Page 3 of 8 FirstFirst 12345 ... LastLast
Results 21 to 30 of 72

Thread: Pressurized oil tank & Burner build - Zapins

  1. #21
    the black smoke is normally insufficient air, the white smoke is insufficient heat to get past the ignition point.

    art b

  2. #22
    Senior Member Zapins's Avatar
    Join Date
    Jun 2010
    Location
    CT, Hamden
    Posts
    2,093
    masteryoda - how do you vary the airflow on that beast? Seems like quite a powerful fan. Also, how do you have the air pressure lines going to it? Are you using a compressor to run the pressure tank and the same compressor to run the burner itself to atomize the fuel?

    What fuel needle valve would you guys recommend? It would be nice to control the exact fuel every time without having to fight with the pressure valve on the compressor.

    r4z0r7o3 - What is a dump gate?

    Vilbert - do you have a link to the airflow control mechanism you mentioned?

    Petee - I initially was atomizing the fuel but it wasn't making a large enough flame inside the furnace. Maybe the nozzle was a bit clogged? Then I disconnected the line that atomizes the fuel and just ran the fuel through the nozzle under pressure. That made a stream of fuel that I showed in my video.

    I think I'm going to have to devote a whole week to figuring out this oil burner problem at some point. It seems like it needs a lot of tinkering to get it tuned and working correctly. Preferably when I don't have a pressing need to cast a lot of shells.

    Here is my furnace running on propane for comparison. Just pure power at the touch of a valve.

  3. #23
    Senior Member r4z0r7o3's Avatar
    Join Date
    Jul 2015
    Location
    Raleigh, North Carolina
    Posts
    1,117
    A dump gate or waste-gate simply exhausts the excess airflow that you don't need. That's why you use a Tee fitting. You open the gate to "waste" airflow and NOT send it to the burner. Close it and more flow goes to the burner. The main point is, it allows the blower to always run at 100% (which nearly all are designed for). Some motors get mad if you block off the intake or exhaust, and it can lead to over-speed and/or over-heating, then premature death (possibly during a melt).

    However, you'll hear from folks here, that it doesn't matter in hobby/quick-n-dirty applications, and maybe they're right, sometimes

    Think of it like the argument of drip-style vs siphon vs pressure nozzle burners. There's no right answer for everybody for all applications/uses.

    I only suggest a dump-gate b/c it's universally applicable for all setups and I like happy motors and ridiculous reliability (it's a personal problem)

    The OTHER way may be perfectly fine for your usage.
    "Things that are complex are not useful, things that are useful are simple."
    - Mikhail Kalashnikov

  4. #24
    Senior Member
    Join Date
    Nov 2012
    Location
    Ontario, Canada
    Posts
    2,122
    Motors are designed to reach their rated rpm... Unloading a motor only allows it to reach said spd with less effort (power). In terms of a blower, unloading the motor is achieved by restricting air flow. Many blowers will actually cook the motor if not restricted in some fashion. Dust collectors for example are rated by the manufacturer without any restriction. This provides maximum cfm capabilities, (which is the main selling feature of dust collectors). However running a dust collector without restriction will cause the motor to die a very early death.

    In my particular situation (which is probably the same for any running a bouncy castle blower), if I were to use a waste gate I'd have an insane amount of focused air blasting away within my work area. I guess I could plumb that away, but then I'd have an added trip hazard, and more stuff to manage.

    Quote Originally Posted by Zapins View Post
    Vilbert - do you have a link to the airflow control mechanism you mentioned?
    I could have sworn I posted this on the forum before, but couldn't find it...

    That build was inspired by Scavenger's furnace build. At the very beginning of the video in this post by him you can see his valve for controlling combustion air...
    http://www.alloyavenue.com/vb/showth...l=1#post165683

    Everyone has their own way, but imho placing a butterfly valve downstream of the blower has to be the cleanest solution. A quarter turn and I go from fully blocked (which I need when starting with propane) to full blast...

    Even speed control suffers the downfall of allowing the burner to pull air unchecked.
    FLAME ON...!!!!

  5. #25
    Senior Member Zapins's Avatar
    Join Date
    Jun 2010
    Location
    CT, Hamden
    Posts
    2,093
    I like that butterfly valve idea. Very compact, but nylon is crazy pricey so I'll probably not make mine out of that. Does this valve strain the motor compared with a dump gate?

    What about this for a fuel needle valve? $10 bucks

    http://www.ebay.com/itm/1-4-Brass-Ne...MAAOSwnHZYZwXn

  6. #26
    Should be no strain on the motor. The way you verify this is with an amp clamp and see it draws less amps when not running at rated speed. Cooling can be an issue, but not likely.

    Yes that's a perfect needle valve. Ordered me a couple too.
    Visit me: WWW.HandcraftedLanterns.com
    "Sometimes by losing a battle you find a new way to win the war"
    -- Donald Trump --

  7. #27
    Senior Member r4z0r7o3's Avatar
    Join Date
    Jul 2015
    Location
    Raleigh, North Carolina
    Posts
    1,117
    Similar to my needle valve as well. It's not a panacea, fine-motor skills are still involved in tweaking it just right, but it's a whole lot easier than a valve designed to cut the flow (as opposed to adjust).


    Seeeeee, no so simple, now you need an ammeter, and are worried about cooling air!

    Personally, I like the dumped (waste) cooling air blowing in my face to keep ME cool

    Joking, not trying to re-ignite a debate.

    Please don't go out and buy a clamp-on ammeter just for this




    What is the blower you're using, can you post pics? Bonus points for taking the lid off and showing us the guts around the motor



    Then again...

    If you're willing to risk blocking the outlet, blocking the inlet does the same thing and is even simpler. I've done it w/ a piece of card-board and some duct-tape. Though sheet-metal gate (door, flap, cover, whatever) and a screw-pivot would be more stout.

    Again, not wanting to restart a debate, just offering ideas. I wouldn't worry too much about blowing up your motor, unless it's some really old, nearly-dead thing. You can also go with a brushed motor and speed controller, as another option (but maybe more complicated). I just don't recommend brush-less and speed controller, not enough low-end torque.

    Anyway, the overarching theme here is, use what you have (or can get cheaply), how you're comfortable using it, and maybe invent something new along the way.

    In the end, the "right" way, is the one that works for you

    In the old days, they used empty animals and someone filling and squishing air in/out. I think any electric blower is worlds better (though arguably more complicated)
    "Things that are complex are not useful, things that are useful are simple."
    - Mikhail Kalashnikov

  8. #28
    Senior Member
    Join Date
    Nov 2012
    Location
    Ontario, Canada
    Posts
    2,122
    Quote Originally Posted by Zapins View Post
    I like that butterfly valve idea. Very compact, but nylon is crazy pricey so I'll probably not make mine out of that. Does this valve strain the motor compared with a dump gate?
    No.. restricting a blower lessens load on the motor, so that is the end of the overloading falsehoods... If motor is designed to be cooled by the air flow that it creates with the blower itself, (an actual HVAC inline furnace fan is the only example I can think of) then yes you need to consider overheating. I would love to see a real world combustion air design that uses an HVAC inline motor for combustion air...lol.

    When I first started testing with my bouncy castle blower I would place a piece of paper over the inlet. I found that covering the inlet didn't actually completely choke the flow. Not sure where it was pulling the air in, but it was still moving a tiny amount. Enough to blow out my propane preheat at low volume.

    So, one last time for the crowd.... There is absolutely no risk to your motor if you restrict air flow. It's physics, not opinion.
    FLAME ON...!!!!

  9. #29
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
    Posts
    2,477
    Put a notch or indelible mark on the top of the valve knob near the edge. It's a helpful reference.
    I use an old Kirby vacuum cleaner with a router speed controller. I paid 5 bucks for it at an auction. I had to replace the brushes in it for about $10, but otherwise it works fine. I have it inside the barn and pipe the air through the wall so I don't have it underfoot or have to hear it howling.

    Pete

  10. #30
    the actual formulas for power explain the load situation on fans. power = weight x distance lifted per time unit. Ok Air volume has weight about 1 pound per 12.5 cubic ft the fan curves show the CFM changes as the pressure changes across the fan, as the pressure difference goes up the cfm goes down. and the motor load goes down. The lowest current draw and internal heat is a free running motor. But a free running fan is moving the highest volume of air, or the most weight and draws the highest current. By putting a restriction on either side of a fan increases the pressure across the fan lowering the cfm and motor load. I use fixed orifice dampers on my burners when i have fixed firing rates I only vary air flow if I have different amounts of fuel going in. It does take a little bit of initial adjusting but once adjusted it is always the same open the main valves turn on the fan and light the burner and your off and running. I use a PVC water valve for air control on my titling furnace for adjustment below the lowest speed setting on the leaf blower.

    Art B

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •