuum pump
这种小泵一般做收藏了
Mercury tilt switches?
I have enough mercury but I really don't want to use it in a diffusion pump :D
Like a Bernoulli effect?
have you tested the pump yet? And measured what kind of vacuum it creates?
Sadly no. I did not have the money to buy the oil. But I will make a video as soon as that changes :)
Did it come with a manual with what wattage or did you custom make it yourself? And what kind of roughing pump will you use? And if you do have a manual or made it yourself, what kind of pumping speed and ultimate vacuum can you achieve? I assume the bigger the pump, the fast and more ultimate the vacuum becomes. I just spent 200 euros for a wet dual stage rotary vane pump that goes to about 3x10E-3 mbar. So looking for my second stage part. I'm working on additive manufacturing so I only really need to look at a high vacuum. I wish ion pumps would work for this type but physics are against me :/(they seem the most interesting and cheap to diy build) but they would start to break easily at this type of roughing pump.
Great videos by the way, just subscribed very interesting projects
if you use mercury as your fluid you can get very very high vacuum though it would take a few days to get there and your setup has to be very very fine tuned.
Mercúrio é altamente tóxico melhor mesmo é óleo silicone amigo 🇧🇷
what so how does it pump? why would you use one of these
As someone without in depth knowledge of vacuum systems it doesn't appear that he actually explain how the pump removes gas from the chamber. I get the idea of the liquid evaporating and condensing but he doesn't then say how that removes gas molecules.
you can purify silicon oil to use in the difusion pump but you first have to boild it in vacuum to purify it like czcams.com/video/SehXEOk2CHE/video.html do i love your videos by the way. you can build a vacuum furnace and try to sinter to sinter 3d printed parts
@@joel_mckay I understand I don’t have any knowledge about this subject but it will be cool using mercury as the liquid and using a spregel vacuum pump as the rough vacuum like and old school death vacuum machine
@@joel_mckay Jajajaja i can imagine what a implosion it would make I recommend the Chanel X-MANY soo you can laughter a little bit about security and PPE
my wife also has one of these. it pumps chocolate or cheese.
Is mercury cheaper lol
10^-9 mBar ... so 10^-12 Bar ... wow thats increadibly low
This is some Harry Potter stuff. I have no idea why this contraption interacts with pressure
Pretty nerdy stuff
okay but... how does it work?? LoL
Nice explanation of parts, but ...
"its almost cute" lol
"I demand a video of a machine with *NO MOVING PARTS*, or else!!"
Get a grip, troll, lest your bridge collapse.
Boh, that german english pronounciation makes me shivering.
Are you serious? You didn't show the pump in operation? I will be sure not to watch anymore of your videos and waste my time.