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At 21:13 24/01/2007, Phil Keck wrote:
>Does anyone have any exhibits, or does anyone have any type of
>programming, where visitors directly interact with fire?  I'm thinking
>anything like Bunsen burners or any of that stuff.  Did you have any
>problems getting approval/permission to do have fire?  Have you had any
>problems with safety or anything else?  Any other thoughts?

Fifteen years ago I designed a hands-on adjustable bunsen-burner in a 
glass case for the Launch Pad gallery in the London Science Museum. I 
was short of work or I'd never have attempted it. In fact it was 
successful, trouble-free and popular for a number of years until 
Launch Pad moved to a space with no gas supply.

The flame temperature changed as visitors adjusted the gas-air 
mixture and the temperature was measured by a thermocouple and 
indicated by an LED bar-graph. A thin sheet of ceramic paper held 
vertically inside the flame showed a glowing inverted 'V' where the 
air-rich gas mixture hit the inside of the roaring blue flame. A 
point-source of bright light formed a shadow-graph of the flame and 
the turbulence above it, back-projected onto an opaque screen at one 
end of the glass case..

I used proprietary domestic gas boiler safety cut-out components, so 
the system was fail-safe. I still use the same electronics specialist 
who developed the circuitry. The gas supply to the burner passed 
through a solenoid valve which snapped shut if the electrical power 
supply stopped. This happened if the case was tilted or shaken, if 
the door of the glass case opened, if the temperature became too 
high, if the burner's flame stopped heating a (standard) closed metal 
tube, or if the mains electrical power failed.

You always encounter the unexpected safety risk. Before it was 
finished, the workshop people discovered that children would be able 
to use the control knob to make excitingly large fireballs by rapidly 
opening and closing the Bunsen burner's air-mixing aperture. So the 
rotation of the burner's 'collar' had to be geared down and operated 
with a little crank-handle.

And yes, I believe there were massive problems getting this 
safety-approved. But British Gas was the official sponsor. I heard 
that the buck was passed all the way up to the County Fire Officer, 
who told his subordinates not to fuss because it was no riskier than 
any domestic gas boiler.


[log in to unmask] * http://www.interactives.co.uk
*
Give people facts and you feed their minds for an hour.
Awaken curiosity and they feed their own minds for a lifetime.
*
Ian Russell 

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