Vacuum pump

[tomahack]

Would it be a good buy for a small vacuum clamping setup?

http://cgi.ebay.ca/New-Model-Rotary-Vacuum-Pump-29-9-Hg-3CFM-AC-HVAC-Light_W0QQitemZ320241384485QQihZ011QQcategoryZ6699 9QQtcZphotoQQcmdZViewItem

[tuck]

29.9" Hg and 3 CFM? Ain't that pretty dang good?

I'm not the guy to ask, Jean, because I really don't know. But the experts will weigh in shortly and I'll be keeping my eyes glued to this thread, you bet. Looks like they have a warehouse full of 'em!

Edit to say, the 9-15 Imperial vacuum system is 95 CFM for each motor and I'm thinking THAT makes all the difference, even though they have a lower Hg. (Whatever THAT is! LOL!)

To build a powerful vacuum table, it's probably too good to be true even with multiple units, I'm guessing here.

[thewoodcrafter]

That pump would work fine for vacuum pucks and dedicated jigs like that. With an oil bath you could run it continuously. That is a good price for a new 3CFM oil bath pump. They usually cost about $300 - $350.

[tomahack]

Different models available. Wich one to choose?

http://www.bizlisted.com/HVAC/

[jseiler]

Are either of these continuous duty?

[dana_swift]

FYI: Beware with oil bath pumps- while they draw a very good vacuum they also emit an oil-mist in their output "air". This effect is worst at about 15" Hg, but it happens at all pressures. This oil mist if release it into your shop can become EXPLOSIVE. You must vent the output air from such a pump to the outside where it will make dissipate safely.

I use a single 5CFM continuous duty oil pump (from an air conditioning parts house), and am looking to set up a group of them so I can get higher CFM, but the vacuum is really great.

Also beware these things run pretty hot.. the manual with my pump indicates 170F is a NORMAL running temperature, so just be sure to give it a lot of airspace to get adequate cooling and not cause something else to overheat or catch fire.

They also require almost daily maintenance as the oil level is not very forgiving. Also you must have a check-valve or bleeder solenoid to prevent your vacuum accumulator from sucking the oil out of the pump when the pump is switched off.

A physicist friend of mine has used these pumps for lab work, and although the pumps claim to require a monthly oil change, his experience is that you just need to keep the oil level up. The particle buildup in the oil bath is not as bad as the owners manuals might lead you to think.

All that being said, i like getting close to 15psi of hold-down force. I work with a lot of small parts and that (usually) does the trick.

If these things work out well for you let me know..

D

[knight_toolworks]

also all of the moisture in the air is hard on the oil. I have a big pump that pulls 29" but a couple of hours with some leaking it os down it 23"

[rb99]

"A physicist friend of mine has used these pumps for lab work, and although the pumps claim to require a monthly oil change, his experience is that you just need to keep the oil level up. The particle buildup in the oil bath is not as bad as the owners manuals might lead you to think."

I would think any particles could ruin the seal and this would reduce the capacity of the pump...maybe that is why it is recommended monthly?

RB