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Author: Subject: How to prevent pressure suck back
Romix
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[*] posted on 14-11-2021 at 11:02
How to prevent pressure suck back


Hello Dear forum members,
I think I've seen it here on a forum, set up with pictures and videos on how to prevent pressure suck back during distillation and filtering the gases through something...
Can you please direct me to that thread and explain how it works?
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macckone
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[*] posted on 15-11-2021 at 07:50


there are two methods, the trap method and the funnel method.

With the trap method, you have an intermediate container that captures liquid during suckback.
With the funnel method, you have the funnel just below the surface of the liquid which will prevent suckback because it doesn't fill sufficiently before air gets sucked back.
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ManyInterests
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[*] posted on 19-11-2021 at 14:04


I had this problem with my first two nitric acid attempts. I might try that again, but I will use the absolute minimum of sodium hydroxide AND I will move the funnel slightly out of the solution once I feel all the NO2 gasses are done.
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draculic acid69
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[*] posted on 20-11-2021 at 00:03


Quote: Originally posted by Romix  
Hello Dear forum members,
I think I've seen it here on a forum, set up with pictures and videos on how to prevent pressure suck back during distillation and filtering the gases through something...
Can you please direct me to that thread and explain how it works?


Buy a $3 plastic check valve off eBay and you will never have suckback happen again
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Sulaiman
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[*] posted on 20-11-2021 at 06:37


For an inverted funnel trap it is best if the funnel is of only slightly smaller diameter than the liquid container,
(eg 90mm diameter funnel in a 100mm diameter beaker)
this way, as the liquid is sucked up into the funnel the level of liquid in the container simultaneously drops significantly.

Clamp the funnel rather than letting it sit on the bottom of the container to allow the use of a large quantity of liquid,
enabling the use of a larger volume of liquid absorbent.

Test/play with water to get a feel for it.
With water you can use your mouth as a suction source.




CAUTION : Hobby Chemist, not Professional or even Amateur
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