Fog machines pipes and pumps.

[Dr Laser]

I have 5 seconds before I have to run...
here it is

[buffo]

Ok - Perfect. That's the same pump I have. I can show you how to take it apart and fix it. Give me a day or two to take the photos and I'll post them here in the PL gallery. (Would do it now, but I gotta work an 18 hour shift tomorrow...) Hmmm... Maybe I'll take it in to work and do it there...

Adam

[The_Doctor]

How does it work; oscillating piston? Peristalsis? Centrifuge? I'm after something to replace the horrible pump in a Martin 700. The rest of that machine is awesome, but the pump really sucks. Literally, which is part of the problem, it sucks back too much fluid, and airlocks itself. Daft little mechanism.

[buffo]

Hi Doc;

Yeah, basically an oscillating piston, though it's magnetically coupled rather than driven from some offset crankshaft. It's wierd the way it's put together... The pumping chamber is actually in the base of the unit. There is a check valve on the inlet to the chamber. The piston is at the top of this chamber, and moves up to draw fluid into the chamber through the check valve. Then, when the piston moves down it expells fluid through a port in the body of the pump that leads to the upper chamber. The fluid then flows around the piston's upper half and out the top.

The piston is held in place by an o-ring seal on the bottom (the seal is between the lower and upper chambers), and by a sleve and spring that it rides into on top. All this is sealed together, and outside of all this is the coil that energizes to move the piston up and down. (Just like a solenoid.) The coil never touches the fluid, nor does it come in contact with any moving parts. In fact, aside from the check valve, the piston is the only other moving part in the whole pump.

I haven't bothered to look into how the pump's speed is controlled; I'm guessing it's a combination of voltage regulation and duty cycle. But if you hit it with straight 110 V AC, the pump moves a shitload of fog juice! Yet if you dial the controller down to decrease the fog intensity, the pump will pump very little liquid.

I like the desgin because there's very little that can go wrong with it. The coil doesn't require any cooling, and apart from a mechanical failure it should last darned near forever. Likewise, the piston really only touches the o-ring seal, and even in the absence of lubrication from the fog joice, the worst that could happen would be the destruction of the o-ring. I don't see how you could ever sieze the piston. So while the piston might get stuck due to crystalized fog juice, it's an easy task to free it up. (Unlike a traditional centrifugal pump, which can really eat itself if run dry.)

Adam

[The_Doctor]

Sounds cool, I want one because it looks neat and small. I remember a big oscillating piston pump in a large nameless fogger I repaired once. Wasn't noted for changeable speed which would be a nice extra. I like their simple design too. Only snag is that the Martin 700 seems to have really needed at least some backflush to clear the heater of juice during rests, and I can't see how I might do that with this kind of pump. I'll probably best use some kind of peristaltic pump. Stepper motor drive would be a neat way to precisely control the backflush as well as forward speed.

But I'll probably just live with what I have, it's not like anything major depends on it.

[buffo]

Dr Laser;

Ok - I finally got some free time to play with my fog machine. I took the pump apart and took pictures as I went. Then I put everything back together again, all the while taking more pictures. Everything has been uploaded to the gallery along with descriptions of what to do for each step.

It took me about 30 minutes total, and that's including all the pictures. So it's certainly a job you can handle in a single sitting.

Here's the link to the gallery I set up. Hope you can get one of those foggers working again! Once you see the pics, you understand when I say that it's almost impossible to ruin these pumps. Clog them, yes, but not ruin them.

Remember that once you get it put back together, you may want to test it before you put the lid back on the fogger. You can unplug the pump from the control board and apply 110 V power yourself directly to the pump. You'll know in a few seconds if the pump is working or not. If all you hear is a soft hum of the coil, then the piston is still siezed, which means you need to take it apart and clean it some more. But once you get it freed up you'll hear it rattling, and you should see it start sucking fog juice into the pump. (Would probably be a good idea to pump an ounce or two through the pump to flush it before you hook everything back up...) Note too that you may need to adjust the discharge pressure regulator once you're all finished. (See the gallery for details.)

One final tip: On most foggers there is a tip on the end of the heater that you can remove. Often the oriface plate in this tip gets plugged with gunk, and this will hurt the fogger's performance. However, on the Antari Z1200 and similar units, the tip is actually a long shaft with a spiral groove that runs the entire length of the heater. Pulling this long shaft out and cleaning it and the interior cavity of the heater will help ensure it never plugs up. (It has some fine threads at the end that screw into the heater, but the fog juice travels through the deeper spiral groove that runs along the length of the shaft.)

Adam

[Dr Laser]

The steel piston on the top can just be pulled up? Nothing have to be unscrewed? I will try that! Thanx a LOT!

[buffo]

The steel piston on the top can just be pulled up? Nothing have to be unscrewed? I will try that! Thanx a LOT!

Yep, that piston comes right out. Well, not right out... On mine the whole damn upper chamber was encrusted with all kinds of goop and snot. I had to work at it for about 10 minutes to get it out. (I actually was able to push it down slightly at first, but then I had to really work it to get it out.) But yeah, once you get all the boogers out from around the o-ring, that piston assembly will lift right out. Then you can clean inside the lower pumping chamber, and once that's done you should be all set.

Glad to help! Hope it works out for you dude... Gotta be cheaper than buying a new pump, right? Let us know how it ends up...

Adam

[Dr Laser]

THANX! for this tutorial. It worked. Club machine is as powerful as new. I have 2 more pumps to clean....

[buffo]

Excellent! Glad it worked for you. (And a little work sure beats buying more parts, right?) Rock on pal!

Adam