Parts of a burner - missing anything?

[dragonorb13]

So, I just dropped way more on the shell, the insulation, etc, than I'd wanted to for my first forge... since my funds are a a little... let's say lacking, I was wanting to possibly build my own burners for it. The problem is that, while I've found several HUNDRED pictures here and just on google of the end product, a several hour dive into google didn't provide me a list of parts or an explination as to how they work. So, I'm going to list what I could figure out from pics and videos, and if I'm missing anything, I'd like it if someone stopped me from blowing myself up.

 

   1) fuel assembly (copper tubing, with with pressure regulators, shut off valves, etc) - supplies fuel to burner

 

   2) assembly attachment point - attaches fuel assembly to (yeah, i know, seems obvious, but if someone else uses this in the future, i want the list as complete as possible)

 

   3) supply tube - moves the fuel away from the fuel assembly, so it doesn't overheat and kersplode and kill me

 

   4) expansion chamber - allows fuel and air to mix, if air is supplied... not sure, if no air is supplied

 

   5) air inlet (optional, seemingly) - I've only actually seen a few models that include this, but they supply constant air flow to increase temp of fuel burn, or to optimize it depending on the explination, usually with a fan (one guy actually used a hair dryer)... attaches to the expansion chamber.

 

 

I haven't seen anything that has specified you need any 'special hardware', as in the burners on my stove look different, but i assume that's for dispersion of heat and fuel. Most of them I've seen just use some kind of threaded steel piping, though a few have been welded together. Am I missing anything? Am I wrong about any of the parts? I'll gladly edit and update (with notes) anything I've screwed up, becuase I'll probabably use it as reference material on future, larger forges.

 

Thanks!

[ThomasPowers]

Lets see: regulator, hose, pipe with orifice, reducer bell, shaft pipe; better ones will incorporate a choke.

[dragonorb13]

Alright, questions, then:

 

1) Choke would go on the burner itself, at the start right after the fuel supply goes into the burner?

2) The regulater and hose are parts of the fuel assembly?

3) Is the 'shaft pipe' the part between the fuel assembly/choke and the expansion chamber?

4) If 3 is yes, would the bell reducer be the attachment point between the 'shaft pipe' and the expansion chamber?

5) What, precisely, do you mean by 'pipe with orifice? Do you mean the pipe I'm using as my forge chamber needs entry into it for the burners, or is there something special with the pipes I use as my burner?

[ThomasPowers]

Choke controls how much air mixes with the fuel it "chokes" the supply whereever it comes into the system.

 

Regulator attaches to the propane tank and drops the gas pressure from around 130psi at 72degF to the working pressure of the burner (varies per burner).  Hose transmits propane gas to burner.

 

There aint no expansion chamber!  The shaft connects to the bell and transmits the gas/air mixture from where the orifice introduces the propane into the air to where it ends in a burner flare, flame holder or just dumps into the propane forge body cavity.

 

Many home built burners use a small pipe mounted crossways to the bell with a small hole drilled into it for an orifice to introduce higher pressure fuel gas into the burner assembly to mix with the air.  Others get around drilling a small tricky hole by drilling and tapping the pipe for a mig tip.

 

May I STRONGLY suggest you look through the link provided below---it's the Artist Blacksmith Association of North America's site with information on building propane forge burners

http://www.abana.org/ronreil/design1.shtml

[Dodge]

So, I just dropped way more on the shell, the insulation, etc, than I'd wanted to for my first forge... since my funds are a a little... let's say lacking, I was wanting to possibly build my own burners for it. The problem is that, while I've found several HUNDRED pictures here and just on google of the end product, a several hour dive into google didn't provide me a list of parts or an explination as to how they work. So, I'm going to list what I could figure out from pics and videos, and if I'm missing anything, I'd like it if someone stopped me from blowing myself up.

 

   1) fuel assembly (copper tubing, with with pressure regulators, shut off valves, etc) - supplies fuel to burner

 

   2) assembly attachment point - attaches fuel assembly to (yeah, i know, seems obvious, but if someone else uses this in the future, i want the list as complete as possible)

 

   3) supply tube - moves the fuel away from the fuel assembly, so it doesn't overheat and kersplode and kill me

 

   4) expansion chamber - allows fuel and air to mix, if air is supplied... not sure, if no air is supplied

 

   5) air inlet (optional, seemingly) - I've only actually seen a few models that include this, but they supply constant air flow to increase temp of fuel burn, or to optimize it depending on the explination, usually with a fan (one guy actually used a hair dryer)... attaches to the expansion chamber.

 

 

I haven't seen anything that has specified you need any 'special hardware', as in the burners on my stove look different, but i assume that's for dispersion of heat and fuel. Most of them I've seen just use some kind of threaded steel piping, though a few have been welded together. Am I missing anything? Am I wrong about any of the parts? I'll gladly edit and update (with notes) anything I've screwed up, becuase I'll probabably use it as reference material on future, larger forges.

 

Thanks!

 

NOT optional. Fuel has to have air (because of the fire triangle) Whether it is naturally introduced, or forced by a fan, it has to get in there somehow.

[dragonorb13]

I meant that the forced air introduction was optional, assuming of course that you have sufficient air being introduced naturally. For clarification, are you saying that the air inlet itself isn't optional, as in I'll need SOMETHING in the line to mix in air, or just that air itself isn't optional? I want to be certain I've got a proper understanding of the system before I start, so I don't do something wrong and, best case, have to start from scratch or, worst case, blow something up. My landlord doesn't mind a forge, but I'm pretty sure he wont' appreciate the "new, glamorous crater" in the back yard.

[Frosty]

Take a look in this section. The "T" burner I've been building for a while is there with parts list and a description of how to put it together. At today's prices, not counting necessary tools, drill bits and taps, the regulator, hose, copper tube and fittings, a 3/4" burner costs about $10.00.

 

Right now I feel you should do more reading as you don't know enough to ask good questions or understand the answers. I'm not being mean but you aren't quite to the dangerous level of knowledge and I do NOT want anyone getting hurt if it can be helped.

 

Naturally aspirated burners are simple devices based on air entrainment devices. Gun (blown) burners are simple as well but require less precision to build and tune. Still, it has to be done right or BAD things can happen.

 

Don't go away, I'll be pleased as punch to help but you need at least a little more knowledge and NOT what you're asking about. I hope that isn't as confusing as it sounds but there it is.

 

Frosty The Lucky.

[Dodge]

I may have misinterpreted what you said in op, dragon ;) But, what Frosty said. Read, Read, Read :) I use his style of burner and they work great with even a bit more margin for error than some (At least in my experience) however I suggest that when you do choose a design,  at first, choose a proven design, be it Frosty's or who ever, and build it EXACTLY like the plan. That way, it will either work from the get go and/or troubleshooting will be easier.

[LastRonin]

One more note of caution I have seen mentioned by many more experienced blacksmiths than myself in other posts, but not yet here... if you choose to go with a blown burner, be sure to include a safety cutoff for your gas-line that automatically shuts off the flow if the blower loses power. (I have already acquired a 120VAC solenoid operated normally closed gas valve to use when I get the chance to build one.)

[ThomasPowers]

I've never found a need for a safety cut off.  In fact I start the burner by turning on the gas and lighting it and *then* add air until I get a proper burn.  If the power gets cut I walk over and turn off the gas at the bottle---no big deal!

 

Now the safety item that might be appropriate would be an IR flame sensor that will turn off the gas automatically like is required for schools.  However for my set up I don't leave the forge on if I'm not around and there isn't anything that can get damaged by a flame up from the air being cut off.

[timgunn1962]

Not wishing to come aross as pedantic, but I think the flame sensing used for gas flames is normally UV, rather than IR.

 

As I understand things (and I could be wrong), the reason for using U/V is that it senses the UV radiation from the actual flame and doesn't "see" the IR from the chamber lining.

 

Purely on loss of air supply, I'm not sure either would necessarily work to cut the gas feed to a blown forge fast enough to be a useful safety feature. With IR, the lining is likely to remain hot enough to trigger the sensor for a while, and with U/V, there is likely to still be some combustion going on, albeit very rich, after the air supply fails in most designs. I suspect a simple air pressure switch would get the job done cheaper, quicker and more reliably.

 

My feeling is that if you are building a blown burner because it is easier to build than a Venturi, adding in all the safety features will actually make it harder to build than a good Venturi system.

 

If you are building a blown system because you have insufficient gas pressure for a good Venturi (perhaps you are using mains NG), then go ahead and build the best/safest blown system you can. Please research it properly first though.

[ThomasPowers]

Thanks for catching that! The old edit time limit hammered me again as I posted and went to church.

[BobL]

My safety cut off operates instantaneously on loss of mains power to the blower, by switching off a solenoid valve.

It also contains an air flow/pressure sensor which kicks turns off the gas if there is any loss of air pressure.

This is not as quick as when the mains power fails and takes about 3 seconds to kick in but it's better than nothing.

 

Because I am using mains natural gas which is at a very low pressure (0.2 psi) in my area my BIG problem was finding a gas solenoid that would fully open under such a low pressure as most switches require more pressure than this to drive them fully open. When I investigated solenoid valves most would not open fully and restrict the gas flow too much plus the correct low pressure valves cost ~$150 .I was lucky to find one amongst a a pile of used valves that were being thrown away during a big clean out at work.

 

One problem with using an air pressure based cut-off is that the air flow sensor has to be bypassed on start up so a few switches and indicator mechanisms are needed.

 

Details of my setup are at the end of this thread

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