Is a welch 2052B-01 a good pump to use on my 5L, currently have an Edwards 8 Welch self cleaning pump I run in tandom but I’m having to fraction at relatively high temps wondering if this pump alone will be able to pull deep enough to lower my fraction temps, didn’t see anything in search so I figured I’d come to the experts
Would not recommend a diaphragm pump. The Terps will eat the seals pretty quickly. Alcatel 2021i’s can be had for pretty cheap on eBay and linked in tandem.
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The welch diaphram pumps are excellent for etoh filtering and a 5L rotovap. You need a much deeper pulling vacuum pump for a spd setup
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Thank you all how about a edwards 30 vs a leybold d25b had friend recommend the leybold but everyone else I know is using a 30
Both pumps are great but the Edwards has a higher cfm so i would chose the Edwards
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when your friends are all doing it and @Roguelab recommends it…that’s a really solid indicator 
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Leybold 25 and Edward’s 28/30 are practically the same thing, edwards is the name brand and the other is the value brand
You see everyone using Edward’s, cuz they coudldnt find a good deal on a value brand. Not necessarily cuz its much better
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Hmmm small detail is that leybold has a deeper vac depth 1x10 4 and the Edwards 7 x 10 4 at 220 V
Cfm must also be looked at at volts and hertz of the power supply used
For they may differ making a choice more selective
And last tip check what Spares and refurbushing kit s cost for that makes sense 
Iv just bought new Edwards RV8 and a leybold bi 30 as roughing pump, im currently only running 2L SPD, have 5L wide bore coming this week, is that pump combo sufficient for 5L set up, were hitting around 180 microns on main fraction on 2l hoping the wide bore will improve on that number
I hit 67 microns on my 2L spd wirh my leybold trivac all they the run.
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The rv 8 is good for 2 liters but poor for 5
L the letbold is perfect for roughening on both
I also find a 180 micron a sign for a leak or a pump thats not running at iT s best
I would suggest to take the 8 rv and Measure it s vacuum isolated and running for at least 30 min the Reading You get is what your empty system should give you
If not You have Some leaks
If the pump is good i would try iT on. The 5 L system
And keep an eye open for a larger pump in the mean while
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Thanks for the reply,. that was my fear iv only just bought the Rv 8 new. I was told it be good for 2 & 5l. Iv pulled 10 microns on dead head, were usually around 170ish on first pass mains its lower around 130 microns on the second. I suspected that our cold trap may have have temperamental leak the only other thing it could be if not system or pump is the bullseye gauge might need calibrating. I’m swapping out the glass trap for stainless. where im based Its not easy trying to acquire the best equipment from Ireland we don’t have the selection here just yet and shipping anything from US costs a small fortune plus 30% importation tax its very frustrating when trying to progress. I’ll try run system dry see how it does. Would u recommend E28 or 30?
I rock elcheapo china glass and mantle with out any issues.
I did not skimp on my vac pump or vac gauge.
Leybold trivac and a bullseye digivac.
One trick I found to drop another 10-15 micron…
The recieving flask for the cold trap, fully surround the RF in a standard cooking pot with dry ice. And keep dry ice topped off in the ct ae well.
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I bought Chinese glass to start off with but had no confidence in it im still using Chinese mantle. I wouldn’t of classed an Edwards 8 & Leyboldold sv 40 as cheap, were using same bullseye gauge from digi vac. If its pulling 10 microns on head we must have a tiny leak somewhere. Were using the same method dry ice on cold trap flask iv only just swapped out glass trap for 304 ss already the microns are lower well see how the numbers are on a dry run
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Look at there specs for your situation about voltage and hertz
Diffrance is small so get Wich one suits You best but If i would have to choose i would go with 30
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Our voltage is 230v 50hz standard , specs i can find are for 115 @60hz. Pressure rated 1.5 x 10-3 torr (2 x10-3 mbar)
Yea hindsight should of waited gather funds for E30. Hoping these stainless traps will help, plan on running two in series using LN2, ones standard stainless trap the others on casters, its not bad for chinese made trap you can hook up a chiller if stuck for dry ice or LN
Second hand can score You Some great pumps believe me
And since You are in Ierland i can send You Some pump If You want
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Sounds good wel chat soon for sure, i want to see how we do with wide bore if the vac numbers arent good wel have to upgrade
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Ok so When running SPD
You start with the welch on and the rv8 running but not in line
Because If You have both pumps on in line
The welch steals vacuum from the rv 8
Once mains are about to reach You start running both pumps at the same time for a few minutes and then close the welch off
And catch mains running only the rv 8
On second pass i would run the whole run on the. Rv8
Would the Edwards 28/30 suffice for a 12L?
The 2021i from Alcatel has been awesome on a 1L, but I think I’ll need a new pump for something past 2L