Gear-pump pressure nozzle burner

Discussion in 'Burners and their construction' started by PatJ, Jun 9, 2019.

  1. PatJ

    PatJ Silver Banner Member

    Here is the gear-pump pressure nozzle burner I am building to replace my siphon nozzle burner.
    My siphon nozzle burner will become my backup burner.

    The intent of this design is to build a burner that has the excellent atomization/control/consistency/reliability, and instant-start full-ouput capability (without propane) that a siphon nozzle burner running on diesel has, but without using an air compressor.
    The gear pump and associated motor are inexpensive compared to a good air compressor, and if this burner works as well as I think it will, I will build two of them, and keep one as a spare.

    Here is the motor.
    Definitely oversized, but this is the one I got.


    Last edited: Jun 9, 2019
  2. PatJ

    PatJ Silver Banner Member

    Here is the gear pump.
    I got the 1725 rpm unit, since I figured a lower speed pump and motor would last longer.


  3. PatJ

    PatJ Silver Banner Member

    I bought a couple of pressure nozzles, and will try 2.5 gal/hr and 3.0 gal/hr.

  4. PatJ

    PatJ Silver Banner Member

    Here is how it works.


  5. PatJ

    PatJ Silver Banner Member

    Here is the coupling between the pump and the motor.
    These pieces are bored to match the exact shafts on the pump and motor that you use, so don't assume these are universal items.

  6. PatJ

    PatJ Silver Banner Member

    Here is the spin-on fuel filter I will use.
    It is diesel-rated.

  7. PatJ

    PatJ Silver Banner Member

    Here is the initial schematic I came up with.
    I am not sure it will go together exactly like this, but this is the starting point for the design.

  8. PatJ

    PatJ Silver Banner Member

    Here is the frame mocked-up in a couple of different configurations.



  9. PatJ

    PatJ Silver Banner Member

    Here is the stainless burner tube that I will use for the pressure-style burner.
    I used this temporarily to test the failed drip-style burner.













    Jason, oldironfarmer and joe yard like this.
  10. PatJ

    PatJ Silver Banner Member

    A pressure-style nozzle uses the same adapter as a siphon-nozzle burner, but it does not use compressed air.
    Instead the fuel is pumped to the nozzle at 100 psi, and atomization is achieved as explained in the post above.

    The pump produces 7 gph at 100 psi, and so I will shunt the excess fuel flow back to the fuel tank via the return line.

    Here is the schematic for the Delavan "Variflo" pressure nozzle, which is not the same exact nozzle type I am using, but the schematic is similar.
    I will use a needle valve in the return line to control fuel flow to the nozzle indirectly, but controlling how much fuel flows back to the fuel tank.
    I will not use a solenoid or a PRV.
    The needle valve will go where the PRV is shown.

  11. PatJ

    PatJ Silver Banner Member

    This is what the pressure nozzle looks like, and I think I have standardized on the solid cone "blue" style, in as narrow an angle as I can find online, which I think is 45 degrees.


    Last edited: Jun 9, 2019
  12. oldironfarmer

    oldironfarmer Silver Banner Member

    Looks like your wrap fit pretty good.
  13. PatJ

    PatJ Silver Banner Member

    The burner will operate between 2.5 and 3.0 gal/hr, which gives the following values.
    3 gal/hr = 415,500 Btu/hr (121.77 kW)

    If you were using an induction melter, you could perhaps melt the same amount of iron using 25 kW, assuming 12% efficiency for an oil-fired crucible furnace and 60% efficiency for an induction melter.
    Last edited: Jun 9, 2019
  14. PatJ

    PatJ Silver Banner Member

    For previous burner designs, I used a rubber plumbing boot to seal the end on the burner tube, but I had some blow-by on the old furnace, and it started to melt the rubber.

    These days I use a piece of stainless steel sheet metal, which looks similar to the one below, without the rubber piece.

  15. PatJ

    PatJ Silver Banner Member

    The gear pump pressure nozzle detailed above is the same type as is used in a combo burner unit that some backyard folks use, as shown below.

    The unit below combines the motor, gear pump, combustion air blower, and the pressure nozzle into one unit.
    While this arrangement works well for home and industrial heating units, I don't like to get all that equipment right up next to the furnace, since any leaks out the tuyere or furnace walls will ruin the equipment.

  16. PatJ

    PatJ Silver Banner Member

    And a pressure-style nozzle does not use an o-ring.

  17. Zapins

    Zapins Silver


    I may adapt these plans for use with my peristaltic pump to move the oil instead of the heated motor. Very useful so far.

    How do you cut those tubes so well by the way? What's that graph paper you used?
  18. PatJ

    PatJ Silver Banner Member

    I used that free online program for pipe joints.
    Someone recommended it, I forget who.
    I think it was this program:

    I input the burner tube diameter into the program, along with the angle between the two tubes, and printed the templates out 1:1 on a generic printer, ie: 1 increment equals 1".
    It worked pretty well.

  19. Jason

    Jason Gold Banner Member

    Rock on.. This should be a bad larry!
  20. OMM

    OMM Silver Banner Member

    Pat, very neat. Subscribed!

Share This Page