Multiple burner ignition schemes.

[itsmoked]

I have a case where four burners, (100-150kBTU), need to be ignited at the same time. They're all mounted in a square pattern about 20 inches to a side.

They will be automatically cycled. The configuration contemplated is a pilot tube running around the entire perimeter. The customary thermopile monitoring the end of the pilot tube. At first glance I'm not comfortable with this method as I've seen areas of pilot-tube-like burners go out for various reasons. This of course would mean a burner going on for a while unlit. (bang) Heck, it could mean three of the four burners going on for a while unlit!

Is this a typical solution or is something else more commonly used now?

I was looking at individual electric ignition detection systems and considering using one per burner but this gets kinda pricey at about $200 per burner.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[dcasto]

I've always put controls on every other burner. The uncontrolled burners will ignite off the controlled.

 

[itsmoked]

So in this scheme you'd maybe use two igniter/provers on a pair of the diagonal corner burners?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[rmw]

itsmoked,

Please give a little more description of your gadget. In your OP I didn't get a picture of diagonal corner burners. Maybe it is just the old boiler guy in me but I envisioned 4 burners on one wall in a square pattern.

rmw

 

[dcasto]

like rmw, a quick picture is worth 1000 words. If you number the burners, then others could jump in too.

 

[itsmoked]

Sorry rmw; I'll give it another whirl.

All burners point straight up.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[IRstuff]

How often does it need to happen? That might determine some constraints.

I think the pilotless ignition should be cheaper than what you've cited, particularly in quantity:

http://www.howards.com/details.cfm?c=50&b=3&s=52&id=gg09r0111grdwi

That's a 4-burner stovetop with 4 ignitors, which should mean that they run less than $25 each. If this is a one-of, then you might go to your local stovetop store and cannibalize one for its ignitors.

Worst comes to worse, you could get a standard, 4-cylinder electronic car ignition retrofit kit, or build one yourself. Worst case scenario is 4 ignition coils with 4 12-V drivers.

TTFN

FAQ731-376

 

[dcasto]

This is big enough system to make sure you have flame detection and shutdown. A pilotless ignition is good for lighting, but you'll need a control system to detect flame out and either initiate a restart or shutdown.

you say the burners will be automatically cycled, will a pilots heat be lost, if not, then a pilot is much safer than auto ignition of the entire buner, it would still be best to ignite a pilot, which in turn ignites the burners once a flame is detected.

 

[itsmoked]

This is for some sort of kiln upgrade. It will cycle I'm guessing about 100 times a job run. It will then be off for some period 4~10days before another job run.

IRstuff; That's an inexpensive novel idea to cannibalize a stove top. A concern would be the ignition system for 9kBTU burners not supporting 100kBTU burners for some reason. ??

Just so I'm clear on this your suggestion is like a continuous spark that just shows up next to a valved-on burner. Testing during setup that the burner always lights?

dcasto; You're suggesting something like:

http://www.grainger.com/Grainger/items/5E757

Which proves a pilot light is positively on and assumes that if the pilot light is on, then the burner shall ignite.

If these burners are all pointed into a kiln that's >>1000F would not any gas ignite automatically? Of course since they have to initially ignite with a cold kiln... I guess that's a moot point.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[IRstuff]

My stovetop actually produces about 4 sparks per second. The commercial stove tops can put out in excess of 30 kBTU per burner. The spark ignitors are not unlike spark plugs, a bit of metal protruding beyond a ceramic cylinder. Total spark gap is about 0.1 inches, so that still shouldn't take more than about 20 kV, since it's higher pressure than in a engine cylinder. The ignitor is actually inset into the burner assembly, and will normally be out of the path of the flame.

Can't think of any reason why an even larger burner would have problems, unless it's air flow and mixing.

Actually, my only problem has been that the gas doesn't turn on like it's supposed, and takes up to about 20 seconds, but that's all mechanical, so it's likely to bew sticky valves somewhere.

TTFN

FAQ731-376

 

[Oxidation]

You ever heard of NFPA-85....sets the rules regarding burners.

 

[lownox]

outfit each burner with direct spark ignition with flame rod supervision. These control shouldn't run you more than $30-50 each burner. Look at Honeywell S87 controls.

I assume these are power burners???

 

[itsmoked]

lownox; those S87s list at $295 then you need the gas control valves...

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[lownox]

Sorry... OEM pricing on the S87 is not $300. List may be that high, but actual price after multiplier is very low. Also, since you said "automatically cycled", I assumed you had gas valves in the system. I could give you some more ideas if I knew more about the system as a whole and the budget. Can I call you Monday @ Flamin?

 

[itsmoked]

Sure! After 11AM PT would be best. Or leave a message.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com