What kind of compressor should I use ?

First off, an oil lubricated compressor is definitely not called for as oil contaminates the entire air plumbing system of the centrifuge.  Even if you have the filter assembly installed, it will eventually cause operational problems with the centrifuge as the filter is primarily for moisture.  If you don't have the filter assembly installed then you've already pretty much messed up the tubing system of the centrifuge.  Oil will definitely cause problems with the solenoids.

Your assumption relative to the leak is probably correct.  Leak detection is really not the difficult.  In most cases, you should be able to hear the leak if there is one.  Does the centrifuge appear to operate properly when you close the lid, turn the timer on and start to turn the lid closure knob?  Again, there should not be any excessive air noise apparent except for the noise of the rotor accelerating.  The bottom plate of the centrifuge can be easily removed to check for leaks without a rotor installed, too.

Don

Hi Don, It has been a month since I posted and read your comments. I appreciate your expertise and have made several changes as you suggested. First off, I sent the oil-lubed compressor back to the vendor and got a used Craftsman Professional 3.5 HP, 175 psi, 25 gal, 2-stage oil-free compressor that is rated at 5.1 scfm @ 90psi. As you suggested, I took the bottom off and checked for leaks within the instrument: I found none. I DID find a leak at one the side of the (external) Norgren air/oil filter unit and have repaired that. The levitation flow rate has been adjusted to Beckman specs. When I did a test spin, the compressor kicked on after about 30 seconds of run-time, so I'm guessing that it is just due to the flow demands of the Airfuge, right ? Thanks for the help! Mike

Sorry that I haven't gotten back to you sooner but I've been off line for a bit. Anyway, your last response only shows up very truncated so I'm really not sure what you said after telling me that you now have a Craftsman 3.5hp compressor. Please resend me the information so we can pick up from there.

Hi Don- The truncation is strange, since I can see my complete post on the LW web page after logging in. Anyway here is the rest of the story distilled: The compressor is rated  at 5.1 scfm @ 90psi.  I took the bottom off the Airfuge and checked for leaks at each air fitting: I found none. I adjusted levitation flow rate to Beckman specs. When I did a test spin, the compressor kicked on after about 30 seconds of run-time, so I'm guessing that it is just due to the flow demands of the Airfuge, right ? Thanks for the help! Mike

Mike,

   Today when I opened it up everything was visible.  Go figure.  Anyway, the demands for air is directly related to how fast you wantthe rotor to spin so the duty cycle of your compressor will be determined by the speed of the rotor.  I'm not sure what rotor you are using or if your unit has the optional tachometer attached to the lid.  Otherwise, you can use a phototachometer to determine the speed.  Some people would black out half of the plastic sealing material that covers the tubes in the rotor.  Again, unless it's really doing rapid cycling I wouldn't be too concerned.  Quite frankly, most people are running off of clean house air where the compressor is located some distance away from the centrifuge so they never know how often the compressor is cycling if at all dependent on the capacity of the compressor and its storage tank.  I think that you should just use it as is.  Just make sure that the unit is PERFECTLY level and that if it gets moved at all then you need to check it again.  The leveling feet turn very easily and an airfuge out of level will have the rotor chew up the plastic pieces inside of the centrifuge chamber very quickly.

Don