Forced air blower question

D

deker

Joined
Nov 14, 2005
Messages
3,496
After a couple of months of not being able to do much (schedule first, car accident second) I'm finally getting around to getting my new forge from Darren Ellis going. I'm having a problem getting a good flame going from the burner. All I seem to get is a nice loose yellow/blue flame, no "roaring jet engine" like I expected. I'm wondering if I have enough blower attached. What's attached now is the blower I use for my coal forge (which is one of these with a variable speed control). It seems to work just fine for coal, but no dice on the gas burner. The one time I was able to get the forge up to a low forging heat it took running a lower pressure than I would have expected (~5psi by the regulator's gauge...I haven't installed a proper pressure gauge yet) and the air from a second blower headed into the intake of the attached blower. Even then it didn't really seem right.

Any suggestions? How much air (in CFM I suppose) should I have running to get a good flame going?

Thanks for any help,

-d
 
I've never used that blower, and I don't know its CFM, but I usually choke my blowers way back. That is to say that it looks like plenty. One thing I know that Darren usually uses gate valves on his burners. You might try opening the gate valve all the way and controlling airflow with a flap over the blower's own intake. This would also mean not using your speed control, I suppose.

John
 
Sounds like something isn't right. It takes very little pressure to run a blown forge,5PSI is about right.Check all the valves and make sure the gas is coming in right. It takes very little air flow to run one of these properly,maybe you have too much air coming in? Try gating down the air intake on the blower.Posting a photo of the setup might help,too.
Stacy
 
Deker - is the flame just a small flame coming out of the burner or is it a large flame coming out of the forge door? If the latter, it's not getting enough oxygeb and is looking for more outside. I don't know much about that blower (how many cfm?) but maybe it just isn't putting out enough air for the amount of gas you're running.

On my forge, I usually run the gas at less than 1 psi and I adjust the airflow with a gate valve (I bought a burner kit from Darren too.) Try running yours at much lower gas pressures and give it plenty of air. See what happens.

Also, sometimes it helps to let the forge warm up a bit first so that the gas ignites as soon as it gets into the chamber. Often, when the chamber isn't hot yet, it will sputter a bit.
 
The blown forge I built runs at 15 lbs of gas pressure with a needle valve to adjust the volume [1/4 turn open] a 100 cfm pole blower that has an adjustable gate is the air suply. I know this only muddys the waters but thats where this thing runs. Addjusting a forge by the way it sounds is one way to help you tune a forge in.

Stacy, Have you got your ht forge up and running yet?

Fred
 
Wulf said:
Deker - is the flame just a small flame coming out of the burner or is it a large flame coming out of the forge door? If the latter, it's not getting enough oxygeb and is looking for more outside. I don't know much about that blower (how many cfm?) but maybe it just isn't putting out enough air for the amount of gas you're running.
Click to expand...

Well, the flame is definitely coming well out of the front of the forge...

On my forge, I usually run the gas at less than 1 psi and I adjust the airflow with a gate valve (I bought a burner kit from Darren too.) Try running yours at much lower gas pressures and give it plenty of air. See what happens.

Also, sometimes it helps to let the forge warm up a bit first so that the gas ignites as soon as it gets into the chamber. Often, when the chamber isn't hot yet, it will sputter a bit.
Click to expand...

Clearly I need to get a proper gauge on the regulator, but I couldn't even hear any gas flow at <5psi or so. I'm wondering if I have a clogged line or somesuch. There's no sputtering until hot (I kind of expected that). It just never gets hot enough to start with.

I'm going to re-read Darren's instruction sheet and see if there's something dumb I missed.

Thanks,

-d
 
Just wanted to follow up on this one. I emailed back and forth with Darren and tried a different air source today (a leaf blower I never use :) ). Seems I didn't have near enough air. The leaf blower is overkill (and LOUD), but it did prove the point that my wimpy squirrel cage blower just wasn't enough.

Now, to find a bigger blower that doesn't scream like a leaf blower and doesn't cost an arm and a leg....


-d
 
Fred - The design work is all done,and the all materials are on hand.The burner manifold is assembled. I still have to do some work on the exhaust manifold.I am hoping to get it finished after the Christmas rush.This is going to be one huge forge oven.
 
bladsmth said:
Fred - The design work is all done,and the all materials are on hand.The burner manifold is assembled. I still have to do some work on the exhaust manifold.I am hoping to get it finished after the Christmas rush.This is going to be one huge forge oven.
Click to expand...
Stacy,
It will be a nice Christmas gift. I am looking forward to seeing your design
up and running. I was a muscle car kid and love big, powerfull, machines of any flavor. Fred

Being able to adjust both, the volume and pressure of the air and fuel that enters a forge, allows you to compensate for design oversights. If you can adjust these, you will be able to find the "sweet spot" where your forge runs best.
 
Try Mankel, they make some nice blower forges, you can get one of the blowers that they use. should do the trick
 
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