Sizing a diffusion pump for a 10l spd

I’m just wondering how one might go about sizing a diffusion pump for a spd. I’ve been looking at the Edwards Diffstak 63 & 100 for my 10l setup, but have no idea what i really need. I’m looking at those two because they can be had for a reasonable price new or rebuilt and can be found on ebay. Does anyone have some information on what performance level diffusion pump i’d need for a 10l spd? My current vacuum setup is a 10l with dual alcetel 2021’s and a sogevac sv65. I pull sub 20-30 micron first pass main and sub 10-15 micron second pass main. I appreciate any input.



I would also love to hear some input on this as well!
I have a 10L with two Edwards E2M28’S and a Sogevac svs65! And have been thinking about acquiring a diffusion pump too! But what model of Edwards Diffstak should I get for my system?

And how cold of a chiller would I need for that pump, and how many liters should the chiller be?

Any other special care notes, tips, tricks, that I may need for diffusion?
(I heard they can screw up gauges, but I also heard that’s Bs…)
Thanks for any help! It’s greatly needed!

Get am Edwards diff stak 250 if you can, it’s the biggest baddest diff pump around.

2140 liters a second

Needs a chiller though

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Minimum 400 lps and don’t get accumulation diffusion pumps. The year drop ones have less oil and contaminate much faster. They pull vacuum but now as fast and the smaller body ones.

I have some diffusion pumps on super sale and the specialist sensors required to use them.

Remember a diffusion pump is nearly useless you have the 1800-3400 control gauge on it telling you what it’s doing.

The Edwards diffusion are accumulation pumps. They are last ditch effort. There are other pumps that opperate much better and won’t die during the run of it soaks.

I was the first person in the cannabis industry since we’ve been afloat to use, master and integrate diffusion pumps into short path table top systems. I know more about thier success than anyone on here. I am also the only supplier who stocks both the diffusion. Pumps, sensors, controllers, chillers and complete turn key diffusion packages. We sell them weekly. Nobody else stocks them because they don’t know shit and would rather drop ship and lie to you.

If you want lower temps, brighter colors, and better results with fabulous speeds hit me up. I won’t lie to you or force you to buy half ass used junk online and run it blindly. I have tested them all. I can tell you telle what model pumps don’t work, what work half ass, and what isn’t worth your time.


Not true. The diffstack is a kf40 inlet. Wich means it’s the basis of CFM that a single inlet can handle. The range of Wich is kf40. If you take that down to kf25 where you should be to keep molecules moving then your cutting CFM in half almost.

The pump you mentioned is a accumulation diffusion pump. Meaning it has less oil in it and takes a bit longer to accumulate vacuum.

Accumulation diffusion pumps contaminate much faster, slow down, and soak very quickly and cannot eject contamination as fast as others. what you want is a straight wall diffusion pump. They have massive Regen oil capacities and the vapors inject into the pump much faster and generate vacuum much much faster. They do not as deep vacuum as accumulation diffusion pumps but the range Wich they dip happens nearly immediately in process.

Hey @spdking I was wondering is a diffusion pump only for larger scale operations?

No it alters the opperation and process. It changes the sop considerably. You’ll run the short path different.

Would you say it can be used more or as effectively in a 2L fractional distillation setup?

I have a smaller one that doesn’t sputter rates on a 2l. It’s a couple Grand and it works. The Edwards 50/60 version or also known now as Welch diff models aren’t good. They splash oil out of the chamber almost immediately with vapor movement. Yes my first runs with diffusion was on my 2l bent neck hosed setup. It worked but terribly, compared to how we use diffusion now. It doesn’t matter what you hook a diff up to. I mean size wise. But it does matter what diffusion pump you use based on size.

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The diff stak 250 is kf 25, do I need to go find my post where breaking dabs was drooling over my diff?

Here you go talking out your ass again elliot

Btw what happened to cfm doesnt matter after a certain vacuum level?

The diff pump isnt about cfm -_-

Technically the sogevac is kf 40, why do you use it if its incapable of using all the cfm because kf 25 is too small?

There’s a reason why they make three types of diffusion pumps. They opperate differently … You are welcome to come by my shop and I can hook up all three types and show you onna digital pump down curve. I’m only stating facts. Straighter walls, more oil, will produce better diffusion rates and eject the molecules from the oil more efficiently.