exposure unit vacuum pump

[rmonks]

My National Brand exposure unit just today has lost 99% vacuum suction that draws down the rubber blanket. Anyone know where to get a replacement pump. I pulled the back off the unit but do not see any CFM info. Can the old one be rebuilt. thanks

[Homer]

grainger? I'm not too sure what the draw cfm is but amazon has a ton of small vacuum pumps.

[SBrem]

Is it just not drawing down? Look for leaks is my first guess, not necessarily in the blanket, but maybe between the pump and the blanket. I'm not familiar with your unit, but there's a motor with a pump attached, and a line to the area to be vacuumed. I would try disconnecting the hose from the pump and putting my finger over the intake hole to see if it is working, no draw, bad pump (considering the motor is indeed spinning) or perhaps whatever couples the pump to the motor's shaft is not intact. After that, I would check the hose, then the seal of the blanket.

Steve

[bimmridder]

I'd also check the hinges on the lid. If any screws have loosened, it's possible the lid is not sealing. Grainger carries a big variety of vacuum pumps

[rmonks]

I pulled the hose off at the pump, and have a very slight suction.

[inkmyt]

Does it use oil? I've had vacuum pumps that would not pull a vacuum when low on oil.

[rmonks]

I did not see any place to put oil, the only other orphus was an exhaust port on the motor.

[Baron265]

Monks, Can you post a picture of the pump?

[rmonks]

If this works here is a picture of the vacuum pump.

[Northland]

Some of these pumps have carbon vanes (similar to a carbon motor brush).
The centrifugal force of the motor slings the carbon out against the housing, so it can grab air and move it (compress it or suck it).
Maybe the carbon brush is stuck. If the thing is not functioning at all... there's little risk in tearing it apart.

[SBrem]

This is the first I've seen with the pump on top. Usually, it's a pump assembly that bolts right onto the face of the motor. Have you contacted National about it? I'm not completely sure what I'm looking at here... never mind, I see National is gone and parts can be had from Global somebody...
For the slight suction you are getting, and the motor is spinning normally, I feel the pump is the culprit. It would be nice to have a reference point, such as "I've felt it before, and it's not as strong now..." Can you blow air through the hose to be sure it's not obstructed, and lastly, does the motor sound like it's suddenly working overtime due to drag from the pump? Can you hook it up to another vacuum to test it? That's all I got...

Steve

I just saw the post about the carbon vanes, my pump has those. I've occasionally had to take the pump apart, not very hard at all, and clean and oil lightly the vanes and reassemble. If the vanes are stuck, then they won't slide out and pull any air. If you get it apart and see it, you'll understand how it works, very clever.

[Baron265]

It definately looks like it's oil free. Does the motor run?

[rmonks]

Yeap the motor runs, I think I will take it apart this weekend and see if there is something that needs cleaned.
Do you think I could use a shop vac to suck the blanket down till I fix it. Got to keep printing.

[rmonks]

I think I found something on ebay that will work. Thanks All

[inkmyt]

Yep, that's oil free. So sorry to send ya down a dead ended street. That shop vac will get you by until you get a replacement..