Ax165Xj
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Metal Bellows Vacuum Pump
I was recently given a non-working General Electric MB-158. This is a metal bellows pump, which works by compressing and decompressing a piston with
expandable bellows and two one way valves. Fortunately, fixing it was fairly simple (fixed an electrical short and tightened the bolts holding the
bellows on). So now I have a perfectly fine, albeit a little old, vacuum pump.
I know that MB pumps have the advantage of needing no pump oil. So I don't really have to worry so much about protecting my pump oil with traps etc.
So this got me thinking "Why don't I see more MB pumps around?" So I figure there has to be some disadvantage that I don't know about.
So, long story short: does anyone know the advantages/disadvantages of a MB pump?
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Galinstan
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i'm not very familiar with MB pumps but i would imagine the reason there not used very often is if they use a piston it is probably made of metal
witch tends to corrode when exposed to any number of chemicals that we deal with.
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Magpie
lab constructor
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I've never used or even seen a metal bellows pump. This might be fine for vacuum filtration. But the best vacuum it might pull would be <28" Hg
according to the MB pumps on this website:
http://www.metalbellows.com/documents/OTS_Pumps-Compressors....
This is equivalent to ~50mmHg absolute. For some vacuum distillations this may not be low enough.
Edit: I see for the MB-151 the best vacuum is 22"Hg which is equivalent to ~200mmHg absolute.
[Edited on 28-3-2014 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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amp_samb
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Ax165xj - regarding your question, I think I can provide some insight as to the metal bellows pumps. I am an account manager at metal bellows,
specifically responsible for the pump line of products.
To briefly answer your question, metal bellows pumps are best used in gaseous applications, where zero particulate discharge and reliability are
important. I can't cite any limitations, other than I would not consider our pumps as low cost options. For reference, the MB-158 is around $2700 for
our standard model.
Just so you are aware, we do not use a piston in our pumps. We build a bellows capsule that is driven by a forged driver that is offset with a cam.
The valves are reeds welded to a plate. The materials are 300 series stainless with a Teflon or Viton gasket.
You can visit our website at www.metalbellows.com for our standard catalogs. I can also send you a manual to reference so that you can operate and maintain your pump properly.
Give me a call anytime.
Alex Pope
781-302-1309
apope@metalbellows.com
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Zombie
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It all comes down to the metal components being vulnerable to chemical interactions.
I'm working on a "home built" vacuum pump, and isolating the pump workings from the chemicals in use is my main goal.
PTFE is the industry standard for laboratory grade vacuum pump internals. Short of that... Steps must be taken to protect the pump.
odd timing here...
[Edited on 5-2-2015 by Zombie]
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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