charley1957
Hazard to Others
Posts: 137
Registered: 18-2-2012
Location: Texas
Member Is Offline
Mood: Extracted
|
|
Vacuum pump protection
Seems I've seen somewhere in the forums where someone built a scrubber of sorts for their vacuum pump. Best I remember, it was a series of, I think,
Mason jars, each holding a different chemical to neutralize something or other. Seems like there were four or five of them in series before the
vacuum pump. Yes, I've UTFSE now for several hours and I can't find that post, and it had pics. Does anybody else remember seeing this, and if so,
where?
You can’t claim you drank all day if you didn’t start early in the morning.
|
|
|
j_sum1
Administrator
Posts: 6219
Registered: 4-10-2014
Location: Unmoved
Member Is Offline
Mood: Organised
|
|
As I recall it was praxichys who did this. It might be on his yt chnnel -- Doug's Lab.
(Or I may be misremembering.)
|
|
|
NedsHead
Hazard to Others
Posts: 409
Registered: 9-12-2014
Location: South Australia
Member Is Offline
Mood: No Mood
|
|
May have been zts16, not sure, it was a long time ago
|
|
|
LearnedAmateur
National Hazard
Posts: 513
Registered: 30-3-2017
Location: Somewhere in the UK
Member Is Offline
Mood: Free Radical
|
|
My opinion would be that at least three of the jars contain distilled water, diluted (30-50%?) sulphuric acid, and sodium hydroxide solution -
potentially an organic solvent depending on what is coming over. I've seen this sort of setup as well, where two or three jars of NaOH are sometimes
used and they tend to be at the end of the chain but it may not matter regarding the order. I assume that you're wondering what is used to scrub the
gases, but I haven't seen the video myself so I can't give you any pointers there.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
|
|
|
charley1957
Hazard to Others
Posts: 137
Registered: 18-2-2012
Location: Texas
Member Is Offline
Mood: Extracted
|
|
Sciencemadness Discussion Board » Fundamentals » Chemistry in General » Everyday Chemistry. I found it on page 1. It was zts16 who did it back in
2015. I knew I could find it again if I just had enough time. Thanks for all your suggestions!
[Edited on Nov11-13-2017 by charley1957]
You can’t claim you drank all day if you didn’t start early in the morning.
|
|
|
Texium
Administrator
Posts: 4508
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
Quote: Originally posted by charley1957  | Seems I've seen somewhere in the forums where someone built a scrubber of sorts for their vacuum pump. Best I remember, it was a series of, I think,
Mason jars, each holding a different chemical to neutralize something or other. Seems like there were four or five of them in series before the
vacuum pump. Yes, I've UTFSE now for several hours and I can't find that post, and it had pics. Does anybody else remember seeing this, and if so,
where?
|
Yeah, that was mine... it was terrible and broke the first time that I used it. Wouldn't recommend! Now I
just stick a calcium chloride guard tube on mine, and I have a Dewar condenser that I can load with dry ice if I need to.
|
|
|
BromicAcid
International Hazard
Posts: 3227
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
If you have anything before your pump it better not boil under the vacuum your are applying (like pretty much any aqueous solution) better yet it
should have pretty much nil volatility or you're going to suck it to your pump anyway. That's why people usually use KOH traps or cold traps.
Nothing to suck to the pump.
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
The first thing that struck me about this idea was that the Mason jars would be under vacuum and might implode. What broke zts16?
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
Texium
Administrator
Posts: 4508
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: PhD candidate!
|
|
The mason jars were alright (my pump is just a single stage rotary vane, so it's not the most powerful), but the way I sealed the tubing to the lids
was terrible. I used hot glue because it was what I had available. It was quickly chewed up by the NaOH solution. The sulfuric acid also wreaked havoc
on the lids of the jars, and I had a lot of issues with suckback. The alternating empty jars were meant to solve that issue, but it was still really
annoying to empty them out all the time.
Overall, it was just an ineffective and overcomplicated design.
|
|
|
Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
just a side note;
a single stage oil sealed rotary vane vacuum pump and a dual stage create almost identical forces on evacuated vssels ...
1 Atmosphere - almost nothing.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
markx
National Hazard
Posts: 645
Registered: 7-8-2003
Location: Northern kingdom
Member Is Offline
Mood: Very Jolly
|
|
Yeah....basically any sort of scrubbing system will eventually allow the harmful components through and into the pump. Either due to breakage,
suckback, deterioration of scrubbing media or human error. It is inevitable and not a question of "if?" but a question of "when?". Hence I see no
point in trying to build a massive failureproof scrubbing system....I find it is much more reasonable to just select the right type of pump for the
job. When filtrations and distillations are the main objective, then building or sourcing a closed loop aspirator system is far more sensible than
trying to build a contaminant scrubber for a rotary vane pump. The aspirator system can be quite bulky, but it is robust and can handle basically any
contaminants without fear of irreversible damage. Or one can use a Teflon lined pump that is designed to handle aggressive contaminants...a much more
compact solution, but the pricetag can be quite rich.
Exact science is a figment of imagination.......
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
