beerwiz
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Best way to reduce noise/silence a vacuum pump?
I do vacuum distillations quite often using a rotary vane vaccum pump and the noise during the distillation is annoying and unbearable. Running
distillations for hours at a time with these noise levels is a problem.
What is the best way to run the pump silently or at least to a more quiet level?
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Lefaucheux10
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hi guy,
Why not use a long vacuum tube to permit the pump to be far away from you ?
instead you can use insulation wool to do a box for the pump but it will probably heat the pump up
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j_sum1
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Check out Nurdrage's latest offering released today. He sets up a nice little operation using an aspirator (available from dechem and nanshinsales
amongst others). He makes a good case for using these in a variety of situations including mentioning noise issues. He also discusses their
limitations, how they can be made even more effective and when they should be avoided.
You might want to consider his setup.
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Mechanical Animal
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Personally, I direct the output of my pump into a container full of fiber glass to dampen the sound of the exhaust and I put that container along with
the pump into a heavy wooden cabinet about 5 or so feet from my work area. I still hear the pump but it's anything but loud. Also, if you need/want to
get your pump further away from you, you can use push-to-connect fittings and polyethylene tubing that can be bought at any hardware store in rolls of
25 and 50 feet for only a couple bucks. This translucent tubing is fairly flexible but rigid enough to hold even high vacuum and polyethylene is
compatible with more solvents, fumes, vapors, gases, etc than your pump and its oil so it will resist anything that you would subject your pump to
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XeonTheMGPony
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Quote: Originally posted by Mechanical Animal  | | Personally, I direct the output of my pump into a container full of fiber glass to dampen the sound of the exhaust and I put that container along with
the pump into a heavy wooden cabinet about 5 or so feet from my work area. I still hear the pump but it's anything but loud. Also, if you need/want to
get your pump further away from you, you can use push-to-connect fittings and polyethylene tubing that can be bought at any hardware store in rolls of
25 and 50 feet for only a couple bucks. This translucent tubing is fairly flexible but rigid enough to hold even high vacuum and polyethylene is
compatible with more solvents, fumes, vapors, gases, etc than your pump and its oil so it will resist anything that you would subject your pump to
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That's good advice, but then going one step further a 3 sided box lined with 2 inches of fiber glass open side aimed out a window or into a panel of
fiber glass set back a foot will drastically reduce ambient noise.
I use rotary vans for every thing often and yes it does get dreadfully tedious!
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PHILOU Zrealone
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Put the pump onto silent blocks.
Put the pump into vaccuum    ... Just cynical
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Praxichys
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You could run the pump in a different room and just have a long vacuum line.
Rotary vane pumps are notoriously noisy without a decent amount of backpressure. The vanes clatter around when there is insufficient pressure to keep
them in place. You could try partially blocking off the exhaust, but then you'd have the hiss to deal with still.
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aga
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Just switch it off
... then buy a quieter one.
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Magpie
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I have a related problem with my rotary vane vacuum pump. When I want to control the vacuum to something less than full vacuum I bleed air into the
suction. But this causes a significant amount of oil loss thru mist in the exhaust. Is there a better way to do this? Or is this just "the nature
of the beast" and I have to live with it?
The single most important condition for a successful synthesis is good mixing - Nicodem
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aga
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I get the same with mine.
It's on the wooden floor of the shed, so the oil does a great job of protecting the wood, and makes it much more flammable.
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XeonTheMGPony
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| Quote: Originally posted by Magpie | | I have a related problem with my rotary vane vacuum pump. When I want to control the vacuum to something less than full vacuum I bleed air into the
suction. But this causes a significant amount of oil loss thru mist in the exhaust. Is there a better way to do this? Or is this just "the nature
of the beast" and I have to live with it? |
just the way she works, you can make a better scrubber though that will help
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Dr.Bob
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You can always build a vacuum controller, where you have two valves, one limiting the flow to the vacuum pump, and one bleeding air into the system.
There are even switching controllers which do this automatically, which are useful if trying to use a high vacuum to create a mild vacuum. But I
prefer to use a weaker pump when I want a low vacuum, the ones for rotovaps or a diaphragm pump or aspirator are all good choices then.
For noice, enclosing the pump or putting it in another room are OK, but the longer the vac line, the lower the ultimate vacuum. Fine for most cases,
but bad for high vacuum work. And insulating the pump can cause it to overheat, we had cases of that when people put them in boxes with fiberglass
insulation, so make sure that you create a cooling airflow through the box as well. If the pump is pulling a high vacuum, there will be almost no
flow from it, so it will not cool well.
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Sulaiman
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based on only a little experience using a Chinese 2-stage rotary vac pump,
most of the noise and all of the gasses/vapours can be vented away using just flexible hose from the output port.
using my pump on a wooden table amplifies the mechanical noise
using it on the concrete floor is much quieter.
On an old carpet mat on the concrete floor even quieter.
[Edited on 30-8-2016 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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unionised
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OK so he was probably joking but, if your system doesn't leak, what is the pump doing once it has pulled the air out of the system?
Fit a set of suitable valves and turn the pump off once it has done its job.
You might need to turn it back on again from time to time to compensate for leaks but if that's a problem then you don't have a proper system set up.
Also- long pipes are a bad idea for vacuum systems.
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chemrox
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| Quote: Originally posted by Magpie | I have a related problem with my rotary vane vacuum pump. When I want to control the vacuum to something less than full vacuum I bleed air into the
suction. But this causes a significant amount of oil loss thru mist in the exhaust. Is there a better way to do this? Or is this just "the nature
of the beast" and I have to live with it?[/rquote
I use a vacuum control. Several types; one bleeds part of the suction with a needle valve, the other is a manostat. I have two types made of
glassware. One (Cartesian) uses Hg vapor pressure and a float, the other uses a low vapor pressure organic compound. There's diagram of the latter in
Vogel's 3rd. I had a glassblower make it. It's for sale for the right price. It's limited to the vapor pressure of the liquid inside and the orifice
of a bubbling tube. Cartesian manostats are a little dicey to set up but work well provided you get leak out of the system. NB: low oil levels make
mechanical vane pumps louder. Aspirators are fine with moderate vacuum requirements. I use a double aspirator pump for my Buchi evaporators.
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"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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S.C. Wack
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Agilent makes an isolation box that fits standard pumps; this is something I saw on ebay once. It was fantastically expensive new, and heavy. Looked
like it cost about $60 to make. The Quiet Cover.
BTW a good pump will run too hot (maybe even with a fan) with air bled into it and it's just unthinkable anyways IMHO. Why not have a cheap pump for
that.
[Edited on 30-8-2016 by S.C. Wack]
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Magpie
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My pump is cheap: $100 from Harbor Freight. At first I thought that running air trough the pump would cool it then I realized moving air takes work.
The single most important condition for a successful synthesis is good mixing - Nicodem
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phlogiston
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At work, we have a couple of those agilent isolation boxes to house the noisy roughing pumps of the mass spectrometers. They are not cheap but it
would cost more to duplicate one ourselves. They really are very simple. Just a box of thin sheet metal with foam on the inside. It is very effective
and if you only have to pay material costs it would be an excellent solution. A Waters employee told me many labs have a separate room to house
roughing pumps and use a longer vacuum hose, but you'd need to have space for that and there is also the problem of heat dissipation to deal with.
[Edited on 30-8-2016 by phlogiston]
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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Panache
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Use an old refrigerator, drill a snug hole through the side for your vacuum, turn it on when using the vacuum pump (cooling)
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