tegwin
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| posted on 1/3/12 at 11:58 PM |
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Any boiler engineers Hago BPS
Do we have any boiler engineers or knowledegable folk?
I need some information on Hago (Danfoss) BPS nozzles. I want to use one in a non boiler application but need to understand how it works inside the
boiler. Struggling to figure out what is used to control the bypass pressure. I guess some sort of servo valve?
Also trying to find somewhere that stocks them in the UK...
[Edited on 1/3/12 by tegwin]
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t16turbotone
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| posted on 2/3/12 at 07:59 AM |
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Hi, BPS nozzles are not that common and i only see them in large Riello oil burners, they are very costly compared to standard nozzles but i will try
to explain what you need to know. The return oil line in a bypassing burner is normally set up to include a hand or automated valve and a pressure
gauge. When the valve is opened
it allows a portion of the incoming oil to return (bypass) to the tank. This
reduces the flow rate through the nozzle orifice because opening the valve
has reduced the pressure of th oil reaching the nozzle orifice. As the valve
opening is increased, the flow through the orifice continues to drop. By
reading the gauge and matching the pressure readings against flow charts
supplied with each nozzle, the serviceman can determine approximately
how much oil is passing through the orifice. Of course, since the orifice flow
is changing, it means the air delivery to the burner must also be adjusted
accordingly. This is normally accomplished automatically with a linkage built
into these special burners. I do have some extra info if you need it!!!!
Tony
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tegwin
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| posted on 2/3/12 at 10:18 AM |
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Hi Tony
Thanks for your reply.
My understanding of the BPS is that it allows better "throttling' of the burner without loosing proper atomisation of the fuel which you
may get in a standard non bypassing nozzle?
My plan was to use one in a small jet engine burning diesel fuel. If I select the nozzle properly the engine would idle with the bypass fully open and
reach max RPMs when the bypass is fully closed. This should allow me to run a lower pressure pump than I would have had to if I went for a normal
nozzle.
Because I dont want to build an evaporator system for the diesel a really good atomising nozzle is vital for all flow rates otherwise the diesel wont
light off properly.
When you say costly, what sort of money are we talking? I cant find anywhere to get a price from.
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t16turbotone
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| posted on 2/3/12 at 12:16 PM |
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Sounds like you have an interesting project on the go! For clarity we use these nozzles on oil burners to get a modulating flame output. As a point of
interest a normal nozzle is about 4-5 quid, the last time i ordered a bypass nozzle it was 90 quid with its manifold system
Tony
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tegwin
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| posted on 2/3/12 at 02:40 PM |
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Wow... thats a big price hike! Maybe better off with multiple standard jets... Not as "neat" though.
I guess if they are not used much, finding surplus stock on ebay is not going to happen!
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tegwin
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| posted on 3/3/12 at 12:10 AM |
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On a slightly differnet note... Do you have any ideas what sort of maximum pressure and flow I could get from a domestic Danfoss oil pump like this
one? Danfoss BFP21L3 oil pump 071N0156 BNIB | eBay
If I cant get hold of a BPS nozzle I might try a standard 3gph hollow 60 degree nozzle and vary the pressure to see if I can get a good enough spread
of flows to allow an idle and fast speeds.
I guess I would need max 300psi..
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t16turbotone
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| posted on 3/3/12 at 10:05 AM |
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According to my crib shets the pump you mention has "light oil" classification, 3450 rpm rotation CCW, max pressure 20 bar, max delivery
of 24L per hour
Tony
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