Invention dampens stove-top fires

00:26, Feb 13 2009
Munro: the potential for SensorJet is a no-brainer.

A diverting but near disastrous chat with a neighbour over the back fence while his breakfast fry-up began to smoulder led Graham Munro on a two-year pursuit of an idea which should find a place in every Kiwi home.

The Auckland entrepreneur has invented a cost-effective, easily installed and unobtrusive automatic fire suppression system which quickly and efficiently puts out stove-top fires.

Munro says the potential for SensorJet is a no-brainer: fires cost New Zealand $1 billion a year a third of which are domestic fires. "And more than one-third of domestic fires start on the stove top."

But even more important is the potential to save lives lost in fires like the devastating kitchen fire in a Mangere home that claimed four lives earlier this month and which was caused by chip oil being left on the stove.

The patented device is simplicity itself. A small bench-top silver dome next to the stove houses an infra-red sensor which monitors the temperature of the ceiling above. When things get too hot, the device releases a targeted mist of water over the stove which douses the flames of the fiercest fat fire in less than 25 seconds.

Throwing buckets of water on burning fat is a no-no. All it does is cause an explosion of burning oil globules. But the intense, fine water-mist particles smother the flames like a wet blanket, Munro says. "A fire needs heat, oxygen and fuel," he says.


"This device reduces the heat and removes the oxygen."

Munro has built a test-kitchen with a difference in the front garden of his Devonport home. One recent test drew a score of anxious neighbours one of whom was on the verge of making a 111 call as flames leapt and smoke darkened above a pot of burning cooking oil.

Within seconds of SensorJet's automatic activation, the flames die in a cloud of white steam and, as the ceiling temperature falls, SensorJet switches itself off. If there's no one around to turn off the stove and the fire reactivates, the SensorJet kicks in again and again.

"I get ideas, but this is one which has stayed with me," says Munro, a physics graduate and businessman, who believes his device is compelling in its simplicity and effectiveness.

The only automatic fire suppressant device available for dwellings of any description is a fire sprinkler system, which Munro says costs $5000-plus.

He plans to market his Sensorjet unit for around $250, with installation bringing all-up cost to between $300 and $400.

It appears as no more than a slight protrusion on a kitchen benchtop and is easily connected to mains-pressure water. And unlike a sprinkler system, it leaves no collateral damage.

Munro set up SensorJet Ltd last year, and is now in discussions with what he says are major New Zealand companies about manufacturing, marketing and seeking a new round of investment.

As far as he can tell, there is nothing like SensorJet in countries similar to New Zealand, and he has his eyes on early expansion into countries including Australia, the UK and the United States.

He plans to begin making and marketing the device by the end of the year.



Sunday Star Times