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Linda A

Pressure gauge reading

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Hello

I am wondering if anyone can give me some advise.

When I turn my kiln on and burners are lit the pressure on the gauge at the 100 pound propane tank is set to four.

Is this the correct pressure.  I have a downdraft kiln with a soon to be installed 10 ft chimney ,  with 60,000 BTU Venturi burners.

My gauge looks like it has a screw that can be adjusted to increase or decrease pressure. Am I correct in this assumption.  There is also a regulator further on in the line.

I will add photos to clarify.

Thanks      Linda

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Well you'll prob get better advice but in my gas set up the regulator at the tank regulated gas coming out of tank  I also had a gauge which indicated level in tank.

The pressure gauge close to burners I turned up to give a certain no. Of psi which flowed to burner thus  giving me a certain temperature rise (depending on damper position also).

Hope that helps

If you find that you cannot get the psi required to get to temp the regulator at tank may be able to be adjusted but I'd ask a gas installer as your line may need it to remain on 4.....

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Well Linda I was hoping that a reposting might attract someone who knew  the answer to your problem.

 If I had your problem I would shut off all valves down stream from the regulator at the tank.

 I am not sure how things work in the rest of the world;  WE insist we are correct and the rest of the planet should get in line,  but turning the valve to the right should increase the pressure reading on the gauge. Turning it to the left should lessen the pressure. If there is no change there then it is either a bad gauge or the regulator.

If you read the description of the regulators that Ward sells on his site you might get a better idea of what you are dealing with.

I am not pushing Mark Ward it is just the only thing I know and the only person I have dealt with    http://wardburner.com/burnersparts/regulatorsblowers.html

 

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It's difficult and potentially unsafe to give advice on this matter without knowing everything about the setup. Your best bet is to have the folks you get your gas from to check it out, or talk to the burner manufacturer to see what pressure range they work best at. Have you confirmed that your burners are set up to use propane, not natural gas?

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Talk to the people you buy your gas from and the manufacturer.  Or failing that, the previous owner.

Also, I might look at getting new fittings.  That redhead’s definitely seen better days.  They’re not that expensive.  The pressure gauges especially like to seize and give all sorts of random readings.  That 4 psi may be a very different number on a new head.

Edited by Tyler Miller

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Yeh new stuff for sure.

The regulator next to tank is not to be fiddled with. That one is to regulate the pressure delivered to your line, your line has been constructed under those constraints.

The regulator just next to burner is the one you would be operating to control your kiln.

In fact good policy to turn Tank outlet off.i.e.screw tank to off as well as regulator at kiln in case regulators get stuck open.

Discuss with supplier and gas fitter as Neil suggested

Edited by Babs
Clarity

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35 minutes ago, Babs said:

 

The regulator next to tank is not to be fiddled with. That one is to regulate the pressure delivered to your line, your line has been constructed under those constraints.

The regulator just next to burner is the one you would be operating to control your kiln.

 

 

Not always true.  A red head (0-30 psi) is indeed meant to be adjusted.  Any propane firing blacksmith  will tell you about what psi they work at for regular forge work and what temp they work at for welding/heat treat etc.  The lines can handle the psi for sure—provided they’re the right lines.

This is something that’s different between nat gas and propane.  Nat gas usually has a fixed pressure (0.25 psi for household stuff, I think), whereas propane has greater leeway.  

I think we should probably leave off saying too much about the operation of this particular kiln and burner setup.  Gas kilns can be really idiosyncratic and this one, I suspect, is no different.

Edited by Tyler Miller

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Agree as you state . .."if they are the right lines and why I wrote what I wrote.

Don't know ANY  gas kiln operators who adjust straight from the tank.

Don' know any who would buy and install a redhead in line themselves. Illegal in many areas actually.

So as Neil said way back, and I agreed with , consult dealer, supplier and gas installing person and also legality of gas firing kilns in you location.

Advice on these forums is just that  advice and advice given to this poster can be taken on board or not...

One would hope the directions here are clear to most............ 

Blacksmithing is not firing a gas kiln or am I mistaken?????

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7 minutes ago, Babs said:

 

Don't know ANY  gas kiln operators who adjust straight from the tank.

Don' know any who would buy and install a redhead in line themselves. Illegal in many areas actually.

Blacksmithing is not firing a gas kiln or am I mistaken?????

Hi, Babs,  I adjust straight from the tank.  

So do a lot of raku operators.  I’ve been inspected by the fire marshall as well.  My setup is pretty normal.  And I’ve fired literally hundreds of loads of pots in it.  Including that celado  teapot in my profile pic and the crystalline tenmoku background.

So, there’s that.

Not sure who said it was illegal to install a redhead yourself or in what jurisdictions, but that information definitely doesn’t apply here (or most places I know).  Maybe things are diff’nt in ‘Straya.  Running a redhead from a propane bottle is not the same as running from a home line (large horizontal tank).

The burners, lines, and fittings for a forge vs. kiln are identical, except kiln burners can be left unattended due to shutoff valves.  So, there’s that.

 

 

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I assume raku people have a small g bottle . .... similar to a Barbie operation

Anyway not about you or me or the various legalities of localities, and best practice when firing kilns to1200 degC plus,  I think the poster got the message way back , go to the horse's mouth.

 

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6 minutes ago, Babs said:

I assume raku people have a small g bottle . .... similar to a Barbie operation

Anyway not about you or me or the various legalities of localities, and best practice when firing kilns to1200 degC plus,  I think the poster got the message way back , go to the horse's mouth.

 

I run a 100 lber with my redhead just like the OP.   It is the biggest of the barbie bottles.  Big enough to not freeze up, small enough that I can transport solo.

I corrected you because I wouldn’t want to confuse the OP about what she could and couldn’t do.  Especially when the words “legal and “illegal” get thrown around.

Not about you or me, but the quality of the advice.  I have direct, real world experience wth using a kiln with a redhead.

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Well?

 Something of a discussion got started. 

 Since your kiln manufacture is no longer in business and you cant find an owners manual on line then how about calling out a furnace tech to look over the system and help you with your trouble shooting.

 Linda,  what is the name of the kiln manufacture?    

Maybe some of the instructors who visit the sight might have come in contact with a kiln version like yours with a similar set up?

 I wish my kiln had wheels! 

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I run that adjustable red head  on my outdoor heavy duty stove. It needs lots of gas .I have it set for high flow.I boil 5 gallons of salt water for the salt kiln or 3 gallons to steam crabs and I like it boiling right NOW.

Edited by Mark C.

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I assume raku people have a small g bottle . .... similar to a Barbie operation

Anyway not about you or me or the various legalities of localities, and best practice when firing kilns to1200 degC plus,  I think the poster got the message way back , go to the horse's mouth.

 

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Not knowing constraints of the poster's line , the fact that the tank regulator is set on 4 the fact that there is a furtherf regulator positioned nearer the burner was what I based my advice on.

I ran a similar system for 20 years, safer as it included a heat sensitive probe which shut off gas on flame failure.

Safer because there was a button on line which meant until I pressed it and lit flame, no gas escaped unlit into the kiln. So gas turned on at tank, gas line opened at first regul. Button and probe line opened and pilot light ignited, regulator  line near kiln opened and air adjusted for correct flame, way you go...

So it depends on lots including the legalities of locations etc etc

Poor quality advice....c'est la vie, it's free.

So poster get advice from a couple of experts or 3.

 

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Linda just another thought. Don't know the capacity of your kiln but I would get a number of firings from an 80kg bottle.However as the bottle aporoached about 2/3  empty and this coincided with top end of firing the bottle would freeze. You can pour water over it but it's a big waste of time and gas if you still don't reach required temp .I got 2  bottles actually three in the end, connected up so it was a mere flick of a valve to switch bottles mid firing. Just saying. Can be a soul saving extra.  Just in case You're talking to a supplier soon:-)

Can use up gas in nearly empty bottle at start of firing or a bisque..

Good luck. Let's know how you go.

Do you know other gas firers in your area?

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Hello all.

Thanks for all of your advice.

My kiln is a 9  cubic foot estrin downdraft kiln.  It is no longer made. The company is not in business anymore.  This kiln is 20 years old but had only been fired a couple of times and then was in storage. The owner was a metal sculptor and he has passed away. Supposedly he used the kiln for melting metal not ceramics.. I live in Canada and I am hoping this is a legal setup.

My kiln is not setup in a building , it will be fired outside sitting on a cement slab and when firing is done and kiln has cooled will then be  wheeled back into carport.

The tank I am using is a portable 100 pound propane tank and the burners are for use with propane   We do not have natural gas on our little island where I live.

I have safety systems in place, a thermocouple and a pilot light.  I also have a digital controller which controls solenoids whichturns the gas on and off based on what temp  I have set per hour till the kiln reaches the final temp. The temp can be increased or decreased during firing and can be turned off at any time.  The kiln will be attended throughout the entire firing.

I will call ward burner systems and see if they can give me any advice on the pressure regulator.  Again thanks for all your comments.

 

 

 

I t

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Happy firing, I am envious of your kiln  Only reason I no longer fire with gas well 2 reasons, my kiln was falling to bits, early ceramic fibre jobby , finding it harder to lug the bottles around on my own .

Strongly advise getting 2 bottles in line for reasons given above.

If you are screwing and unscrewing lines on your own and I'm not advising that, can check for leaks by slapping thick liquid soap around joins and checking for any bubbling when gas is moving through the line. 

All the best, keep us posted

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It is useful to understand the physical process going on inside the tank. Propane is more precisely LPG, liquified petroleum gas. The gas is pumped into the tank under very high pressure, and in accordance with the Ideal Gas Law from your high school chemistry class (PV=NRT), the gas condenses into liquid - so long as it remains under pressure in the tank. As you release the pressure in the tank by opening the valve, the liquified gas evaporates from the top of the pool in the tank and escapes out the valve (and then travels down the line to the burner). Simultaneously, as discussed in another high school chemistry lecture, an evaporating liquid takes thermal energy with it during the phase change from liquid to gas, leaving the surface from which it evaporated colder.  In our nearly closed system where liquid, gas, pressure, and temperature of the LPG are in tight balance, the cooling effect of the evaporation can cause the phase change to reverse, i.e, the LPG will freeze instead of continuing to evaporate. The faster you draw off the propane, the faster it must evaporate from the surface of the liquid inside the tank, and thus the faster it will freeze instead of evaporate, causing the burner to go out.

There are two solutions: 1) You can provide external (relative) warmth to the bottle by pouring water over it or setting the tank in a tub of water; or 2) You can increase the surface area of the pool of liquid so that the rate of evaporation (as determined by your usage of gas at the burner) per unit of surface area in the tank is lower, thus reducing the speed at which the balance tips into freezing, or preferably, eliminating the tank freeze. This second solution is achieved by using a tank with a larger diameter (up to and including the very large tanks that sit sideways, but a taller tank of the same diameter is ineffective as the surface area of the pool of liquid is unchanged) or by linking together multiple tanks through a manifold (which could be a simple Y connection between 2 tanks) so that the rate of evaporation from the combined tank surface areas does not result in the tanks freezing.

And so, beyond understanding the process going on inside the tank, I will leave the hardware specifics (regulators, connectors, valves, and safety systems) to Mr. Ward's recommendations.

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3 hours ago, Dick White said:

 

There are two solutions: 1) You can provide external (relative) warmth to the bottle by pouring water over it or setting the tank in a tub of water; or 2) You can increase the surface area of the pool of liquid so that the rate of evaporation (as determined by your usage of gas at the burner) per unit of surface area in the tank is lower, thus reducing the speed at which the balance tips into freezing, or preferably, eliminating the tank freeze. This second solution is achieved by using a tank with a larger diameter (up to and including the very large tanks that sit sideways, but a taller tank of the same diameter is ineffective as the surface area of the pool of liquid is unchanged) or by linking together multiple tanks through a manifold (which could be a simple Y connection between 2 tanks) so that the rate of evaporation from the combined tank surface areas does not result in the tanks freezing.

Solution 1:

this is generally ineffective.  It also prematurely ages the tank and its fittings due to the thermal stresses of freezing/thawing rapidly.  Which is sortof a big deal since a tanks seals have an expiry date.  Don’t do this.  Ever.  If your tank  begins freeze up, shut down and try again a different day.  Warm/hot water isn’t going to help at that point except to shorten the life of your tank.

Solution 2: 

Surface area isn’t really relevant—in fact it might be working the opposite way.  It’s thermal mass that keeps the tank from freezing.  This is why a full tank won’t freeze up,  but a near empty one will.  Don’t fire below like -5 C and your hundred 100 lb tanks should be fine. Two on a Y connection isn’t a bad idea though. More thermal mass, more work to freeze.

8 hours ago, Linda A said:

I live in Canada and I am hoping this is a legal setup.

The regulations will be provincial.  I know that at least two people who have had trouble certifying gas kilns for insurance (which might be where it’s tough).

Good luck!

Edited by Tyler Miller
More info needed to flesh out point. And typos.

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In regards to the digital controller being used to control the rate of climb- if it's simply turning the gas on and off to control the rate of climb, the way an electric kiln turns the power on and off, it will probably work fine for bisque, but I wouldn't try to use it for a glaze firing. Gas kilns require consistent pressure inside in order to fire evenly. If the gas is turning on and off, the pressure is rising and falling, and you can't keep the temperature even. Nor can you maintain an specific reducing or neutral atmosphere. So plan on firing manually for glaze.

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I have tried looking back through your pictures but I can't exactly work out how it is plumbed together. I think this thing is regulator that only outputs one pressure. I have seen one on my friends natural gas kiln. Are you sure these burners are set up for propane? If this is just before the burners then they will be getting a constant pressure I think.

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