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Thread: Centrifugal pump question

  1. #1

    Centrifugal pump question

    Hello everyone.

    I'm working on improving the current siphon nozzle burner setup. I've just added a 50 mesh filter and a 12V 0.7amp centrifugal pump to move the oil along since this filter adds resistance. I don't seem to be getting the oil flow I want though. I'm wondering if placing the filter upstream of the pump is limiting my flow. Do any of you know much about centrifugal pump setup?

    Here's a link to the video of my test from earlier today. It lights instantly off heated vegetable oil and seems promising, but I'd really like to see a larger flame.

    https://www.youtube.com/watch?v=P0_zFMolUDE
    Use those coffee makers with the spout out the bottom to preheat you oil!

    My foundry: http://www.alloyavenue.com/vb/album.php?albumid=1

    My waste oil burner:http://www.youtube.com/watch?v=NwpKCsiWKls
    Metal casting video:http://www.youtube.com/watch?v=8ui24..._order&list=UL

    My website : maniacmechanics.blogspot.com

  2. #2
    Senior Member TRYPHON974's Avatar
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    Don't know much about the pump but I watched the video and the flame seems to be lazy in my opinion, I think you need more air.
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  3. #3
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    There's no way to really know what you've got until you get it in the furnace. I'm seeing a lot of oil in the video. Plug that into a furnace bore and move the nozzle toward the end so your not hitting and pooling in the burner tube and you will get a much different result. All the oil dripping out is being delivered but is unutilized in your demonstration so you're not getting the full picture of the setup's potential.

    Pete

  4. #4
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    If anything you're getting way more oil than the rest of the set up can support. I'm not a nozzle guy, but if I understand it correctly, you should be able to get a complete burn without the need for a "up to temp" furnace environment.

    To answer your question. I think you'd be better off keeping the filter after (up stream) the pump. If you starve it at the inlet it won't build pressure.
    FLAME ON...!!!!

  5. #5
    J, if the filter is setup like this.... Tank>>>filter>>>> pump>>>>> Nozzle, then how is the oil going to get pushed through the filter? Won't this require the use of a 2nd pump?

    If the filter is downstream of the pump, then it will require adjusting as the filter gets dirty... Looks like a catch 22. FWIW, I run NO filter. I just strain it a few times before I burn it. No issues so far. He appears to have to the pressure too high that's for sure. It's pissing oil all over the place. As Pete said, I bet that nozzle is up that pipe and not near the end. I went down that road with my kwiky too.
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  6. #6
    Quote Originally Posted by jagboy69 View Post
    J, if the filter is setup like this.... Tank>>>filter>>>> pump>>>>> Nozzle, then how is the oil going to get pushed through the filter? Won't this require the use of a 2nd pump?

    If the filter is downstream of the pump, then it will require adjusting as the filter gets dirty... Looks like a catch 22. FWIW, I run NO filter. I just strain it a few times before I burn it. No issues so far. He appears to have to the pressure too high that's for sure. It's pissing oil all over the place. As Pete said, I bet that nozzle is up that pipe and not near the end. I went down that road with my kwiky too.
    I definitely need to look at shortening the tube so the nozzle is closer to the end. Right now it is about 5 inches back. I could move it 4 inches forward and still have it mount in the matching sleeve on my furnace.

    Regarding oil flow, I ran some tests and found average numbers for 4 trials each.

    With just the filter, pump and fuel line I could deliver 30 gph. After attaching the nozzle, I could deliver 2.1gph. It seems like the nozzle is definitely the limiting factor more so than the filter. I still question if my pressure is limited to atmospheric differential by trying to suck though the filter.

    What sort of waste oil flow rates do we generally see here for iron melting? I've always had about 3gph in my head as proper iron melting oil flow.
    Use those coffee makers with the spout out the bottom to preheat you oil!

    My foundry: http://www.alloyavenue.com/vb/album.php?albumid=1

    My waste oil burner:http://www.youtube.com/watch?v=NwpKCsiWKls
    Metal casting video:http://www.youtube.com/watch?v=8ui24..._order&list=UL

    My website : maniacmechanics.blogspot.com

  7. #7
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    Quote Originally Posted by J. Vibert View Post
    If anything you're getting way more oil than the rest of the set up can support. I'm not a nozzle guy, but if I understand it correctly, you should be able to get a complete burn without the need for a "up to temp" furnace environment.
    I would almost bet that the nozzle being 5" up the tube has a lot to do with the combustion even being present let alone self sustaining. Thick fuels arent very cooperative in open air. Thats not to say they won't burn at all, but it's not an effective way to test your burner. The furnace environment doesn't need to be up to temp to burn it but the enclosed environment helps to sustain the flame by swirling and reigniting the atomized fuel (veg in this case) at least until the bore is hot. We've seen Jag light his torch outside the furnace but I don't think it's thick stuff.

    Bill- How does compressed air fit into this equation? Your video was dark and I couldn't see or hear compressed air nor have you mentioned it.

    Your nozzle has to be inside the tube but close enough to the end so the atomized mist doesnt hit the inside of the tube and will clear the tuyere when its in the furnace. Thats at least one of the reasons its dripping.

    One thing to watch for is tiny trimmings from your recently fitted hoses getting into the nozzle and obstructing it. I've gotten plugged up a couple of times that way.

    Pete

  8. #8
    This burner uses the rotary vane pump from a reddy heater, which I think is about 5psi max, coupled with a siphon nozzle. I have had one successful melt with it running on pure gravity feed from a 3 foot head, but subsequent attempts failed due to small clogs. Its because of these clogs that I'm now using the filter, which requires a pump. Also, I'd like to get away from relying on pure gravity feed, so that means a pump.

    The small amount of air pressure shouldn't be adding massively to fuel flow. From my bench test afterwards, I saw 2.1 gph, so I'm thinking I need more.

    Tonight or tomorrow morning, I'll switch around the pump and filter and see if that increases flow.
    Use those coffee makers with the spout out the bottom to preheat you oil!

    My foundry: http://www.alloyavenue.com/vb/album.php?albumid=1

    My waste oil burner:http://www.youtube.com/watch?v=NwpKCsiWKls
    Metal casting video:http://www.youtube.com/watch?v=8ui24..._order&list=UL

    My website : maniacmechanics.blogspot.com

  9. #9
    Ok some more results to share...

    I switched the filter and the pump position. The result was not particularly impressive. I measured 2.4 gph flow vs 2.2 gph flow from before. I'm not even sure yet if this is a "statistically significant" change.

    The plan is to cut the oil with kerosene for the cast iron attempt. I think that will take me past 3 gph without trouble. I'll let you guys know.
    Use those coffee makers with the spout out the bottom to preheat you oil!

    My foundry: http://www.alloyavenue.com/vb/album.php?albumid=1

    My waste oil burner:http://www.youtube.com/watch?v=NwpKCsiWKls
    Metal casting video:http://www.youtube.com/watch?v=8ui24..._order&list=UL

    My website : maniacmechanics.blogspot.com

  10. #10
    Can you pre-filter your oil? There are setups for running waste oil through an automotive oil filter

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