Spark Ignition in Gas Cookers?

[turkster]

I've always wondered what powers the spark ignition systems in most gas cookers. The ones where you press a button and it goes spark spark spark etc on all the hobs/grills/ovens at once.

So i was looking at the Gas cooker in my flat today and it has no connection for an external power source ie plug into the mains. Maybe I am wrong but, I would have thought it would require quite a considerable amount of energy to generate the high voltage sparking current necessary. More than could be provided by a reasonable battery over a long period anyway.

So does anyone know do they have batteries or how do they get the power?

[Rave]

They use piezo-electric crystals. When they're bent they generate enough of a voltage to create a spark. Those handheld gas cooker lighters, and 'electronic' cigarette lighters work the same way.

Rich :¬)

[turkster]

Yeah but piezo electric crystals only give out electricity when energy is being applied to them (ie during the act of compressing or bending them).

The spark mechanism I am talking about keeps sparking about twice a second and keeps going. You just press the button and hold it. In a normal piezo electric device you would have to keep pressing it once for every spark.

[BUFF]

My gas hob has a battery. (LR1 size)

[Rob]

Turks, check the bottom of your cooker. There's usually a 'pan drawer' under the oven. This is a favourite place for the battery.

[turkster]

Well I'm surprised they work for very long with just an LR1 size battery .

Yeah will have a better look tonight although mine doesnt have a 'pan drawer' .

I'm disappointed I was imagining that they had some snazzy way of generating electricity from some of the gas or something like that .

[Rob]

mine doesnt have a 'pan drawer' .

Nor does mine, but what looks like one is a pull down flap.

I was imagining that they had some snazzy way of generating electricity from some of the gas or something like that

How cool would that be? . An ickle weeny gas turbine generator the size of a bean tin
<runs off to find screwdriver and duck tape>

[turkster]

An ickle weeny gas turbine generator the size of a bean tin
<runs off to find screwdriver and duck tape>

Something like this?


You'll need more than a screwdriver and duck tape

You can get gasturbines (like the one above) for Radio control jets that are smaller than a mug . See here They make a lot of noise though at 150,000 RPM.

PS My cooker does not have a 'pan drawer' of any discription drawer or flap. The oven is right at the bottom of the cooker

[TeePee]

My gas hob is mains powered.

[Rob]

Something like this?

[Rave]

An LR1 battery (which is one of those lantern sized ones is it not?) could actually work for a long time. The spark has a very high voltage but a tiny amount of charge, the actual amount of energy transferred is minimal.

My mum's old gas cooker had a plug to power the oven light and sparking mechanism.

I agree that the little jet engine is . You'd need a fairly complex gearbox to step 150,000rpm down to a workable energy generating speed though.

Rich :¬)

[stytagm]

Wow @ the ickle gas turbine, just brainstormed their entire site and look at some of the things people are doing with them:

http://www.wren-turbines.com/B52-Finals.jpg
Same thing:
http://forums.vwvortex.com/zerothrea...int&id=1518269
And the videos here: (There goes his bandwidth!)
http://www.mcgirt.net/RC/VIDEOS/Giant_B52/

Way too cool, I want one!

[Zak33]

battery...9v square thing.

I have had the same one for....blimey.....8 years ! No ..I lie...I put a new one in cos I needed the original to test a bulb and I lost it

Normally on the same side as the HINGE of the door, on a little pull out metal bracket underneath the cooker.

Covered in grease

and fat..

and old food

in the grime you didnt know you had

stained with bacteria

and smelling bad



I'll get my apron and go

[Rob]

These are the items I know we have down the side of ours...

A mushroom

A spoon

A big dollop of redcurrant and mint sauce

a beansprout

And a very fat spider

[turkster]

Sorry guys I got stuck under the cooker while looking for the battery .

But yeah it has a little AA size battery hidden right underneath on a little circuit board . Looks like its been there for years too .

[SilentDeath]

Even a watch size battery is plenty and would last years.

All you need to ignite gas is heat - about 400°c I think is the ignition temp for town gas.

Then you just need a high voltage spark, the amount of current doesnt matter, a spark with that much voltage is enough to heat the air, make ozone and ignite the gas.

There will be a little circuit to switch the DC battery on and off really fast to simulate AC. This then goes to a transformer which steps it up to a few kv - 1.1kv will make a 1mm spark, so you can guess how much by the length

Voltage above 70 isnt safe, so dont touch the little circuit board