Hey everyone!
Was wondering what the best “value” vacuum pumps are for SPD!
Wondering if anyone has any input at the following sizes
2L
5L
20L
Seems like the Alcatel 2021i has the fav spot for 5L? Has anyone tried any of the Chinese pumps with success/failure? Thanks!
2021i I
Or go dual/triple 2021i maybe for a 20l lol
Lol alright 
Only ones available to me are about $12-1400 after shipping (Canadian dollars). Hoping there’s something at about 50-70% that price, but I’m fairly certain that’s wishful thinking!
For that price get an Edward’s e2m28 or e2m30. I wouldn’t pay more than 400 for a working 2021i
Leybold trivac
Welch 1400 series
How big of volume do those run?
Is it just a CFM reading I’m looking for once it gets under a certain micron?
8cfm on the 2 liter flask. Is a good avarage minimum at 12 cfm about max
Pumps with a 1x10 4 are good
Second hand pumps are often good
Take your micron gauge along When buying
Alcatel
Welch. Leybold
Edwards
Are tanks so might look soso but they often can still pull a deep vac
Don t get Chinese for service pacs
Are hard to find
Get good oil oil can make a diffrance
Use firstpass oil for firstpasses and second pass oil for seconds
Read the manual Some good underrstanding of your pump makes sense
Guys, how can you estimate the size of the pump?.
I mean, as @Roguelab says pumps with 1x10-4 are good, but how can I compare the volume of the flask with the CFM of the pump? there is an equation, or something like that?.
For instance Labsociety says that 2L SP need an air displacement from 0.6 - 6 cfm. I dont know how precise it is, so a 20 L SP will need a pump between 6 -60 cfm?.
I appreciated if anyone can help me with that.
I have see Chinese pump with simmilar characteristics, is it real?
As a rule if thumb 4cfm for every liter of flask
Lab sosiety are fools selling 0.6. Cfm pumps to spd folks
Check the max vacuum of your chinees pump if it puls below 100 mic it s a start
If it pulls below 50 mic your good
If it pulls below 5 mic it s great
Main isseu is displacement under high vacuum with chinees pumps
I there for advise western pumps
Of the big brands not hvac pumps either
Apart from pump flow and pressure, is there another important factor in choosing a pump?
parts and electrical. make sure you can get a rebuild kit.
what pump so you have?
It comes handy if the exaust of the pump can be atached to a hose
Terps can stink and several tricks here to handel that if you have a exaust hose atached
Info on the gaskets might be useful not all gaskets can handel solvents and terps
A good sight glass on the pump is handy to check the oil
Gives info on what is boiling off
Oil is murkey most likely water
Noise most western pumps are quite but i have worked with pumps that where not quiet anoying on a long run
I have a 2L SPD, and i was looking for a Welch 3 8910, with 3 cfm displacement, but maybe is not enough.
Do u think this pump will work?
Go for a 8. Cfm pump they are very comon and can be found in good condition on secondhand markets
Welch wAnts you to use welch oil wich can get expensive
You can never oversize a vacuum pump i run a 2 liter with a Edwards 30 no problem even smoother run
Island 19 general vac oil is a perfect substitute for $ welch oil.
Alcatel 2021i is an absolute perfect vac pump for 2l, 5l spd.
Super budget option for 2L - Amazon kozyvacu 8cfm 2-stage rotary vane for under $200. Advertised at 25micron ultimate vac but it pulls down to single digit micron on my bullseye.
Anyone clock one of these in on a bullseye? Says ultimate vacuum is 2x10-1 Pa
What you wan t to use it for ?