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Coke side blast fire management


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Does anyone have any advice on fire management pertaining to coke fired side blast forges? All information I can find is for coal fired bottom blast forges.

How should I shape the ash bed (or sand in my case, no ashes yet) to create an efficient fire? How high above the tue do I build the coke and where do I find the best part of the fire?

Thanks, Tom

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How big is the tuyer? Tuyer size has a bering on how much air you can force in to the fire, and how deap it needs to be. What I have seen from our British brothers look like they stick a can (beer, fruit etc) down no lower than the bottom edge of the end of the plate the tuyre sticks threw or one inch below the tuyer hole (its kind of a pain if the slag gets under the tuyer, so welding a big washer over the end certanly helps. 

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  • 3 weeks later...

Hi Tom, I'm guessing you're here in the UK. If you edit your profile to show your general location you might find quite a few folk on the forum live nearby. 

 

The ash bed can be arranged something like a trough, with a bit of a raised area a short way in front of the tue. Pile on the coke and get it burning then you will soon get a feel for what you need. 

I don't have a lot of experience with the big side blast forges I'm afraid so that's all the advice I can offer. 

 

Andy

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Hi Tom, whereabouts in the UK are you? 

This is a sketch I made for students coming on the courses at Westpoint in Devon, to try to illustrate/explain the relevant theoretical workings of a side blast hearth, the proportions of the nest in front of the tuyere will depend on the size of the work being done in the fire.

In practice the sand/ash tends to level out with the top of the tue, and new fuel is added from the rear to maintain the overall height of the fire, the hot spot/working area is above the air hole in the tue,

you need space between the sand /ash under the front of the tue to allow for the clinker to settle and collect, but if you pack it as illustrated, the clinker should not form under the tue making it difficult to remove.

Key in using these hearths is fire management, and positioning of the workpiece, far too often I see fires far in excess of what is necessary, due to too much air being used, this just wastes fuel, creates clinker, burns the outside of large section metal before it is thoroughly soaked through for forging.

The other thing students tend to do is to poke the metal into the clinker area, rather than lay it at a shallow angle or horizontal into the hot spot area.

When clinker becomes a problem, you can tell by the heat spread on your workpiece. This is usually identified by different heat colour bands on your workpiece IE where clinker is,  the air  gets deflected /dispersed and gives a fiercer fire around its periphery, so what happens is that where you are expecting to get your work hot in the what was the hot spot, but due to the air deflection the hot spot(s) have moved, and your workpiece gets hotter or burns where you don't expect it.

Each hearth has its own idiosyncrasies, but the theory is the same. 

In the picture the tank/tuyere is tilted to allow air bubbles not to be trapped at the front of the tue . this was done because ordinary tube was used to con

Have fun

Side blast forge positioning.jpg

The tank/tuyere shown is tilted slightly so there will be no air trapped behind the front plate allowing the front to burn through. traditionally the tuyeres were conically shaped so this problem did not arise.

Edited by John B
explain tilt of tank
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