# Vacuum source



## markqf1 (Oct 9, 2009)

I'll share this with you guys because it just occured to me, how impressed with it I am.
For over a year I've been using a PELA oil extractor (model # 6000) as a vacuum source.

You can control the exact amount of vacuum you want, by hand.
It has worked excellently for me and continues to do so.

http://www.pelaproducts.com

Mark


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## 4metals (Oct 9, 2009)

An aspirator type vacuum is cheaper and it doesn't require pumping. Then again in Georgia you either have drought or flood! Pumping may be greener!!


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## markqf1 (Oct 9, 2009)

:lol: :lol: 
This is true.
When you're dealing with real fine particles sometimes, less is best.
I have an aspirater type too, but it's not nearly as good or cost effective, for what I need.
Neither is my electric one. :lol: 

Mark


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## 4metals (Oct 9, 2009)

Are you filtering in a Buchner funnel?


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## Anonymous (Oct 9, 2009)

An old refrigeration compressor becomes a handy shop tool, the two small steel lines near the bottom of the can you can ignore. These were tied into the cooling system to circulate freon to the base of the compressor to help cool the motor. Compressing gas into a liquid all day long generates heat

For what your going to use the old compressor for it can run day and night without overheating. Next on the can you'll see another pair of lines one steel and the other a larger copper one.

The oil cooler lines are looped inside the can, if you were to blow on one side the air would come out the other. When you cut this pair leave a 1/4 inch stub or your can could leak oil.

First time run with out being tied into the refrigeration system you will get some oil blowing out the high side, freon has an affinity for oil and no matter how long the unit was under evacuation there will still be some freon in the oil and when you start the motor the heat will drive it out casing some oil to escape with it. This situation does not last long and nothing to worry about, do it outdoors and be sure to use a catch pan or cloth over the pipe to catch any oil.

The larger copper line in the suction line, these compressors is good used condition will still pump down to 29 inches, the small steel line is known as the high side this is your pressure side or outlet. 

The high side can and will pump pressure in access of 400 psi, so it your using the compressor as a tire pump never leave it unattended, unless you like surprising your neighbors with loud noises. Possible bodily harm could result along with law suits - use at your own discretion. 

Those nickel and dime garages that have pay for air, this is exactly the system they're using along with some extra safety features factory installed.

From the Dentist office we recently cleaned out, the compressor used is a modified twin cylinder 1 HP. refrigeration compressor. The compressor body no longer hermetically sealed as the factory installed oil filler the sight glass still in the stock location, has a muffler/filter combination on the suction side along with an air dryer installed with more water filters and a regulator. This thing is 22 years old and runs as good the day it was installed.

The home fridge uses a splash lubricating system versus a pressurized system on the commercial unit, but you're still sure to get your moneys worth from a recycled unit.


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## Oz (Oct 10, 2009)

Gustavus,

I inherited an old homebuilt air pump that was an old refrigerator compressor, it has served me well many years. Just how many atmospheres do you think an average refrigerator compressor could pull if you restricted the input?


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## markqf1 (Oct 10, 2009)

Buchner funnel and filtering flask with # 2 Whatman filters.
As I said, I have other vacuum sources but, this contraption provides a nice slow vacuum for real fine particles that tend to get through the filter, when using too much vacuum.
I don't use it for all of my filtering but it sure is handy in certain situations.
Sometimes I find gravity alone to be good enough, although slow.

Mark


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## Anonymous (Oct 10, 2009)

Oz said:


> Gustavus,
> 
> I inherited an old homebuilt air pump that was an old refrigerator compressor, it has served me well many years. Just how many atmospheres do you think an average refrigerator compressor could pull if you restricted the input?



The compressor will pull an easy 29 inches vacuum, compressors used for domestic service do not have piston rings they depend on a close fitting piston with the crankcase oil to complete the seal. same as the model airplane engines. Like the old cox 049.

When choosing a commercial compressor, look for the valve body plate, it's visible between the cylinder head and the block, otherwise the valve's are installed directly into the piston top.

Refrigeration compressors use reed valves, if the motor runs and will not pull a vacuum or build pressure one of the reeds will be broken or cracked.

If the valves are installed into the piston these compressors circulate the oil from the crankcase along with the freon through the system and would soon pump the lubricating oil out of the unit. Another way to identify these valve in piston types the intake port will be located on the cast iron block not the cylinder head. By circulating the oil, it went through the condenser of the refrigeration unit aka the high side were it dissipated heat from the electric motor.


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## goldsilverpro (Oct 10, 2009)

An aspirator can be plumbed to a sump pump and the pump then placed in a vessel of water. The water is recirculated through the pump. That way, there is essentially no water usage.

In some applications, I prefer just using gravity. Some stuff packs so hard in a vacuum filter that it is actually slower than gravity. Large amounts of aged silver chloride or metal hydroxides come to mind.

BTW, the drying of material can easily and quickly be done by placing a light bulb over the vacuum filter and sucking the heat through the material. This works great for gold powder. For a large Buchner, I used an IR bulb. For a small Buchner, a regular 100W bulb works well. Whatever you use, don't place the bulb too close, as it will burn the paper. If you burn the paper, you will have a mess. Start out with about a 6"-8" spacing and go from there. Remove the material just as soon as it's dry.


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## Anonymous (Oct 10, 2009)

vacuum filtering, questing instead of pulling vacuum on the low side which would draw chemical fumes through your pump, could you not use a funnel that is sealed and pump air on the high side to 14 psig, making the low side a vacuum compared to the high side and your chemicals could vent to air without going through the pump.

thanks
Jim


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## Anonymous (Oct 10, 2009)

james122964 said:


> vacuum filtering, questing instead of pulling vacuum on the low side which would draw chemical fumes through your pump, could you not use a funnel that is sealed and pump air on the high side to 14 psig, making the low side a vacuum compared to the high side and your chemicals could vent to air without going through the pump.
> 
> thanks
> Jim



The wine art supply store has just such a canister - plastic approximately 6" diameter, with a 5 micron filter. The liquid is put into an enclosed canister then pressurized forcing the fluid through the filter. That nice heavy walled blue sewer pipe would be an excellent choice for the canister.

Introducing 60 psi into the canister would have a much better effect to filter than 29 inches vacuum - atmosphere is 15 psi at sea level. If you live above sea level your ability to obtain 29 inches or greater vacuum will depreciate whereas 60 psi at any altitude on the face of the earth is still obtainable.

Personally I think a pressurized filter wins hands down for performance. Cheap enough to build you could have several.


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## Anonymous (Oct 11, 2009)

Modified refrigeration compressor which was used by a Dentist to run his pneumatic equipment, twenty two years old and still humming along.

Because it runs much cheaper than my 5 HP, I'm going to install it under my bench for use at the metal lathe and my air staplers and pin nailer's.

I also came home with one of those Halogen lights that hang from the ceiling over the dentist chair, I'm going to hang the light over the lathe.


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## Anonymous (Oct 11, 2009)

is that a copelamatic? wow, that seems like something a turn of the century dentist might do, but will all the tort lawyers..........

Jim


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