Rotary Vane Vacuum Pump Question

[sagreen83]

I recently purchased this vacuum pump from Amazon, and it seems pretty nice... I bury my vacuum gage past 30" and the hold down seems fantastic...

http://www.amazon.com/gp/product/B000JFNAJE

Here's the problem... This is an oil based system, and the pump part of this unit gets very hot. Hot enough that a small amount of smoke comes out of the exaust after about 15 minutes of operation. Is this a normal function of an oil based rotary vane pump?

Scott...

[thewoodcrafter]

Normal.
Oil bath pumps do that.
Just try to keep it contained. The oil mist can make a mess.

[cnc_works]

I've gotta say that my experience with oil bath vacuum pumps has been very negative. Even though my first vacuum pump was out of refrigerator and actually did the job I needed at the time. Anyway, they all seem to put an oil mist into the air that can get pretty nasty just to breathe, some far worse than others. Automotive style air conditioner evacuators are some of the worst. OK for short periods, but after they get warm the oil mist gets worser and worser.

Personally, I'd keep my eye out for a regular carbon vane pump if you need high vac. I found a great continuous duty 3/4hp on Craigslist for $75.

Donn

[thewoodcrafter]

The only problem with non-oil bath pumps is the duty cycle.
An oil bath pump can run continuously for days.
Anything else should be on a pressure switch because they are not 100% duty and will toast if run too long.
I have an old 3CFM HVAC vacuum pump. I really don't notice the oil mist mine puts out. My shop is 2700ft with an 18ft ceiling, lots of volume there. If it bother you, you can always pipe the exhaust to the outside.

[dana_swift]

Scott- Read my post from a few days ago:

http://www.talkshopbot.com/forum/show.cgi?tpc=312&post=66979#POST66979

Good luck Scott.

D

[cnc_works]

Roger, I don't know specifically about any others, but according to the manufacturer of both my small and my larger dry carbon vane pumps, they are designed for continuous duty at 0 cfm. I know I've used the smaller 3/4hp for many hours at a time at 0 cfm (fully blocked, no air movement) and I've had it for five or six years.

They did say that eventually the vanes wear down and have to be replaced, but so far I've not had to do that.

Donn

[waynelocke]

I bought my 1/3 hp oilless vacuum pump in about 1983 and use it primarily for vacuum bagging. I have run it almost 24 hours a day for several days to a week at times. I have never done anything to it. It's the Eveready Bunny with no oil mist.

[sagreen83]

Thanks for all of the input guys... I'll work on exausting the output somewhere else. Do you know if there is a duty cycle on these things? i.e. can I run this for hours at a time?

[dana_swift]

Scott, usually these things are good for continuous duty. Like a car it will run continuous duty also, but eventually the oil becomes depleted and you have to shut down to add (or change) the oil.

Mine runs for 4-5 hours at a time regularly.

D