[Stoves] Inverted top lit updraught

[Crispin Pemberton-Pigott]

Dear Peter in Auz

 

Thanks for the shout.

 

>I think the nozzle of an oxygen-acetylene cutting torch is identical to a
propane-oxygen ditto. The ring of small premixed flames serves to preheat
the workpiece (steel) to a temperature where the central jet of oxygen can
begin to burn, heat, melt and disperse the molten steel.

 

They 'work' in the same way but the flame pattern is different. The Oxy-Acet
has perhaps 6 holes and the propane-oxy has perhaps 10-20 little ones. There
is a great picture of the two at
http://www.cousesteel.com/AndysPlace/PropaneAcetylene.html 

 

That is the smallest number of holes I have seen for propane. And the shape
is odd to. Usually the whole circumference is like a W bent around in a
circle: wwwwwwww like that.

 

The explanation about cutting and welding with propane is incorrect but the
pictures are good.

 

I am including a small portion of a zoomed photo from
http://www.alibaba.com/product-gs/433428317/Cutting_Torch_Welding_Torch/show
image.html

 

 



 

The left part is a sleeve and the right part is the brass core. There are
linear grooves cut perhaps 40mm long leading to the tip. The sleeve closes
over the grooves providing a number of high velocity jets of propane around
the central O2 hole. I think the reason for them is that the flame speed of
the propane is higher than the acetylene and the increased velocity through
small holes prevents flashbacks when hot.

 

Starting a cut with propane is more difficult because of the higher velocity
gas stream (more than double the air is needed) so localising the heating at
the beginning is important. The multi-jet approach might assist that.

 

Regards

Crispin the (long suffering) welder

 

 

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