Oil Burner nozzle capacities

[John.g]

What is the significance of the kg/hr stamped on danfoss nozzles, I have a 0.6 usgpm nozzle fitted in my 20/26kw Firebird SE boiler. 0.6 usgpm is 2.27LPH and my boiler output of 20kw at 84% efficiency reflects this more or less. 2.27 LPH = 1.79 kgs/hr (see table) at a kerosene SG of 0.79, there is also 2.37kgs/hr stamped on the nozzle, all other sized danfoss nozzles have two values on them as well. I thought it may have something to do with the pump pressures ie the usgpm at 6.9bar (100psi) and the 2.37kgs/hr at 8bar but increasing the pressure from 6.9 to 8 bar only gives a ~ output of, 1.79*(8/6.9)^2, 1.93kgs/hr.
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[Timmy D]

It’s the output of the nozzle at 8 bar pressure.

The gph with the pump pressure allows you to work out the kg/h when using a different pressure.

I’ve not worked on kerosene but believe the max pressure is 10 bar due to different atomisation characteristics compared to light oil (typical pressure between 10-14 bar).

Here’s one I serviced last week. Running on 3.5gph nozzles (2 stage).

 

[John.g]

I always had it in my head that the usgph was at 100psi=6.9bar, if so, then 2.27LPH or 1.79kgs/hr equals 2.37kgs/hr at 12.1bar or if 1.79kgs/hr @ 8bar=2.37kgs/hr@14bar which may explain why the kgs/hr is under the heading "Capacity" on Danfoss Tables.