# High End Vacuum Pump



## Joeforbes (Nov 15, 2011)

Hello Forum!

I'm looking to install a vacuum system for at most 10 - 1000ml filter flasks to be in use at a single time. 

I know there have been threads about this, but I haven't been able to find a pump (or pumps) to suit my situation. I've tried the pumps from harbor freight and pumps like it. Even with condensers they didn't last all that long. 

Anyone have any suggestions for high capacity corrosion resistant vacuum pumps? I can spend in the range of $2,000-$3,000 per pump.

Thank you in advance.


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## Smack (Nov 15, 2011)

Sounds like a custom fab job to me, that way you can have it just the way you want. You should need just one vac. pump with main line going into a manifold or something equivalent so you can have shut off valves on each individual line so you could just run 1, 3, 6 or however many you want to run at once. Will be way cheaper with one pump so don't skimp on the vacuum hose. The vac hose should have a rating for how much vacuum it can maintain without collapse. The medical Industry has some nice quick connects that would work nice if you need to connect and disconnect often. I could post some pic's of some if you want. The one's I'm thinking of are used in Dialysis on oh lets say a Re-use Machine. Just some ideas for ya to ponder.


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## element47 (Nov 15, 2011)

Unless I misunderstand your application, that sounds awfully high $$ for vacuum pumps to drive filtering for chemical reactions. You are not evacuating vacuum tubes and don't need to get down to thousandths of an atmosphere, do you? I appreciate your wanting a quality item but that still seems like a really high price point for getting a maybe a dozen inches of mercury pressure differential. Am I wrong?


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## element47 (Nov 15, 2011)

By the way......I have found some truly spectacular gas manifold rigs with multiple regulators and lots of stainless tubing and plumbing fittings for very cheap on ebay. I will see if I can point you to a few.


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## Joeforbes (Nov 16, 2011)

I was basing that price mostly around the KNF pumps. They get pretty pricey. I was looking at one of their models that is capable of 29.3 inHg.


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## butcher (Nov 16, 2011)

I wonder if we could find a fiberglass tank with a bladder (similar to what well pumps use) the bladder and tank would have to be able to stand up to the acids.

Rusty had a post today of a heated tank for SSN leach he is working on, with a tank.
it seems Rusty said the bladder in his tank was HDPE.

my idea is if we could use this to isolate our vacuum pump from the acidic enviroment.

old compressor's from air conditioner or refridgerator can be made into air compressors, or vacuum pumps, I have one I converted and have used for years (for other uses not in this acidic enviroment), changing oil in it every now and then I think is part of the reason it has survived using it the way I do.

any ideas?


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## skippy (Nov 16, 2011)

Butcher, it was I who said that about the construction. From the product sheets I've seen, the fibrewound pressure tanks have hdpe liners, that is an attached liner to the shell and which is not to be confused with the bladder, which is some sort of rubber. I like the idea though of using the tank to isolate a vacuum.


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## 4metals (Nov 16, 2011)

I know a custom PVC fabricator that builds packaged eductor systems for my clients complete with a recirculation pump, an eductor and a 90 gallon reservoir tank with sight glass. He charges $3750 for the unit. It will easily handle 10 vacuum flasks simultaneously. http://www.chemteksys.com


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## butcher (Nov 16, 2011)

Thanks Skippy,
I get things mixed up sometimes.
Maybe we could find a suitable bladder for the well type tank. 

In hospital's when the patient is hooked up to the vacuum system, their is a plastic canister that has an bladder bag, that captures liquid, keeping this liquid from going into the copper lines possibly clogging then and traveling back to the vacuum tank and pumps, I wonder if something like this could be used to isolate our vacuum pumps from acidic fumes and solutions?


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## Joeforbes (Nov 17, 2011)

4metals said:


> I know a custom PVC fabricator that builds packaged eductor systems for my clients complete with a recirculation pump, an eductor and a 90 gallon reservoir tank with sight glass. He charges $3750 for the unit. It will easily handle 10 vacuum flasks simultaneously. http://www.chemteksys.com



Thank you 4metals. I will contact them. Would you like me to let them know you referred me to them?


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## kadriver (Dec 5, 2011)

joeforbes:

Hello. I have been using an hvac vacuum pump that I bought from Harbor Freight. The one I bought in September of 2010 finally died the other day (Tuesday 29 Nov 2011). It lasted for nearly 15 months - cost $79 plus tax.

I went to buy a new one off the shelf and they had increased the price to $109 for the same unit.

I think it is 2.5 cfm. I have it connected to, and drawing from, a heavy 8 gallon air compressor tank that I bought for $30. this tank acts as a vacuum reservior. I can take it all the down to 29.9 inches of vacuum (mercury) in about 45 seconds with that vacuum pump.

I connected a standard 15 foot air pressure hose to the tank and use this air hose to connect to a shut off valve. the air hose is only about 1/4 inch inside diameter and it does not collaspe under full vacuum.

Before the valve is a "T" connection for a vacuum gage. I bought a vacuum gage at Harbor Freight for about $15. It is used to diagnose and test diesel engines but works great to give a reading of the amount of vacuum on the entire system before the shut off valve.

It has a large 4 or 5 inch face.

I could easily connect a ten place manifold to the air hose and put 10 individual shut off valves with hose connections for 10 flasks.

I am certain that this system, while inexpensive, could handle the load of filtering 10 flasks at once. The vacuum pumps performance is excellent.

You could buy a spare vacuum pump and keep it on hand in case of a failure. Of course it will fail at the exact moment you need it the most.

I have about $200 invested in my vacuum filter system.

Hope this is helpful to you.

kadriver


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## butcher (Dec 6, 2011)

Vacuum source?
For that ole miser cheap skates like me here is an Idea.

Old refrigeration compressors can be had for free (I have done refrigeration and HVAC work for years), people even have a hard time getting rid of them, if you already do not have a pile of them on your property.

I have made vacuum pumps and air compressors out of these; they last for years if you change oil every so often. (Now I was not vacuuming acidic fumes).

They may hold up for a while if using them with these acidic fumes, but who wants to keep burning them up.

But lets see if this idea will work, use a large thick wall tank, maybe an old 15 gallon or larger, water heater, these are fiberglass lined tanks (we would need to protect pipe fitting to tank), we would hook our vacuum pump to this tank (valve between pump and tank), now a valve to our filter funnel line, (vacuum gage, and drain vent valve on tank.

Now we pull vacuum on tank (valve to filter funnel and drain closed), (it would take some time large volume, larger compressor the faster it would be), once we have tank in vacuum we turn off pump, isolate pump with valve, and open valve to our filter system (needle valve, or orifice fitting to control flow), this should give us enough vacuum for some time (not sure how much vacuum time we would need (larger tank), drain valve vent opened before tank evacuated again.

We could get a little fancier (two small tanks alternating system, one tank pulling vacuum from filter, while pump is pulling vacuum on second tank), (compressor could also blow air to clean fumes from tank to evacuate fumes, before next vacuum cycle, with a little more valve and piping), We could even add some controls (circuit panel to control operation, solenoid valves, and so on),

Possibly some type of scrubber between tank and our acidic fumes,
All built from the scrap pile.


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## Woodmizer (Mar 3, 2012)

Joeforbes said:


> Hello Forum!
> 
> I'm looking to install a vacuum system for at most 10 - 1000ml filter flasks to be in use at a single time.
> 
> ...




Hi Joe,
I don't know diddly about vacuum pumps but I recently bought 2 brand new boxed pumps from the state of Washington and can look at them for data if you are still looking. I do know they are large and have lots of "Doo-Dads" (srry) on them, and they look very expensive. I will let them go at whatever is a fair price. I bought them to use for vacuum bagging a fuselage mold for an airplane project and never used them.
I have two and if these are what you want I will sell one.
Will post tomorrow after I dig them out.
Mike


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