blower control is really important on glory holes

[Garner Britt]

Ok, let me first state that contrary to what I'm about to write, I am a smart guy. I have a masters degree (that I'm still paying for)

here's the story:

I built a small square glory hole and have had it hot twice. This afternoon, I lit it again in preparation of doing a little work. The fuel train is totally little rascals at this point, ie, no control of air other than the flap on my blower.

Once warm, I turned up the gas. In the process, and unbeknownst to me, the flap on the blower, following the laws of gravity, fell down, effectively turning the air off.....

can you guess what happened?

flames, big blue flames. In a stroke brilliance, I thought "this thing needs more air" and as such I opened the door....

BOOOOOMMMMM!!!!!, 4 foot fire ball out the door and a massive and bone shaking explosion which actually cracked mortar joint in the bricks of the glory hole....

I'm fine, I was standing to the side and the hole was outside my shop at the time but I quickly realized the importance of proper fuel train plumbing and more so, the importance of controlling the air side of the equation. I removed the flap from my blower and threw it in the yard. moments ago I ordered what I had thought was an over priced nicety (a 2" butterfly valve)

This is meant to be a real world warning. Let's not reflect on how dumb and/or lucky I am but how serious this stuff is. It's far too easy to get overly comfortable with equipment that should be taken very seriously.....

What stupid things have you done that nearly turned tragic?

[Glenn Randle]

Would you do it again, just once, so I can get a photo??


Btw, that flap falls down about once a week around here. How did you get the cool explosion sound?:feathers:

[Rollin Karg]

And what do you think you will accomplish by restricting the air?

[George Tessman]

i use velcro strips that way the flap always stays put

[Brian Gingras]

ok,

several things..

no flapper on the blower, BIG ball valve on the air line...and an air pressure switch...did I mention the air pressure switch? In case your wondering you should try an air pressure switch...it saves on the eyebrows being burned off...the ball valve just helps with fine tuning and jumping between reduction and high fire.

[Rollin Karg]

Well, if you leave the ball valve and flapper off and position a torch in front of the burner you should be good to go. With the air on and the lit torch on slowly open the gas. You should get a nice even start.

[George Tessman]

We have shut offs next to and before the needle valves and close enought to the hole to control and light. Air is set and on.Then set the needle valve to be rich insert torch and open shut off. By being rich no chance of blow out before it gets hot. When hot enough to keep running we adjust needle valve. By the way every glory hole has 2 shut offs one at the main one at the needle valve.

[Hugh Jenkins]

Glenn, You're a devil!!! I have dropped blowers long ago. I use compressed air. Never saw a regulator slip. If interested, check many past discussions on venturis used for air supply. Infinite control is within reach!!

[Garner Britt]

Originally posted by Glenn Randle
Would you do it again, just once, so I can get a photo??


Btw, that flap falls down about once a week around here. How did you get the cool explosion sound?:feathers:


The key to the massive explosion is letting the flap close off, build up a really rich mixture in the hole and then open the door for a backdraft them BBOOOOOMMMMMM!!!!

You can do it your self and I'll take the photo.




Just so were clear, This was not during start up. The hole had been hot for about 15 minutes. I had no intention of restricting the air flow, the flap on the blower did it itself while adjusting the gas.

garner

[Pete VanderLaan]

Originally posted by Garner Britt

What stupid things have you done that nearly turned tragic?

*********
Going on the board of GAS... Moderating this website.... Eating green chili after 10:00PM. I'm sure there's more.

I would advocate that damping down the intake on a blower capable of producing decent water column ( six inch water column or more) is going to really make the motor overwork. Far better to have an air bleeder between the blower and the burner as well as adding a gate valve on the bleeder side to release excess pressure.

It doesn't matter much on a squirrel cage since they can't really produce decent water column anyway but you have obviously found out why damping down the intake is a great way to check on the relative health of your adrenal glands.

Brian is right about the air pressure switch.
But , I'm with Glenn. Could you do it again and put it on Utube?

[Garner Britt]

Originally posted by Pete VanderLaan

I would advocate that damping down the intake on a blower capable of producing decent water column ( six inch water column or more) is going to really make the motor overwork. Far better to have an air bleeder between the blower and the burner as well as adding a gate valve on the bleeder side to release excess pressure.



Brian is right about the air pressure switch.
But , I'm with Glenn. Could you do it again and put it on Utube?

Is that to say, have a T coming off in front of the blower with a gate valve to allow the bleeding of excess pressure? Take the flap of the blower, run it wide open and use the bleed valve to adjust how much air actually gets to the mixer and blower?

I'm using a pretty strong blower to run a GH590 ribbon. The blower is the one Tom recommends.

Any recommendations for a pressure switch. I have seen lots of glory holes with a solinoid valve which allows gas to flow only with the power to the burner on. That wouldn't have helped me last night. Those seem meant to prevent flame out at light up....

If I do this experiment again, It will be with the mythbusters crew.

I just looked at the glory hole again this morning, Some pretty good size cracks in the joints. It seems the explosion had enough power to lift the 50lb arched crown casting about a 1/4". I'll try to post a picture.

garner

[Glenn Randle]

I'd reccomend doing it after dark & after a few brews.

Btw, This technique might also be a fun way to dispose of that EzTherm in HI, probably about the only way to ever find a bit of pleasure with it. Might want to fill it with hydrogen instead of propane, to maximize the "Fun"!


Only thing more fun than "Fire" is "Explosion"!! :eek:

[Garner Britt]

not sure how well it will show up but here's a photo. The top course of brick moved back about 1/4 in and the crown casting up about the same.

Next time I'll try a mix of oxygen and acetylene....

[Edward Skeels]

Originally posted by Pete VanderLaan
[B
I would advocate that damping down the intake on a blower capable of producing decent water column ( six inch water column or more) is going to really make the motor overwork. Far better to have an air bleeder between the blower and the burner as well as adding a gate valve on the bleeder side to release excess pressure.

It doesn't matter much on a squirrel cage

[/B]

Don't put a bleed on a radial vane wheel blower, it will make the motor work harder.

Pete may be thinking of regenerative blowers.

[Garner Britt]

This is the blower I'm using.

http://www.blacksmithsdepot.com/Templates/cart_templates/cart-detail.php?theLocation=/Resources/Products/Forges_and_Parts/blowers/164_CFM_Blower

[Edward Skeels]

The easy way to tell is use a clamp on amp meter around one leg of power. If the amps go up when you open the bleed (not inlet) your motor is working harder and you're spending more on electricity.

I've never used a motor with a damper on the inlet; have always used downstream butterfly valves.

40 oz pressure (2.5psi) for $120? Wow :eek:

[Garner Britt]

Originally posted by Edward Skeels

40 oz pressure (2.5psi) for $120? Wow :eek:

It's a great blower for the price and quiet too.

I plan to leave the damper where I threw it and run the blower wide open with a butterfly valve down stream

garner

[Rick Sherbert]

Garner,

I just put a blower/solinoid/pressure switch on my glory. I will get you the part numbers tomorrow.

I have a momentary contact switch to start the blower and once the pressure comes up, a relay latches it on and opens the gas valve. If the pressure drops or the power goes away the gas valve closes and doesn't re-open until you manually start it again with the momentary contact switch. This is in case the power goes off for awhile and someone forgets to turn off the gas. The blower will not restart and the gas valve won't open back up just by the power coming back on.

Cheers,
Rick

[Dave Hilty]

Hope this won't be taken as off-topic but while we are on glory hole issues, can someone point me in the right direction to assemble a foot-actuated gizmo (valve or whatever) so that I can push more gas for reduction on demand rather than having to reach in and bump the gas valve up. The gas valve I have now is a lever that is difficult to fine-tune and stupid to reach.

[Pete VanderLaan]

It's probably not code, but a gas line with a solenoid tapped into the air gas line that opens when you step on the switch and closes when you step off would work fine and be pretty cheap. You can use your imagination as to how much extra gas you would need and adjust it with a needle valve once.

[Garner Britt]

I've also seem a system rigged up with one of this gas saver/torch minder torch shut-off dodads, definately not code but it worked.

garner

[Kraig Richard]

Originally posted by Dave Hilty
Hope this won't be taken as off-topic but while we are on glory hole issues, can someone point me in the right direction to assemble a foot-actuated gizmo (valve or whatever) so that I can push more gas for reduction on demand rather than having to reach in and bump the gas valve up. The gas valve I have now is a lever that is difficult to fine-tune and stupid to reach.

Made a few reduction foot switch gizmoes.

You need to install a bypass line around your current gas control valve. Two T fittings and a few nipples and 2 valves and a switch.

This bypass has a solenoind valve controlled with electricity. They either need a powersupply or they run on 110 volts. I like 110 because the powersupply dosent die that way. This bypass also wants a control valve so you get the right amount of gas through the pipe.

first there are 2 kinds of switches ...double throw or single throw. ....do you want to hold your foot on the switch or click it once for on and click it again to shut it off. Thats the difference.

Graingers has really nice heavy duty foot switches I think around 50 bucks. I have made my own foot switches from a relatively obscure device known as a foot operated dimmer switch once popular in the previous millenium. (and past due for a resurgance)

For wiring the foot switch I prefer antique looking cloth covered wires inside an oversized ( 3/4 or 1 inch) flexible electrical conduit. This has proven long lasting and burn resistant for me

Something worth consideration....Bumping up the gas does get the hole much hotter then closing the air for reduction .....which might or might not be desireable for the surface.

What I need help figuring is a gizmo that gives more air in addition to the gas boost .

Before I hit Graingers for these parts I'd check out eBay. I just noticed awsome deals on controllers, pyrometers and solid state relays. register as a seller to see past auction prices of these devices for advice on bidding.

[Dave Hilty]

Thanks Pete & Kraig! I understood there had to be a bypass line but didn't really have it worked out in my head. Now to go scrounging for the parts.

[Brody Shaw]

you want something like this in the gas line...


http://cgi.ebay.com/New-IB-1-25-Solenoid-GAS-VALVE-CAT-K3A672T-2-way_W0QQitemZ120168876720QQihZ002QQcategoryZ87087Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

key thing to note is the 'normally closed' in the listing......so you don't buy one open :) that way when valve gets electricity it either opens(which we want) or closes....reduction

[Peter Bowles]

Originally posted by Kraig Richard


Something worth consideration....Bumping up the gas does get the hole much hotter then closing the air for reduction .....which might or might not be desireable for the surface.

[/B]



Which suggests that you are running your glory hole with too much excess air and thereby making it less efficient that it could be.

If you are set with good balance the temp should drop when you have excess gas.

[Ray Laubs]

my squirrel cage is laying on its side so that the flapper is horizontal. Its never flopped open or closed on its own.

[Richard Huntrods]

unfortunately, putting mine horizontal would require an elbow in the flow, so it remains vertical. I use a 1/4" wide rubber band under the flap to keep it in place. I've not had a problem using the rubber band.

-R

[Steve Stadelman]

Luckily Steve Stadelman Glassworks can supply several sizes of U.L. listed rubber bands.

[Kraig Richard]

Originally posted by Peter Bowles
Which suggests that you are running your glory hole with too much excess air and thereby making it less efficient that it could be.

If you are set with good balance the temp should drop when you have excess gas.

I think it might have something to do with a relative slow chimney speed... but Nope.. Going rich from neutral ....it gets hotter, up until near (just before) where the ratio has soot coming out in the flame. It would be even hotter if you gave it more air but just the gas alone gives a bump up in my experiance.

Getting Natural Gas to really run hot ( cone 25 ) 3650f the richness level is ridiculous. Mega flame shooting out of every orafice. Not economical or stoichiometric but it does get hotter.

The cooler ( shut off the air method) of reduction lets you stay in there and reduce a little longer which might help an effect

A foot switch that kills the blower would work for reduction too!. After a while one could probably get good at tossing fireballs that way !

[Eben Horton]

Originally posted by Kraig Richard

What I need help figuring is a gizmo that gives more air in addition to the gas boost .



Um kraig... its looking right at you. ;)